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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Shared application/kernel submission and completion ring pairs, for
4 * supporting fast/efficient IO.
5 *
6 * A note on the read/write ordering memory barriers that are matched between
7 * the application and kernel side.
8 *
9 * After the application reads the CQ ring tail, it must use an
10 * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
11 * before writing the tail (using smp_load_acquire to read the tail will
12 * do). It also needs a smp_mb() before updating CQ head (ordering the
13 * entry load(s) with the head store), pairing with an implicit barrier
14 * through a control-dependency in io_get_cqe (smp_store_release to
15 * store head will do). Failure to do so could lead to reading invalid
16 * CQ entries.
17 *
18 * Likewise, the application must use an appropriate smp_wmb() before
19 * writing the SQ tail (ordering SQ entry stores with the tail store),
20 * which pairs with smp_load_acquire in io_get_sqring (smp_store_release
21 * to store the tail will do). And it needs a barrier ordering the SQ
22 * head load before writing new SQ entries (smp_load_acquire to read
23 * head will do).
24 *
25 * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
26 * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
27 * updating the SQ tail; a full memory barrier smp_mb() is needed
28 * between.
29 *
30 * Also see the examples in the liburing library:
31 *
32 * git://git.kernel.dk/liburing
33 *
34 * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
35 * from data shared between the kernel and application. This is done both
36 * for ordering purposes, but also to ensure that once a value is loaded from
37 * data that the application could potentially modify, it remains stable.
38 *
39 * Copyright (C) 2018-2019 Jens Axboe
40 * Copyright (c) 2018-2019 Christoph Hellwig
41 */
42#include <linux/kernel.h>
43#include <linux/init.h>
44#include <linux/errno.h>
45#include <linux/syscalls.h>
46#include <net/compat.h>
47#include <linux/refcount.h>
48#include <linux/uio.h>
49#include <linux/bits.h>
50
51#include <linux/sched/signal.h>
52#include <linux/fs.h>
53#include <linux/file.h>
54#include <linux/fdtable.h>
55#include <linux/mm.h>
56#include <linux/mman.h>
57#include <linux/percpu.h>
58#include <linux/slab.h>
59#include <linux/bvec.h>
60#include <linux/net.h>
61#include <net/sock.h>
62#include <net/af_unix.h>
63#include <linux/anon_inodes.h>
64#include <linux/sched/mm.h>
65#include <linux/uaccess.h>
66#include <linux/nospec.h>
67#include <linux/highmem.h>
68#include <linux/fsnotify.h>
69#include <linux/fadvise.h>
70#include <linux/task_work.h>
71#include <linux/io_uring.h>
72#include <linux/io_uring/cmd.h>
73#include <linux/audit.h>
74#include <linux/security.h>
75#include <asm/shmparam.h>
76
77#define CREATE_TRACE_POINTS
78#include <trace/events/io_uring.h>
79
80#include <uapi/linux/io_uring.h>
81
82#include "io-wq.h"
83
84#include "io_uring.h"
85#include "opdef.h"
86#include "refs.h"
87#include "tctx.h"
88#include "register.h"
89#include "sqpoll.h"
90#include "fdinfo.h"
91#include "kbuf.h"
92#include "rsrc.h"
93#include "cancel.h"
94#include "net.h"
95#include "notif.h"
96#include "waitid.h"
97#include "futex.h"
98
99#include "timeout.h"
100#include "poll.h"
101#include "rw.h"
102#include "alloc_cache.h"
103
104#define IORING_MAX_ENTRIES 32768
105#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
106
107#define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \
108 IOSQE_IO_HARDLINK | IOSQE_ASYNC)
109
110#define SQE_VALID_FLAGS (SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \
111 IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS)
112
113#define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \
114 REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \
115 REQ_F_ASYNC_DATA)
116
117#define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\
118 IO_REQ_CLEAN_FLAGS)
119
120#define IO_TCTX_REFS_CACHE_NR (1U << 10)
121
122#define IO_COMPL_BATCH 32
123#define IO_REQ_ALLOC_BATCH 8
124
125enum {
126 IO_CHECK_CQ_OVERFLOW_BIT,
127 IO_CHECK_CQ_DROPPED_BIT,
128};
129
130struct io_defer_entry {
131 struct list_head list;
132 struct io_kiocb *req;
133 u32 seq;
134};
135
136/* requests with any of those set should undergo io_disarm_next() */
137#define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)
138#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)
139
140/*
141 * No waiters. It's larger than any valid value of the tw counter
142 * so that tests against ->cq_wait_nr would fail and skip wake_up().
143 */
144#define IO_CQ_WAKE_INIT (-1U)
145/* Forced wake up if there is a waiter regardless of ->cq_wait_nr */
146#define IO_CQ_WAKE_FORCE (IO_CQ_WAKE_INIT >> 1)
147
148static bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
149 struct task_struct *task,
150 bool cancel_all);
151
152static void io_queue_sqe(struct io_kiocb *req);
153
154struct kmem_cache *req_cachep;
155
156static int __read_mostly sysctl_io_uring_disabled;
157static int __read_mostly sysctl_io_uring_group = -1;
158
159#ifdef CONFIG_SYSCTL
160static struct ctl_table kernel_io_uring_disabled_table[] = {
161 {
162 .procname = "io_uring_disabled",
163 .data = &sysctl_io_uring_disabled,
164 .maxlen = sizeof(sysctl_io_uring_disabled),
165 .mode = 0644,
166 .proc_handler = proc_dointvec_minmax,
167 .extra1 = SYSCTL_ZERO,
168 .extra2 = SYSCTL_TWO,
169 },
170 {
171 .procname = "io_uring_group",
172 .data = &sysctl_io_uring_group,
173 .maxlen = sizeof(gid_t),
174 .mode = 0644,
175 .proc_handler = proc_dointvec,
176 },
177 {},
178};
179#endif
180
181static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
182{
183 if (!wq_list_empty(&ctx->submit_state.compl_reqs) ||
184 ctx->submit_state.cqes_count)
185 __io_submit_flush_completions(ctx);
186}
187
188static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
189{
190 return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
191}
192
193static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx)
194{
195 return READ_ONCE(ctx->rings->cq.tail) - READ_ONCE(ctx->rings->cq.head);
196}
197
198static bool io_match_linked(struct io_kiocb *head)
199{
200 struct io_kiocb *req;
201
202 io_for_each_link(req, head) {
203 if (req->flags & REQ_F_INFLIGHT)
204 return true;
205 }
206 return false;
207}
208
209/*
210 * As io_match_task() but protected against racing with linked timeouts.
211 * User must not hold timeout_lock.
212 */
213bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
214 bool cancel_all)
215{
216 bool matched;
217
218 if (task && head->task != task)
219 return false;
220 if (cancel_all)
221 return true;
222
223 if (head->flags & REQ_F_LINK_TIMEOUT) {
224 struct io_ring_ctx *ctx = head->ctx;
225
226 /* protect against races with linked timeouts */
227 spin_lock_irq(&ctx->timeout_lock);
228 matched = io_match_linked(head);
229 spin_unlock_irq(&ctx->timeout_lock);
230 } else {
231 matched = io_match_linked(head);
232 }
233 return matched;
234}
235
236static inline void req_fail_link_node(struct io_kiocb *req, int res)
237{
238 req_set_fail(req);
239 io_req_set_res(req, res, 0);
240}
241
242static inline void io_req_add_to_cache(struct io_kiocb *req, struct io_ring_ctx *ctx)
243{
244 wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list);
245}
246
247static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref)
248{
249 struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
250
251 complete(&ctx->ref_comp);
252}
253
254static __cold void io_fallback_req_func(struct work_struct *work)
255{
256 struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
257 fallback_work.work);
258 struct llist_node *node = llist_del_all(&ctx->fallback_llist);
259 struct io_kiocb *req, *tmp;
260 struct io_tw_state ts = { .locked = true, };
261
262 percpu_ref_get(&ctx->refs);
263 mutex_lock(&ctx->uring_lock);
264 llist_for_each_entry_safe(req, tmp, node, io_task_work.node)
265 req->io_task_work.func(req, &ts);
266 if (WARN_ON_ONCE(!ts.locked))
267 return;
268 io_submit_flush_completions(ctx);
269 mutex_unlock(&ctx->uring_lock);
270 percpu_ref_put(&ctx->refs);
271}
272
273static int io_alloc_hash_table(struct io_hash_table *table, unsigned bits)
274{
275 unsigned hash_buckets = 1U << bits;
276 size_t hash_size = hash_buckets * sizeof(table->hbs[0]);
277
278 table->hbs = kmalloc(hash_size, GFP_KERNEL);
279 if (!table->hbs)
280 return -ENOMEM;
281
282 table->hash_bits = bits;
283 init_hash_table(table, hash_buckets);
284 return 0;
285}
286
287static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
288{
289 struct io_ring_ctx *ctx;
290 int hash_bits;
291
292 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
293 if (!ctx)
294 return NULL;
295
296 xa_init(&ctx->io_bl_xa);
297
298 /*
299 * Use 5 bits less than the max cq entries, that should give us around
300 * 32 entries per hash list if totally full and uniformly spread, but
301 * don't keep too many buckets to not overconsume memory.
302 */
303 hash_bits = ilog2(p->cq_entries) - 5;
304 hash_bits = clamp(hash_bits, 1, 8);
305 if (io_alloc_hash_table(&ctx->cancel_table, hash_bits))
306 goto err;
307 if (io_alloc_hash_table(&ctx->cancel_table_locked, hash_bits))
308 goto err;
309 if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
310 0, GFP_KERNEL))
311 goto err;
312
313 ctx->flags = p->flags;
314 atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT);
315 init_waitqueue_head(&ctx->sqo_sq_wait);
316 INIT_LIST_HEAD(&ctx->sqd_list);
317 INIT_LIST_HEAD(&ctx->cq_overflow_list);
318 INIT_LIST_HEAD(&ctx->io_buffers_cache);
319 INIT_HLIST_HEAD(&ctx->io_buf_list);
320 io_alloc_cache_init(&ctx->rsrc_node_cache, IO_NODE_ALLOC_CACHE_MAX,
321 sizeof(struct io_rsrc_node));
322 io_alloc_cache_init(&ctx->apoll_cache, IO_ALLOC_CACHE_MAX,
323 sizeof(struct async_poll));
324 io_alloc_cache_init(&ctx->netmsg_cache, IO_ALLOC_CACHE_MAX,
325 sizeof(struct io_async_msghdr));
326 io_futex_cache_init(ctx);
327 init_completion(&ctx->ref_comp);
328 xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
329 mutex_init(&ctx->uring_lock);
330 init_waitqueue_head(&ctx->cq_wait);
331 init_waitqueue_head(&ctx->poll_wq);
332 init_waitqueue_head(&ctx->rsrc_quiesce_wq);
333 spin_lock_init(&ctx->completion_lock);
334 spin_lock_init(&ctx->timeout_lock);
335 INIT_WQ_LIST(&ctx->iopoll_list);
336 INIT_LIST_HEAD(&ctx->io_buffers_comp);
337 INIT_LIST_HEAD(&ctx->defer_list);
338 INIT_LIST_HEAD(&ctx->timeout_list);
339 INIT_LIST_HEAD(&ctx->ltimeout_list);
340 INIT_LIST_HEAD(&ctx->rsrc_ref_list);
341 init_llist_head(&ctx->work_llist);
342 INIT_LIST_HEAD(&ctx->tctx_list);
343 ctx->submit_state.free_list.next = NULL;
344 INIT_WQ_LIST(&ctx->locked_free_list);
345 INIT_HLIST_HEAD(&ctx->waitid_list);
346#ifdef CONFIG_FUTEX
347 INIT_HLIST_HEAD(&ctx->futex_list);
348#endif
349 INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
350 INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
351 INIT_HLIST_HEAD(&ctx->cancelable_uring_cmd);
352 return ctx;
353err:
354 kfree(ctx->cancel_table.hbs);
355 kfree(ctx->cancel_table_locked.hbs);
356 kfree(ctx->io_bl);
357 xa_destroy(&ctx->io_bl_xa);
358 kfree(ctx);
359 return NULL;
360}
361
362static void io_account_cq_overflow(struct io_ring_ctx *ctx)
363{
364 struct io_rings *r = ctx->rings;
365
366 WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1);
367 ctx->cq_extra--;
368}
369
370static bool req_need_defer(struct io_kiocb *req, u32 seq)
371{
372 if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
373 struct io_ring_ctx *ctx = req->ctx;
374
375 return seq + READ_ONCE(ctx->cq_extra) != ctx->cached_cq_tail;
376 }
377
378 return false;
379}
380
381static void io_clean_op(struct io_kiocb *req)
382{
383 if (req->flags & REQ_F_BUFFER_SELECTED) {
384 spin_lock(&req->ctx->completion_lock);
385 io_put_kbuf_comp(req);
386 spin_unlock(&req->ctx->completion_lock);
387 }
388
389 if (req->flags & REQ_F_NEED_CLEANUP) {
390 const struct io_cold_def *def = &io_cold_defs[req->opcode];
391
392 if (def->cleanup)
393 def->cleanup(req);
394 }
395 if ((req->flags & REQ_F_POLLED) && req->apoll) {
396 kfree(req->apoll->double_poll);
397 kfree(req->apoll);
398 req->apoll = NULL;
399 }
400 if (req->flags & REQ_F_INFLIGHT) {
401 struct io_uring_task *tctx = req->task->io_uring;
402
403 atomic_dec(&tctx->inflight_tracked);
404 }
405 if (req->flags & REQ_F_CREDS)
406 put_cred(req->creds);
407 if (req->flags & REQ_F_ASYNC_DATA) {
408 kfree(req->async_data);
409 req->async_data = NULL;
410 }
411 req->flags &= ~IO_REQ_CLEAN_FLAGS;
412}
413
414static inline void io_req_track_inflight(struct io_kiocb *req)
415{
416 if (!(req->flags & REQ_F_INFLIGHT)) {
417 req->flags |= REQ_F_INFLIGHT;
418 atomic_inc(&req->task->io_uring->inflight_tracked);
419 }
420}
421
422static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
423{
424 if (WARN_ON_ONCE(!req->link))
425 return NULL;
426
427 req->flags &= ~REQ_F_ARM_LTIMEOUT;
428 req->flags |= REQ_F_LINK_TIMEOUT;
429
430 /* linked timeouts should have two refs once prep'ed */
431 io_req_set_refcount(req);
432 __io_req_set_refcount(req->link, 2);
433 return req->link;
434}
435
436static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
437{
438 if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT)))
439 return NULL;
440 return __io_prep_linked_timeout(req);
441}
442
443static noinline void __io_arm_ltimeout(struct io_kiocb *req)
444{
445 io_queue_linked_timeout(__io_prep_linked_timeout(req));
446}
447
448static inline void io_arm_ltimeout(struct io_kiocb *req)
449{
450 if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT))
451 __io_arm_ltimeout(req);
452}
453
454static void io_prep_async_work(struct io_kiocb *req)
455{
456 const struct io_issue_def *def = &io_issue_defs[req->opcode];
457 struct io_ring_ctx *ctx = req->ctx;
458
459 if (!(req->flags & REQ_F_CREDS)) {
460 req->flags |= REQ_F_CREDS;
461 req->creds = get_current_cred();
462 }
463
464 req->work.list.next = NULL;
465 req->work.flags = 0;
466 req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
467 if (req->flags & REQ_F_FORCE_ASYNC)
468 req->work.flags |= IO_WQ_WORK_CONCURRENT;
469
470 if (req->file && !(req->flags & REQ_F_FIXED_FILE))
471 req->flags |= io_file_get_flags(req->file);
472
473 if (req->file && (req->flags & REQ_F_ISREG)) {
474 bool should_hash = def->hash_reg_file;
475
476 /* don't serialize this request if the fs doesn't need it */
477 if (should_hash && (req->file->f_flags & O_DIRECT) &&
478 (req->file->f_mode & FMODE_DIO_PARALLEL_WRITE))
479 should_hash = false;
480 if (should_hash || (ctx->flags & IORING_SETUP_IOPOLL))
481 io_wq_hash_work(&req->work, file_inode(req->file));
482 } else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) {
483 if (def->unbound_nonreg_file)
484 req->work.flags |= IO_WQ_WORK_UNBOUND;
485 }
486}
487
488static void io_prep_async_link(struct io_kiocb *req)
489{
490 struct io_kiocb *cur;
491
492 if (req->flags & REQ_F_LINK_TIMEOUT) {
493 struct io_ring_ctx *ctx = req->ctx;
494
495 spin_lock_irq(&ctx->timeout_lock);
496 io_for_each_link(cur, req)
497 io_prep_async_work(cur);
498 spin_unlock_irq(&ctx->timeout_lock);
499 } else {
500 io_for_each_link(cur, req)
501 io_prep_async_work(cur);
502 }
503}
504
505void io_queue_iowq(struct io_kiocb *req, struct io_tw_state *ts_dont_use)
506{
507 struct io_kiocb *link = io_prep_linked_timeout(req);
508 struct io_uring_task *tctx = req->task->io_uring;
509
510 BUG_ON(!tctx);
511 BUG_ON(!tctx->io_wq);
512
513 /* init ->work of the whole link before punting */
514 io_prep_async_link(req);
515
516 /*
517 * Not expected to happen, but if we do have a bug where this _can_
518 * happen, catch it here and ensure the request is marked as
519 * canceled. That will make io-wq go through the usual work cancel
520 * procedure rather than attempt to run this request (or create a new
521 * worker for it).
