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1/*
2 * Copyright (C) 2013 Shaohua Li <shli@kernel.org>
3 * Copyright (C) 2014 Red Hat, Inc.
4 * Copyright (C) 2015 Arrikto, Inc.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
20#include <linux/spinlock.h>
21#include <linux/module.h>
22#include <linux/idr.h>
23#include <linux/kernel.h>
24#include <linux/timer.h>
25#include <linux/parser.h>
26#include <linux/vmalloc.h>
27#include <linux/uio_driver.h>
28#include <linux/stringify.h>
29#include <linux/bitops.h>
30#include <net/genetlink.h>
31#include <scsi/scsi_common.h>
32#include <scsi/scsi_proto.h>
33#include <target/target_core_base.h>
34#include <target/target_core_fabric.h>
35#include <target/target_core_backend.h>
36
37#include <linux/target_core_user.h>
38
39/*
40 * Define a shared-memory interface for LIO to pass SCSI commands and
41 * data to userspace for processing. This is to allow backends that
42 * are too complex for in-kernel support to be possible.
43 *
44 * It uses the UIO framework to do a lot of the device-creation and
45 * introspection work for us.
46 *
47 * See the .h file for how the ring is laid out. Note that while the
48 * command ring is defined, the particulars of the data area are
49 * not. Offset values in the command entry point to other locations
50 * internal to the mmap()ed area. There is separate space outside the
51 * command ring for data buffers. This leaves maximum flexibility for
52 * moving buffer allocations, or even page flipping or other
53 * allocation techniques, without altering the command ring layout.
54 *
55 * SECURITY:
56 * The user process must be assumed to be malicious. There's no way to
57 * prevent it breaking the command ring protocol if it wants, but in
58 * order to prevent other issues we must only ever read *data* from
59 * the shared memory area, not offsets or sizes. This applies to
60 * command ring entries as well as the mailbox. Extra code needed for
61 * this may have a 'UAM' comment.
62 */
63
64
65#define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
66
67#define DATA_BLOCK_BITS 256
68#define DATA_BLOCK_SIZE 4096
69
70#define CMDR_SIZE (16 * 4096)
71#define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)
72
73#define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
74
75static struct device *tcmu_root_device;
76
77struct tcmu_hba {
78 u32 host_id;
79};
80
81#define TCMU_CONFIG_LEN 256
82
83struct tcmu_dev {
84 struct se_device se_dev;
85
86 char *name;
87 struct se_hba *hba;
88
89#define TCMU_DEV_BIT_OPEN 0
90#define TCMU_DEV_BIT_BROKEN 1
91 unsigned long flags;
92
93 struct uio_info uio_info;
94
95 struct tcmu_mailbox *mb_addr;
96 size_t dev_size;
97 u32 cmdr_size;
98 u32 cmdr_last_cleaned;
99 /* Offset of data ring from start of mb */
100 /* Must add data_off and mb_addr to get the address */
101 size_t data_off;
102 size_t data_size;
103
104 DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
105
106 wait_queue_head_t wait_cmdr;
107 /* TODO should this be a mutex? */
108 spinlock_t cmdr_lock;
109
110 struct idr commands;
111 spinlock_t commands_lock;
112
113 struct timer_list timeout;
114
115 char dev_config[TCMU_CONFIG_LEN];
116};
117
118#define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
119
120#define CMDR_OFF sizeof(struct tcmu_mailbox)
121
122struct tcmu_cmd {
123 struct se_cmd *se_cmd;
124 struct tcmu_dev *tcmu_dev;
125
126 uint16_t cmd_id;
127
128 /* Can't use se_cmd when cleaning up expired cmds, because if
129 cmd has been completed then accessing se_cmd is off limits */
130 DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
131
132 unsigned long deadline;
133
134#define TCMU_CMD_BIT_EXPIRED 0
135 unsigned long flags;
136};
137
138static struct kmem_cache *tcmu_cmd_cache;
139
140/* multicast group */
141enum tcmu_multicast_groups {
142 TCMU_MCGRP_CONFIG,
143};
144
145static const struct genl_multicast_group tcmu_mcgrps[] = {
146 [TCMU_MCGRP_CONFIG] = { .name = "config", },
147};
148
149/* Our generic netlink family */
150static struct genl_family tcmu_genl_family = {
151 .id = GENL_ID_GENERATE,
152 .hdrsize = 0,
153 .name = "TCM-USER",
154 .version = 1,
155 .maxattr = TCMU_ATTR_MAX,
156 .mcgrps = tcmu_mcgrps,
157 .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
158 .netnsok = true,
159};
160
161static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
162{
163 struct se_device *se_dev = se_cmd->se_dev;
164 struct tcmu_dev *udev = TCMU_DEV(se_dev);
165 struct tcmu_cmd *tcmu_cmd;
166 int cmd_id;
167
168 tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL);
169 if (!tcmu_cmd)
170 return NULL;
171
172 tcmu_cmd->se_cmd = se_cmd;
173 tcmu_cmd->tcmu_dev = udev;
174 tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT);
175
176 idr_preload(GFP_KERNEL);
177 spin_lock_irq(&udev->commands_lock);
178 cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0,
179 USHRT_MAX, GFP_NOWAIT);
180 spin_unlock_irq(&udev->commands_lock);
181 idr_preload_end();
182
183 if (cmd_id < 0) {
184 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
185 return NULL;
186 }
187 tcmu_cmd->cmd_id = cmd_id;
188
189 return tcmu_cmd;
190}
191
192static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
193{
194 unsigned long offset = offset_in_page(vaddr);
195
196 size = round_up(size+offset, PAGE_SIZE);
197 vaddr -= offset;
198
199 while (size) {
200 flush_dcache_page(virt_to_page(vaddr));
201 size -= PAGE_SIZE;
202 }
203}
204
205/*
206 * Some ring helper functions. We don't assume size is a power of 2 so
207 * we can't use circ_buf.h.
