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