522 */
523 if (WARN_ON_ONCE(!same_thread_group(req->task, current)))
524 req->work.flags |= IO_WQ_WORK_CANCEL;
525
526 trace_io_uring_queue_async_work(req, io_wq_is_hashed(&req->work));
527 io_wq_enqueue(tctx->io_wq, &req->work);
528 if (link)
529 io_queue_linked_timeout(link);
530}
531
532static __cold void io_queue_deferred(struct io_ring_ctx *ctx)
533{
534 while (!list_empty(&ctx->defer_list)) {
535 struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
536 struct io_defer_entry, list);
537
538 if (req_need_defer(de->req, de->seq))
539 break;
540 list_del_init(&de->list);
541 io_req_task_queue(de->req);
542 kfree(de);
543 }
544}
545
546void io_eventfd_ops(struct rcu_head *rcu)
547{
548 struct io_ev_fd *ev_fd = container_of(rcu, struct io_ev_fd, rcu);
549 int ops = atomic_xchg(&ev_fd->ops, 0);
550
551 if (ops & BIT(IO_EVENTFD_OP_SIGNAL_BIT))
552 eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
553
554 /* IO_EVENTFD_OP_FREE_BIT may not be set here depending on callback
555 * ordering in a race but if references are 0 we know we have to free
556 * it regardless.
557 */
558 if (atomic_dec_and_test(&ev_fd->refs)) {
559 eventfd_ctx_put(ev_fd->cq_ev_fd);
560 kfree(ev_fd);
561 }
562}
563
564static void io_eventfd_signal(struct io_ring_ctx *ctx)
565{
566 struct io_ev_fd *ev_fd = NULL;
567
568 rcu_read_lock();
569 /*
570 * rcu_dereference ctx->io_ev_fd once and use it for both for checking
571 * and eventfd_signal
572 */
573 ev_fd = rcu_dereference(ctx->io_ev_fd);
574
575 /*
576 * Check again if ev_fd exists incase an io_eventfd_unregister call
577 * completed between the NULL check of ctx->io_ev_fd at the start of
578 * the function and rcu_read_lock.
579 */
580 if (unlikely(!ev_fd))
581 goto out;
582 if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
583 goto out;
584 if (ev_fd->eventfd_async && !io_wq_current_is_worker())
585 goto out;
586
587 if (likely(eventfd_signal_allowed())) {
588 eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
589 } else {
590 atomic_inc(&ev_fd->refs);
591 if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops))
592 call_rcu_hurry(&ev_fd->rcu, io_eventfd_ops);
593 else
594 atomic_dec(&ev_fd->refs);
595 }
596
597out:
598 rcu_read_unlock();
599}
600
601static void io_eventfd_flush_signal(struct io_ring_ctx *ctx)
602{
603 bool skip;
604
605 spin_lock(&ctx->completion_lock);
606
607 /*
608 * Eventfd should only get triggered when at least one event has been
609 * posted. Some applications rely on the eventfd notification count
610 * only changing IFF a new CQE has been added to the CQ ring. There's
611 * no depedency on 1:1 relationship between how many times this
612 * function is called (and hence the eventfd count) and number of CQEs
613 * posted to the CQ ring.
614 */
615 skip = ctx->cached_cq_tail == ctx->evfd_last_cq_tail;
616 ctx->evfd_last_cq_tail = ctx->cached_cq_tail;
617 spin_unlock(&ctx->completion_lock);
618 if (skip)
619 return;
620
621 io_eventfd_signal(ctx);
622}
623
624void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
625{
626 if (ctx->poll_activated)
627 io_poll_wq_wake(ctx);
628 if (ctx->off_timeout_used)
629 io_flush_timeouts(ctx);
630 if (ctx->drain_active) {
631 spin_lock(&ctx->completion_lock);
632 io_queue_deferred(ctx);
633 spin_unlock(&ctx->completion_lock);
634 }
635 if (ctx->has_evfd)
636 io_eventfd_flush_signal(ctx);
637}
638
639static inline void __io_cq_lock(struct io_ring_ctx *ctx)
640{
641 if (!ctx->lockless_cq)
642 spin_lock(&ctx->completion_lock);
643}
644
645static inline void io_cq_lock(struct io_ring_ctx *ctx)
646 __acquires(ctx->completion_lock)
647{
648 spin_lock(&ctx->completion_lock);
649}
650
651static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
652{
653 io_commit_cqring(ctx);
654 if (!ctx->task_complete) {
655 if (!ctx->lockless_cq)
656 spin_unlock(&ctx->completion_lock);
657 /* IOPOLL rings only need to wake up if it's also SQPOLL */
658 if (!ctx->syscall_iopoll)
659 io_cqring_wake(ctx);
660 }
661 io_commit_cqring_flush(ctx);
662}
663
664static void io_cq_unlock_post(struct io_ring_ctx *ctx)
665 __releases(ctx->completion_lock)
666{
667 io_commit_cqring(ctx);
668 spin_unlock(&ctx->completion_lock);
669 io_cqring_wake(ctx);
670 io_commit_cqring_flush(ctx);
671}
672
673/* Returns true if there are no backlogged entries after the flush */
674static void io_cqring_overflow_kill(struct io_ring_ctx *ctx)
675{
676 struct io_overflow_cqe *ocqe;
677 LIST_HEAD(list);
678
679 spin_lock(&ctx->completion_lock);
680 list_splice_init(&ctx->cq_overflow_list, &list);
681 clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
682 spin_unlock(&ctx->completion_lock);
683
684 while (!list_empty(&list)) {
685 ocqe = list_first_entry(&list, struct io_overflow_cqe, list);
686 list_del(&ocqe->list);
687 kfree(ocqe);
688 }
689}
690
691static void __io_cqring_overflow_flush(struct io_ring_ctx *ctx)
692{
693 size_t cqe_size = sizeof(struct io_uring_cqe);
694
695 if (__io_cqring_events(ctx) == ctx->cq_entries)
696 return;
697
698 if (ctx->flags & IORING_SETUP_CQE32)
699 cqe_size <<= 1;
700
701 io_cq_lock(ctx);
702 while (!list_empty(&ctx->cq_overflow_list)) {
703 struct io_uring_cqe *cqe;
704 struct io_overflow_cqe *ocqe;
705
706 if (!io_get_cqe_overflow(ctx, &cqe, true))
707 break;
708 ocqe = list_first_entry(&ctx->cq_overflow_list,
709 struct io_overflow_cqe, list);
710 memcpy(cqe, &ocqe->cqe, cqe_size);
711 list_del(&ocqe->list);
712 kfree(ocqe);
713 }
714
715 if (list_empty(&ctx->cq_overflow_list)) {
716 clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
717 atomic_andnot(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
718 }
719 io_cq_unlock_post(ctx);
720}
721
722static void io_cqring_do_overflow_flush(struct io_ring_ctx *ctx)
723{
724 /* iopoll syncs against uring_lock, not completion_lock */
725 if (ctx->flags & IORING_SETUP_IOPOLL)
726 mutex_lock(&ctx->uring_lock);
727 __io_cqring_overflow_flush(ctx);
728 if (ctx->flags & IORING_SETUP_IOPOLL)
729 mutex_unlock(&ctx->uring_lock);
730}
731
732static void io_cqring_overflow_flush(struct io_ring_ctx *ctx)
733{
734 if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
735 io_cqring_do_overflow_flush(ctx);
736}
737
738/* can be called by any task */
739static void io_put_task_remote(struct task_struct *task)
740{
741 struct io_uring_task *tctx = task->io_uring;
742
743 percpu_counter_sub(&tctx->inflight, 1);
744 if (unlikely(atomic_read(&tctx->in_cancel)))
745 wake_up(&tctx->wait);
746 put_task_struct(task);
747}
748
749/* used by a task to put its own references */
750static void io_put_task_local(struct task_struct *task)
751{
752 task->io_uring->cached_refs++;
753}
754
755/* must to be called somewhat shortly after putting a request */
756static inline void io_put_task(struct task_struct *task)
757{
758 if (likely(task == current))
759 io_put_task_local(task);
760 else
761 io_put_task_remote(task);
762}
763
764void io_task_refs_refill(struct io_uring_task *tctx)
765{
766 unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR;
767
768 percpu_counter_add(&tctx->inflight, refill);
769 refcount_add(refill, ¤t->usage);
770 tctx->cached_refs += refill;
771}
772
773static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
774{
775 struct io_uring_task *tctx = task->io_uring;
776 unsigned int refs = tctx->cached_refs;
777
778 if (refs) {
779 tctx->cached_refs = 0;
780 percpu_counter_sub(&tctx->inflight, refs);
781 put_task_struct_many(task, refs);
782 }
783}
784
785static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
786 s32 res, u32 cflags, u64 extra1, u64 extra2)
787{
788 struct io_overflow_cqe *ocqe;
789 size_t ocq_size = sizeof(struct io_overflow_cqe);
790 bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32);
791
792 lockdep_assert_held(&ctx->completion_lock);
793
794 if (is_cqe32)
795 ocq_size += sizeof(struct io_uring_cqe);
796
797 ocqe = kmalloc(ocq_size, GFP_ATOMIC | __GFP_ACCOUNT);
798 trace_io_uring_cqe_overflow(ctx, user_data, res, cflags, ocqe);
799 if (!ocqe) {
800 /*
801 * If we're in ring overflow flush mode, or in task cancel mode,
802 * or cannot allocate an overflow entry, then we need to drop it
803 * on the floor.
804 */
805 io_account_cq_overflow(ctx);
806 set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq);
807 return false;
808 }
809 if (list_empty(&ctx->cq_overflow_list)) {
810 set_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
811 atomic_or(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
812
813 }
814 ocqe->cqe.user_data = user_data;
815 ocqe->cqe.res = res;
816 ocqe->cqe.flags = cflags;
817 if (is_cqe32) {
818 ocqe->cqe.big_cqe[0] = extra1;
819 ocqe->cqe.big_cqe[1] = extra2;
820 }
821 list_add_tail(&ocqe->list, &ctx->cq_overflow_list);
822 return true;
823}
824
825void io_req_cqe_overflow(struct io_kiocb *req)
826{
827 io_cqring_event_overflow(req->ctx, req->cqe.user_data,
828 req->cqe.res, req->cqe.flags,
829 req->big_cqe.extra1, req->big_cqe.extra2);
830 memset(&req->big_cqe, 0, sizeof(req->big_cqe));
831}
832
833/*
834 * writes to the cq entry need to come after reading head; the
835 * control dependency is enough as we're using WRITE_ONCE to
836 * fill the cq entry
837 */
838bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow)
839{
840 struct io_rings *rings = ctx->rings;
841 unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);
842 unsigned int free, queued, len;
843
844 /*
845 * Posting into the CQ when there are pending overflowed CQEs may break
846 * ordering guarantees, which will affect links, F_MORE users and more.
847 * Force overflow the completion.
848 */
849 if (!overflow && (ctx->check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)))
850 return false;
851
852 /* userspace may cheat modifying the tail, be safe and do min */
853 queued = min(__io_cqring_events(ctx), ctx->cq_entries);
854 free = ctx->cq_entries - queued;
855 /* we need a contiguous range, limit based on the current array offset */
856 len = min(free, ctx->cq_entries - off);
857 if (!len)
858 return false;
859
860 if (ctx->flags & IORING_SETUP_CQE32) {
861 off <<= 1;
862 len <<= 1;
863 }
864
865 ctx->cqe_cached = &rings->cqes[off];
866 ctx->cqe_sentinel = ctx->cqe_cached + len;
867 return true;
868}
869
870static bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res,
871 u32 cflags)
872{
873 struct io_uring_cqe *cqe;
874
875 ctx->cq_extra++;
876
877 /*
878 * If we can't get a cq entry, userspace overflowed the
879 * submission (by quite a lot). Increment the overflow count in
880 * the ring.
881 */
882 if (likely(io_get_cqe(ctx, &cqe))) {
883 trace_io_uring_complete(ctx, NULL, user_data, res, cflags, 0, 0);
884
885 WRITE_ONCE(cqe->user_data, user_data);
886 WRITE_ONCE(cqe->res, res);
887 WRITE_ONCE(cqe->flags, cflags);
888
889 if (ctx->flags & IORING_SETUP_CQE32) {
890 WRITE_ONCE(cqe->big_cqe[0], 0);
891 WRITE_ONCE(cqe->big_cqe[1], 0);
892 }
893 return true;
894 }
895 return false;
896}
897
898static void __io_flush_post_cqes(struct io_ring_ctx *ctx)
899 __must_hold(&ctx->uring_lock)
900{
901 struct io_submit_state *state = &ctx->submit_state;
902 unsigned int i;
903
904 lockdep_assert_held(&ctx->uring_lock);
905 for (i = 0; i < state->cqes_count; i++) {
906 struct io_uring_cqe *cqe = &ctx->completion_cqes[i];
907
908 if (!io_fill_cqe_aux(ctx, cqe->user_data, cqe->res, cqe->flags)) {
909 if (ctx->lockless_cq) {
910 spin_lock(&ctx->completion_lock);
911 io_cqring_event_overflow(ctx, cqe->user_data,
912 cqe->res, cqe->flags, 0, 0);
913 spin_unlock(&ctx->completion_lock);
914 } else {
915 io_cqring_event_overflow(ctx, cqe->user_data,
916 cqe->res, cqe->flags, 0, 0);
917 }
918 }
919 }
920 state->cqes_count = 0;
921}
922
923static bool __io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags,
924 bool allow_overflow)
925{
926 bool filled;
927
928 io_cq_lock(ctx);
929 filled = io_fill_cqe_aux(ctx, user_data, res, cflags);
930 if (!filled && allow_overflow)
931 filled = io_cqring_event_overflow(ctx, user_data, res, cflags, 0, 0);
932
933 io_cq_unlock_post(ctx);
934 return filled;
935}
936
937bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags)
938{
939 return __io_post_aux_cqe(ctx, user_data, res, cflags, true);
940}
941
942/*
943 * A helper for multishot requests posting additional CQEs.
944 * Should only be used from a task_work including IO_URING_F_MULTISHOT.
945 */
946bool io_fill_cqe_req_aux(struct io_kiocb *req, bool defer, s32 res, u32 cflags)
947{
948 struct io_ring_ctx *ctx = req->ctx;
949 u64 user_data = req->cqe.user_data;
950 struct io_uring_cqe *cqe;
951
952 if (!defer)
953 return __io_post_aux_cqe(ctx, user_data, res, cflags, false);
954
955 lockdep_assert_held(&ctx->uring_lock);
956
957 if (ctx->submit_state.cqes_count == ARRAY_SIZE(ctx->completion_cqes)) {
958 __io_cq_lock(ctx);
959 __io_flush_post_cqes(ctx);
960 /* no need to flush - flush is deferred */
961 __io_cq_unlock_post(ctx);
962 }
963
964 /* For defered completions this is not as strict as it is otherwise,
965 * however it's main job is to prevent unbounded posted completions,
966 * and in that it works just as well.
967 */
968 if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
969 return false;
970
971 cqe = &ctx->completion_cqes[ctx->submit_state.cqes_count++];
972 cqe->user_data = user_data;
973 cqe->res = res;
974 cqe->flags = cflags;
975 return true;
976}
977
978static void __io_req_complete_post(struct io_kiocb *req, unsigned issue_flags)
979{
980 struct io_ring_ctx *ctx = req->ctx;
981 struct io_rsrc_node *rsrc_node = NULL;
982
983 io_cq_lock(ctx);
984 if (!(req->flags & REQ_F_CQE_SKIP)) {
985 if (!io_fill_cqe_req(ctx, req))
986 io_req_cqe_overflow(req);
987 }
988
989 /*
990 * If we're the last reference to this request, add to our locked
991 * free_list cache.
992 */
993 if (req_ref_put_and_test(req)) {
994 if (req->flags & IO_REQ_LINK_FLAGS) {
995 if (req->flags & IO_DISARM_MASK)
996 io_disarm_next(req);
997 if (req->link) {
998 io_req_task_queue(req->link);
999 req->link = NULL;
1000 }
1001 }
1002 io_put_kbuf_comp(req);
1003 if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
1004 io_clean_op(req);
1005 io_put_file(req);
1006
1007 rsrc_node = req->rsrc_node;
1008 /*
1009 * Selected buffer deallocation in io_clean_op() assumes that
1010 * we don't hold ->completion_lock. Clean them here to avoid
1011 * deadlocks.
1012 */
1013 io_put_task_remote(req->task);
1014 wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
1015 ctx->locked_free_nr++;
1016 }
1017 io_cq_unlock_post(ctx);
1018
1019 if (rsrc_node) {
1020 io_ring_submit_lock(ctx, issue_flags);
1021 io_put_rsrc_node(ctx, rsrc_node);
1022 io_ring_submit_unlock(ctx, issue_flags);
1023 }
1024}
1025
1026void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags)
1027{
1028 if (req->ctx->task_complete && req->ctx->submitter_task != current) {
1029 req->io_task_work.func = io_req_task_complete;
1030 io_req_task_work_add(req);
1031 } else if (!(issue_flags & IO_URING_F_UNLOCKED) ||
1032 !(req->ctx->flags & IORING_SETUP_IOPOLL)) {
1033 __io_req_complete_post(req, issue_flags);
1034 } else {
1035 struct io_ring_ctx *ctx = req->ctx;
1036
1037 mutex_lock(&ctx->uring_lock);
1038 __io_req_complete_post(req, issue_flags & ~IO_URING_F_UNLOCKED);
1039 mutex_unlock(&ctx->uring_lock);
1040 }
1041}
1042
1043void io_req_defer_failed(struct io_kiocb *req, s32 res)
1044 __must_hold(&ctx->uring_lock)
1045{
1046 const struct io_cold_def *def = &io_cold_defs[req->opcode];
1047
1048 lockdep_assert_held(&req->ctx->uring_lock);
1049
1050 req_set_fail(req);
1051 io_req_set_res(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED));
1052 if (def->fail)
1053 def->fail(req);
1054 io_req_complete_defer(req);
1055}
1056
1057/*
1058 * Don't initialise the fields below on every allocation, but do that in
1059 * advance and keep them valid across allocations.
1060 */
1061static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
1062{
1063 req->ctx = ctx;
1064 req->link = NULL;
1065 req->async_data = NULL;
1066 /* not necessary, but safer to zero */
1067 memset(&req->cqe, 0, sizeof(req->cqe));
1068 memset(&req->big_cqe, 0, sizeof(req->big_cqe));
1069}
1070
1071static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx,
1072 struct io_submit_state *state)
1073{
1074 spin_lock(&ctx->completion_lock);
1075 wq_list_splice(&ctx->locked_free_list, &state->free_list);
1076 ctx->locked_free_nr = 0;
1077 spin_unlock(&ctx->completion_lock);
1078}
1079
1080/*
1081 * A request might get retired back into the request caches even before opcode
1082 * handlers and io_issue_sqe() are done with it, e.g. inline completion path.