208 */
209static inline size_t spc_used(size_t head, size_t tail, size_t size)
210{
211 int diff = head - tail;
212
213 if (diff >= 0)
214 return diff;
215 else
216 return size + diff;
217}
218
219static inline size_t spc_free(size_t head, size_t tail, size_t size)
220{
221 /* Keep 1 byte unused or we can't tell full from empty */
222 return (size - spc_used(head, tail, size) - 1);
223}
224
225static inline size_t head_to_end(size_t head, size_t size)
226{
227 return size - head;
228}
229
230static inline void new_iov(struct iovec **iov, int *iov_cnt,
231 struct tcmu_dev *udev)
232{
233 struct iovec *iovec;
234
235 if (*iov_cnt != 0)
236 (*iov)++;
237 (*iov_cnt)++;
238
239 iovec = *iov;
240 memset(iovec, 0, sizeof(struct iovec));
241}
242
243#define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
244
245/* offset is relative to mb_addr */
246static inline size_t get_block_offset(struct tcmu_dev *dev,
247 int block, int remaining)
248{
249 return dev->data_off + block * DATA_BLOCK_SIZE +
250 DATA_BLOCK_SIZE - remaining;
251}
252
253static inline size_t iov_tail(struct tcmu_dev *udev, struct iovec *iov)
254{
255 return (size_t)iov->iov_base + iov->iov_len;
256}
257
258static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
259 struct scatterlist *data_sg, unsigned int data_nents,
260 struct iovec **iov, int *iov_cnt, bool copy_data)
261{
262 int i, block;
263 int block_remaining = 0;
264 void *from, *to;
265 size_t copy_bytes, to_offset;
266 struct scatterlist *sg;
267
268 for_each_sg(data_sg, sg, data_nents, i) {
269 int sg_remaining = sg->length;
270 from = kmap_atomic(sg_page(sg)) + sg->offset;
271 while (sg_remaining > 0) {
272 if (block_remaining == 0) {
273 block = find_first_zero_bit(udev->data_bitmap,
274 DATA_BLOCK_BITS);
275 block_remaining = DATA_BLOCK_SIZE;
276 set_bit(block, udev->data_bitmap);
277 }
278 copy_bytes = min_t(size_t, sg_remaining,
279 block_remaining);
280 to_offset = get_block_offset(udev, block,
281 block_remaining);
282 to = (void *)udev->mb_addr + to_offset;
283 if (*iov_cnt != 0 &&
284 to_offset == iov_tail(udev, *iov)) {
285 (*iov)->iov_len += copy_bytes;
286 } else {
287 new_iov(iov, iov_cnt, udev);
288 (*iov)->iov_base = (void __user *) to_offset;
289 (*iov)->iov_len = copy_bytes;
290 }
291 if (copy_data) {
292 memcpy(to, from + sg->length - sg_remaining,
293 copy_bytes);
294 tcmu_flush_dcache_range(to, copy_bytes);
295 }
296 sg_remaining -= copy_bytes;
297 block_remaining -= copy_bytes;
298 }
299 kunmap_atomic(from - sg->offset);
300 }
301}
302
303static void free_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd)
304{
305 bitmap_xor(udev->data_bitmap, udev->data_bitmap, cmd->data_bitmap,
306 DATA_BLOCK_BITS);
307}
308
309static void gather_data_area(struct tcmu_dev *udev, unsigned long *cmd_bitmap,
310 struct scatterlist *data_sg, unsigned int data_nents)
311{
312 int i, block;
313 int block_remaining = 0;
314 void *from, *to;
315 size_t copy_bytes, from_offset;
316 struct scatterlist *sg;
317
318 for_each_sg(data_sg, sg, data_nents, i) {
319 int sg_remaining = sg->length;
320 to = kmap_atomic(sg_page(sg)) + sg->offset;
321 while (sg_remaining > 0) {
322 if (block_remaining == 0) {
323 block = find_first_bit(cmd_bitmap,
324 DATA_BLOCK_BITS);
325 block_remaining = DATA_BLOCK_SIZE;
326 clear_bit(block, cmd_bitmap);
327 }
328 copy_bytes = min_t(size_t, sg_remaining,
329 block_remaining);
330 from_offset = get_block_offset(udev, block,
331 block_remaining);
332 from = (void *) udev->mb_addr + from_offset;
333 tcmu_flush_dcache_range(from, copy_bytes);
334 memcpy(to + sg->length - sg_remaining, from,
335 copy_bytes);
336
337 sg_remaining -= copy_bytes;
338 block_remaining -= copy_bytes;
339 }
340 kunmap_atomic(to - sg->offset);
341 }
342}
343
344static inline size_t spc_bitmap_free(unsigned long *bitmap)
345{
346 return DATA_BLOCK_SIZE * (DATA_BLOCK_BITS -
347 bitmap_weight(bitmap, DATA_BLOCK_BITS));
348}
349
350/*
351 * We can't queue a command until we have space available on the cmd ring *and*
352 * space available on the data ring.
353 *
354 * Called with ring lock held.
355 */
356static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed)
357{
358 struct tcmu_mailbox *mb = udev->mb_addr;
359 size_t space, cmd_needed;
360 u32 cmd_head;
361
362 tcmu_flush_dcache_range(mb, sizeof(*mb));
