1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 1999 Eric Youngdale
4 * Copyright (C) 2014 Christoph Hellwig
5 *
6 * SCSI queueing library.
7 * Initial versions: Eric Youngdale (eric@andante.org).
8 * Based upon conversations with large numbers
9 * of people at Linux Expo.
10 */
11
12 #include <linux/bio.h>
13 #include <linux/bitops.h>
14 #include <linux/blkdev.h>
15 #include <linux/completion.h>
16 #include <linux/kernel.h>
17 #include <linux/export.h>
18 #include <linux/init.h>
19 #include <linux/pci.h>
20 #include <linux/delay.h>
21 #include <linux/hardirq.h>
22 #include <linux/scatterlist.h>
23 #include <linux/blk-mq.h>
24 #include <linux/blk-integrity.h>
25 #include <linux/ratelimit.h>
26 #include <asm/unaligned.h>
27
28 #include <scsi/scsi.h>
29 #include <scsi/scsi_cmnd.h>
30 #include <scsi/scsi_dbg.h>
31 #include <scsi/scsi_device.h>
32 #include <scsi/scsi_driver.h>
33 #include <scsi/scsi_eh.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_transport.h> /* scsi_init_limits() */
36 #include <scsi/scsi_dh.h>
37
38 #include <trace/events/scsi.h>
39
40 #include "scsi_debugfs.h"
41 #include "scsi_priv.h"
42 #include "scsi_logging.h"
43
44 /*
45 * Size of integrity metadata is usually small, 1 inline sg should
46 * cover normal cases.
47 */
48 #ifdef CONFIG_ARCH_NO_SG_CHAIN
49 #define SCSI_INLINE_PROT_SG_CNT 0
50 #define SCSI_INLINE_SG_CNT 0
51 #else
52 #define SCSI_INLINE_PROT_SG_CNT 1
53 #define SCSI_INLINE_SG_CNT 2
54 #endif
55
56 static struct kmem_cache *scsi_sense_cache;
57 static DEFINE_MUTEX(scsi_sense_cache_mutex);
58
59 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
60
scsi_init_sense_cache(struct Scsi_Host * shost)61 int scsi_init_sense_cache(struct Scsi_Host *shost)
62 {
63 int ret = 0;
64
65 mutex_lock(&scsi_sense_cache_mutex);
66 if (!scsi_sense_cache) {
67 scsi_sense_cache =
68 kmem_cache_create_usercopy("scsi_sense_cache",
69 SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
70 0, SCSI_SENSE_BUFFERSIZE, NULL);
71 if (!scsi_sense_cache)
72 ret = -ENOMEM;
73 }
74 mutex_unlock(&scsi_sense_cache_mutex);
75 return ret;
76 }
77
78 static void
scsi_set_blocked(struct scsi_cmnd * cmd,int reason)79 scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
80 {
81 struct Scsi_Host *host = cmd->device->host;
82 struct scsi_device *device = cmd->device;
83 struct scsi_target *starget = scsi_target(device);
84
85 /*
86 * Set the appropriate busy bit for the device/host.
87 *
88 * If the host/device isn't busy, assume that something actually
89 * completed, and that we should be able to queue a command now.
90 *
91 * Note that the prior mid-layer assumption that any host could
92 * always queue at least one command is now broken. The mid-layer
93 * will implement a user specifiable stall (see
94 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
95 * if a command is requeued with no other commands outstanding
96 * either for the device or for the host.
97 */
98 switch (reason) {
99 case SCSI_MLQUEUE_HOST_BUSY:
100 atomic_set(&host->host_blocked, host->max_host_blocked);
101 break;
102 case SCSI_MLQUEUE_DEVICE_BUSY:
103 case SCSI_MLQUEUE_EH_RETRY:
104 atomic_set(&device->device_blocked,
105 device->max_device_blocked);
106 break;
107 case SCSI_MLQUEUE_TARGET_BUSY:
108 atomic_set(&starget->target_blocked,
109 starget->max_target_blocked);
110 break;
111 }
112 }
113
scsi_mq_requeue_cmd(struct scsi_cmnd * cmd,unsigned long msecs)114 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd, unsigned long msecs)
115 {
116 struct request *rq = scsi_cmd_to_rq(cmd);
117
118 if (rq->rq_flags & RQF_DONTPREP) {
119 rq->rq_flags &= ~RQF_DONTPREP;
120 scsi_mq_uninit_cmd(cmd);
121 } else {
122 WARN_ON_ONCE(true);
123 }
124
125 blk_mq_requeue_request(rq, false);
126 if (!scsi_host_in_recovery(cmd->device->host))
127 blk_mq_delay_kick_requeue_list(rq->q, msecs);
128 }
129
130 /**
131 * __scsi_queue_insert - private queue insertion
132 * @cmd: The SCSI command being requeued
133 * @reason: The reason for the requeue
134 * @unbusy: Whether the queue should be unbusied
135 *
136 * This is a private queue insertion. The public interface
137 * scsi_queue_insert() always assumes the queue should be unbusied
138 * because it's always called before the completion. This function is
139 * for a requeue after completion, which should only occur in this
140 * file.
141 */
__scsi_queue_insert(struct scsi_cmnd * cmd,int reason,bool unbusy)142 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
143 {
144 struct scsi_device *device = cmd->device;
145
146 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
147 "Inserting command %p into mlqueue\n", cmd));
148
149 scsi_set_blocked(cmd, reason);
150
151 /*
152 * Decrement the counters, since these commands are no longer
153 * active on the host/device.
154 */
155 if (unbusy)
156 scsi_device_unbusy(device, cmd);
157
158 /*
159 * Requeue this command. It will go before all other commands
160 * that are already in the queue. Schedule requeue work under
161 * lock such that the kblockd_schedule_work() call happens
162 * before blk_mq_destroy_queue() finishes.
163 */
164 cmd->result = 0;
165
166 blk_mq_requeue_request(scsi_cmd_to_rq(cmd),
167 !scsi_host_in_recovery(cmd->device->host));
168 }
169
170 /**
171 * scsi_queue_insert - Reinsert a command in the queue.
172 * @cmd: command that we are adding to queue.
173 * @reason: why we are inserting command to queue.
174 *
175 * We do this for one of two cases. Either the host is busy and it cannot accept
176 * any more commands for the time being, or the device returned QUEUE_FULL and
177 * can accept no more commands.
178 *
179 * Context: This could be called either from an interrupt context or a normal
180 * process context.
181 */
scsi_queue_insert(struct scsi_cmnd * cmd,int reason)182 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
183 {
184 __scsi_queue_insert(cmd, reason, true);
185 }
186
scsi_failures_reset_retries(struct scsi_failures * failures)187 void scsi_failures_reset_retries(struct scsi_failures *failures)
188 {
189 struct scsi_failure *failure;
190
191 failures->total_retries = 0;
192
193 for (failure = failures->failure_definitions; failure->result;
194 failure++)
195 failure->retries = 0;
196 }
197 EXPORT_SYMBOL_GPL(scsi_failures_reset_retries);
198
199 /**
200 * scsi_check_passthrough - Determine if passthrough scsi_cmnd needs a retry.