1083 * Because of that, io_alloc_req() should be called only under ->uring_lock
1084 * and with extra caution to not get a request that is still worked on.
1085 */
1086__cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx)
1087 __must_hold(&ctx->uring_lock)
1088{
1089 gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
1090 void *reqs[IO_REQ_ALLOC_BATCH];
1091 int ret, i;
1092
1093 /*
1094 * If we have more than a batch's worth of requests in our IRQ side
1095 * locked cache, grab the lock and move them over to our submission
1096 * side cache.
1097 */
1098 if (data_race(ctx->locked_free_nr) > IO_COMPL_BATCH) {
1099 io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
1100 if (!io_req_cache_empty(ctx))
1101 return true;
1102 }
1103
1104 ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs);
1105
1106 /*
1107 * Bulk alloc is all-or-nothing. If we fail to get a batch,
1108 * retry single alloc to be on the safe side.
1109 */
1110 if (unlikely(ret <= 0)) {
1111 reqs[0] = kmem_cache_alloc(req_cachep, gfp);
1112 if (!reqs[0])
1113 return false;
1114 ret = 1;
1115 }
1116
1117 percpu_ref_get_many(&ctx->refs, ret);
1118 for (i = 0; i < ret; i++) {
1119 struct io_kiocb *req = reqs[i];
1120
1121 io_preinit_req(req, ctx);
1122 io_req_add_to_cache(req, ctx);
1123 }
1124 return true;
1125}
1126
1127__cold void io_free_req(struct io_kiocb *req)
1128{
1129 /* refs were already put, restore them for io_req_task_complete() */
1130 req->flags &= ~REQ_F_REFCOUNT;
1131 /* we only want to free it, don't post CQEs */
1132 req->flags |= REQ_F_CQE_SKIP;
1133 req->io_task_work.func = io_req_task_complete;
1134 io_req_task_work_add(req);
1135}
1136
1137static void __io_req_find_next_prep(struct io_kiocb *req)
1138{
1139 struct io_ring_ctx *ctx = req->ctx;
1140
1141 spin_lock(&ctx->completion_lock);
1142 io_disarm_next(req);
1143 spin_unlock(&ctx->completion_lock);
1144}
1145
1146static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)
1147{
1148 struct io_kiocb *nxt;
1149
1150 /*
1151 * If LINK is set, we have dependent requests in this chain. If we
1152 * didn't fail this request, queue the first one up, moving any other
1153 * dependencies to the next request. In case of failure, fail the rest
1154 * of the chain.
1155 */
1156 if (unlikely(req->flags & IO_DISARM_MASK))
1157 __io_req_find_next_prep(req);
1158 nxt = req->link;
1159 req->link = NULL;
1160 return nxt;
1161}
1162
1163static void ctx_flush_and_put(struct io_ring_ctx *ctx, struct io_tw_state *ts)
1164{
1165 if (!ctx)
1166 return;
1167 if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
1168 atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
1169 if (ts->locked) {
1170 io_submit_flush_completions(ctx);
1171 mutex_unlock(&ctx->uring_lock);
1172 ts->locked = false;
1173 }
1174 percpu_ref_put(&ctx->refs);
1175}
1176
1177static unsigned int handle_tw_list(struct llist_node *node,
1178 struct io_ring_ctx **ctx,
1179 struct io_tw_state *ts,
1180 struct llist_node *last)
1181{
1182 unsigned int count = 0;
1183
1184 while (node && node != last) {
1185 struct llist_node *next = node->next;
1186 struct io_kiocb *req = container_of(node, struct io_kiocb,
1187 io_task_work.node);
1188
1189 prefetch(container_of(next, struct io_kiocb, io_task_work.node));
1190
1191 if (req->ctx != *ctx) {
1192 ctx_flush_and_put(*ctx, ts);
1193 *ctx = req->ctx;
1194 /* if not contended, grab and improve batching */
1195 ts->locked = mutex_trylock(&(*ctx)->uring_lock);
1196 percpu_ref_get(&(*ctx)->refs);
1197 }
1198 INDIRECT_CALL_2(req->io_task_work.func,
1199 io_poll_task_func, io_req_rw_complete,
1200 req, ts);
1201 node = next;
1202 count++;
1203 if (unlikely(need_resched())) {
1204 ctx_flush_and_put(*ctx, ts);
1205 *ctx = NULL;
1206 cond_resched();
1207 }
1208 }
1209
1210 return count;
1211}
1212
1213/**
1214 * io_llist_xchg - swap all entries in a lock-less list
1215 * @head: the head of lock-less list to delete all entries
1216 * @new: new entry as the head of the list
1217 *
1218 * If list is empty, return NULL, otherwise, return the pointer to the first entry.
1219 * The order of entries returned is from the newest to the oldest added one.
1220 */
1221static inline struct llist_node *io_llist_xchg(struct llist_head *head,
1222 struct llist_node *new)
1223{
1224 return xchg(&head->first, new);
1225}
1226
1227/**
1228 * io_llist_cmpxchg - possibly swap all entries in a lock-less list
1229 * @head: the head of lock-less list to delete all entries
1230 * @old: expected old value of the first entry of the list
1231 * @new: new entry as the head of the list
1232 *
1233 * perform a cmpxchg on the first entry of the list.
1234 */
1235
1236static inline struct llist_node *io_llist_cmpxchg(struct llist_head *head,
1237 struct llist_node *old,
1238 struct llist_node *new)
1239{
1240 return cmpxchg(&head->first, old, new);
1241}
1242
1243static __cold void io_fallback_tw(struct io_uring_task *tctx, bool sync)
1244{
1245 struct llist_node *node = llist_del_all(&tctx->task_list);
1246 struct io_ring_ctx *last_ctx = NULL;
1247 struct io_kiocb *req;
1248
1249 while (node) {
1250 req = container_of(node, struct io_kiocb, io_task_work.node);
1251 node = node->next;
1252 if (sync && last_ctx != req->ctx) {
1253 if (last_ctx) {
1254 flush_delayed_work(&last_ctx->fallback_work);
1255 percpu_ref_put(&last_ctx->refs);
1256 }
1257 last_ctx = req->ctx;
1258 percpu_ref_get(&last_ctx->refs);
1259 }
1260 if (llist_add(&req->io_task_work.node,
1261 &req->ctx->fallback_llist))
1262 schedule_delayed_work(&req->ctx->fallback_work, 1);
1263 }
1264
1265 if (last_ctx) {
1266 flush_delayed_work(&last_ctx->fallback_work);
1267 percpu_ref_put(&last_ctx->refs);
1268 }
1269}
1270
1271void tctx_task_work(struct callback_head *cb)
1272{
1273 struct io_tw_state ts = {};
1274 struct io_ring_ctx *ctx = NULL;
1275 struct io_uring_task *tctx = container_of(cb, struct io_uring_task,
1276 task_work);
1277 struct llist_node fake = {};
1278 struct llist_node *node;
1279 unsigned int loops = 0;
1280 unsigned int count = 0;
1281
1282 if (unlikely(current->flags & PF_EXITING)) {
1283 io_fallback_tw(tctx, true);
1284 return;
1285 }
1286
1287 do {
1288 loops++;
1289 node = io_llist_xchg(&tctx->task_list, &fake);
1290 count += handle_tw_list(node, &ctx, &ts, &fake);
1291
1292 /* skip expensive cmpxchg if there are items in the list */
1293 if (READ_ONCE(tctx->task_list.first) != &fake)
1294 continue;
1295 if (ts.locked && !wq_list_empty(&ctx->submit_state.compl_reqs)) {
1296 io_submit_flush_completions(ctx);
1297 if (READ_ONCE(tctx->task_list.first) != &fake)
1298 continue;
1299 }
1300 node = io_llist_cmpxchg(&tctx->task_list, &fake, NULL);
1301 } while (node != &fake);
1302
1303 ctx_flush_and_put(ctx, &ts);
1304
1305 /* relaxed read is enough as only the task itself sets ->in_cancel */
1306 if (unlikely(atomic_read(&tctx->in_cancel)))
1307 io_uring_drop_tctx_refs(current);
1308
1309 trace_io_uring_task_work_run(tctx, count, loops);
1310}
1311
1312static inline void io_req_local_work_add(struct io_kiocb *req, unsigned flags)
1313{
1314 struct io_ring_ctx *ctx = req->ctx;
1315 unsigned nr_wait, nr_tw, nr_tw_prev;
1316 struct llist_node *head;
1317
1318 /* See comment above IO_CQ_WAKE_INIT */
1319 BUILD_BUG_ON(IO_CQ_WAKE_FORCE <= IORING_MAX_CQ_ENTRIES);
1320
1321 /*
1322 * We don't know how many reuqests is there in the link and whether
1323 * they can even be queued lazily, fall back to non-lazy.
1324 */
1325 if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK))
1326 flags &= ~IOU_F_TWQ_LAZY_WAKE;
1327
1328 head = READ_ONCE(ctx->work_llist.first);
1329 do {
1330 nr_tw_prev = 0;
1331 if (head) {
1332 struct io_kiocb *first_req = container_of(head,
1333 struct io_kiocb,
1334 io_task_work.node);
1335 /*
1336 * Might be executed at any moment, rely on
1337 * SLAB_TYPESAFE_BY_RCU to keep it alive.
1338 */
1339 nr_tw_prev = READ_ONCE(first_req->nr_tw);
1340 }
1341
1342 /*
1343 * Theoretically, it can overflow, but that's fine as one of
1344 * previous adds should've tried to wake the task.
1345 */
1346 nr_tw = nr_tw_prev + 1;
1347 if (!(flags & IOU_F_TWQ_LAZY_WAKE))
1348 nr_tw = IO_CQ_WAKE_FORCE;
1349
1350 req->nr_tw = nr_tw;
1351 req->io_task_work.node.next = head;
1352 } while (!try_cmpxchg(&ctx->work_llist.first, &head,
1353 &req->io_task_work.node));
1354
1355 /*
1356 * cmpxchg implies a full barrier, which pairs with the barrier
1357 * in set_current_state() on the io_cqring_wait() side. It's used
1358 * to ensure that either we see updated ->cq_wait_nr, or waiters
1359 * going to sleep will observe the work added to the list, which
1360 * is similar to the wait/wawke task state sync.
1361 */
1362
1363 if (!head) {
1364 if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
1365 atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
1366 if (ctx->has_evfd)
1367 io_eventfd_signal(ctx);
1368 }
1369
1370 nr_wait = atomic_read(&ctx->cq_wait_nr);
1371 /* not enough or no one is waiting */
1372 if (nr_tw < nr_wait)
1373 return;
1374 /* the previous add has already woken it up */
1375 if (nr_tw_prev >= nr_wait)
1376 return;
1377 wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE);
1378}
1379
1380static void io_req_normal_work_add(struct io_kiocb *req)
1381{
1382 struct io_uring_task *tctx = req->task->io_uring;
1383 struct io_ring_ctx *ctx = req->ctx;
1384
1385 /* task_work already pending, we're done */
1386 if (!llist_add(&req->io_task_work.node, &tctx->task_list))
1387 return;
1388
1389 if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
1390 atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
1391
1392 if (likely(!task_work_add(req->task, &tctx->task_work, ctx->notify_method)))
1393 return;
1394
1395 io_fallback_tw(tctx, false);
1396}
1397
1398void __io_req_task_work_add(struct io_kiocb *req, unsigned flags)
1399{
1400 if (req->ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
1401 rcu_read_lock();
1402 io_req_local_work_add(req, flags);
1403 rcu_read_unlock();
1404 } else {
1405 io_req_normal_work_add(req);
1406 }
1407}
1408
1409static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)
1410{
1411 struct llist_node *node;
1412
1413 node = llist_del_all(&ctx->work_llist);
1414 while (node) {
1415 struct io_kiocb *req = container_of(node, struct io_kiocb,
1416 io_task_work.node);
1417
1418 node = node->next;
1419 io_req_normal_work_add(req);
1420 }
1421}
1422
1423static int __io_run_local_work(struct io_ring_ctx *ctx, struct io_tw_state *ts)
1424{
1425 struct llist_node *node;
1426 unsigned int loops = 0;
1427 int ret = 0;
1428
1429 if (WARN_ON_ONCE(ctx->submitter_task != current))
1430 return -EEXIST;
1431 if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
1432 atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
1433again:
1434 /*
1435 * llists are in reverse order, flip it back the right way before
1436 * running the pending items.
1437 */
1438 node = llist_reverse_order(io_llist_xchg(&ctx->work_llist, NULL));
1439 while (node) {
1440 struct llist_node *next = node->next;
1441 struct io_kiocb *req = container_of(node, struct io_kiocb,
1442 io_task_work.node);
1443 prefetch(container_of(next, struct io_kiocb, io_task_work.node));
1444 INDIRECT_CALL_2(req->io_task_work.func,
1445 io_poll_task_func, io_req_rw_complete,
1446 req, ts);
1447 ret++;
1448 node = next;
1449 }
1450 loops++;
1451
1452 if (!llist_empty(&ctx->work_llist))
1453 goto again;
1454 if (ts->locked) {
1455 io_submit_flush_completions(ctx);
1456 if (!llist_empty(&ctx->work_llist))
1457 goto again;
1458 }
1459 trace_io_uring_local_work_run(ctx, ret, loops);
1460 return ret;
1461}
1462
1463static inline int io_run_local_work_locked(struct io_ring_ctx *ctx)
1464{
1465 struct io_tw_state ts = { .locked = true, };
1466 int ret;
1467
1468 if (llist_empty(&ctx->work_llist))
1469 return 0;
1470
1471 ret = __io_run_local_work(ctx, &ts);
1472 /* shouldn't happen! */
1473 if (WARN_ON_ONCE(!ts.locked))
1474 mutex_lock(&ctx->uring_lock);
1475 return ret;
1476}
1477
1478static int io_run_local_work(struct io_ring_ctx *ctx)
1479{
1480 struct io_tw_state ts = {};
1481 int ret;
1482
1483 ts.locked = mutex_trylock(&ctx->uring_lock);
1484 ret = __io_run_local_work(ctx, &ts);
1485 if (ts.locked)
1486 mutex_unlock(&ctx->uring_lock);
1487
1488 return ret;
1489}
1490
1491static void io_req_task_cancel(struct io_kiocb *req, struct io_tw_state *ts)
1492{
1493 io_tw_lock(req->ctx, ts);
1494 io_req_defer_failed(req, req->cqe.res);
1495}
1496
1497void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts)
1498{
1499 io_tw_lock(req->ctx, ts);
1500 /* req->task == current here, checking PF_EXITING is safe */
1501 if (unlikely(req->task->flags & PF_EXITING))
1502 io_req_defer_failed(req, -EFAULT);
1503 else if (req->flags & REQ_F_FORCE_ASYNC)
1504 io_queue_iowq(req, ts);
1505 else
1506 io_queue_sqe(req);
1507}
1508
1509void io_req_task_queue_fail(struct io_kiocb *req, int ret)
1510{
1511 io_req_set_res(req, ret, 0);
1512 req->io_task_work.func = io_req_task_cancel;
1513 io_req_task_work_add(req);
1514}
1515
1516void io_req_task_queue(struct io_kiocb *req)
1517{
1518 req->io_task_work.func = io_req_task_submit;
1519 io_req_task_work_add(req);
1520}
1521
1522void io_queue_next(struct io_kiocb *req)
1523{
1524 struct io_kiocb *nxt = io_req_find_next(req);
1525
1526 if (nxt)
1527 io_req_task_queue(nxt);
1528}
1529
1530static void io_free_batch_list(struct io_ring_ctx *ctx,
1531 struct io_wq_work_node *node)
1532 __must_hold(&ctx->uring_lock)
1533{
1534 do {
1535 struct io_kiocb *req = container_of(node, struct io_kiocb,
1536 comp_list);
1537
1538 if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) {
1539 if (req->flags & REQ_F_REFCOUNT) {
1540 node = req->comp_list.next;
1541 if (!req_ref_put_and_test(req))
1542 continue;
1543 }
1544 if ((req->flags & REQ_F_POLLED) && req->apoll) {
1545 struct async_poll *apoll = req->apoll;
1546
1547 if (apoll->double_poll)
1548 kfree(apoll->double_poll);
1549 if (!io_alloc_cache_put(&ctx->apoll_cache, &apoll->cache))
1550 kfree(apoll);
1551 req->flags &= ~REQ_F_POLLED;
1552 }
1553 if (req->flags & IO_REQ_LINK_FLAGS)
1554 io_queue_next(req);
1555 if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
1556 io_clean_op(req);
1557 }
1558 io_put_file(req);
1559
1560 io_req_put_rsrc_locked(req, ctx);
1561
1562 io_put_task(req->task);
1563 node = req->comp_list.next;
1564 io_req_add_to_cache(req, ctx);
1565 } while (node);
1566}
1567
1568void __io_submit_flush_completions(struct io_ring_ctx *ctx)
1569 __must_hold(&ctx->uring_lock)
1570{
1571 struct io_submit_state *state = &ctx->submit_state;
1572 struct io_wq_work_node *node;
1573
1574 __io_cq_lock(ctx);
1575 /* must come first to preserve CQE ordering in failure cases */
1576 if (state->cqes_count)
1577 __io_flush_post_cqes(ctx);
1578 __wq_list_for_each(node, &state->compl_reqs) {
1579 struct io_kiocb *req = container_of(node, struct io_kiocb,
1580 comp_list);
1581
1582 if (!(req->flags & REQ_F_CQE_SKIP) &&
1583 unlikely(!io_fill_cqe_req(ctx, req))) {
1584 if (ctx->lockless_cq) {
1585 spin_lock(&ctx->completion_lock);
1586 io_req_cqe_overflow(req);
1587 spin_unlock(&ctx->completion_lock);
1588 } else {
1589 io_req_cqe_overflow(req);
1590 }
1591 }
1592 }
1593 __io_cq_unlock_post(ctx);
1594
1595 if (!wq_list_empty(&ctx->submit_state.compl_reqs)) {
1596 io_free_batch_list(ctx, state->compl_reqs.first);
1597 INIT_WQ_LIST(&state->compl_reqs);
1598 }
1599}
1600
1601static unsigned io_cqring_events(struct io_ring_ctx *ctx)
1602{
1603 /* See comment at the top of this file */
1604 smp_rmb();
1605 return __io_cqring_events(ctx);
1606}
1607
1608/*
1609 * We can't just wait for polled events to come to us, we have to actively
1610 * find and complete them.