363
364 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
365
366 /*
367 * If cmd end-of-ring space is too small then we need space for a NOP plus
368 * original cmd - cmds are internally contiguous.
369 */
370 if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
371 cmd_needed = cmd_size;
372 else
373 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
374
375 space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
376 if (space < cmd_needed) {
377 pr_debug("no cmd space: %u %u %u\n", cmd_head,
378 udev->cmdr_last_cleaned, udev->cmdr_size);
379 return false;
380 }
381
382 space = spc_bitmap_free(udev->data_bitmap);
383 if (space < data_needed) {
384 pr_debug("no data space: only %zu available, but ask for %zu\n",
385 space, data_needed);
386 return false;
387 }
388
389 return true;
390}
391
392static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
393{
394 struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
395 struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
396 size_t base_command_size, command_size;
397 struct tcmu_mailbox *mb;
398 struct tcmu_cmd_entry *entry;
399 struct iovec *iov;
400 int iov_cnt;
401 uint32_t cmd_head;
402 uint64_t cdb_off;
403 bool copy_to_data_area;
404 size_t data_length;
405 DECLARE_BITMAP(old_bitmap, DATA_BLOCK_BITS);
406
407 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
408 return -EINVAL;
409
410 /*
411 * Must be a certain minimum size for response sense info, but
412 * also may be larger if the iov array is large.
413 *
414 * We prepare way too many iovs for potential uses here, because it's
415 * expensive to tell how many regions are freed in the bitmap
416 */
417 base_command_size = max(offsetof(struct tcmu_cmd_entry,
418 req.iov[se_cmd->t_bidi_data_nents +
419 se_cmd->t_data_nents]),
420 sizeof(struct tcmu_cmd_entry));
421 command_size = base_command_size
422 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
423
424 WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
425
426 spin_lock_irq(&udev->cmdr_lock);
427
428 mb = udev->mb_addr;
429 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
430 data_length = se_cmd->data_length;
431 if (se_cmd->se_cmd_flags & SCF_BIDI) {
432 BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
433 data_length += se_cmd->t_bidi_data_sg->length;
434 }
435 if ((command_size > (udev->cmdr_size / 2))
436 || data_length > udev->data_size)
437 pr_warn("TCMU: Request of size %zu/%zu may be too big for %u/%zu "
438 "cmd/data ring buffers\n", command_size, data_length,
439 udev->cmdr_size, udev->data_size);
440
441 while (!is_ring_space_avail(udev, command_size, data_length)) {
442 int ret;
443 DEFINE_WAIT(__wait);
444
445 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
446
447 pr_debug("sleeping for ring space\n");
448 spin_unlock_irq(&udev->cmdr_lock);
449 ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
450 finish_wait(&udev->wait_cmdr, &__wait);
451 if (!ret) {
452 pr_warn("tcmu: command timed out\n");
453 return -ETIMEDOUT;
454 }
455
456 spin_lock_irq(&udev->cmdr_lock);
457
458 /* We dropped cmdr_lock, cmd_head is stale */
459 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
460 }
461
462 /* Insert a PAD if end-of-ring space is too small */
463 if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
464 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
465
466 entry = (void *) mb + CMDR_OFF + cmd_head;
467 tcmu_flush_dcache_range(entry, sizeof(*entry));
468 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
469 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
470 entry->hdr.cmd_id = 0; /* not used for PAD */
471 entry->hdr.kflags = 0;
472 entry->hdr.uflags = 0;
473
474 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
475
476 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
477 WARN_ON(cmd_head != 0);
478 }
479
480 entry = (void *) mb + CMDR_OFF + cmd_head;
481 tcmu_flush_dcache_range(entry, sizeof(*entry));
482 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
483 tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
484 entry->hdr.cmd_id = tcmu_cmd->cmd_id;
485 entry->hdr.kflags = 0;
486 entry->hdr.uflags = 0;
487
488 bitmap_copy(old_bitmap, udev->data_bitmap, DATA_BLOCK_BITS);
489
490 /*
491 * Fix up iovecs, and handle if allocation in data ring wrapped.