201 * @scmd: scsi_cmnd to check.
202 * @failures: scsi_failures struct that lists failures to check for.
203 *
204 * Returns -EAGAIN if the caller should retry else 0.
205 */
scsi_check_passthrough(struct scsi_cmnd * scmd,struct scsi_failures * failures)206 static int scsi_check_passthrough(struct scsi_cmnd *scmd,
207 struct scsi_failures *failures)
208 {
209 struct scsi_failure *failure;
210 struct scsi_sense_hdr sshdr;
211 enum sam_status status;
212
213 if (!failures)
214 return 0;
215
216 for (failure = failures->failure_definitions; failure->result;
217 failure++) {
218 if (failure->result == SCMD_FAILURE_RESULT_ANY)
219 goto maybe_retry;
220
221 if (host_byte(scmd->result) &&
222 host_byte(scmd->result) == host_byte(failure->result))
223 goto maybe_retry;
224
225 status = status_byte(scmd->result);
226 if (!status)
227 continue;
228
229 if (failure->result == SCMD_FAILURE_STAT_ANY &&
230 !scsi_status_is_good(scmd->result))
231 goto maybe_retry;
232
233 if (status != status_byte(failure->result))
234 continue;
235
236 if (status_byte(failure->result) != SAM_STAT_CHECK_CONDITION ||
237 failure->sense == SCMD_FAILURE_SENSE_ANY)
238 goto maybe_retry;
239
240 if (!scsi_command_normalize_sense(scmd, &sshdr))
241 return 0;
242
243 if (failure->sense != sshdr.sense_key)
244 continue;
245
246 if (failure->asc == SCMD_FAILURE_ASC_ANY)
247 goto maybe_retry;
248
249 if (failure->asc != sshdr.asc)
250 continue;
251
252 if (failure->ascq == SCMD_FAILURE_ASCQ_ANY ||
253 failure->ascq == sshdr.ascq)
254 goto maybe_retry;
255 }
256
257 return 0;
258
259 maybe_retry:
260 if (failure->allowed) {
261 if (failure->allowed == SCMD_FAILURE_NO_LIMIT ||
262 ++failure->retries <= failure->allowed)
263 return -EAGAIN;
264 } else {
265 if (failures->total_allowed == SCMD_FAILURE_NO_LIMIT ||
266 ++failures->total_retries <= failures->total_allowed)
267 return -EAGAIN;
268 }
269
270 return 0;
271 }
272
273 /**
274 * scsi_execute_cmd - insert request and wait for the result
275 * @sdev: scsi_device
276 * @cmd: scsi command
277 * @opf: block layer request cmd_flags
278 * @buffer: data buffer
279 * @bufflen: len of buffer
280 * @timeout: request timeout in HZ
281 * @ml_retries: number of times SCSI midlayer will retry request
282 * @args: Optional args. See struct definition for field descriptions
283 *
284 * Returns the scsi_cmnd result field if a command was executed, or a negative
285 * Linux error code if we didn't get that far.
286 */
scsi_execute_cmd(struct scsi_device * sdev,const unsigned char * cmd,blk_opf_t opf,void * buffer,unsigned int bufflen,int timeout,int ml_retries,const struct scsi_exec_args * args)287 int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
288 blk_opf_t opf, void *buffer, unsigned int bufflen,
289 int timeout, int ml_retries,
290 const struct scsi_exec_args *args)
291 {
292 static const struct scsi_exec_args default_args;
293 struct request *req;
294 struct scsi_cmnd *scmd;
295 int ret;
296
297 if (!args)
298 args = &default_args;
299 else if (WARN_ON_ONCE(args->sense &&
300 args->sense_len != SCSI_SENSE_BUFFERSIZE))
301 return -EINVAL;
302
303 retry:
304 req = scsi_alloc_request(sdev->request_queue, opf, args->req_flags);
305 if (IS_ERR(req))
306 return PTR_ERR(req);
307
308 if (bufflen) {
309 ret = blk_rq_map_kern(sdev->request_queue, req,
310 buffer, bufflen, GFP_NOIO);
311 if (ret)
312 goto out;
313 }
314 scmd = blk_mq_rq_to_pdu(req);
315 scmd->cmd_len = COMMAND_SIZE(cmd[0]);
316 memcpy(scmd->cmnd, cmd, scmd->cmd_len);
317 scmd->allowed = ml_retries;
318 scmd->flags |= args->scmd_flags;
319 req->timeout = timeout;
320 req->rq_flags |= RQF_QUIET;
321
322 /*
323 * head injection *required* here otherwise quiesce won't work
324 */
325 blk_execute_rq(req, true);
326
327 if (scsi_check_passthrough(scmd, args->failures) == -EAGAIN) {
328 blk_mq_free_request(req);
329 goto retry;
330 }
331
332 /*
333 * Some devices (USB mass-storage in particular) may transfer
334 * garbage data together with a residue indicating that the data
335 * is invalid. Prevent the garbage from being misinterpreted
336 * and prevent security leaks by zeroing out the excess data.
337 */
338 if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
339 memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
340
341 if (args->resid)
342 *args->resid = scmd->resid_len;
343 if (args->sense)
344 memcpy(args->sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
345 if (args->sshdr)
346 scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
347 args->sshdr);
348
349 ret = scmd->result;
350 out:
351 blk_mq_free_request(req);
352
353 return ret;
354 }
355 EXPORT_SYMBOL(scsi_execute_cmd);
356
357 /*
358 * Wake up the error handler if necessary. Avoid as follows that the error
359 * handler is not woken up if host in-flight requests number ==
360 * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
361 * with an RCU read lock in this function to ensure that this function in
362 * its entirety either finishes before scsi_eh_scmd_add() increases the
363 * host_failed counter or that it notices the shost state change made by
364 * scsi_eh_scmd_add().
365 */
scsi_dec_host_busy(struct Scsi_Host * shost,struct scsi_cmnd * cmd)366 static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
367 {
368 unsigned long flags;
369
370 rcu_read_lock();
371 __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
372 if (unlikely(scsi_host_in_recovery(shost))) {
373 unsigned int busy = scsi_host_busy(shost);
374
375 spin_lock_irqsave(shost->host_lock, flags);
376 if (shost->host_failed || shost->host_eh_scheduled)
377 scsi_eh_wakeup(shost, busy);
378 spin_unlock_irqrestore(shost->host_lock, flags);
379 }
380 rcu_read_unlock();
381 }
382
scsi_device_unbusy(struct scsi_device * sdev,struct scsi_cmnd * cmd)383 void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
384 {
385 struct Scsi_Host *shost = sdev->host;
386 struct scsi_target *starget = scsi_target(sdev);
387
388 scsi_dec_host_busy(shost, cmd);
389
390 if (starget->can_queue > 0)
391 atomic_dec(&starget->target_busy);
392
393 sbitmap_put(&sdev->budget_map, cmd->budget_token);
394 cmd->budget_token = -1;
395 }
396
397 /*
398 * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with
399 * interrupts disabled.