1611 */
1612static __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
1613{
1614 if (!(ctx->flags & IORING_SETUP_IOPOLL))
1615 return;
1616
1617 mutex_lock(&ctx->uring_lock);
1618 while (!wq_list_empty(&ctx->iopoll_list)) {
1619 /* let it sleep and repeat later if can't complete a request */
1620 if (io_do_iopoll(ctx, true) == 0)
1621 break;
1622 /*
1623 * Ensure we allow local-to-the-cpu processing to take place,
1624 * in this case we need to ensure that we reap all events.
1625 * Also let task_work, etc. to progress by releasing the mutex
1626 */
1627 if (need_resched()) {
1628 mutex_unlock(&ctx->uring_lock);
1629 cond_resched();
1630 mutex_lock(&ctx->uring_lock);
1631 }
1632 }
1633 mutex_unlock(&ctx->uring_lock);
1634}
1635
1636static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
1637{
1638 unsigned int nr_events = 0;
1639 unsigned long check_cq;
1640
1641 if (!io_allowed_run_tw(ctx))
1642 return -EEXIST;
1643
1644 check_cq = READ_ONCE(ctx->check_cq);
1645 if (unlikely(check_cq)) {
1646 if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
1647 __io_cqring_overflow_flush(ctx);
1648 /*
1649 * Similarly do not spin if we have not informed the user of any
1650 * dropped CQE.
1651 */
1652 if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT))
1653 return -EBADR;
1654 }
1655 /*
1656 * Don't enter poll loop if we already have events pending.
1657 * If we do, we can potentially be spinning for commands that
1658 * already triggered a CQE (eg in error).
1659 */
1660 if (io_cqring_events(ctx))
1661 return 0;
1662
1663 do {
1664 int ret = 0;
1665
1666 /*
1667 * If a submit got punted to a workqueue, we can have the
1668 * application entering polling for a command before it gets
1669 * issued. That app will hold the uring_lock for the duration
1670 * of the poll right here, so we need to take a breather every
1671 * now and then to ensure that the issue has a chance to add
1672 * the poll to the issued list. Otherwise we can spin here
1673 * forever, while the workqueue is stuck trying to acquire the
1674 * very same mutex.
1675 */
1676 if (wq_list_empty(&ctx->iopoll_list) ||
1677 io_task_work_pending(ctx)) {
1678 u32 tail = ctx->cached_cq_tail;
1679
1680 (void) io_run_local_work_locked(ctx);
1681
1682 if (task_work_pending(current) ||
1683 wq_list_empty(&ctx->iopoll_list)) {
1684 mutex_unlock(&ctx->uring_lock);
1685 io_run_task_work();
1686 mutex_lock(&ctx->uring_lock);
1687 }
1688 /* some requests don't go through iopoll_list */
1689 if (tail != ctx->cached_cq_tail ||
1690 wq_list_empty(&ctx->iopoll_list))
1691 break;
1692 }
1693 ret = io_do_iopoll(ctx, !min);
1694 if (unlikely(ret < 0))
1695 return ret;
1696
1697 if (task_sigpending(current))
1698 return -EINTR;
1699 if (need_resched())
1700 break;
1701
1702 nr_events += ret;
1703 } while (nr_events < min);
1704
1705 return 0;
1706}
1707
1708void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts)
1709{
1710 if (ts->locked)
1711 io_req_complete_defer(req);
1712 else
1713 io_req_complete_post(req, IO_URING_F_UNLOCKED);
1714}
1715
1716/*
1717 * After the iocb has been issued, it's safe to be found on the poll list.
1718 * Adding the kiocb to the list AFTER submission ensures that we don't
1719 * find it from a io_do_iopoll() thread before the issuer is done
1720 * accessing the kiocb cookie.
1721 */
1722static void io_iopoll_req_issued(struct io_kiocb *req, unsigned int issue_flags)
1723{
1724 struct io_ring_ctx *ctx = req->ctx;
1725 const bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
1726
1727 /* workqueue context doesn't hold uring_lock, grab it now */
1728 if (unlikely(needs_lock))
1729 mutex_lock(&ctx->uring_lock);
1730
1731 /*
1732 * Track whether we have multiple files in our lists. This will impact
1733 * how we do polling eventually, not spinning if we're on potentially
1734 * different devices.
1735 */
1736 if (wq_list_empty(&ctx->iopoll_list)) {
1737 ctx->poll_multi_queue = false;
1738 } else if (!ctx->poll_multi_queue) {
1739 struct io_kiocb *list_req;
1740
1741 list_req = container_of(ctx->iopoll_list.first, struct io_kiocb,
1742 comp_list);
1743 if (list_req->file != req->file)
1744 ctx->poll_multi_queue = true;
1745 }
1746
1747 /*
1748 * For fast devices, IO may have already completed. If it has, add
1749 * it to the front so we find it first.
1750 */
1751 if (READ_ONCE(req->iopoll_completed))
1752 wq_list_add_head(&req->comp_list, &ctx->iopoll_list);
1753 else
1754 wq_list_add_tail(&req->comp_list, &ctx->iopoll_list);
1755
1756 if (unlikely(needs_lock)) {
1757 /*
1758 * If IORING_SETUP_SQPOLL is enabled, sqes are either handle
1759 * in sq thread task context or in io worker task context. If
1760 * current task context is sq thread, we don't need to check
1761 * whether should wake up sq thread.
1762 */
1763 if ((ctx->flags & IORING_SETUP_SQPOLL) &&
1764 wq_has_sleeper(&ctx->sq_data->wait))
1765 wake_up(&ctx->sq_data->wait);
1766
1767 mutex_unlock(&ctx->uring_lock);
1768 }
1769}
1770
1771unsigned int io_file_get_flags(struct file *file)
1772{
1773 unsigned int res = 0;
1774
1775 if (S_ISREG(file_inode(file)->i_mode))
1776 res |= REQ_F_ISREG;
1777 if ((file->f_flags & O_NONBLOCK) || (file->f_mode & FMODE_NOWAIT))
1778 res |= REQ_F_SUPPORT_NOWAIT;
1779 return res;
1780}
1781
1782bool io_alloc_async_data(struct io_kiocb *req)
1783{
1784 WARN_ON_ONCE(!io_cold_defs[req->opcode].async_size);
1785 req->async_data = kmalloc(io_cold_defs[req->opcode].async_size, GFP_KERNEL);
1786 if (req->async_data) {
1787 req->flags |= REQ_F_ASYNC_DATA;
1788 return false;
1789 }
1790 return true;
1791}
1792
1793int io_req_prep_async(struct io_kiocb *req)
1794{
1795 const struct io_cold_def *cdef = &io_cold_defs[req->opcode];
1796 const struct io_issue_def *def = &io_issue_defs[req->opcode];
1797
1798 /* assign early for deferred execution for non-fixed file */
1799 if (def->needs_file && !(req->flags & REQ_F_FIXED_FILE) && !req->file)
1800 req->file = io_file_get_normal(req, req->cqe.fd);
1801 if (!cdef->prep_async)
1802 return 0;
1803 if (WARN_ON_ONCE(req_has_async_data(req)))
1804 return -EFAULT;
1805 if (!def->manual_alloc) {
1806 if (io_alloc_async_data(req))
1807 return -EAGAIN;
1808 }
1809 return cdef->prep_async(req);
1810}
1811
1812static u32 io_get_sequence(struct io_kiocb *req)
1813{
1814 u32 seq = req->ctx->cached_sq_head;
1815 struct io_kiocb *cur;
1816
1817 /* need original cached_sq_head, but it was increased for each req */
1818 io_for_each_link(cur, req)
1819 seq--;
1820 return seq;
1821}
1822
1823static __cold void io_drain_req(struct io_kiocb *req)
1824 __must_hold(&ctx->uring_lock)
1825{
1826 struct io_ring_ctx *ctx = req->ctx;
1827 struct io_defer_entry *de;
1828 int ret;
1829 u32 seq = io_get_sequence(req);
1830
1831 /* Still need defer if there is pending req in defer list. */
1832 spin_lock(&ctx->completion_lock);
1833 if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) {
1834 spin_unlock(&ctx->completion_lock);
1835queue:
1836 ctx->drain_active = false;
1837 io_req_task_queue(req);
1838 return;
1839 }
1840 spin_unlock(&ctx->completion_lock);
1841
1842 io_prep_async_link(req);
1843 de = kmalloc(sizeof(*de), GFP_KERNEL);
1844 if (!de) {
1845 ret = -ENOMEM;
1846 io_req_defer_failed(req, ret);
1847 return;
1848 }
1849
1850 spin_lock(&ctx->completion_lock);
1851 if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
1852 spin_unlock(&ctx->completion_lock);
1853 kfree(de);
1854 goto queue;
1855 }
1856
1857 trace_io_uring_defer(req);
1858 de->req = req;
1859 de->seq = seq;
1860 list_add_tail(&de->list, &ctx->defer_list);
1861 spin_unlock(&ctx->completion_lock);
1862}
1863
1864static bool io_assign_file(struct io_kiocb *req, const struct io_issue_def *def,
1865 unsigned int issue_flags)
1866{
1867 if (req->file || !def->needs_file)
1868 return true;
1869
1870 if (req->flags & REQ_F_FIXED_FILE)
1871 req->file = io_file_get_fixed(req, req->cqe.fd, issue_flags);
1872 else
1873 req->file = io_file_get_normal(req, req->cqe.fd);
1874
1875 return !!req->file;
1876}
1877
1878static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
1879{
1880 const struct io_issue_def *def = &io_issue_defs[req->opcode];
1881 const struct cred *creds = NULL;
1882 int ret;
1883
1884 if (unlikely(!io_assign_file(req, def, issue_flags)))
1885 return -EBADF;
1886
1887 if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred()))
1888 creds = override_creds(req->creds);
1889
1890 if (!def->audit_skip)
1891 audit_uring_entry(req->opcode);
1892
1893 ret = def->issue(req, issue_flags);
1894
1895 if (!def->audit_skip)
1896 audit_uring_exit(!ret, ret);
1897
1898 if (creds)
1899 revert_creds(creds);
1900
1901 if (ret == IOU_OK) {
1902 if (issue_flags & IO_URING_F_COMPLETE_DEFER)
1903 io_req_complete_defer(req);
1904 else
1905 io_req_complete_post(req, issue_flags);
1906
1907 return 0;
1908 }
1909
1910 if (ret == IOU_ISSUE_SKIP_COMPLETE) {
1911 ret = 0;
1912 io_arm_ltimeout(req);
1913
1914 /* If the op doesn't have a file, we're not polling for it */
1915 if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue)
1916 io_iopoll_req_issued(req, issue_flags);
1917 }
1918 return ret;
1919}
1920
1921int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts)
1922{
1923 io_tw_lock(req->ctx, ts);
1924 return io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_MULTISHOT|
1925 IO_URING_F_COMPLETE_DEFER);
1926}
1927
1928struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
1929{
1930 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
1931 struct io_kiocb *nxt = NULL;
1932
1933 if (req_ref_put_and_test(req)) {
1934 if (req->flags & IO_REQ_LINK_FLAGS)
1935 nxt = io_req_find_next(req);
1936 io_free_req(req);
1937 }
1938 return nxt ? &nxt->work : NULL;
1939}
1940
1941void io_wq_submit_work(struct io_wq_work *work)
1942{
1943 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
1944 const struct io_issue_def *def = &io_issue_defs[req->opcode];
1945 unsigned int issue_flags = IO_URING_F_UNLOCKED | IO_URING_F_IOWQ;
1946 bool needs_poll = false;
1947 int ret = 0, err = -ECANCELED;
1948
1949 /* one will be dropped by ->io_wq_free_work() after returning to io-wq */
1950 if (!(req->flags & REQ_F_REFCOUNT))
1951 __io_req_set_refcount(req, 2);
1952 else
1953 req_ref_get(req);
1954
1955 io_arm_ltimeout(req);
1956
1957 /* either cancelled or io-wq is dying, so don't touch tctx->iowq */
1958 if (work->flags & IO_WQ_WORK_CANCEL) {
1959fail:
1960 io_req_task_queue_fail(req, err);
1961 return;
1962 }
1963 if (!io_assign_file(req, def, issue_flags)) {
1964 err = -EBADF;
1965 work->flags |= IO_WQ_WORK_CANCEL;
1966 goto fail;
1967 }
1968
1969 if (req->flags & REQ_F_FORCE_ASYNC) {
1970 bool opcode_poll = def->pollin || def->pollout;
1971
1972 if (opcode_poll && file_can_poll(req->file)) {
1973 needs_poll = true;
1974 issue_flags |= IO_URING_F_NONBLOCK;
1975 }
1976 }
1977
1978 do {
1979 ret = io_issue_sqe(req, issue_flags);
1980 if (ret != -EAGAIN)
1981 break;
1982
1983 /*
1984 * If REQ_F_NOWAIT is set, then don't wait or retry with
1985 * poll. -EAGAIN is final for that case.
1986 */
1987 if (req->flags & REQ_F_NOWAIT)
1988 break;
1989
1990 /*
1991 * We can get EAGAIN for iopolled IO even though we're
1992 * forcing a sync submission from here, since we can't
1993 * wait for request slots on the block side.
1994 */
1995 if (!needs_poll) {
1996 if (!(req->ctx->flags & IORING_SETUP_IOPOLL))
1997 break;
1998 if (io_wq_worker_stopped())
1999 break;
2000 cond_resched();
2001 continue;
2002 }
2003
2004 if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK)
2005 return;
2006 /* aborted or ready, in either case retry blocking */
2007 needs_poll = false;
2008 issue_flags &= ~IO_URING_F_NONBLOCK;
2009 } while (1);
2010
2011 /* avoid locking problems by failing it from a clean context */
2012 if (ret < 0)
2013 io_req_task_queue_fail(req, ret);
2014}
2015
2016inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
2017 unsigned int issue_flags)
2018{
2019 struct io_ring_ctx *ctx = req->ctx;
2020 struct io_fixed_file *slot;
2021 struct file *file = NULL;
2022
2023 io_ring_submit_lock(ctx, issue_flags);
2024
2025 if (unlikely((unsigned int)fd >= ctx->nr_user_files))
2026 goto out;
2027 fd = array_index_nospec(fd, ctx->nr_user_files);
2028 slot = io_fixed_file_slot(&ctx->file_table, fd);
2029 if (!req->rsrc_node)
2030 __io_req_set_rsrc_node(req, ctx);
2031 req->flags |= io_slot_flags(slot);
2032 file = io_slot_file(slot);
2033out:
2034 io_ring_submit_unlock(ctx, issue_flags);
2035 return file;
2036}
2037
2038struct file *io_file_get_normal(struct io_kiocb *req, int fd)
2039{
2040 struct file *file = fget(fd);
2041
2042 trace_io_uring_file_get(req, fd);
2043
2044 /* we don't allow fixed io_uring files */
2045 if (file && io_is_uring_fops(file))
2046 io_req_track_inflight(req);
2047 return file;
2048}
2049
2050static void io_queue_async(struct io_kiocb *req, int ret)
2051 __must_hold(&req->ctx->uring_lock)
2052{
2053 struct io_kiocb *linked_timeout;
2054
2055 if (ret != -EAGAIN || (req->flags & REQ_F_NOWAIT)) {
2056 io_req_defer_failed(req, ret);
2057 return;
2058 }
2059
2060 linked_timeout = io_prep_linked_timeout(req);
2061
2062 switch (io_arm_poll_handler(req, 0)) {
2063 case IO_APOLL_READY:
2064 io_kbuf_recycle(req, 0);
2065 io_req_task_queue(req);
2066 break;
2067 case IO_APOLL_ABORTED:
2068 io_kbuf_recycle(req, 0);
2069 io_queue_iowq(req, NULL);
2070 break;
2071 case IO_APOLL_OK:
2072 break;
2073 }
2074
2075 if (linked_timeout)
2076 io_queue_linked_timeout(linked_timeout);
2077}
2078
2079static inline void io_queue_sqe(struct io_kiocb *req)
2080 __must_hold(&req->ctx->uring_lock)
2081{
2082 int ret;
2083
2084 ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);
2085
2086 /*
2087 * We async punt it if the file wasn't marked NOWAIT, or if the file
2088 * doesn't support non-blocking read/write attempts
2089 */
2090 if (unlikely(ret))
2091 io_queue_async(req, ret);
2092}
2093
2094static void io_queue_sqe_fallback(struct io_kiocb *req)
2095 __must_hold(&req->ctx->uring_lock)
2096{
2097 if (unlikely(req->flags & REQ_F_FAIL)) {
2098 /*
2099 * We don't submit, fail them all, for that replace hardlinks
2100 * with normal links. Extra REQ_F_LINK is tolerated.
2101 */
2102 req->flags &= ~REQ_F_HARDLINK;
2103 req->flags |= REQ_F_LINK;
2104 io_req_defer_failed(req, req->cqe.res);
2105 } else {
2106 int ret = io_req_prep_async(req);
2107
2108 if (unlikely(ret)) {
2109 io_req_defer_failed(req, ret);
2110 return;
2111 }
2112
2113 if (unlikely(req->ctx->drain_active))
2114 io_drain_req(req);
2115 else
2116 io_queue_iowq(req, NULL);
2117 }
2118}
2119
2120/*
2121 * Check SQE restrictions (opcode and flags).
2122 *
2123 * Returns 'true' if SQE is allowed, 'false' otherwise.