492 */
493 iov = &entry->req.iov[0];
494 iov_cnt = 0;
495 copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE
496 || se_cmd->se_cmd_flags & SCF_BIDI);
497 alloc_and_scatter_data_area(udev, se_cmd->t_data_sg,
498 se_cmd->t_data_nents, &iov, &iov_cnt, copy_to_data_area);
499 entry->req.iov_cnt = iov_cnt;
500 entry->req.iov_dif_cnt = 0;
501
502 /* Handle BIDI commands */
503 iov_cnt = 0;
504 alloc_and_scatter_data_area(udev, se_cmd->t_bidi_data_sg,
505 se_cmd->t_bidi_data_nents, &iov, &iov_cnt, false);
506 entry->req.iov_bidi_cnt = iov_cnt;
507
508 /* cmd's data_bitmap is what changed in process */
509 bitmap_xor(tcmu_cmd->data_bitmap, old_bitmap, udev->data_bitmap,
510 DATA_BLOCK_BITS);
511
512 /* All offsets relative to mb_addr, not start of entry! */
513 cdb_off = CMDR_OFF + cmd_head + base_command_size;
514 memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
515 entry->req.cdb_off = cdb_off;
516 tcmu_flush_dcache_range(entry, sizeof(*entry));
517
518 UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
519 tcmu_flush_dcache_range(mb, sizeof(*mb));
520
521 spin_unlock_irq(&udev->cmdr_lock);
522
523 /* TODO: only if FLUSH and FUA? */
524 uio_event_notify(&udev->uio_info);
525
526 mod_timer(&udev->timeout,
527 round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT)));
528
529 return 0;
530}
531
532static int tcmu_queue_cmd(struct se_cmd *se_cmd)
533{
534 struct se_device *se_dev = se_cmd->se_dev;
535 struct tcmu_dev *udev = TCMU_DEV(se_dev);
536 struct tcmu_cmd *tcmu_cmd;
537 int ret;
538
539 tcmu_cmd = tcmu_alloc_cmd(se_cmd);
540 if (!tcmu_cmd)
541 return -ENOMEM;
542
543 ret = tcmu_queue_cmd_ring(tcmu_cmd);
544 if (ret < 0) {
545 pr_err("TCMU: Could not queue command\n");
546 spin_lock_irq(&udev->commands_lock);
547 idr_remove(&udev->commands, tcmu_cmd->cmd_id);
548 spin_unlock_irq(&udev->commands_lock);
549
550 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
551 }
552
553 return ret;
554}
555
556static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
557{
558 struct se_cmd *se_cmd = cmd->se_cmd;
559 struct tcmu_dev *udev = cmd->tcmu_dev;
560
561 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
562 /*
563 * cmd has been completed already from timeout, just reclaim
564 * data ring space and free cmd
565 */
566 free_data_area(udev, cmd);
567
568 kmem_cache_free(tcmu_cmd_cache, cmd);
569 return;
570 }
571
572 if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
573 free_data_area(udev, cmd);
574 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
575 cmd->se_cmd);
576 entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION;
577 } else if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
578 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
579 se_cmd->scsi_sense_length);
580 free_data_area(udev, cmd);
581 } else if (se_cmd->se_cmd_flags & SCF_BIDI) {
582 DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
583
584 /* Get Data-In buffer before clean up */
585 bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
586 gather_data_area(udev, bitmap,
587 se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents);
588 free_data_area(udev, cmd);
589 } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
590 DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
591
592 bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
593 gather_data_area(udev, bitmap,
594 se_cmd->t_data_sg, se_cmd->t_data_nents);
595 free_data_area(udev, cmd);
596 } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
597 free_data_area(udev, cmd);
598 } else if (se_cmd->data_direction != DMA_NONE) {
599 pr_warn("TCMU: data direction was %d!\n",
600 se_cmd->data_direction);
601 }
602
603 target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
604 cmd->se_cmd = NULL;
605
606 kmem_cache_free(tcmu_cmd_cache, cmd);
607}
608
609static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
610{
611 struct tcmu_mailbox *mb;