400 */
scsi_kick_sdev_queue(struct scsi_device * sdev,void * data)401 static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data)
402 {
403 struct scsi_device *current_sdev = data;
404
405 if (sdev != current_sdev)
406 blk_mq_run_hw_queues(sdev->request_queue, true);
407 }
408
409 /*
410 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
411 * and call blk_run_queue for all the scsi_devices on the target -
412 * including current_sdev first.
413 *
414 * Called with *no* scsi locks held.
415 */
scsi_single_lun_run(struct scsi_device * current_sdev)416 static void scsi_single_lun_run(struct scsi_device *current_sdev)
417 {
418 struct Scsi_Host *shost = current_sdev->host;
419 struct scsi_target *starget = scsi_target(current_sdev);
420 unsigned long flags;
421
422 spin_lock_irqsave(shost->host_lock, flags);
423 starget->starget_sdev_user = NULL;
424 spin_unlock_irqrestore(shost->host_lock, flags);
425
426 /*
427 * Call blk_run_queue for all LUNs on the target, starting with
428 * current_sdev. We race with others (to set starget_sdev_user),
429 * but in most cases, we will be first. Ideally, each LU on the
430 * target would get some limited time or requests on the target.
431 */
432 blk_mq_run_hw_queues(current_sdev->request_queue,
433 shost->queuecommand_may_block);
434
435 spin_lock_irqsave(shost->host_lock, flags);
436 if (!starget->starget_sdev_user)
437 __starget_for_each_device(starget, current_sdev,
438 scsi_kick_sdev_queue);
439 spin_unlock_irqrestore(shost->host_lock, flags);
440 }
441
scsi_device_is_busy(struct scsi_device * sdev)442 static inline bool scsi_device_is_busy(struct scsi_device *sdev)
443 {
444 if (scsi_device_busy(sdev) >= sdev->queue_depth)
445 return true;
446 if (atomic_read(&sdev->device_blocked) > 0)
447 return true;
448 return false;
449 }
450
scsi_target_is_busy(struct scsi_target * starget)451 static inline bool scsi_target_is_busy(struct scsi_target *starget)
452 {
453 if (starget->can_queue > 0) {
454 if (atomic_read(&starget->target_busy) >= starget->can_queue)
455 return true;
456 if (atomic_read(&starget->target_blocked) > 0)
457 return true;
458 }
459 return false;
460 }
461
scsi_host_is_busy(struct Scsi_Host * shost)462 static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
463 {
464 if (atomic_read(&shost->host_blocked) > 0)
465 return true;
466 if (shost->host_self_blocked)
467 return true;
468 return false;
469 }
470
scsi_starved_list_run(struct Scsi_Host * shost)471 static void scsi_starved_list_run(struct Scsi_Host *shost)
472 {
473 LIST_HEAD(starved_list);
474 struct scsi_device *sdev;
475 unsigned long flags;
476
477 spin_lock_irqsave(shost->host_lock, flags);
478 list_splice_init(&shost->starved_list, &starved_list);
479
480 while (!list_empty(&starved_list)) {
481 struct request_queue *slq;
482
483 /*
484 * As long as shost is accepting commands and we have
485 * starved queues, call blk_run_queue. scsi_request_fn
486 * drops the queue_lock and can add us back to the
487 * starved_list.
488 *
489 * host_lock protects the starved_list and starved_entry.
490 * scsi_request_fn must get the host_lock before checking
491 * or modifying starved_list or starved_entry.
492 */
493 if (scsi_host_is_busy(shost))
494 break;
495
496 sdev = list_entry(starved_list.next,
497 struct scsi_device, starved_entry);
498 list_del_init(&sdev->starved_entry);
499 if (scsi_target_is_busy(scsi_target(sdev))) {
500 list_move_tail(&sdev->starved_entry,
501 &shost->starved_list);
502 continue;
503 }
504
505 /*
506 * Once we drop the host lock, a racing scsi_remove_device()
507 * call may remove the sdev from the starved list and destroy
508 * it and the queue. Mitigate by taking a reference to the
509 * queue and never touching the sdev again after we drop the
510 * host lock. Note: if __scsi_remove_device() invokes
511 * blk_mq_destroy_queue() before the queue is run from this
512 * function then blk_run_queue() will return immediately since
513 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING.
514 */
515 slq = sdev->request_queue;
516 if (!blk_get_queue(slq))
517 continue;
518 spin_unlock_irqrestore(shost->host_lock, flags);
519
520 blk_mq_run_hw_queues(slq, false);
521 blk_put_queue(slq);
522
523 spin_lock_irqsave(shost->host_lock, flags);
524 }
525 /* put any unprocessed entries back */
526 list_splice(&starved_list, &shost->starved_list);
527 spin_unlock_irqrestore(shost->host_lock, flags);
528 }
529
530 /**
531 * scsi_run_queue - Select a proper request queue to serve next.
532 * @q: last request's queue
533 *
534 * The previous command was completely finished, start a new one if possible.
535 */
scsi_run_queue(struct request_queue * q)536 static void scsi_run_queue(struct request_queue *q)
537 {
538 struct scsi_device *sdev = q->queuedata;
539
540 if (scsi_target(sdev)->single_lun)
541 scsi_single_lun_run(sdev);
542 if (!list_empty(&sdev->host->starved_list))
543 scsi_starved_list_run(sdev->host);
544
545 /* Note: blk_mq_kick_requeue_list() runs the queue asynchronously. */
546 blk_mq_kick_requeue_list(q);
547 }
548
scsi_requeue_run_queue(struct work_struct * work)549 void scsi_requeue_run_queue(struct work_struct *work)
550 {
551 struct scsi_device *sdev;
552 struct request_queue *q;
553
554 sdev = container_of(work, struct scsi_device, requeue_work);
555 q = sdev->request_queue;
556 scsi_run_queue(q);
557 }
558
scsi_run_host_queues(struct Scsi_Host * shost)559 void scsi_run_host_queues(struct Scsi_Host *shost)
560 {
561 struct scsi_device *sdev;
562
563 shost_for_each_device(sdev, shost)
564 scsi_run_queue(sdev->request_queue);
565 }
566
scsi_uninit_cmd(struct scsi_cmnd * cmd)567 static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
568 {
569 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
570 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
571
572 if (drv->uninit_command)
573 drv->uninit_command(cmd);
574 }
575 }
576
scsi_free_sgtables(struct scsi_cmnd * cmd)577 void scsi_free_sgtables(struct scsi_cmnd *cmd)
578 {
579 if (cmd->sdb.table.nents)
580 sg_free_table_chained(&cmd->sdb.table,
581 SCSI_INLINE_SG_CNT);
582 if (scsi_prot_sg_count(cmd))
583 sg_free_table_chained(&cmd->prot_sdb->table,
584 SCSI_INLINE_PROT_SG_CNT);
585 }
586 EXPORT_SYMBOL_GPL(scsi_free_sgtables);
587
scsi_mq_uninit_cmd(struct scsi_cmnd * cmd)588 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
589 {
590 scsi_free_sgtables(cmd);
591 scsi_uninit_cmd(cmd);
592 }
593
scsi_run_queue_async(struct scsi_device * sdev)594 static void scsi_run_queue_async(struct scsi_device *sdev)
595 {
596 if (scsi_host_in_recovery(sdev->host))
597 return;
598
599 if (scsi_target(sdev)->single_lun ||
600 !list_empty(&sdev->host->starved_list)) {
601 kblockd_schedule_work(&sdev->requeue_work);
602 } else {
603 /*
604 * smp_mb() present in sbitmap_queue_clear() or implied in
605 * .end_io is for ordering writing .device_busy in
606 * scsi_device_unbusy() and reading sdev->restarts.