2124 */
2125static inline bool io_check_restriction(struct io_ring_ctx *ctx,
2126 struct io_kiocb *req,
2127 unsigned int sqe_flags)
2128{
2129 if (!test_bit(req->opcode, ctx->restrictions.sqe_op))
2130 return false;
2131
2132 if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=
2133 ctx->restrictions.sqe_flags_required)
2134 return false;
2135
2136 if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |
2137 ctx->restrictions.sqe_flags_required))
2138 return false;
2139
2140 return true;
2141}
2142
2143static void io_init_req_drain(struct io_kiocb *req)
2144{
2145 struct io_ring_ctx *ctx = req->ctx;
2146 struct io_kiocb *head = ctx->submit_state.link.head;
2147
2148 ctx->drain_active = true;
2149 if (head) {
2150 /*
2151 * If we need to drain a request in the middle of a link, drain
2152 * the head request and the next request/link after the current
2153 * link. Considering sequential execution of links,
2154 * REQ_F_IO_DRAIN will be maintained for every request of our
2155 * link.
2156 */
2157 head->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
2158 ctx->drain_next = true;
2159 }
2160}
2161
2162static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
2163 const struct io_uring_sqe *sqe)
2164 __must_hold(&ctx->uring_lock)
2165{
2166 const struct io_issue_def *def;
2167 unsigned int sqe_flags;
2168 int personality;
2169 u8 opcode;
2170
2171 /* req is partially pre-initialised, see io_preinit_req() */
2172 req->opcode = opcode = READ_ONCE(sqe->opcode);
2173 /* same numerical values with corresponding REQ_F_*, safe to copy */
2174 req->flags = sqe_flags = READ_ONCE(sqe->flags);
2175 req->cqe.user_data = READ_ONCE(sqe->user_data);
2176 req->file = NULL;
2177 req->rsrc_node = NULL;
2178 req->task = current;
2179
2180 if (unlikely(opcode >= IORING_OP_LAST)) {
2181 req->opcode = 0;
2182 return -EINVAL;
2183 }
2184 def = &io_issue_defs[opcode];
2185 if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {
2186 /* enforce forwards compatibility on users */
2187 if (sqe_flags & ~SQE_VALID_FLAGS)
2188 return -EINVAL;
2189 if (sqe_flags & IOSQE_BUFFER_SELECT) {
2190 if (!def->buffer_select)
2191 return -EOPNOTSUPP;
2192 req->buf_index = READ_ONCE(sqe->buf_group);
2193 }
2194 if (sqe_flags & IOSQE_CQE_SKIP_SUCCESS)
2195 ctx->drain_disabled = true;
2196 if (sqe_flags & IOSQE_IO_DRAIN) {
2197 if (ctx->drain_disabled)
2198 return -EOPNOTSUPP;
2199 io_init_req_drain(req);
2200 }
2201 }
2202 if (unlikely(ctx->restricted || ctx->drain_active || ctx->drain_next)) {
2203 if (ctx->restricted && !io_check_restriction(ctx, req, sqe_flags))
2204 return -EACCES;
2205 /* knock it to the slow queue path, will be drained there */
2206 if (ctx->drain_active)
2207 req->flags |= REQ_F_FORCE_ASYNC;
2208 /* if there is no link, we're at "next" request and need to drain */
2209 if (unlikely(ctx->drain_next) && !ctx->submit_state.link.head) {
2210 ctx->drain_next = false;
2211 ctx->drain_active = true;
2212 req->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
2213 }
2214 }
2215
2216 if (!def->ioprio && sqe->ioprio)
2217 return -EINVAL;
2218 if (!def->iopoll && (ctx->flags & IORING_SETUP_IOPOLL))
2219 return -EINVAL;
2220
2221 if (def->needs_file) {
2222 struct io_submit_state *state = &ctx->submit_state;
2223
2224 req->cqe.fd = READ_ONCE(sqe->fd);
2225
2226 /*
2227 * Plug now if we have more than 2 IO left after this, and the
2228 * target is potentially a read/write to block based storage.
2229 */
2230 if (state->need_plug && def->plug) {
2231 state->plug_started = true;
2232 state->need_plug = false;
2233 blk_start_plug_nr_ios(&state->plug, state->submit_nr);
2234 }
2235 }
2236
2237 personality = READ_ONCE(sqe->personality);
2238 if (personality) {
2239 int ret;
2240
2241 req->creds = xa_load(&ctx->personalities, personality);
2242 if (!req->creds)
2243 return -EINVAL;
2244 get_cred(req->creds);
2245 ret = security_uring_override_creds(req->creds);
2246 if (ret) {
2247 put_cred(req->creds);
2248 return ret;
2249 }
2250 req->flags |= REQ_F_CREDS;
2251 }
2252
2253 return def->prep(req, sqe);
2254}
2255
2256static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe,
2257 struct io_kiocb *req, int ret)
2258{
2259 struct io_ring_ctx *ctx = req->ctx;
2260 struct io_submit_link *link = &ctx->submit_state.link;
2261 struct io_kiocb *head = link->head;
2262
2263 trace_io_uring_req_failed(sqe, req, ret);
2264
2265 /*
2266 * Avoid breaking links in the middle as it renders links with SQPOLL
2267 * unusable. Instead of failing eagerly, continue assembling the link if
2268 * applicable and mark the head with REQ_F_FAIL. The link flushing code
2269 * should find the flag and handle the rest.
2270 */
2271 req_fail_link_node(req, ret);
2272 if (head && !(head->flags & REQ_F_FAIL))
2273 req_fail_link_node(head, -ECANCELED);
2274
2275 if (!(req->flags & IO_REQ_LINK_FLAGS)) {
2276 if (head) {
2277 link->last->link = req;
2278 link->head = NULL;
2279 req = head;
2280 }
2281 io_queue_sqe_fallback(req);
2282 return ret;
2283 }
2284
2285 if (head)
2286 link->last->link = req;
2287 else
2288 link->head = req;
2289 link->last = req;
2290 return 0;
2291}
2292
2293static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
2294 const struct io_uring_sqe *sqe)
2295 __must_hold(&ctx->uring_lock)
2296{
2297 struct io_submit_link *link = &ctx->submit_state.link;
2298 int ret;
2299
2300 ret = io_init_req(ctx, req, sqe);
2301 if (unlikely(ret))
2302 return io_submit_fail_init(sqe, req, ret);
2303
2304 trace_io_uring_submit_req(req);
2305
2306 /*
2307 * If we already have a head request, queue this one for async
2308 * submittal once the head completes. If we don't have a head but
2309 * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
2310 * submitted sync once the chain is complete. If none of those
2311 * conditions are true (normal request), then just queue it.
2312 */
2313 if (unlikely(link->head)) {
2314 ret = io_req_prep_async(req);
2315 if (unlikely(ret))
2316 return io_submit_fail_init(sqe, req, ret);
2317
2318 trace_io_uring_link(req, link->head);
2319 link->last->link = req;
2320 link->last = req;
2321
2322 if (req->flags & IO_REQ_LINK_FLAGS)
2323 return 0;
2324 /* last request of the link, flush it */
2325 req = link->head;
2326 link->head = NULL;
2327 if (req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL))
2328 goto fallback;
2329
2330 } else if (unlikely(req->flags & (IO_REQ_LINK_FLAGS |
2331 REQ_F_FORCE_ASYNC | REQ_F_FAIL))) {
2332 if (req->flags & IO_REQ_LINK_FLAGS) {
2333 link->head = req;
2334 link->last = req;
2335 } else {
2336fallback:
2337 io_queue_sqe_fallback(req);
2338 }
2339 return 0;
2340 }
2341
2342 io_queue_sqe(req);
2343 return 0;
2344}
2345
2346/*
2347 * Batched submission is done, ensure local IO is flushed out.
2348 */
2349static void io_submit_state_end(struct io_ring_ctx *ctx)
2350{
2351 struct io_submit_state *state = &ctx->submit_state;
2352
2353 if (unlikely(state->link.head))
2354 io_queue_sqe_fallback(state->link.head);
2355 /* flush only after queuing links as they can generate completions */
2356 io_submit_flush_completions(ctx);
2357 if (state->plug_started)
2358 blk_finish_plug(&state->plug);
2359}
2360
2361/*
2362 * Start submission side cache.
2363 */
2364static void io_submit_state_start(struct io_submit_state *state,
2365 unsigned int max_ios)
2366{
2367 state->plug_started = false;
2368 state->need_plug = max_ios > 2;
2369 state->submit_nr = max_ios;
2370 /* set only head, no need to init link_last in advance */
2371 state->link.head = NULL;
2372}
2373
2374static void io_commit_sqring(struct io_ring_ctx *ctx)
2375{
2376 struct io_rings *rings = ctx->rings;
2377
2378 /*
2379 * Ensure any loads from the SQEs are done at this point,
2380 * since once we write the new head, the application could
2381 * write new data to them.
2382 */
2383 smp_store_release(&rings->sq.head, ctx->cached_sq_head);
2384}
2385
2386/*
2387 * Fetch an sqe, if one is available. Note this returns a pointer to memory
2388 * that is mapped by userspace. This means that care needs to be taken to
2389 * ensure that reads are stable, as we cannot rely on userspace always
2390 * being a good citizen. If members of the sqe are validated and then later
2391 * used, it's important that those reads are done through READ_ONCE() to
2392 * prevent a re-load down the line.
2393 */
2394static bool io_get_sqe(struct io_ring_ctx *ctx, const struct io_uring_sqe **sqe)
2395{
2396 unsigned mask = ctx->sq_entries - 1;
2397 unsigned head = ctx->cached_sq_head++ & mask;
2398
2399 if (!(ctx->flags & IORING_SETUP_NO_SQARRAY)) {
2400 head = READ_ONCE(ctx->sq_array[head]);
2401 if (unlikely(head >= ctx->sq_entries)) {
2402 /* drop invalid entries */
2403 spin_lock(&ctx->completion_lock);
2404 ctx->cq_extra--;
2405 spin_unlock(&ctx->completion_lock);
2406 WRITE_ONCE(ctx->rings->sq_dropped,
2407 READ_ONCE(ctx->rings->sq_dropped) + 1);
2408 return false;
2409 }
2410 }
2411
2412 /*
2413 * The cached sq head (or cq tail) serves two purposes:
2414 *
2415 * 1) allows us to batch the cost of updating the user visible
2416 * head updates.
2417 * 2) allows the kernel side to track the head on its own, even
2418 * though the application is the one updating it.
2419 */
2420
2421 /* double index for 128-byte SQEs, twice as long */
2422 if (ctx->flags & IORING_SETUP_SQE128)
2423 head <<= 1;
2424 *sqe = &ctx->sq_sqes[head];
2425 return true;
2426}
2427
2428int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
2429 __must_hold(&ctx->uring_lock)
2430{
2431 unsigned int entries = io_sqring_entries(ctx);
2432 unsigned int left;
2433 int ret;
2434
2435 if (unlikely(!entries))
2436 return 0;
2437 /* make sure SQ entry isn't read before tail */
2438 ret = left = min(nr, entries);
2439 io_get_task_refs(left);
2440 io_submit_state_start(&ctx->submit_state, left);
2441
2442 do {
2443 const struct io_uring_sqe *sqe;
2444 struct io_kiocb *req;
2445
2446 if (unlikely(!io_alloc_req(ctx, &req)))
2447 break;
2448 if (unlikely(!io_get_sqe(ctx, &sqe))) {
2449 io_req_add_to_cache(req, ctx);
2450 break;
2451 }
2452
2453 /*
2454 * Continue submitting even for sqe failure if the
2455 * ring was setup with IORING_SETUP_SUBMIT_ALL
2456 */
2457 if (unlikely(io_submit_sqe(ctx, req, sqe)) &&
2458 !(ctx->flags & IORING_SETUP_SUBMIT_ALL)) {
2459 left--;
2460 break;
2461 }
2462 } while (--left);
2463
2464 if (unlikely(left)) {
2465 ret -= left;
2466 /* try again if it submitted nothing and can't allocate a req */
2467 if (!ret && io_req_cache_empty(ctx))
2468 ret = -EAGAIN;
2469 current->io_uring->cached_refs += left;
2470 }
2471
2472 io_submit_state_end(ctx);
2473 /* Commit SQ ring head once we've consumed and submitted all SQEs */
2474 io_commit_sqring(ctx);
2475 return ret;
2476}
2477
2478struct io_wait_queue {
2479 struct wait_queue_entry wq;
2480 struct io_ring_ctx *ctx;
2481 unsigned cq_tail;
2482 unsigned nr_timeouts;
2483 ktime_t timeout;
2484};
2485
2486static inline bool io_has_work(struct io_ring_ctx *ctx)
2487{
2488 return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) ||
2489 !llist_empty(&ctx->work_llist);
2490}
2491
2492static inline bool io_should_wake(struct io_wait_queue *iowq)
2493{
2494 struct io_ring_ctx *ctx = iowq->ctx;
2495 int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail;
2496
2497 /*
2498 * Wake up if we have enough events, or if a timeout occurred since we
2499 * started waiting. For timeouts, we always want to return to userspace,
2500 * regardless of event count.
2501 */
2502 return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
2503}
2504
2505static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
2506 int wake_flags, void *key)
2507{
2508 struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq);
2509
2510 /*
2511 * Cannot safely flush overflowed CQEs from here, ensure we wake up
2512 * the task, and the next invocation will do it.
2513 */
2514 if (io_should_wake(iowq) || io_has_work(iowq->ctx))
2515 return autoremove_wake_function(curr, mode, wake_flags, key);
2516 return -1;
2517}
2518
2519int io_run_task_work_sig(struct io_ring_ctx *ctx)
2520{
2521 if (!llist_empty(&ctx->work_llist)) {
2522 __set_current_state(TASK_RUNNING);
2523 if (io_run_local_work(ctx) > 0)
2524 return 0;
2525 }
2526 if (io_run_task_work() > 0)
2527 return 0;
2528 if (task_sigpending(current))
2529 return -EINTR;
2530 return 0;
2531}
2532
2533static bool current_pending_io(void)
2534{
2535 struct io_uring_task *tctx = current->io_uring;
2536
2537 if (!tctx)
2538 return false;
2539 return percpu_counter_read_positive(&tctx->inflight);
2540}
2541
2542/* when returns >0, the caller should retry */
2543static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
2544 struct io_wait_queue *iowq)
2545{
2546 int io_wait, ret;
2547
2548 if (unlikely(READ_ONCE(ctx->check_cq)))
2549 return 1;
2550 if (unlikely(!llist_empty(&ctx->work_llist)))
2551 return 1;
2552 if (unlikely(test_thread_flag(TIF_NOTIFY_SIGNAL)))
2553 return 1;
2554 if (unlikely(task_sigpending(current)))
2555 return -EINTR;
2556 if (unlikely(io_should_wake(iowq)))
2557 return 0;
2558
2559 /*
2560 * Mark us as being in io_wait if we have pending requests, so cpufreq
2561 * can take into account that the task is waiting for IO - turns out
2562 * to be important for low QD IO.
2563 */
2564 io_wait = current->in_iowait;
2565 if (current_pending_io())
2566 current->in_iowait = 1;
2567 ret = 0;
2568 if (iowq->timeout == KTIME_MAX)
2569 schedule();
2570 else if (!schedule_hrtimeout(&iowq->timeout, HRTIMER_MODE_ABS))
2571 ret = -ETIME;
2572 current->in_iowait = io_wait;
2573 return ret;
2574}
2575
2576/*
2577 * Wait until events become available, if we don't already have some. The
2578 * application must reap them itself, as they reside on the shared cq ring.
2579 */
2580static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
2581 const sigset_t __user *sig, size_t sigsz,
2582 struct __kernel_timespec __user *uts)
2583{
2584 struct io_wait_queue iowq;
2585 struct io_rings *rings = ctx->rings;
2586 int ret;
2587
2588 if (!io_allowed_run_tw(ctx))
2589 return -EEXIST;
2590 if (!llist_empty(&ctx->work_llist))
2591 io_run_local_work(ctx);
2592 io_run_task_work();
2593 io_cqring_overflow_flush(ctx);
2594 /* if user messes with these they will just get an early return */
2595 if (__io_cqring_events_user(ctx) >= min_events)
2596 return 0;
2597
2598 if (sig) {
2599#ifdef CONFIG_COMPAT
2600 if (in_compat_syscall())
2601 ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
2602 sigsz);
2603 else
2604#endif
2605 ret = set_user_sigmask(sig, sigsz);
2606
2607 if (ret)
2608 return ret;
2609 }
2610
2611 init_waitqueue_func_entry(&iowq.wq, io_wake_function);
2612 iowq.wq.private = current;
2613 INIT_LIST_HEAD(&iowq.wq.entry);
2614 iowq.ctx = ctx;
2615 iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
2616 iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;
2617 iowq.timeout = KTIME_MAX;
2618
2619 if (uts) {
2620 struct timespec64 ts;
2621
2622 if (get_timespec64(&ts, uts))
2623 return -EFAULT;
2624 iowq.timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
2625 }
2626
2627 trace_io_uring_cqring_wait(ctx, min_events);
2628 do {
2629 unsigned long check_cq;
2630
2631 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
2632 int nr_wait = (int) iowq.cq_tail - READ_ONCE(ctx->rings->cq.tail);
2633
2634 atomic_set(&ctx->cq_wait_nr, nr_wait);
2635 set_current_state(TASK_INTERRUPTIBLE);
2636 } else {
2637 prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
2638 TASK_INTERRUPTIBLE);
2639 }
2640
2641 ret = io_cqring_wait_schedule(ctx, &iowq);
2642 __set_current_state(TASK_RUNNING);
2643 atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT);
2644
2645 /*
2646 * Run task_work after scheduling and before io_should_wake().
2647 * If we got woken because of task_work being processed, run it
2648 * now rather than let the caller do another wait loop.
2649 */
2650 io_run_task_work();
2651 if (!llist_empty(&ctx->work_llist))
2652 io_run_local_work(ctx);
2653
2654 /*
2655 * Non-local task_work will be run on exit to userspace, but
2656 * if we're using DEFER_TASKRUN, then we could have waited
2657 * with a timeout for a number of requests. If the timeout
2658 * hits, we could have some requests ready to process. Ensure
2659 * this break is _after_ we have run task_work, to avoid
2660 * deferring running potentially pending requests until the
2661 * next time we wait for events.