612 unsigned long flags;
613 int handled = 0;
614
615 if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
616 pr_err("ring broken, not handling completions\n");
617 return 0;
618 }
619
620 spin_lock_irqsave(&udev->cmdr_lock, flags);
621
622 mb = udev->mb_addr;
623 tcmu_flush_dcache_range(mb, sizeof(*mb));
624
625 while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) {
626
627 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
628 struct tcmu_cmd *cmd;
629
630 tcmu_flush_dcache_range(entry, sizeof(*entry));
631
632 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
633 UPDATE_HEAD(udev->cmdr_last_cleaned,
634 tcmu_hdr_get_len(entry->hdr.len_op),
635 udev->cmdr_size);
636 continue;
637 }
638 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
639
640 spin_lock(&udev->commands_lock);
641 cmd = idr_find(&udev->commands, entry->hdr.cmd_id);
642 if (cmd)
643 idr_remove(&udev->commands, cmd->cmd_id);
644 spin_unlock(&udev->commands_lock);
645
646 if (!cmd) {
647 pr_err("cmd_id not found, ring is broken\n");
648 set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
649 break;
650 }
651
652 tcmu_handle_completion(cmd, entry);
653
654 UPDATE_HEAD(udev->cmdr_last_cleaned,
655 tcmu_hdr_get_len(entry->hdr.len_op),
656 udev->cmdr_size);
657
658 handled++;
659 }
660
661 if (mb->cmd_tail == mb->cmd_head)
662 del_timer(&udev->timeout); /* no more pending cmds */
663
664 spin_unlock_irqrestore(&udev->cmdr_lock, flags);
665
666 wake_up(&udev->wait_cmdr);
667
668 return handled;
669}
670
671static int tcmu_check_expired_cmd(int id, void *p, void *data)
672{
673 struct tcmu_cmd *cmd = p;
674
675 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
676 return 0;
677
678 if (!time_after(jiffies, cmd->deadline))
679 return 0;
680
681 set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
682 target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
683 cmd->se_cmd = NULL;
684
685 kmem_cache_free(tcmu_cmd_cache, cmd);
686
687 return 0;
688}
689
690static void tcmu_device_timedout(unsigned long data)
691{
692 struct tcmu_dev *udev = (struct tcmu_dev *)data;
693 unsigned long flags;
694 int handled;
695
696 handled = tcmu_handle_completions(udev);
697
698 pr_warn("%d completions handled from timeout\n", handled);
699
700 spin_lock_irqsave(&udev->commands_lock, flags);
701 idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
702 spin_unlock_irqrestore(&udev->commands_lock, flags);
703
704 /*
705 * We don't need to wakeup threads on wait_cmdr since they have their
706 * own timeout.
707 */
708}
709
710static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
711{
712 struct tcmu_hba *tcmu_hba;
713
714 tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
715 if (!tcmu_hba)
716 return -ENOMEM;
717
718 tcmu_hba->host_id = host_id;
719 hba->hba_ptr = tcmu_hba;
720
721 return 0;
722}
723
724static void tcmu_detach_hba(struct se_hba *hba)
725{
726 kfree(hba->hba_ptr);
727 hba->hba_ptr = NULL;
728}
729
730static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
731{
732 struct tcmu_dev *udev;
733
734 udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
735 if (!udev)
736 return NULL;
737
738 udev->name = kstrdup(name, GFP_KERNEL);
739 if (!udev->name) {
740 kfree(udev);
741 return NULL;
742 }
743
744 udev->hba = hba;
745
746 init_waitqueue_head(&udev->wait_cmdr);
747 spin_lock_init(&udev->cmdr_lock);
748
749 idr_init(&udev->commands);
750 spin_lock_init(&udev->commands_lock);
751
752 setup_timer(&udev->timeout, tcmu_device_timedout,
753 (unsigned long)udev);
754
755 return &udev->se_dev;
756}
757
758static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
759{
760 struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
761
762 tcmu_handle_completions(tcmu_dev);
763
764 return 0;
765}
766
767/*
768 * mmap code from uio.c. Copied here because we want to hook mmap()
769 * and this stuff must come along.