607 */
608 int old = atomic_read(&sdev->restarts);
609
610 /*
611 * ->restarts has to be kept as non-zero if new budget
612 * contention occurs.
613 *
614 * No need to run queue when either another re-run
615 * queue wins in updating ->restarts or a new budget
616 * contention occurs.
617 */
618 if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
619 blk_mq_run_hw_queues(sdev->request_queue, true);
620 }
621 }
622
623 /* Returns false when no more bytes to process, true if there are more */
scsi_end_request(struct request * req,blk_status_t error,unsigned int bytes)624 static bool scsi_end_request(struct request *req, blk_status_t error,
625 unsigned int bytes)
626 {
627 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
628 struct scsi_device *sdev = cmd->device;
629 struct request_queue *q = sdev->request_queue;
630
631 if (blk_update_request(req, error, bytes))
632 return true;
633
634 // XXX:
635 if (blk_queue_add_random(q))
636 add_disk_randomness(req->q->disk);
637
638 WARN_ON_ONCE(!blk_rq_is_passthrough(req) &&
639 !(cmd->flags & SCMD_INITIALIZED));
640 cmd->flags = 0;
641
642 /*
643 * Calling rcu_barrier() is not necessary here because the
644 * SCSI error handler guarantees that the function called by
645 * call_rcu() has been called before scsi_end_request() is
646 * called.
647 */
648 destroy_rcu_head(&cmd->rcu);
649
650 /*
651 * In the MQ case the command gets freed by __blk_mq_end_request,
652 * so we have to do all cleanup that depends on it earlier.
653 *
654 * We also can't kick the queues from irq context, so we
655 * will have to defer it to a workqueue.
656 */
657 scsi_mq_uninit_cmd(cmd);
658
659 /*
660 * queue is still alive, so grab the ref for preventing it
661 * from being cleaned up during running queue.
662 */
663 percpu_ref_get(&q->q_usage_counter);
664
665 __blk_mq_end_request(req, error);
666
667 scsi_run_queue_async(sdev);
668
669 percpu_ref_put(&q->q_usage_counter);
670 return false;
671 }
672
673 /**
674 * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
675 * @result: scsi error code
676 *
677 * Translate a SCSI result code into a blk_status_t value.
678 */
scsi_result_to_blk_status(int result)679 static blk_status_t scsi_result_to_blk_status(int result)
680 {
681 /*
682 * Check the scsi-ml byte first in case we converted a host or status
683 * byte.
684 */
685 switch (scsi_ml_byte(result)) {
686 case SCSIML_STAT_OK:
687 break;
688 case SCSIML_STAT_RESV_CONFLICT:
689 return BLK_STS_RESV_CONFLICT;
690 case SCSIML_STAT_NOSPC:
691 return BLK_STS_NOSPC;
692 case SCSIML_STAT_MED_ERROR:
693 return BLK_STS_MEDIUM;
694 case SCSIML_STAT_TGT_FAILURE:
695 return BLK_STS_TARGET;
696 case SCSIML_STAT_DL_TIMEOUT:
697 return BLK_STS_DURATION_LIMIT;
698 }
699
700 switch (host_byte(result)) {
701 case DID_OK:
702 if (scsi_status_is_good(result))
703 return BLK_STS_OK;
704 return BLK_STS_IOERR;
705 case DID_TRANSPORT_FAILFAST:
706 case DID_TRANSPORT_MARGINAL:
707 return BLK_STS_TRANSPORT;
708 default:
709 return BLK_STS_IOERR;
710 }
711 }
712
713 /**
714 * scsi_rq_err_bytes - determine number of bytes till the next failure boundary
715 * @rq: request to examine
716 *
717 * Description:
718 * A request could be merge of IOs which require different failure
719 * handling. This function determines the number of bytes which
720 * can be failed from the beginning of the request without
721 * crossing into area which need to be retried further.
722 *
723 * Return:
724 * The number of bytes to fail.
725 */
scsi_rq_err_bytes(const struct request * rq)726 static unsigned int scsi_rq_err_bytes(const struct request *rq)
727 {
728 blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK;
729 unsigned int bytes = 0;
730 struct bio *bio;
731
732 if (!(rq->rq_flags & RQF_MIXED_MERGE))
733 return blk_rq_bytes(rq);
734
735 /*
736 * Currently the only 'mixing' which can happen is between
737 * different fastfail types. We can safely fail portions
738 * which have all the failfast bits that the first one has -
739 * the ones which are at least as eager to fail as the first
740 * one.
741 */
742 for (bio = rq->bio; bio; bio = bio->bi_next) {
743 if ((bio->bi_opf & ff) != ff)
744 break;
745 bytes += bio->bi_iter.bi_size;
746 }
747
748 /* this could lead to infinite loop */
749 BUG_ON(blk_rq_bytes(rq) && !bytes);
750 return bytes;
751 }
752
scsi_cmd_runtime_exceeced(struct scsi_cmnd * cmd)753 static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
754 {
755 struct request *req = scsi_cmd_to_rq(cmd);
756 unsigned long wait_for;
757
758 if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
759 return false;
760
761 wait_for = (cmd->allowed + 1) * req->timeout;
762 if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
763 scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
764 wait_for/HZ);
765 return true;
766 }
767 return false;
768 }
769
770 /*
771 * When ALUA transition state is returned, reprep the cmd to
772 * use the ALUA handler's transition timeout. Delay the reprep
773 * 1 sec to avoid aggressive retries of the target in that
774 * state.