2662 */
2663 if (ret < 0)
2664 break;
2665
2666 check_cq = READ_ONCE(ctx->check_cq);
2667 if (unlikely(check_cq)) {
2668 /* let the caller flush overflows, retry */
2669 if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
2670 io_cqring_do_overflow_flush(ctx);
2671 if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)) {
2672 ret = -EBADR;
2673 break;
2674 }
2675 }
2676
2677 if (io_should_wake(&iowq)) {
2678 ret = 0;
2679 break;
2680 }
2681 cond_resched();
2682 } while (1);
2683
2684 if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
2685 finish_wait(&ctx->cq_wait, &iowq.wq);
2686 restore_saved_sigmask_unless(ret == -EINTR);
2687
2688 return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
2689}
2690
2691void io_mem_free(void *ptr)
2692{
2693 if (!ptr)
2694 return;
2695
2696 folio_put(virt_to_folio(ptr));
2697}
2698
2699static void io_pages_free(struct page ***pages, int npages)
2700{
2701 struct page **page_array;
2702 int i;
2703
2704 if (!pages)
2705 return;
2706
2707 page_array = *pages;
2708 if (!page_array)
2709 return;
2710
2711 for (i = 0; i < npages; i++)
2712 unpin_user_page(page_array[i]);
2713 kvfree(page_array);
2714 *pages = NULL;
2715}
2716
2717static void *__io_uaddr_map(struct page ***pages, unsigned short *npages,
2718 unsigned long uaddr, size_t size)
2719{
2720 struct page **page_array;
2721 unsigned int nr_pages;
2722 void *page_addr;
2723 int ret, i;
2724
2725 *npages = 0;
2726
2727 if (uaddr & (PAGE_SIZE - 1) || !size)
2728 return ERR_PTR(-EINVAL);
2729
2730 nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
2731 if (nr_pages > USHRT_MAX)
2732 return ERR_PTR(-EINVAL);
2733 page_array = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
2734 if (!page_array)
2735 return ERR_PTR(-ENOMEM);
2736
2737 ret = pin_user_pages_fast(uaddr, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
2738 page_array);
2739 if (ret != nr_pages) {
2740err:
2741 io_pages_free(&page_array, ret > 0 ? ret : 0);
2742 return ret < 0 ? ERR_PTR(ret) : ERR_PTR(-EFAULT);
2743 }
2744
2745 page_addr = page_address(page_array[0]);
2746 for (i = 0; i < nr_pages; i++) {
2747 ret = -EINVAL;
2748
2749 /*
2750 * Can't support mapping user allocated ring memory on 32-bit
2751 * archs where it could potentially reside in highmem. Just
2752 * fail those with -EINVAL, just like we did on kernels that
2753 * didn't support this feature.
2754 */
2755 if (PageHighMem(page_array[i]))
2756 goto err;
2757
2758 /*
2759 * No support for discontig pages for now, should either be a
2760 * single normal page, or a huge page. Later on we can add
2761 * support for remapping discontig pages, for now we will
2762 * just fail them with EINVAL.
2763 */
2764 if (page_address(page_array[i]) != page_addr)
2765 goto err;
2766 page_addr += PAGE_SIZE;
2767 }
2768
2769 *pages = page_array;
2770 *npages = nr_pages;
2771 return page_to_virt(page_array[0]);
2772}
2773
2774static void *io_rings_map(struct io_ring_ctx *ctx, unsigned long uaddr,
2775 size_t size)
2776{
2777 return __io_uaddr_map(&ctx->ring_pages, &ctx->n_ring_pages, uaddr,
2778 size);
2779}
2780
2781static void *io_sqes_map(struct io_ring_ctx *ctx, unsigned long uaddr,
2782 size_t size)
2783{
2784 return __io_uaddr_map(&ctx->sqe_pages, &ctx->n_sqe_pages, uaddr,
2785 size);
2786}
2787
2788static void io_rings_free(struct io_ring_ctx *ctx)
2789{
2790 if (!(ctx->flags & IORING_SETUP_NO_MMAP)) {
2791 io_mem_free(ctx->rings);
2792 io_mem_free(ctx->sq_sqes);
2793 ctx->rings = NULL;
2794 ctx->sq_sqes = NULL;
2795 } else {
2796 io_pages_free(&ctx->ring_pages, ctx->n_ring_pages);
2797 ctx->n_ring_pages = 0;
2798 io_pages_free(&ctx->sqe_pages, ctx->n_sqe_pages);
2799 ctx->n_sqe_pages = 0;
2800 }
2801}
2802
2803void *io_mem_alloc(size_t size)
2804{
2805 gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
2806 void *ret;
2807
2808 ret = (void *) __get_free_pages(gfp, get_order(size));
2809 if (ret)
2810 return ret;
2811 return ERR_PTR(-ENOMEM);
2812}
2813
2814static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries,
2815 unsigned int cq_entries, size_t *sq_offset)
2816{
2817 struct io_rings *rings;
2818 size_t off, sq_array_size;
2819
2820 off = struct_size(rings, cqes, cq_entries);
2821 if (off == SIZE_MAX)
2822 return SIZE_MAX;
2823 if (ctx->flags & IORING_SETUP_CQE32) {
2824 if (check_shl_overflow(off, 1, &off))
2825 return SIZE_MAX;
2826 }
2827
2828#ifdef CONFIG_SMP
2829 off = ALIGN(off, SMP_CACHE_BYTES);
2830 if (off == 0)
2831 return SIZE_MAX;
2832#endif
2833
2834 if (ctx->flags & IORING_SETUP_NO_SQARRAY) {
2835 if (sq_offset)
2836 *sq_offset = SIZE_MAX;
2837 return off;
2838 }
2839
2840 if (sq_offset)
2841 *sq_offset = off;
2842
2843 sq_array_size = array_size(sizeof(u32), sq_entries);
2844 if (sq_array_size == SIZE_MAX)
2845 return SIZE_MAX;
2846
2847 if (check_add_overflow(off, sq_array_size, &off))
2848 return SIZE_MAX;
2849
2850 return off;
2851}
2852
2853static void io_req_caches_free(struct io_ring_ctx *ctx)
2854{
2855 struct io_kiocb *req;
2856 int nr = 0;
2857
2858 mutex_lock(&ctx->uring_lock);
2859 io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
2860
2861 while (!io_req_cache_empty(ctx)) {
2862 req = io_extract_req(ctx);
2863 kmem_cache_free(req_cachep, req);
2864 nr++;
2865 }
2866 if (nr)
2867 percpu_ref_put_many(&ctx->refs, nr);
2868 mutex_unlock(&ctx->uring_lock);
2869}
2870
2871static void io_rsrc_node_cache_free(struct io_cache_entry *entry)
2872{
2873 kfree(container_of(entry, struct io_rsrc_node, cache));
2874}
2875
2876static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
2877{
2878 io_sq_thread_finish(ctx);
2879 /* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */
2880 if (WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list)))
2881 return;
2882
2883 mutex_lock(&ctx->uring_lock);
2884 if (ctx->buf_data)
2885 __io_sqe_buffers_unregister(ctx);
2886 if (ctx->file_data)
2887 __io_sqe_files_unregister(ctx);
2888 io_cqring_overflow_kill(ctx);
2889 io_eventfd_unregister(ctx);
2890 io_alloc_cache_free(&ctx->apoll_cache, io_apoll_cache_free);
2891 io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free);
2892 io_futex_cache_free(ctx);
2893 io_destroy_buffers(ctx);
2894 mutex_unlock(&ctx->uring_lock);
2895 if (ctx->sq_creds)
2896 put_cred(ctx->sq_creds);
2897 if (ctx->submitter_task)
2898 put_task_struct(ctx->submitter_task);
2899
2900 /* there are no registered resources left, nobody uses it */
2901 if (ctx->rsrc_node)
2902 io_rsrc_node_destroy(ctx, ctx->rsrc_node);
2903
2904 WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list));
2905 WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list));
2906
2907 io_alloc_cache_free(&ctx->rsrc_node_cache, io_rsrc_node_cache_free);
2908 if (ctx->mm_account) {
2909 mmdrop(ctx->mm_account);
2910 ctx->mm_account = NULL;
2911 }
2912 io_rings_free(ctx);
2913 io_kbuf_mmap_list_free(ctx);
2914
2915 percpu_ref_exit(&ctx->refs);
2916 free_uid(ctx->user);
2917 io_req_caches_free(ctx);
2918 if (ctx->hash_map)
2919 io_wq_put_hash(ctx->hash_map);
2920 kfree(ctx->cancel_table.hbs);
2921 kfree(ctx->cancel_table_locked.hbs);
2922 kfree(ctx->io_bl);
2923 xa_destroy(&ctx->io_bl_xa);
2924 kfree(ctx);
2925}
2926
2927static __cold void io_activate_pollwq_cb(struct callback_head *cb)
2928{
2929 struct io_ring_ctx *ctx = container_of(cb, struct io_ring_ctx,
2930 poll_wq_task_work);
2931
2932 mutex_lock(&ctx->uring_lock);
2933 ctx->poll_activated = true;
2934 mutex_unlock(&ctx->uring_lock);
2935
2936 /*
2937 * Wake ups for some events between start of polling and activation
2938 * might've been lost due to loose synchronisation.
2939 */
2940 wake_up_all(&ctx->poll_wq);
2941 percpu_ref_put(&ctx->refs);
2942}
2943
2944__cold void io_activate_pollwq(struct io_ring_ctx *ctx)
2945{
2946 spin_lock(&ctx->completion_lock);
2947 /* already activated or in progress */
2948 if (ctx->poll_activated || ctx->poll_wq_task_work.func)
2949 goto out;
2950 if (WARN_ON_ONCE(!ctx->task_complete))
2951 goto out;
2952 if (!ctx->submitter_task)
2953 goto out;
2954 /*
2955 * with ->submitter_task only the submitter task completes requests, we
2956 * only need to sync with it, which is done by injecting a tw
2957 */
2958 init_task_work(&ctx->poll_wq_task_work, io_activate_pollwq_cb);
2959 percpu_ref_get(&ctx->refs);
2960 if (task_work_add(ctx->submitter_task, &ctx->poll_wq_task_work, TWA_SIGNAL))
2961 percpu_ref_put(&ctx->refs);
2962out:
2963 spin_unlock(&ctx->completion_lock);
2964}
2965
2966static __poll_t io_uring_poll(struct file *file, poll_table *wait)
2967{
2968 struct io_ring_ctx *ctx = file->private_data;
2969 __poll_t mask = 0;
2970
2971 if (unlikely(!ctx->poll_activated))
2972 io_activate_pollwq(ctx);
2973
2974 poll_wait(file, &ctx->poll_wq, wait);
2975 /*
2976 * synchronizes with barrier from wq_has_sleeper call in
2977 * io_commit_cqring
2978 */
2979 smp_rmb();
2980 if (!io_sqring_full(ctx))
2981 mask |= EPOLLOUT | EPOLLWRNORM;
2982
2983 /*
2984 * Don't flush cqring overflow list here, just do a simple check.
2985 * Otherwise there could possible be ABBA deadlock:
2986 * CPU0 CPU1
2987 * ---- ----
2988 * lock(&ctx->uring_lock);
2989 * lock(&ep->mtx);
2990 * lock(&ctx->uring_lock);
2991 * lock(&ep->mtx);
2992 *
2993 * Users may get EPOLLIN meanwhile seeing nothing in cqring, this
2994 * pushes them to do the flush.
2995 */
2996
2997 if (__io_cqring_events_user(ctx) || io_has_work(ctx))
2998 mask |= EPOLLIN | EPOLLRDNORM;
2999
3000 return mask;
3001}
3002
3003struct io_tctx_exit {
3004 struct callback_head task_work;
3005 struct completion completion;
3006 struct io_ring_ctx *ctx;
3007};
3008
3009static __cold void io_tctx_exit_cb(struct callback_head *cb)
3010{
3011 struct io_uring_task *tctx = current->io_uring;
3012 struct io_tctx_exit *work;
3013
3014 work = container_of(cb, struct io_tctx_exit, task_work);
3015 /*
3016 * When @in_cancel, we're in cancellation and it's racy to remove the
3017 * node. It'll be removed by the end of cancellation, just ignore it.
3018 * tctx can be NULL if the queueing of this task_work raced with
3019 * work cancelation off the exec path.
3020 */
3021 if (tctx && !atomic_read(&tctx->in_cancel))
3022 io_uring_del_tctx_node((unsigned long)work->ctx);
3023 complete(&work->completion);
3024}
3025
3026static __cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)
3027{
3028 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
3029
3030 return req->ctx == data;
3031}
3032
3033static __cold void io_ring_exit_work(struct work_struct *work)
3034{
3035 struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work);
3036 unsigned long timeout = jiffies + HZ * 60 * 5;
3037 unsigned long interval = HZ / 20;
3038 struct io_tctx_exit exit;
3039 struct io_tctx_node *node;
3040 int ret;
3041
3042 /*
3043 * If we're doing polled IO and end up having requests being
3044 * submitted async (out-of-line), then completions can come in while
3045 * we're waiting for refs to drop. We need to reap these manually,
3046 * as nobody else will be looking for them.
3047 */
3048 do {
3049 if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) {
3050 mutex_lock(&ctx->uring_lock);
3051 io_cqring_overflow_kill(ctx);
3052 mutex_unlock(&ctx->uring_lock);
3053 }
3054
3055 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
3056 io_move_task_work_from_local(ctx);
3057
3058 while (io_uring_try_cancel_requests(ctx, NULL, true))
3059 cond_resched();
3060
3061 if (ctx->sq_data) {
3062 struct io_sq_data *sqd = ctx->sq_data;
3063 struct task_struct *tsk;
3064
3065 io_sq_thread_park(sqd);
3066 tsk = sqd->thread;
3067 if (tsk && tsk->io_uring && tsk->io_uring->io_wq)
3068 io_wq_cancel_cb(tsk->io_uring->io_wq,
3069 io_cancel_ctx_cb, ctx, true);
3070 io_sq_thread_unpark(sqd);
3071 }
3072
3073 io_req_caches_free(ctx);
3074
3075 if (WARN_ON_ONCE(time_after(jiffies, timeout))) {
3076 /* there is little hope left, don't run it too often */
3077 interval = HZ * 60;
3078 }
3079 /*
3080 * This is really an uninterruptible wait, as it has to be
3081 * complete. But it's also run from a kworker, which doesn't
3082 * take signals, so it's fine to make it interruptible. This
3083 * avoids scenarios where we knowingly can wait much longer
3084 * on completions, for example if someone does a SIGSTOP on
3085 * a task that needs to finish task_work to make this loop
3086 * complete. That's a synthetic situation that should not
3087 * cause a stuck task backtrace, and hence a potential panic
3088 * on stuck tasks if that is enabled.
3089 */
3090 } while (!wait_for_completion_interruptible_timeout(&ctx->ref_comp, interval));
3091
3092 init_completion(&exit.completion);
3093 init_task_work(&exit.task_work, io_tctx_exit_cb);
3094 exit.ctx = ctx;
3095
3096 mutex_lock(&ctx->uring_lock);
3097 while (!list_empty(&ctx->tctx_list)) {
3098 WARN_ON_ONCE(time_after(jiffies, timeout));
3099
3100 node = list_first_entry(&ctx->tctx_list, struct io_tctx_node,
3101 ctx_node);
3102 /* don't spin on a single task if cancellation failed */
3103 list_rotate_left(&ctx->tctx_list);
3104 ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL);
3105 if (WARN_ON_ONCE(ret))
3106 continue;
3107
3108 mutex_unlock(&ctx->uring_lock);
3109 /*
3110 * See comment above for
3111 * wait_for_completion_interruptible_timeout() on why this
3112 * wait is marked as interruptible.
3113 */
3114 wait_for_completion_interruptible(&exit.completion);
3115 mutex_lock(&ctx->uring_lock);
3116 }
3117 mutex_unlock(&ctx->uring_lock);
3118 spin_lock(&ctx->completion_lock);
3119 spin_unlock(&ctx->completion_lock);
3120
3121 /* pairs with RCU read section in io_req_local_work_add() */
3122 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
3123 synchronize_rcu();
3124
3125 io_ring_ctx_free(ctx);
3126}
3127
3128static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
3129{
3130 unsigned long index;
3131 struct creds *creds;
3132
3133 mutex_lock(&ctx->uring_lock);
3134 percpu_ref_kill(&ctx->refs);
3135 xa_for_each(&ctx->personalities, index, creds)
3136 io_unregister_personality(ctx, index);
3137 if (ctx->rings)
3138 io_poll_remove_all(ctx, NULL, true);
3139 mutex_unlock(&ctx->uring_lock);
3140
3141 /*
3142 * If we failed setting up the ctx, we might not have any rings
3143 * and therefore did not submit any requests
3144 */
3145 if (ctx->rings)
3146 io_kill_timeouts(ctx, NULL, true);
3147
3148 flush_delayed_work(&ctx->fallback_work);
3149
3150 INIT_WORK(&ctx->exit_work, io_ring_exit_work);
3151 /*
3152 * Use system_unbound_wq to avoid spawning tons of event kworkers
3153 * if we're exiting a ton of rings at the same time. It just adds
3154 * noise and overhead, there's no discernable change in runtime
3155 * over using system_wq.