770 */
771static int tcmu_find_mem_index(struct vm_area_struct *vma)
772{
773 struct tcmu_dev *udev = vma->vm_private_data;
774 struct uio_info *info = &udev->uio_info;
775
776 if (vma->vm_pgoff < MAX_UIO_MAPS) {
777 if (info->mem[vma->vm_pgoff].size == 0)
778 return -1;
779 return (int)vma->vm_pgoff;
780 }
781 return -1;
782}
783
784static int tcmu_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
785{
786 struct tcmu_dev *udev = vma->vm_private_data;
787 struct uio_info *info = &udev->uio_info;
788 struct page *page;
789 unsigned long offset;
790 void *addr;
791
792 int mi = tcmu_find_mem_index(vma);
793 if (mi < 0)
794 return VM_FAULT_SIGBUS;
795
796 /*
797 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
798 * to use mem[N].
799 */
800 offset = (vmf->pgoff - mi) << PAGE_SHIFT;
801
802 addr = (void *)(unsigned long)info->mem[mi].addr + offset;
803 if (info->mem[mi].memtype == UIO_MEM_LOGICAL)
804 page = virt_to_page(addr);
805 else
806 page = vmalloc_to_page(addr);
807 get_page(page);
808 vmf->page = page;
809 return 0;
810}
811
812static const struct vm_operations_struct tcmu_vm_ops = {
813 .fault = tcmu_vma_fault,
814};
815
816static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
817{
818 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
819
820 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
821 vma->vm_ops = &tcmu_vm_ops;
822
823 vma->vm_private_data = udev;
824
825 /* Ensure the mmap is exactly the right size */
826 if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
827 return -EINVAL;
828
829 return 0;
830}
831
832static int tcmu_open(struct uio_info *info, struct inode *inode)
833{
834 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
835
836 /* O_EXCL not supported for char devs, so fake it? */
837 if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
838 return -EBUSY;
839
840 pr_debug("open\n");
841
842 return 0;
843}
844
845static int tcmu_release(struct uio_info *info, struct inode *inode)
846{
847 struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
848
849 clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
850
851 pr_debug("close\n");
852
853 return 0;
854}
855
856static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor)
857{
858 struct sk_buff *skb;
859 void *msg_header;
860 int ret = -ENOMEM;
861
862 skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
863 if (!skb)
864 return ret;
865
866 msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
867 if (!msg_header)
868 goto free_skb;
869
870 ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name);
871 if (ret < 0)
872 goto free_skb;
873
874 ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor);
875 if (ret < 0)
876 goto free_skb;
877
878 genlmsg_end(skb, msg_header);
879
880 ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
881 TCMU_MCGRP_CONFIG, GFP_KERNEL);
882
883 /* We don't care if no one is listening */
884 if (ret == -ESRCH)
885 ret = 0;
886
887 return ret;
888free_skb:
889 nlmsg_free(skb);
890 return ret;
891}
892
893static int tcmu_configure_device(struct se_device *dev)
894{
895 struct tcmu_dev *udev = TCMU_DEV(dev);
896 struct tcmu_hba *hba = udev->hba->hba_ptr;
897 struct uio_info *info;
898 struct tcmu_mailbox *mb;
899 size_t size;
900 size_t used;
901 int ret = 0;
902 char *str;
903
904 info = &udev->uio_info;
905
906 size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
907 udev->dev_config);
908 size += 1; /* for \0 */
909 str = kmalloc(size, GFP_KERNEL);
910 if (!str)
911 return -ENOMEM;
912
913 used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
914
915 if (udev->dev_config[0])
916 snprintf(str + used, size - used, "/%s", udev->dev_config);
917
918 info->name = str;
919
920 udev->mb_addr = vzalloc(TCMU_RING_SIZE);
921 if (!udev->mb_addr) {
922 ret = -ENOMEM;
923 goto err_vzalloc;
924 }
925
926 /* mailbox fits in first part of CMDR space */
927 udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