775 */
776 #define ALUA_TRANSITION_REPREP_DELAY 1000
777
778 /* Helper for scsi_io_completion() when special action required. */
scsi_io_completion_action(struct scsi_cmnd * cmd,int result)779 static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
780 {
781 struct request *req = scsi_cmd_to_rq(cmd);
782 int level = 0;
783 enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP,
784 ACTION_RETRY, ACTION_DELAYED_RETRY} action;
785 struct scsi_sense_hdr sshdr;
786 bool sense_valid;
787 bool sense_current = true; /* false implies "deferred sense" */
788 blk_status_t blk_stat;
789
790 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
791 if (sense_valid)
792 sense_current = !scsi_sense_is_deferred(&sshdr);
793
794 blk_stat = scsi_result_to_blk_status(result);
795
796 if (host_byte(result) == DID_RESET) {
797 /* Third party bus reset or reset for error recovery
798 * reasons. Just retry the command and see what
799 * happens.
800 */
801 action = ACTION_RETRY;
802 } else if (sense_valid && sense_current) {
803 switch (sshdr.sense_key) {
804 case UNIT_ATTENTION:
805 if (cmd->device->removable) {
806 /* Detected disc change. Set a bit
807 * and quietly refuse further access.
808 */
809 cmd->device->changed = 1;
810 action = ACTION_FAIL;
811 } else {
812 /* Must have been a power glitch, or a
813 * bus reset. Could not have been a
814 * media change, so we just retry the
815 * command and see what happens.
816 */
817 action = ACTION_RETRY;
818 }
819 break;
820 case ILLEGAL_REQUEST:
821 /* If we had an ILLEGAL REQUEST returned, then
822 * we may have performed an unsupported
823 * command. The only thing this should be
824 * would be a ten byte read where only a six
825 * byte read was supported. Also, on a system
826 * where READ CAPACITY failed, we may have
827 * read past the end of the disk.
828 */
829 if ((cmd->device->use_10_for_rw &&
830 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
831 (cmd->cmnd[0] == READ_10 ||
832 cmd->cmnd[0] == WRITE_10)) {
833 /* This will issue a new 6-byte command. */
834 cmd->device->use_10_for_rw = 0;
835 action = ACTION_REPREP;
836 } else if (sshdr.asc == 0x10) /* DIX */ {
837 action = ACTION_FAIL;
838 blk_stat = BLK_STS_PROTECTION;
839 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
840 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
841 action = ACTION_FAIL;
842 blk_stat = BLK_STS_TARGET;
843 } else
844 action = ACTION_FAIL;
845 break;
846 case ABORTED_COMMAND:
847 action = ACTION_FAIL;
848 if (sshdr.asc == 0x10) /* DIF */
849 blk_stat = BLK_STS_PROTECTION;
850 break;
851 case NOT_READY:
852 /* If the device is in the process of becoming
853 * ready, or has a temporary blockage, retry.
854 */
855 if (sshdr.asc == 0x04) {
856 switch (sshdr.ascq) {
857 case 0x01: /* becoming ready */
858 case 0x04: /* format in progress */
859 case 0x05: /* rebuild in progress */
860 case 0x06: /* recalculation in progress */
861 case 0x07: /* operation in progress */
862 case 0x08: /* Long write in progress */
863 case 0x09: /* self test in progress */
864 case 0x11: /* notify (enable spinup) required */
865 case 0x14: /* space allocation in progress */
866 case 0x1a: /* start stop unit in progress */
867 case 0x1b: /* sanitize in progress */
868 case 0x1d: /* configuration in progress */
869 case 0x24: /* depopulation in progress */
870 case 0x25: /* depopulation restore in progress */
871 action = ACTION_DELAYED_RETRY;
872 break;
873 case 0x0a: /* ALUA state transition */
874 action = ACTION_DELAYED_REPREP;
875 break;
876 default:
877 action = ACTION_FAIL;
878 break;
879 }
880 } else
881 action = ACTION_FAIL;
882 break;
883 case VOLUME_OVERFLOW:
884 /* See SSC3rXX or current. */
885 action = ACTION_FAIL;
886 break;
887 case DATA_PROTECT:
888 action = ACTION_FAIL;
889 if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
890 (sshdr.asc == 0x55 &&
891 (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
892 /* Insufficient zone resources */
893 blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
894 }
895 break;
896 case COMPLETED:
897 fallthrough;
898 default:
899 action = ACTION_FAIL;
900 break;
901 }
902 } else
903 action = ACTION_FAIL;
904
905 if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
906 action = ACTION_FAIL;
907
908 switch (action) {
909 case ACTION_FAIL:
910 /* Give up and fail the remainder of the request */
911 if (!(req->rq_flags & RQF_QUIET)) {
912 static DEFINE_RATELIMIT_STATE(_rs,
913 DEFAULT_RATELIMIT_INTERVAL,
914 DEFAULT_RATELIMIT_BURST);
915
916 if (unlikely(scsi_logging_level))
917 level =
918 SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
919 SCSI_LOG_MLCOMPLETE_BITS);
920
921 /*
922 * if logging is enabled the failure will be printed
923 * in scsi_log_completion(), so avoid duplicate messages
924 */
925 if (!level && __ratelimit(&_rs)) {
926 scsi_print_result(cmd, NULL, FAILED);
927 if (sense_valid)
928 scsi_print_sense(cmd);
929 scsi_print_command(cmd);
930 }
931 }
932 if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req)))
933 return;
934 fallthrough;
935 case ACTION_REPREP:
936 scsi_mq_requeue_cmd(cmd, 0);
937 break;
938 case ACTION_DELAYED_REPREP:
939 scsi_mq_requeue_cmd(cmd, ALUA_TRANSITION_REPREP_DELAY);
940 break;
941 case ACTION_RETRY:
942 /* Retry the same command immediately */
943 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
944 break;
945 case ACTION_DELAYED_RETRY:
946 /* Retry the same command after a delay */
947 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
948 break;
949 }
950 }
951
952 /*
953 * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
954 * new result that may suppress further error checking. Also modifies
955 * *blk_statp in some cases.
956 */
scsi_io_completion_nz_result(struct scsi_cmnd * cmd,int result,blk_status_t * blk_statp)957 static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
958 blk_status_t *blk_statp)
959 {
960 bool sense_valid;
961 bool sense_current = true; /* false implies "deferred sense" */
962 struct request *req = scsi_cmd_to_rq(cmd);
963 struct scsi_sense_hdr sshdr;
964
965 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
966 if (sense_valid)
967 sense_current = !scsi_sense_is_deferred(&sshdr);
968
969 if (blk_rq_is_passthrough(req)) {
970 if (sense_valid) {
971 /*
972 * SG_IO wants current and deferred errors
973 */
974 cmd->sense_len = min(8 + cmd->sense_buffer[7],
975 SCSI_SENSE_BUFFERSIZE);
976 }
977 if (sense_current)
978 *blk_statp = scsi_result_to_blk_status(result);
979 } else if (blk_rq_bytes(req) == 0 && sense_current) {
980 /*
981 * Flush commands do not transfers any data, and thus cannot use
982 * good_bytes != blk_rq_bytes(req) as the signal for an error.