3156 */
3157 queue_work(system_unbound_wq, &ctx->exit_work);
3158}
3159
3160static int io_uring_release(struct inode *inode, struct file *file)
3161{
3162 struct io_ring_ctx *ctx = file->private_data;
3163
3164 file->private_data = NULL;
3165 io_ring_ctx_wait_and_kill(ctx);
3166 return 0;
3167}
3168
3169struct io_task_cancel {
3170 struct task_struct *task;
3171 bool all;
3172};
3173
3174static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
3175{
3176 struct io_kiocb *req = container_of(work, struct io_kiocb, work);
3177 struct io_task_cancel *cancel = data;
3178
3179 return io_match_task_safe(req, cancel->task, cancel->all);
3180}
3181
3182static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,
3183 struct task_struct *task,
3184 bool cancel_all)
3185{
3186 struct io_defer_entry *de;
3187 LIST_HEAD(list);
3188
3189 spin_lock(&ctx->completion_lock);
3190 list_for_each_entry_reverse(de, &ctx->defer_list, list) {
3191 if (io_match_task_safe(de->req, task, cancel_all)) {
3192 list_cut_position(&list, &ctx->defer_list, &de->list);
3193 break;
3194 }
3195 }
3196 spin_unlock(&ctx->completion_lock);
3197 if (list_empty(&list))
3198 return false;
3199
3200 while (!list_empty(&list)) {
3201 de = list_first_entry(&list, struct io_defer_entry, list);
3202 list_del_init(&de->list);
3203 io_req_task_queue_fail(de->req, -ECANCELED);
3204 kfree(de);
3205 }
3206 return true;
3207}
3208
3209static __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx)
3210{
3211 struct io_tctx_node *node;
3212 enum io_wq_cancel cret;
3213 bool ret = false;
3214
3215 mutex_lock(&ctx->uring_lock);
3216 list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
3217 struct io_uring_task *tctx = node->task->io_uring;
3218
3219 /*
3220 * io_wq will stay alive while we hold uring_lock, because it's
3221 * killed after ctx nodes, which requires to take the lock.
3222 */
3223 if (!tctx || !tctx->io_wq)
3224 continue;
3225 cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true);
3226 ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
3227 }
3228 mutex_unlock(&ctx->uring_lock);
3229
3230 return ret;
3231}
3232
3233static bool io_uring_try_cancel_uring_cmd(struct io_ring_ctx *ctx,
3234 struct task_struct *task, bool cancel_all)
3235{
3236 struct hlist_node *tmp;
3237 struct io_kiocb *req;
3238 bool ret = false;
3239
3240 lockdep_assert_held(&ctx->uring_lock);
3241
3242 hlist_for_each_entry_safe(req, tmp, &ctx->cancelable_uring_cmd,
3243 hash_node) {
3244 struct io_uring_cmd *cmd = io_kiocb_to_cmd(req,
3245 struct io_uring_cmd);
3246 struct file *file = req->file;
3247
3248 if (!cancel_all && req->task != task)
3249 continue;
3250
3251 if (cmd->flags & IORING_URING_CMD_CANCELABLE) {
3252 /* ->sqe isn't available if no async data */
3253 if (!req_has_async_data(req))
3254 cmd->sqe = NULL;
3255 file->f_op->uring_cmd(cmd, IO_URING_F_CANCEL);
3256 ret = true;
3257 }
3258 }
3259 io_submit_flush_completions(ctx);
3260
3261 return ret;
3262}
3263
3264static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
3265 struct task_struct *task,
3266 bool cancel_all)
3267{
3268 struct io_task_cancel cancel = { .task = task, .all = cancel_all, };
3269 struct io_uring_task *tctx = task ? task->io_uring : NULL;
3270 enum io_wq_cancel cret;
3271 bool ret = false;
3272
3273 /* set it so io_req_local_work_add() would wake us up */
3274 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
3275 atomic_set(&ctx->cq_wait_nr, 1);
3276 smp_mb();
3277 }
3278
3279 /* failed during ring init, it couldn't have issued any requests */
3280 if (!ctx->rings)
3281 return false;
3282
3283 if (!task) {
3284 ret |= io_uring_try_cancel_iowq(ctx);
3285 } else if (tctx && tctx->io_wq) {
3286 /*
3287 * Cancels requests of all rings, not only @ctx, but
3288 * it's fine as the task is in exit/exec.
3289 */
3290 cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb,
3291 &cancel, true);
3292 ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
3293 }
3294
3295 /* SQPOLL thread does its own polling */
3296 if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) ||
3297 (ctx->sq_data && ctx->sq_data->thread == current)) {
3298 while (!wq_list_empty(&ctx->iopoll_list)) {
3299 io_iopoll_try_reap_events(ctx);
3300 ret = true;
3301 cond_resched();
3302 }
3303 }
3304
3305 if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
3306 io_allowed_defer_tw_run(ctx))
3307 ret |= io_run_local_work(ctx) > 0;
3308 ret |= io_cancel_defer_files(ctx, task, cancel_all);
3309 mutex_lock(&ctx->uring_lock);
3310 ret |= io_poll_remove_all(ctx, task, cancel_all);
3311 ret |= io_waitid_remove_all(ctx, task, cancel_all);
3312 ret |= io_futex_remove_all(ctx, task, cancel_all);
3313 ret |= io_uring_try_cancel_uring_cmd(ctx, task, cancel_all);
3314 mutex_unlock(&ctx->uring_lock);
3315 ret |= io_kill_timeouts(ctx, task, cancel_all);
3316 if (task)
3317 ret |= io_run_task_work() > 0;
3318 return ret;
3319}
3320
3321static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)
3322{
3323 if (tracked)
3324 return atomic_read(&tctx->inflight_tracked);
3325 return percpu_counter_sum(&tctx->inflight);
3326}
3327
3328/*
3329 * Find any io_uring ctx that this task has registered or done IO on, and cancel
3330 * requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation.
3331 */
3332__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd)
3333{
3334 struct io_uring_task *tctx = current->io_uring;
3335 struct io_ring_ctx *ctx;
3336 struct io_tctx_node *node;
3337 unsigned long index;
3338 s64 inflight;
3339 DEFINE_WAIT(wait);
3340
3341 WARN_ON_ONCE(sqd && sqd->thread != current);
3342
3343 if (!current->io_uring)
3344 return;
3345 if (tctx->io_wq)
3346 io_wq_exit_start(tctx->io_wq);
3347
3348 atomic_inc(&tctx->in_cancel);
3349 do {
3350 bool loop = false;
3351
3352 io_uring_drop_tctx_refs(current);
3353 /* read completions before cancelations */
3354 inflight = tctx_inflight(tctx, !cancel_all);
3355 if (!inflight)
3356 break;
3357
3358 if (!sqd) {
3359 xa_for_each(&tctx->xa, index, node) {
3360 /* sqpoll task will cancel all its requests */
3361 if (node->ctx->sq_data)
3362 continue;
3363 loop |= io_uring_try_cancel_requests(node->ctx,
3364 current, cancel_all);
3365 }
3366 } else {
3367 list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
3368 loop |= io_uring_try_cancel_requests(ctx,
3369 current,
3370 cancel_all);
3371 }
3372
3373 if (loop) {
3374 cond_resched();
3375 continue;
3376 }
3377
3378 prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE);
3379 io_run_task_work();
3380 io_uring_drop_tctx_refs(current);
3381 xa_for_each(&tctx->xa, index, node) {
3382 if (!llist_empty(&node->ctx->work_llist)) {
3383 WARN_ON_ONCE(node->ctx->submitter_task &&
3384 node->ctx->submitter_task != current);
3385 goto end_wait;
3386 }
3387 }
3388 /*
3389 * If we've seen completions, retry without waiting. This
3390 * avoids a race where a completion comes in before we did
3391 * prepare_to_wait().
3392 */
3393 if (inflight == tctx_inflight(tctx, !cancel_all))
3394 schedule();
3395end_wait:
3396 finish_wait(&tctx->wait, &wait);
3397 } while (1);
3398
3399 io_uring_clean_tctx(tctx);
3400 if (cancel_all) {
3401 /*
3402 * We shouldn't run task_works after cancel, so just leave
3403 * ->in_cancel set for normal exit.
3404 */
3405 atomic_dec(&tctx->in_cancel);
3406 /* for exec all current's requests should be gone, kill tctx */
3407 __io_uring_free(current);
3408 }
3409}
3410
3411void __io_uring_cancel(bool cancel_all)
3412{
3413 io_uring_cancel_generic(cancel_all, NULL);
3414}
3415
3416static void *io_uring_validate_mmap_request(struct file *file,
3417 loff_t pgoff, size_t sz)
3418{
3419 struct io_ring_ctx *ctx = file->private_data;
3420 loff_t offset = pgoff << PAGE_SHIFT;
3421 struct page *page;
3422 void *ptr;
3423
3424 switch (offset & IORING_OFF_MMAP_MASK) {
3425 case IORING_OFF_SQ_RING:
3426 case IORING_OFF_CQ_RING:
3427 /* Don't allow mmap if the ring was setup without it */
3428 if (ctx->flags & IORING_SETUP_NO_MMAP)
3429 return ERR_PTR(-EINVAL);
3430 ptr = ctx->rings;
3431 break;
3432 case IORING_OFF_SQES:
3433 /* Don't allow mmap if the ring was setup without it */
3434 if (ctx->flags & IORING_SETUP_NO_MMAP)
3435 return ERR_PTR(-EINVAL);
3436 ptr = ctx->sq_sqes;
3437 break;
3438 case IORING_OFF_PBUF_RING: {
3439 unsigned int bgid;
3440
3441 bgid = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
3442 rcu_read_lock();
3443 ptr = io_pbuf_get_address(ctx, bgid);
3444 rcu_read_unlock();
3445 if (!ptr)
3446 return ERR_PTR(-EINVAL);
3447 break;
3448 }
3449 default:
3450 return ERR_PTR(-EINVAL);
3451 }
3452
3453 page = virt_to_head_page(ptr);
3454 if (sz > page_size(page))
3455 return ERR_PTR(-EINVAL);
3456
3457 return ptr;
3458}
3459
3460#ifdef CONFIG_MMU
3461
3462static __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
3463{
3464 size_t sz = vma->vm_end - vma->vm_start;
3465 unsigned long pfn;
3466 void *ptr;
3467
3468 ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
3469 if (IS_ERR(ptr))
3470 return PTR_ERR(ptr);
3471
3472 pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
3473 return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
3474}
3475
3476static unsigned long io_uring_mmu_get_unmapped_area(struct file *filp,
3477 unsigned long addr, unsigned long len,
3478 unsigned long pgoff, unsigned long flags)
3479{
3480 void *ptr;
3481
3482 /*
3483 * Do not allow to map to user-provided address to avoid breaking the
3484 * aliasing rules. Userspace is not able to guess the offset address of
3485 * kernel kmalloc()ed memory area.
3486 */
3487 if (addr)
3488 return -EINVAL;
3489
3490 ptr = io_uring_validate_mmap_request(filp, pgoff, len);
3491 if (IS_ERR(ptr))
3492 return -ENOMEM;
3493
3494 /*
3495 * Some architectures have strong cache aliasing requirements.
3496 * For such architectures we need a coherent mapping which aliases
3497 * kernel memory *and* userspace memory. To achieve that:
3498 * - use a NULL file pointer to reference physical memory, and
3499 * - use the kernel virtual address of the shared io_uring context
3500 * (instead of the userspace-provided address, which has to be 0UL
3501 * anyway).
3502 * - use the same pgoff which the get_unmapped_area() uses to
3503 * calculate the page colouring.
3504 * For architectures without such aliasing requirements, the
3505 * architecture will return any suitable mapping because addr is 0.
3506 */
3507 filp = NULL;
3508 flags |= MAP_SHARED;
3509 pgoff = 0; /* has been translated to ptr above */
3510#ifdef SHM_COLOUR
3511 addr = (uintptr_t) ptr;
3512 pgoff = addr >> PAGE_SHIFT;
3513#else
3514 addr = 0UL;
3515#endif
3516 return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
3517}
3518
3519#else /* !CONFIG_MMU */
3520
3521static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
3522{
3523 return is_nommu_shared_mapping(vma->vm_flags) ? 0 : -EINVAL;
3524}
3525
3526static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
3527{
3528 return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
3529}
3530
3531static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
3532 unsigned long addr, unsigned long len,
3533 unsigned long pgoff, unsigned long flags)
3534{
3535 void *ptr;
3536
3537 ptr = io_uring_validate_mmap_request(file, pgoff, len);
3538 if (IS_ERR(ptr))
3539 return PTR_ERR(ptr);
3540
3541 return (unsigned long) ptr;
3542}
3543
3544#endif /* !CONFIG_MMU */
3545
3546static int io_validate_ext_arg(unsigned flags, const void __user *argp, size_t argsz)
3547{
3548 if (flags & IORING_ENTER_EXT_ARG) {
3549 struct io_uring_getevents_arg arg;
3550
3551 if (argsz != sizeof(arg))
3552 return -EINVAL;
3553 if (copy_from_user(&arg, argp, sizeof(arg)))
3554 return -EFAULT;
3555 }
3556 return 0;
3557}
3558
3559static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz,
3560 struct __kernel_timespec __user **ts,
3561 const sigset_t __user **sig)
3562{
3563 struct io_uring_getevents_arg arg;
3564
3565 /*
3566 * If EXT_ARG isn't set, then we have no timespec and the argp pointer
3567 * is just a pointer to the sigset_t.
3568 */
3569 if (!(flags & IORING_ENTER_EXT_ARG)) {
3570 *sig = (const sigset_t __user *) argp;
3571 *ts = NULL;
3572 return 0;
3573 }
3574
3575 /*
3576 * EXT_ARG is set - ensure we agree on the size of it and copy in our
3577 * timespec and sigset_t pointers if good.
3578 */
3579 if (*argsz != sizeof(arg))
3580 return -EINVAL;
3581 if (copy_from_user(&arg, argp, sizeof(arg)))
3582 return -EFAULT;
3583 if (arg.pad)
3584 return -EINVAL;
3585 *sig = u64_to_user_ptr(arg.sigmask);
3586 *argsz = arg.sigmask_sz;
3587 *ts = u64_to_user_ptr(arg.ts);
3588 return 0;
3589}
3590
3591SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
3592 u32, min_complete, u32, flags, const void __user *, argp,
3593 size_t, argsz)
3594{
3595 struct io_ring_ctx *ctx;
3596 struct file *file;
3597 long ret;
3598
3599 if (unlikely(flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP |
3600 IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG |
3601 IORING_ENTER_REGISTERED_RING)))
3602 return -EINVAL;
3603
3604 /*
3605 * Ring fd has been registered via IORING_REGISTER_RING_FDS, we
3606 * need only dereference our task private array to find it.
3607 */
3608 if (flags & IORING_ENTER_REGISTERED_RING) {
3609 struct io_uring_task *tctx = current->io_uring;
3610
3611 if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX))
3612 return -EINVAL;
3613 fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
3614 file = tctx->registered_rings[fd];
3615 if (unlikely(!file))
3616 return -EBADF;
3617 } else {
3618 file = fget(fd);
3619 if (unlikely(!file))
3620 return -EBADF;
3621 ret = -EOPNOTSUPP;
3622 if (unlikely(!io_is_uring_fops(file)))
3623 goto out;
3624 }
3625
3626 ctx = file->private_data;
3627 ret = -EBADFD;
3628 if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED))
3629 goto out;
3630
3631 /*
3632 * For SQ polling, the thread will do all submissions and completions.
3633 * Just return the requested submit count, and wake the thread if
3634 * we were asked to.
3635 */
3636 ret = 0;
3637 if (ctx->flags & IORING_SETUP_SQPOLL) {
3638 io_cqring_overflow_flush(ctx);
3639
3640 if (unlikely(ctx->sq_data->thread == NULL)) {
3641 ret = -EOWNERDEAD;
3642 goto out;
3643 }
3644 if (flags & IORING_ENTER_SQ_WAKEUP)
3645 wake_up(&ctx->sq_data->wait);
3646 if (flags & IORING_ENTER_SQ_WAIT)
3647 io_sqpoll_wait_sq(ctx);
3648
3649 ret = to_submit;
3650 } else if (to_submit) {
3651 ret = io_uring_add_tctx_node(ctx);
3652 if (unlikely(ret))
3653 goto out;
3654
3655 mutex_lock(&ctx->uring_lock);
3656 ret = io_submit_sqes(ctx, to_submit);
3657 if (ret != to_submit) {
3658 mutex_unlock(&ctx->uring_lock);
3659 goto out;
3660 }
3661 if (flags & IORING_ENTER_GETEVENTS) {
3662 if (ctx->syscall_iopoll)
3663 goto iopoll_locked;
3664 /*
3665 * Ignore errors, we'll soon call io_cqring_wait() and
3666 * it should handle ownership problems if any.
3667 */
3668 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
3669 (void)io_run_local_work_locked(ctx);
3670 }
3671 mutex_unlock(&ctx->uring_lock);
3672 }
3673
3674 if (flags & IORING_ENTER_GETEVENTS) {
3675 int ret2;
3676
3677 if (ctx->syscall_iopoll) {
3678 /*
3679 * We disallow the app entering submit/complete with
3680 * polling, but we still need to lock the ring to
3681 * prevent racing with polled issue that got punted to
3682 * a workqueue.
3683 */
3684 mutex_lock(&ctx->uring_lock);
3685iopoll_locked:
3686 ret2 = io_validate_ext_arg(flags, argp, argsz);
3687 if (likely(!ret2)) {
3688 min_complete = min(min_complete,
3689 ctx->cq_entries);
3690 ret2 = io_iopoll_check(ctx, min_complete);
3691 }
3692 mutex_unlock(&ctx->uring_lock);
3693 } else {
3694 const sigset_t __user *sig;
3695 struct __kernel_timespec __user *ts;
3696
3697 ret2 = io_get_ext_arg(flags, argp, &argsz, &ts, &sig);
3698 if (likely(!ret2)) {
3699 min_complete = min(min_complete,
3700 ctx->cq_entries);
3701 ret2 = io_cqring_wait(ctx, min_complete, sig,
3702 argsz, ts);
3703 }
3704 }
3705
3706 if (!ret) {
3707 ret = ret2;
3708
3709 /*
3710 * EBADR indicates that one or more CQE were dropped.
3711 * Once the user has been informed we can clear the bit
3712 * as they are obviously ok with those drops.