928 udev->data_off = CMDR_SIZE;
929 udev->data_size = TCMU_RING_SIZE - CMDR_SIZE;
930
931 mb = udev->mb_addr;
932 mb->version = TCMU_MAILBOX_VERSION;
933 mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC;
934 mb->cmdr_off = CMDR_OFF;
935 mb->cmdr_size = udev->cmdr_size;
936
937 WARN_ON(!PAGE_ALIGNED(udev->data_off));
938 WARN_ON(udev->data_size % PAGE_SIZE);
939 WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
940
941 info->version = __stringify(TCMU_MAILBOX_VERSION);
942
943 info->mem[0].name = "tcm-user command & data buffer";
944 info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr;
945 info->mem[0].size = TCMU_RING_SIZE;
946 info->mem[0].memtype = UIO_MEM_VIRTUAL;
947
948 info->irqcontrol = tcmu_irqcontrol;
949 info->irq = UIO_IRQ_CUSTOM;
950
951 info->mmap = tcmu_mmap;
952 info->open = tcmu_open;
953 info->release = tcmu_release;
954
955 ret = uio_register_device(tcmu_root_device, info);
956 if (ret)
957 goto err_register;
958
959 /* User can set hw_block_size before enable the device */
960 if (dev->dev_attrib.hw_block_size == 0)
961 dev->dev_attrib.hw_block_size = 512;
962 /* Other attributes can be configured in userspace */
963 dev->dev_attrib.hw_max_sectors = 128;
964 dev->dev_attrib.hw_queue_depth = 128;
965
966 ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name,
967 udev->uio_info.uio_dev->minor);
968 if (ret)
969 goto err_netlink;
970
971 return 0;
972
973err_netlink:
974 uio_unregister_device(&udev->uio_info);
975err_register:
976 vfree(udev->mb_addr);
977err_vzalloc:
978 kfree(info->name);
979
980 return ret;
981}
982
983static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
984{
985 if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
986 kmem_cache_free(tcmu_cmd_cache, cmd);
987 return 0;
988 }
989 return -EINVAL;
990}
991
992static void tcmu_dev_call_rcu(struct rcu_head *p)
993{
994 struct se_device *dev = container_of(p, struct se_device, rcu_head);
995 struct tcmu_dev *udev = TCMU_DEV(dev);
996
997 kfree(udev);
998}
999
1000static void tcmu_free_device(struct se_device *dev)
1001{
1002 struct tcmu_dev *udev = TCMU_DEV(dev);
1003 struct tcmu_cmd *cmd;
1004 bool all_expired = true;
1005 int i;
1006
1007 del_timer_sync(&udev->timeout);
1008
1009 vfree(udev->mb_addr);
1010
1011 /* Upper layer should drain all requests before calling this */
1012 spin_lock_irq(&udev->commands_lock);
1013 idr_for_each_entry(&udev->commands, cmd, i) {
1014 if (tcmu_check_and_free_pending_cmd(cmd) != 0)
1015 all_expired = false;
1016 }
1017 idr_destroy(&udev->commands);
1018 spin_unlock_irq(&udev->commands_lock);
1019 WARN_ON(!all_expired);
1020
1021 /* Device was configured */
1022 if (udev->uio_info.uio_dev) {
1023 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name,
1024 udev->uio_info.uio_dev->minor);
1025
1026 uio_unregister_device(&udev->uio_info);
1027 kfree(udev->uio_info.name);
1028 kfree(udev->name);
1029 }
1030 call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
1031}
1032
1033enum {
1034 Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_err,
1035};
1036
1037static match_table_t tokens = {
1038 {Opt_dev_config, "dev_config=%s"},
1039 {Opt_dev_size, "dev_size=%u"},
1040 {Opt_hw_block_size, "hw_block_size=%u"},
1041 {Opt_err, NULL}
1042};
1043
1044static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
1045 const char *page, ssize_t count)
1046{
1047 struct tcmu_dev *udev = TCMU_DEV(dev);
1048 char *orig, *ptr, *opts, *arg_p;
1049 substring_t args[MAX_OPT_ARGS];
1050 int ret = 0, token;
1051 unsigned long tmp_ul;
1052
1053 opts = kstrdup(page, GFP_KERNEL);
1054 if (!opts)
1055 return -ENOMEM;
1056
1057 orig = opts;
1058
1059 while ((ptr = strsep(&opts, ",\n")) != NULL) {
1060 if (!*ptr)
1061 continue;
1062
1063 token = match_token(ptr, tokens, args);
1064 switch (token) {
1065 case Opt_dev_config:
1066 if (match_strlcpy(udev->dev_config, &args[0],
1067 TCMU_CONFIG_LEN) == 0) {
1068 ret = -EINVAL;
1069 break;
1070 }