983 * This sets *blk_statp explicitly for the problem case.
984 */
985 *blk_statp = scsi_result_to_blk_status(result);
986 }
987 /*
988 * Recovered errors need reporting, but they're always treated as
989 * success, so fiddle the result code here. For passthrough requests
990 * we already took a copy of the original into sreq->result which
991 * is what gets returned to the user
992 */
993 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
994 bool do_print = true;
995 /*
996 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
997 * skip print since caller wants ATA registers. Only occurs
998 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
999 */
1000 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
1001 do_print = false;
1002 else if (req->rq_flags & RQF_QUIET)
1003 do_print = false;
1004 if (do_print)
1005 scsi_print_sense(cmd);
1006 result = 0;
1007 /* for passthrough, *blk_statp may be set */
1008 *blk_statp = BLK_STS_OK;
1009 }
1010 /*
1011 * Another corner case: the SCSI status byte is non-zero but 'good'.
1012 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
1013 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
1014 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
1015 * intermediate statuses (both obsolete in SAM-4) as good.
1016 */
1017 if ((result & 0xff) && scsi_status_is_good(result)) {
1018 result = 0;
1019 *blk_statp = BLK_STS_OK;
1020 }
1021 return result;
1022 }
1023
1024 /**
1025 * scsi_io_completion - Completion processing for SCSI commands.
1026 * @cmd: command that is finished.
1027 * @good_bytes: number of processed bytes.
1028 *
1029 * We will finish off the specified number of sectors. If we are done, the
1030 * command block will be released and the queue function will be goosed. If we
1031 * are not done then we have to figure out what to do next:
1032 *
1033 * a) We can call scsi_mq_requeue_cmd(). The request will be
1034 * unprepared and put back on the queue. Then a new command will
1035 * be created for it. This should be used if we made forward
1036 * progress, or if we want to switch from READ(10) to READ(6) for
1037 * example.
1038 *
1039 * b) We can call scsi_io_completion_action(). The request will be
1040 * put back on the queue and retried using the same command as
1041 * before, possibly after a delay.
1042 *
1043 * c) We can call scsi_end_request() with blk_stat other than
1044 * BLK_STS_OK, to fail the remainder of the request.
1045 */
scsi_io_completion(struct scsi_cmnd * cmd,unsigned int good_bytes)1046 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
1047 {
1048 int result = cmd->result;
1049 struct request *req = scsi_cmd_to_rq(cmd);
1050 blk_status_t blk_stat = BLK_STS_OK;
1051
1052 if (unlikely(result)) /* a nz result may or may not be an error */
1053 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
1054
1055 /*
1056 * Next deal with any sectors which we were able to correctly
1057 * handle.
1058 */
1059 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
1060 "%u sectors total, %d bytes done.\n",
1061 blk_rq_sectors(req), good_bytes));
1062
1063 /*
1064 * Failed, zero length commands always need to drop down
1065 * to retry code. Fast path should return in this block.
1066 */
1067 if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
1068 if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
1069 return; /* no bytes remaining */
1070 }
1071
1072 /* Kill remainder if no retries. */
1073 if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
1074 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
1075 WARN_ONCE(true,
1076 "Bytes remaining after failed, no-retry command");
1077 return;
1078 }
1079
1080 /*
1081 * If there had been no error, but we have leftover bytes in the
1082 * request just queue the command up again.
1083 */
1084 if (likely(result == 0))
1085 scsi_mq_requeue_cmd(cmd, 0);
1086 else
1087 scsi_io_completion_action(cmd, result);
1088 }
1089
scsi_cmd_needs_dma_drain(struct scsi_device * sdev,struct request * rq)1090 static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
1091 struct request *rq)
1092 {
1093 return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
1094 !op_is_write(req_op(rq)) &&
1095 sdev->host->hostt->dma_need_drain(rq);
1096 }
1097
1098 /**
1099 * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
1100 * @cmd: SCSI command data structure to initialize.
1101 *
1102 * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
1103 * for @cmd.
1104 *
1105 * Returns:
1106 * * BLK_STS_OK - on success
1107 * * BLK_STS_RESOURCE - if the failure is retryable
1108 * * BLK_STS_IOERR - if the failure is fatal
1109 */
scsi_alloc_sgtables(struct scsi_cmnd * cmd)1110 blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
1111 {
1112 struct scsi_device *sdev = cmd->device;
1113 struct request *rq = scsi_cmd_to_rq(cmd);
1114 unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
1115 struct scatterlist *last_sg = NULL;
1116 blk_status_t ret;
1117 bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
1118 int count;
1119
1120 if (WARN_ON_ONCE(!nr_segs))
1121 return BLK_STS_IOERR;
1122
1123 /*
1124 * Make sure there is space for the drain. The driver must adjust
1125 * max_hw_segments to be prepared for this.
1126 */
1127 if (need_drain)
1128 nr_segs++;
1129
1130 /*
1131 * If sg table allocation fails, requeue request later.
1132 */
1133 if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1134 cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1135 return BLK_STS_RESOURCE;
1136
1137 /*
1138 * Next, walk the list, and fill in the addresses and sizes of
1139 * each segment.
1140 */
1141 count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1142
1143 if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1144 unsigned int pad_len =
1145 (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1146
1147 last_sg->length += pad_len;
1148 cmd->extra_len += pad_len;
1149 }
1150
1151 if (need_drain) {
1152 sg_unmark_end(last_sg);
1153 last_sg = sg_next(last_sg);
1154 sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1155 sg_mark_end(last_sg);
1156
1157 cmd->extra_len += sdev->dma_drain_len;
1158 count++;
1159 }
1160
1161 BUG_ON(count > cmd->sdb.table.nents);
1162 cmd->sdb.table.nents = count;
1163 cmd->sdb.length = blk_rq_payload_bytes(rq);
1164
1165 if (blk_integrity_rq(rq)) {
1166 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1167 int ivecs;
1168
1169 if (WARN_ON_ONCE(!prot_sdb)) {
1170 /*
1171 * This can happen if someone (e.g. multipath)
1172 * queues a command to a device on an adapter
1173 * that does not support DIX.
1174 */
1175 ret = BLK_STS_IOERR;
1176 goto out_free_sgtables;
1177 }
1178
1179 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1180
1181 if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1182 prot_sdb->table.sgl,
1183 SCSI_INLINE_PROT_SG_CNT)) {
1184 ret = BLK_STS_RESOURCE;
1185 goto out_free_sgtables;
1186 }
1187
1188 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1189 prot_sdb->table.sgl);
1190 BUG_ON(count > ivecs);
1191 BUG_ON(count > queue_max_integrity_segments(rq->q));
1192
1193 cmd->prot_sdb = prot_sdb;
1194 cmd->prot_sdb->table.nents = count;
1195 }
1196
1197 return BLK_STS_OK;
1198 out_free_sgtables:
1199 scsi_free_sgtables(cmd);
1200 return ret;
1201 }
1202 EXPORT_SYMBOL(scsi_alloc_sgtables);
1203
1204 /**
1205 * scsi_initialize_rq - initialize struct scsi_cmnd partially
1206 * @rq: Request associated with the SCSI command to be initialized.