3713 */
3714 if (unlikely(ret2 == -EBADR))
3715 clear_bit(IO_CHECK_CQ_DROPPED_BIT,
3716 &ctx->check_cq);
3717 }
3718 }
3719out:
3720 if (!(flags & IORING_ENTER_REGISTERED_RING))
3721 fput(file);
3722 return ret;
3723}
3724
3725static const struct file_operations io_uring_fops = {
3726 .release = io_uring_release,
3727 .mmap = io_uring_mmap,
3728#ifndef CONFIG_MMU
3729 .get_unmapped_area = io_uring_nommu_get_unmapped_area,
3730 .mmap_capabilities = io_uring_nommu_mmap_capabilities,
3731#else
3732 .get_unmapped_area = io_uring_mmu_get_unmapped_area,
3733#endif
3734 .poll = io_uring_poll,
3735#ifdef CONFIG_PROC_FS
3736 .show_fdinfo = io_uring_show_fdinfo,
3737#endif
3738};
3739
3740bool io_is_uring_fops(struct file *file)
3741{
3742 return file->f_op == &io_uring_fops;
3743}
3744
3745static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
3746 struct io_uring_params *p)
3747{
3748 struct io_rings *rings;
3749 size_t size, sq_array_offset;
3750 void *ptr;
3751
3752 /* make sure these are sane, as we already accounted them */
3753 ctx->sq_entries = p->sq_entries;
3754 ctx->cq_entries = p->cq_entries;
3755
3756 size = rings_size(ctx, p->sq_entries, p->cq_entries, &sq_array_offset);
3757 if (size == SIZE_MAX)
3758 return -EOVERFLOW;
3759
3760 if (!(ctx->flags & IORING_SETUP_NO_MMAP))
3761 rings = io_mem_alloc(size);
3762 else
3763 rings = io_rings_map(ctx, p->cq_off.user_addr, size);
3764
3765 if (IS_ERR(rings))
3766 return PTR_ERR(rings);
3767
3768 ctx->rings = rings;
3769 if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
3770 ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
3771 rings->sq_ring_mask = p->sq_entries - 1;
3772 rings->cq_ring_mask = p->cq_entries - 1;
3773 rings->sq_ring_entries = p->sq_entries;
3774 rings->cq_ring_entries = p->cq_entries;
3775
3776 if (p->flags & IORING_SETUP_SQE128)
3777 size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries);
3778 else
3779 size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
3780 if (size == SIZE_MAX) {
3781 io_rings_free(ctx);
3782 return -EOVERFLOW;
3783 }
3784
3785 if (!(ctx->flags & IORING_SETUP_NO_MMAP))
3786 ptr = io_mem_alloc(size);
3787 else
3788 ptr = io_sqes_map(ctx, p->sq_off.user_addr, size);
3789
3790 if (IS_ERR(ptr)) {
3791 io_rings_free(ctx);
3792 return PTR_ERR(ptr);
3793 }
3794
3795 ctx->sq_sqes = ptr;
3796 return 0;
3797}
3798
3799static int io_uring_install_fd(struct file *file)
3800{
3801 int fd;
3802
3803 fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
3804 if (fd < 0)
3805 return fd;
3806 fd_install(fd, file);
3807 return fd;
3808}
3809
3810/*
3811 * Allocate an anonymous fd, this is what constitutes the application
3812 * visible backing of an io_uring instance. The application mmaps this
3813 * fd to gain access to the SQ/CQ ring details.
3814 */
3815static struct file *io_uring_get_file(struct io_ring_ctx *ctx)
3816{
3817 /* Create a new inode so that the LSM can block the creation. */
3818 return anon_inode_create_getfile("[io_uring]", &io_uring_fops, ctx,
3819 O_RDWR | O_CLOEXEC, NULL);
3820}
3821
3822static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
3823 struct io_uring_params __user *params)
3824{
3825 struct io_ring_ctx *ctx;
3826 struct io_uring_task *tctx;
3827 struct file *file;
3828 int ret;
3829
3830 if (!entries)
3831 return -EINVAL;
3832 if (entries > IORING_MAX_ENTRIES) {
3833 if (!(p->flags & IORING_SETUP_CLAMP))
3834 return -EINVAL;
3835 entries = IORING_MAX_ENTRIES;
3836 }
3837
3838 if ((p->flags & IORING_SETUP_REGISTERED_FD_ONLY)
3839 && !(p->flags & IORING_SETUP_NO_MMAP))
3840 return -EINVAL;
3841
3842 /*
3843 * Use twice as many entries for the CQ ring. It's possible for the
3844 * application to drive a higher depth than the size of the SQ ring,
3845 * since the sqes are only used at submission time. This allows for
3846 * some flexibility in overcommitting a bit. If the application has
3847 * set IORING_SETUP_CQSIZE, it will have passed in the desired number
3848 * of CQ ring entries manually.
3849 */
3850 p->sq_entries = roundup_pow_of_two(entries);
3851 if (p->flags & IORING_SETUP_CQSIZE) {
3852 /*
3853 * If IORING_SETUP_CQSIZE is set, we do the same roundup
3854 * to a power-of-two, if it isn't already. We do NOT impose
3855 * any cq vs sq ring sizing.
3856 */
3857 if (!p->cq_entries)
3858 return -EINVAL;
3859 if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
3860 if (!(p->flags & IORING_SETUP_CLAMP))
3861 return -EINVAL;
3862 p->cq_entries = IORING_MAX_CQ_ENTRIES;
3863 }
3864 p->cq_entries = roundup_pow_of_two(p->cq_entries);
3865 if (p->cq_entries < p->sq_entries)
3866 return -EINVAL;
3867 } else {
3868 p->cq_entries = 2 * p->sq_entries;
3869 }
3870
3871 ctx = io_ring_ctx_alloc(p);
3872 if (!ctx)
3873 return -ENOMEM;
3874
3875 if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
3876 !(ctx->flags & IORING_SETUP_IOPOLL) &&
3877 !(ctx->flags & IORING_SETUP_SQPOLL))
3878 ctx->task_complete = true;
3879
3880 if (ctx->task_complete || (ctx->flags & IORING_SETUP_IOPOLL))
3881 ctx->lockless_cq = true;
3882
3883 /*
3884 * lazy poll_wq activation relies on ->task_complete for synchronisation
3885 * purposes, see io_activate_pollwq()
3886 */
3887 if (!ctx->task_complete)
3888 ctx->poll_activated = true;
3889
3890 /*
3891 * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
3892 * space applications don't need to do io completion events
3893 * polling again, they can rely on io_sq_thread to do polling
3894 * work, which can reduce cpu usage and uring_lock contention.
3895 */
3896 if (ctx->flags & IORING_SETUP_IOPOLL &&
3897 !(ctx->flags & IORING_SETUP_SQPOLL))
3898 ctx->syscall_iopoll = 1;
3899
3900 ctx->compat = in_compat_syscall();
3901 if (!ns_capable_noaudit(&init_user_ns, CAP_IPC_LOCK))
3902 ctx->user = get_uid(current_user());
3903
3904 /*
3905 * For SQPOLL, we just need a wakeup, always. For !SQPOLL, if
3906 * COOP_TASKRUN is set, then IPIs are never needed by the app.
3907 */
3908 ret = -EINVAL;
3909 if (ctx->flags & IORING_SETUP_SQPOLL) {
3910 /* IPI related flags don't make sense with SQPOLL */
3911 if (ctx->flags & (IORING_SETUP_COOP_TASKRUN |
3912 IORING_SETUP_TASKRUN_FLAG |
3913 IORING_SETUP_DEFER_TASKRUN))
3914 goto err;
3915 ctx->notify_method = TWA_SIGNAL_NO_IPI;
3916 } else if (ctx->flags & IORING_SETUP_COOP_TASKRUN) {
3917 ctx->notify_method = TWA_SIGNAL_NO_IPI;
3918 } else {
3919 if (ctx->flags & IORING_SETUP_TASKRUN_FLAG &&
3920 !(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
3921 goto err;
3922 ctx->notify_method = TWA_SIGNAL;
3923 }
3924
3925 /*
3926 * For DEFER_TASKRUN we require the completion task to be the same as the
3927 * submission task. This implies that there is only one submitter, so enforce
3928 * that.
3929 */
3930 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN &&
3931 !(ctx->flags & IORING_SETUP_SINGLE_ISSUER)) {
3932 goto err;
3933 }
3934
3935 /*
3936 * This is just grabbed for accounting purposes. When a process exits,
3937 * the mm is exited and dropped before the files, hence we need to hang
3938 * on to this mm purely for the purposes of being able to unaccount
3939 * memory (locked/pinned vm). It's not used for anything else.
3940 */
3941 mmgrab(current->mm);
3942 ctx->mm_account = current->mm;
3943
3944 ret = io_allocate_scq_urings(ctx, p);
3945 if (ret)
3946 goto err;
3947
3948 ret = io_sq_offload_create(ctx, p);
3949 if (ret)
3950 goto err;
3951
3952 ret = io_rsrc_init(ctx);
3953 if (ret)
3954 goto err;
3955
3956 p->sq_off.head = offsetof(struct io_rings, sq.head);
3957 p->sq_off.tail = offsetof(struct io_rings, sq.tail);
3958 p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
3959 p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
3960 p->sq_off.flags = offsetof(struct io_rings, sq_flags);
3961 p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
3962 if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
3963 p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
3964 p->sq_off.resv1 = 0;
3965 if (!(ctx->flags & IORING_SETUP_NO_MMAP))
3966 p->sq_off.user_addr = 0;
3967
3968 p->cq_off.head = offsetof(struct io_rings, cq.head);
3969 p->cq_off.tail = offsetof(struct io_rings, cq.tail);
3970 p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
3971 p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
3972 p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
3973 p->cq_off.cqes = offsetof(struct io_rings, cqes);
3974 p->cq_off.flags = offsetof(struct io_rings, cq_flags);
3975 p->cq_off.resv1 = 0;
3976 if (!(ctx->flags & IORING_SETUP_NO_MMAP))
3977 p->cq_off.user_addr = 0;
3978
3979 p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
3980 IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
3981 IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
3982 IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED |
3983 IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS |
3984 IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP |
3985 IORING_FEAT_LINKED_FILE | IORING_FEAT_REG_REG_RING;
3986
3987 if (copy_to_user(params, p, sizeof(*p))) {
3988 ret = -EFAULT;
3989 goto err;
3990 }
3991
3992 if (ctx->flags & IORING_SETUP_SINGLE_ISSUER
3993 && !(ctx->flags & IORING_SETUP_R_DISABLED))
3994 WRITE_ONCE(ctx->submitter_task, get_task_struct(current));
3995
3996 file = io_uring_get_file(ctx);
3997 if (IS_ERR(file)) {
3998 ret = PTR_ERR(file);
3999 goto err;
4000 }
4001
4002 ret = __io_uring_add_tctx_node(ctx);
4003 if (ret)
4004 goto err_fput;
4005 tctx = current->io_uring;
4006
4007 /*
4008 * Install ring fd as the very last thing, so we don't risk someone
4009 * having closed it before we finish setup
4010 */
4011 if (p->flags & IORING_SETUP_REGISTERED_FD_ONLY)
4012 ret = io_ring_add_registered_file(tctx, file, 0, IO_RINGFD_REG_MAX);
4013 else
4014 ret = io_uring_install_fd(file);
4015 if (ret < 0)
4016 goto err_fput;
4017
4018 trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
4019 return ret;
4020err:
4021 io_ring_ctx_wait_and_kill(ctx);
4022 return ret;
4023err_fput:
4024 fput(file);
4025 return ret;
4026}
4027
4028/*
4029 * Sets up an aio uring context, and returns the fd. Applications asks for a
4030 * ring size, we return the actual sq/cq ring sizes (among other things) in the
4031 * params structure passed in.
4032 */
4033static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
4034{
4035 struct io_uring_params p;
4036 int i;
4037
4038 if (copy_from_user(&p, params, sizeof(p)))
4039 return -EFAULT;
4040 for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
4041 if (p.resv[i])
4042 return -EINVAL;
4043 }
4044
4045 if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
4046 IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |
4047 IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
4048 IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL |
4049 IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG |
4050 IORING_SETUP_SQE128 | IORING_SETUP_CQE32 |
4051 IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN |
4052 IORING_SETUP_NO_MMAP | IORING_SETUP_REGISTERED_FD_ONLY |
4053 IORING_SETUP_NO_SQARRAY))
4054 return -EINVAL;
4055
4056 return io_uring_create(entries, &p, params);
4057}
4058
4059static inline bool io_uring_allowed(void)
4060{
4061 int disabled = READ_ONCE(sysctl_io_uring_disabled);
4062 kgid_t io_uring_group;
4063
4064 if (disabled == 2)
4065 return false;
4066
4067 if (disabled == 0 || capable(CAP_SYS_ADMIN))
4068 return true;
4069
4070 io_uring_group = make_kgid(&init_user_ns, sysctl_io_uring_group);
4071 if (!gid_valid(io_uring_group))
4072 return false;
4073
4074 return in_group_p(io_uring_group);
4075}
4076
4077SYSCALL_DEFINE2(io_uring_setup, u32, entries,
4078 struct io_uring_params __user *, params)
4079{
4080 if (!io_uring_allowed())
4081 return -EPERM;
4082
4083 return io_uring_setup(entries, params);
4084}
4085
4086static int __init io_uring_init(void)
4087{
4088#define __BUILD_BUG_VERIFY_OFFSET_SIZE(stype, eoffset, esize, ename) do { \
4089 BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
4090 BUILD_BUG_ON(sizeof_field(stype, ename) != esize); \
4091} while (0)
4092
4093#define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
4094 __BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, sizeof(etype), ename)
4095#define BUILD_BUG_SQE_ELEM_SIZE(eoffset, esize, ename) \
4096 __BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, esize, ename)
4097 BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);
4098 BUILD_BUG_SQE_ELEM(0, __u8, opcode);
4099 BUILD_BUG_SQE_ELEM(1, __u8, flags);
4100 BUILD_BUG_SQE_ELEM(2, __u16, ioprio);
4101 BUILD_BUG_SQE_ELEM(4, __s32, fd);
4102 BUILD_BUG_SQE_ELEM(8, __u64, off);
4103 BUILD_BUG_SQE_ELEM(8, __u64, addr2);
4104 BUILD_BUG_SQE_ELEM(8, __u32, cmd_op);
4105 BUILD_BUG_SQE_ELEM(12, __u32, __pad1);
4106 BUILD_BUG_SQE_ELEM(16, __u64, addr);
4107 BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in);
4108 BUILD_BUG_SQE_ELEM(24, __u32, len);
4109 BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags);
4110 BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags);
4111 BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
4112 BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags);
4113 BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events);
4114 BUILD_BUG_SQE_ELEM(28, __u32, poll32_events);
4115 BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags);
4116 BUILD_BUG_SQE_ELEM(28, __u32, msg_flags);
4117 BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags);
4118 BUILD_BUG_SQE_ELEM(28, __u32, accept_flags);
4119 BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags);
4120 BUILD_BUG_SQE_ELEM(28, __u32, open_flags);
4121 BUILD_BUG_SQE_ELEM(28, __u32, statx_flags);
4122 BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice);
4123 BUILD_BUG_SQE_ELEM(28, __u32, splice_flags);
4124 BUILD_BUG_SQE_ELEM(28, __u32, rename_flags);
4125 BUILD_BUG_SQE_ELEM(28, __u32, unlink_flags);
4126 BUILD_BUG_SQE_ELEM(28, __u32, hardlink_flags);
4127 BUILD_BUG_SQE_ELEM(28, __u32, xattr_flags);
4128 BUILD_BUG_SQE_ELEM(28, __u32, msg_ring_flags);
4129 BUILD_BUG_SQE_ELEM(32, __u64, user_data);
4130 BUILD_BUG_SQE_ELEM(40, __u16, buf_index);
4131 BUILD_BUG_SQE_ELEM(40, __u16, buf_group);
4132 BUILD_BUG_SQE_ELEM(42, __u16, personality);
4133 BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in);
4134 BUILD_BUG_SQE_ELEM(44, __u32, file_index);
4135 BUILD_BUG_SQE_ELEM(44, __u16, addr_len);
4136 BUILD_BUG_SQE_ELEM(46, __u16, __pad3[0]);
4137 BUILD_BUG_SQE_ELEM(48, __u64, addr3);
4138 BUILD_BUG_SQE_ELEM_SIZE(48, 0, cmd);
4139 BUILD_BUG_SQE_ELEM(56, __u64, __pad2);
4140
4141 BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
4142 sizeof(struct io_uring_rsrc_update));
4143 BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >
4144 sizeof(struct io_uring_rsrc_update2));
4145
4146 /* ->buf_index is u16 */
4147 BUILD_BUG_ON(offsetof(struct io_uring_buf_ring, bufs) != 0);
4148 BUILD_BUG_ON(offsetof(struct io_uring_buf, resv) !=
4149 offsetof(struct io_uring_buf_ring, tail));
4150
4151 /* should fit into one byte */
4152 BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
4153 BUILD_BUG_ON(SQE_COMMON_FLAGS >= (1 << 8));
4154 BUILD_BUG_ON((SQE_VALID_FLAGS | SQE_COMMON_FLAGS) != SQE_VALID_FLAGS);
4155
4156 BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int));
4157
4158 BUILD_BUG_ON(sizeof(atomic_t) != sizeof(u32));
4159
4160 /* top 8bits are for internal use */
4161 BUILD_BUG_ON((IORING_URING_CMD_MASK & 0xff000000) != 0);
4162
4163 io_uring_optable_init();
4164
4165 /*
4166 * Allow user copy in the per-command field, which starts after the
4167 * file in io_kiocb and until the opcode field. The openat2 handling
4168 * requires copying in user memory into the io_kiocb object in that
4169 * range, and HARDENED_USERCOPY will complain if we haven't
4170 * correctly annotated this range.
4171 */
4172 req_cachep = kmem_cache_create_usercopy("io_kiocb",
4173 sizeof(struct io_kiocb), 0,
4174 SLAB_HWCACHE_ALIGN | SLAB_PANIC |
4175 SLAB_ACCOUNT | SLAB_TYPESAFE_BY_RCU,
4176 offsetof(struct io_kiocb, cmd.data),
4177 sizeof_field(struct io_kiocb, cmd.data), NULL);
4178 io_buf_cachep = kmem_cache_create("io_buffer", sizeof(struct io_buffer), 0,
4179 SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT,
4180 NULL);
4181
4182#ifdef CONFIG_SYSCTL
4183 register_sysctl_init("kernel", kernel_io_uring_disabled_table);
4184#endif
4185
4186 return 0;
4187};
4188__initcall(io_uring_init);