1071 pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
1072 break;
1073 case Opt_dev_size:
1074 arg_p = match_strdup(&args[0]);
1075 if (!arg_p) {
1076 ret = -ENOMEM;
1077 break;
1078 }
1079 ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
1080 kfree(arg_p);
1081 if (ret < 0)
1082 pr_err("kstrtoul() failed for dev_size=\n");
1083 break;
1084 case Opt_hw_block_size:
1085 arg_p = match_strdup(&args[0]);
1086 if (!arg_p) {
1087 ret = -ENOMEM;
1088 break;
1089 }
1090 ret = kstrtoul(arg_p, 0, &tmp_ul);
1091 kfree(arg_p);
1092 if (ret < 0) {
1093 pr_err("kstrtoul() failed for hw_block_size=\n");
1094 break;
1095 }
1096 if (!tmp_ul) {
1097 pr_err("hw_block_size must be nonzero\n");
1098 break;
1099 }
1100 dev->dev_attrib.hw_block_size = tmp_ul;
1101 break;
1102 default:
1103 break;
1104 }
1105 }
1106
1107 kfree(orig);
1108 return (!ret) ? count : ret;
1109}
1110
1111static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
1112{
1113 struct tcmu_dev *udev = TCMU_DEV(dev);
1114 ssize_t bl = 0;
1115
1116 bl = sprintf(b + bl, "Config: %s ",
1117 udev->dev_config[0] ? udev->dev_config : "NULL");
1118 bl += sprintf(b + bl, "Size: %zu\n", udev->dev_size);
1119
1120 return bl;
1121}
1122
1123static sector_t tcmu_get_blocks(struct se_device *dev)
1124{
1125 struct tcmu_dev *udev = TCMU_DEV(dev);
1126
1127 return div_u64(udev->dev_size - dev->dev_attrib.block_size,
1128 dev->dev_attrib.block_size);
1129}
1130
1131static sense_reason_t
1132tcmu_pass_op(struct se_cmd *se_cmd)
1133{
1134 int ret = tcmu_queue_cmd(se_cmd);
1135
1136 if (ret != 0)
1137 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1138 else
1139 return TCM_NO_SENSE;
1140}
1141
1142static sense_reason_t
1143tcmu_parse_cdb(struct se_cmd *cmd)
1144{
1145 return passthrough_parse_cdb(cmd, tcmu_pass_op);
1146}
1147
1148static const struct target_backend_ops tcmu_ops = {
1149 .name = "user",
1150 .owner = THIS_MODULE,
1151 .transport_flags = TRANSPORT_FLAG_PASSTHROUGH,
1152 .attach_hba = tcmu_attach_hba,
1153 .detach_hba = tcmu_detach_hba,
1154 .alloc_device = tcmu_alloc_device,
1155 .configure_device = tcmu_configure_device,
1156 .free_device = tcmu_free_device,
1157 .parse_cdb = tcmu_parse_cdb,
1158 .set_configfs_dev_params = tcmu_set_configfs_dev_params,
1159 .show_configfs_dev_params = tcmu_show_configfs_dev_params,
1160 .get_device_type = sbc_get_device_type,
1161 .get_blocks = tcmu_get_blocks,
1162 .tb_dev_attrib_attrs = passthrough_attrib_attrs,
1163};
1164
1165static int __init tcmu_module_init(void)
1166{
1167 int ret;
1168
1169 BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
1170
1171 tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
1172 sizeof(struct tcmu_cmd),
1173 __alignof__(struct tcmu_cmd),
1174 0, NULL);
1175 if (!tcmu_cmd_cache)
1176 return -ENOMEM;
1177
1178 tcmu_root_device = root_device_register("tcm_user");
1179 if (IS_ERR(tcmu_root_device)) {
1180 ret = PTR_ERR(tcmu_root_device);
1181 goto out_free_cache;
1182 }
1183
1184 ret = genl_register_family(&tcmu_genl_family);
1185 if (ret < 0) {
1186 goto out_unreg_device;
1187 }
1188
1189 ret = transport_backend_register(&tcmu_ops);
1190 if (ret)
1191 goto out_unreg_genl;
1192
1193 return 0;
1194
1195out_unreg_genl:
1196 genl_unregister_family(&tcmu_genl_family);
1197out_unreg_device:
1198 root_device_unregister(tcmu_root_device);
1199out_free_cache:
1200 kmem_cache_destroy(tcmu_cmd_cache);
1201
1202 return ret;
1203}
1204
1205static void __exit tcmu_module_exit(void)
1206{
1207 target_backend_unregister(&tcmu_ops);
1208 genl_unregister_family(&tcmu_genl_family);
1209 root_device_unregister(tcmu_root_device);
1210 kmem_cache_destroy(tcmu_cmd_cache);
1211}
1212
1213MODULE_DESCRIPTION("TCM USER subsystem plugin");
1214MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
1215MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
1216MODULE_LICENSE("GPL");
1217
1218module_init(tcmu_module_init);
1219module_exit(tcmu_module_exit);