1207 *
1208 * This function initializes the members of struct scsi_cmnd that must be
1209 * initialized before request processing starts and that won't be
1210 * reinitialized if a SCSI command is requeued.
1211 */
scsi_initialize_rq(struct request * rq)1212 static void scsi_initialize_rq(struct request *rq)
1213 {
1214 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1215
1216 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1217 cmd->cmd_len = MAX_COMMAND_SIZE;
1218 cmd->sense_len = 0;
1219 init_rcu_head(&cmd->rcu);
1220 cmd->jiffies_at_alloc = jiffies;
1221 cmd->retries = 0;
1222 }
1223
scsi_alloc_request(struct request_queue * q,blk_opf_t opf,blk_mq_req_flags_t flags)1224 struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
1225 blk_mq_req_flags_t flags)
1226 {
1227 struct request *rq;
1228
1229 rq = blk_mq_alloc_request(q, opf, flags);
1230 if (!IS_ERR(rq))
1231 scsi_initialize_rq(rq);
1232 return rq;
1233 }
1234 EXPORT_SYMBOL_GPL(scsi_alloc_request);
1235
1236 /*
1237 * Only called when the request isn't completed by SCSI, and not freed by
1238 * SCSI
1239 */
scsi_cleanup_rq(struct request * rq)1240 static void scsi_cleanup_rq(struct request *rq)
1241 {
1242 if (rq->rq_flags & RQF_DONTPREP) {
1243 scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1244 rq->rq_flags &= ~RQF_DONTPREP;
1245 }
1246 }
1247
1248 /* Called before a request is prepared. See also scsi_mq_prep_fn(). */
scsi_init_command(struct scsi_device * dev,struct scsi_cmnd * cmd)1249 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1250 {
1251 struct request *rq = scsi_cmd_to_rq(cmd);
1252
1253 if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) {
1254 cmd->flags |= SCMD_INITIALIZED;
1255 scsi_initialize_rq(rq);
1256 }
1257
1258 cmd->device = dev;
1259 INIT_LIST_HEAD(&cmd->eh_entry);
1260 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1261 }
1262
scsi_setup_scsi_cmnd(struct scsi_device * sdev,struct request * req)1263 static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1264 struct request *req)
1265 {
1266 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1267
1268 /*
1269 * Passthrough requests may transfer data, in which case they must
1270 * a bio attached to them. Or they might contain a SCSI command
1271 * that does not transfer data, in which case they may optionally
1272 * submit a request without an attached bio.
1273 */
1274 if (req->bio) {
1275 blk_status_t ret = scsi_alloc_sgtables(cmd);
1276 if (unlikely(ret != BLK_STS_OK))
1277 return ret;
1278 } else {
1279 BUG_ON(blk_rq_bytes(req));
1280
1281 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1282 }
1283
1284 cmd->transfersize = blk_rq_bytes(req);
1285 return BLK_STS_OK;
1286 }
1287
1288 static blk_status_t
scsi_device_state_check(struct scsi_device * sdev,struct request * req)1289 scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1290 {
1291 switch (sdev->sdev_state) {
1292 case SDEV_CREATED:
1293 return BLK_STS_OK;
1294 case SDEV_OFFLINE:
1295 case SDEV_TRANSPORT_OFFLINE:
1296 /*
1297 * If the device is offline we refuse to process any
1298 * commands. The device must be brought online
1299 * before trying any recovery commands.
1300 */
1301 if (!sdev->offline_already) {
1302 sdev->offline_already = true;
1303 sdev_printk(KERN_ERR, sdev,
1304 "rejecting I/O to offline device\n");
1305 }
1306 return BLK_STS_IOERR;
1307 case SDEV_DEL:
1308 /*
1309 * If the device is fully deleted, we refuse to
1310 * process any commands as well.
1311 */
1312 sdev_printk(KERN_ERR, sdev,
1313 "rejecting I/O to dead device\n");
1314 return BLK_STS_IOERR;
1315 case SDEV_BLOCK:
1316 case SDEV_CREATED_BLOCK:
1317 return BLK_STS_RESOURCE;
1318 case SDEV_QUIESCE:
1319 /*
1320 * If the device is blocked we only accept power management
1321 * commands.
1322 */
1323 if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1324 return BLK_STS_RESOURCE;
1325 return BLK_STS_OK;
1326 default:
1327 /*
1328 * For any other not fully online state we only allow
1329 * power management commands.
1330 */
1331 if (req && !(req->rq_flags & RQF_PM))
1332 return BLK_STS_OFFLINE;
1333 return BLK_STS_OK;
1334 }
1335 }
1336
1337 /*
1338 * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
1339 * and return the token else return -1.
1340 */
scsi_dev_queue_ready(struct request_queue * q,struct scsi_device * sdev)1341 static inline int scsi_dev_queue_ready(struct request_queue *q,
1342 struct scsi_device *sdev)
1343 {
1344 int token;
1345
1346 token = sbitmap_get(&sdev->budget_map);
1347 if (token < 0)
1348 return -1;
1349
1350 if (!atomic_read(&sdev->device_blocked))
1351 return token;
1352
1353 /*
1354 * Only unblock if no other commands are pending and
1355 * if device_blocked has decreased to zero
1356 */
1357 if (scsi_device_busy(sdev) > 1 ||
1358 atomic_dec_return(&sdev->device_blocked) > 0) {
1359 sbitmap_put(&sdev->budget_map, token);
1360 return -1;
1361 }
1362
1363 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1364 "unblocking device at zero depth\n"));
1365
1366 return token;
1367 }
1368
1369 /*
1370 * scsi_target_queue_ready: checks if there we can send commands to target
1371 * @sdev: scsi device on starget to check.
1372 */
scsi_target_queue_ready(struct Scsi_Host * shost,struct scsi_device * sdev)1373 static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1374 struct scsi_device *sdev)
1375 {
1376 struct scsi_target *starget = scsi_target(sdev);
1377 unsigned int busy;
1378
1379 if (starget->single_lun) {
1380 spin_lock_irq(shost->host_lock);
1381 if (starget->starget_sdev_user &&
1382 starget->starget_sdev_user != sdev) {
1383 spin_unlock_irq(shost->host_lock);
1384 return 0;
1385 }
1386 starget->starget_sdev_user = sdev;
1387 spin_unlock_irq(shost->host_lock);
1388 }
1389
1390 if (starget->can_queue <= 0)
1391 return 1;
1392
1393 busy = atomic_inc_return(&starget->target_busy) - 1;
1394 if (atomic_read(&starget->target_blocked) > 0) {
1395 if (busy)
1396 goto starved;
1397
1398 /*
1399 * unblock after target_blocked iterates to zero
1400 */
1401 if (atomic_dec_return(&starget->target_blocked) > 0)
1402 goto out_dec;
1403
1404 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1405 "unblocking target at zero depth\n"));
1406 }
1407
1408 if (busy >= starget->can_queue)
1409 goto starved;
1410
1411 return 1;
1412
1413 starved:
1414 spin_lock_irq(shost->host_lock);
1415 list_move_tail(&sdev->starved_entry, &shost->starved_list);
1416 spin_unlock_irq(shost->host_lock);
1417 out_dec:
1418 if (starget->can_queue > 0)
1419 atomic_dec(&starget->target_busy);
1420 return 0;
1421 }
1422
1423 /*
1424 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1425 * return 0. We must end up running the queue again whenever 0 is
1426 * returned, else IO can hang.
1427 */
scsi_host_queue_ready(struct request_queue * q,struct Scsi_Host * shost,struct scsi_device * sdev,struct scsi_cmnd * cmd)1428 static inline int scsi_host_queue_ready(struct request_queue *q,
1429 struct Scsi_Host *shost,
1430 struct scsi_device *sdev,
1431 struct scsi_cmnd *cmd)
1432 {
1433 if (atomic_read(&shost->host_blocked) > 0) {
1434 if (scsi_host_busy(shost) > 0)
1435 goto starved;
1436
1437 /*
1438 * unblock after host_blocked iterates to zero
1439 */
1440 if (atomic_dec_return(&shost->host_blocked) > 0)
1441 goto out_dec;
1442
1443 SCSI_LOG_MLQUEUE(3,
1444 shost_printk(KERN_INFO, shost,
1445 "unblocking host at zero depth\n"));
1446 }
1447
1448 if (shost->host_self_blocked)
1449 goto starved;
1450
1451 /* We're OK to process the command, so we can't be starved */
1452 if (!list_empty(&sdev->starved_entry)) {
1453 spin_lock_irq(shost->host_lock);
1454 if (!list_empty(&sdev->starved_entry))
1455 list_del_init(&sdev->starved_entry);
1456 spin_unlock_irq(shost->host_lock);
1457 }
1458
1459 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1460
1461 return 1;
1462
1463 starved:
1464 spin_lock_irq(shost->host_lock);
1465 if (list_empty(&sdev->starved_entry))
1466 list_add_tail(&sdev->starved_entry, &shost->starved_list);
1467 spin_unlock_irq(shost->host_lock);
1468 out_dec:
1469 scsi_dec_host_busy(shost, cmd);
1470 return 0;
1471 }
1472
1473 /*
1474 * Busy state exporting function for request stacking drivers.
1475 *
1476 * For efficiency, no lock is taken to check the busy state of
1477 * shost/starget/sdev, since the returned value is not guaranteed and
1478 * may be changed after request stacking drivers call the function,
1479 * regardless of taking lock or not.
1480 *
1481 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1482 * needs to return 'not busy'. Otherwise, request stacking drivers
1483 * may hold requests forever.
1484 */
scsi_mq_lld_busy(struct request_queue * q)1485 static bool scsi_mq_lld_busy(struct request_queue *q)
1486 {
1487 struct scsi_device *sdev = q->queuedata;
1488 struct Scsi_Host *shost;
1489
1490 if (blk_queue_dying(q))
1491 return false;
1492
1493 shost = sdev->host;
1494
1495 /*
1496 * Ignore host/starget busy state.
1497 * Since block layer does not have a concept of fairness across
1498 * multiple queues, congestion of host/starget needs to be handled
1499 * in SCSI layer.
1500 */
1501 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1502 return true;
1503
1504 return false;
1505 }
1506
1507 /*
1508 * Block layer request completion callback. May be called from interrupt
1509 * context.
1510 */
scsi_complete(struct request * rq)1511 static void scsi_complete(struct request *rq)
1512 {
1513 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1514 enum scsi_disposition disposition;
1515
1516 INIT_LIST_HEAD(&cmd->eh_entry);
1517
1518 atomic_inc(&cmd->device->iodone_cnt);
1519 if (cmd->result)
1520 atomic_inc(&cmd->device->ioerr_cnt);
1521
1522 disposition = scsi_decide_disposition(cmd);
1523 if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1524 disposition = SUCCESS;
1525
1526 scsi_log_completion(cmd, disposition);
1527
1528 switch (disposition) {
1529 case SUCCESS:
1530 scsi_finish_command(cmd);
1531 break;
1532 case NEEDS_RETRY:
1533 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1534 break;
1535 case ADD_TO_MLQUEUE:
1536 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1537 break;
1538 default:
1539 scsi_eh_scmd_add(cmd);
1540 break;
1541 }
1542 }
1543
1544 /**
1545 * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1546 * @cmd: command block we are dispatching.
1547 *
1548 * Return: nonzero return request was rejected and device's queue needs to be
1549 * plugged.
1550 */
scsi_dispatch_cmd(struct scsi_cmnd * cmd)1551 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1552 {
1553 struct Scsi_Host *host = cmd->device->host;
1554 int rtn = 0;
1555
1556 atomic_inc(&cmd->device->iorequest_cnt);
1557
1558 /* check if the device is still usable */
1559 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1560 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1561 * returns an immediate error upwards, and signals
1562 * that the device is no longer present */
1563 cmd->result = DID_NO_CONNECT << 16;
1564 goto done;
1565 }
1566
1567 /* Check to see if the scsi lld made this device blocked. */
1568 if (unlikely(scsi_device_blocked(cmd->device))) {
1569 /*
1570 * in blocked state, the command is just put back on
1571 * the device queue. The suspend state has already
1572 * blocked the queue so future requests should not
1573 * occur until the device transitions out of the
1574 * suspend state.
1575 */
1576 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1577 "queuecommand : device blocked\n"));
1578 atomic_dec(&cmd->device->iorequest_cnt);
1579 return SCSI_MLQUEUE_DEVICE_BUSY;
1580 }
1581
1582 /* Store the LUN value in cmnd, if needed. */
1583 if (cmd->device->lun_in_cdb)
1584 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1585 (cmd->device->lun << 5 & 0xe0);
1586
1587 scsi_log_send(cmd);
1588
1589 /*
1590 * Before we queue this command, check if the command
1591 * length exceeds what the host adapter can handle.
1592 */
1593 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1594 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1595 "queuecommand : command too long. "
1596 "cdb_size=%d host->max_cmd_len=%d\n",
1597 cmd->cmd_len, cmd->device->host->max_cmd_len));
1598 cmd->result = (DID_ABORT << 16);
1599 goto done;
1600 }
1601
1602 if (unlikely(host->shost_state == SHOST_DEL)) {
1603 cmd->result = (DID_NO_CONNECT << 16);
1604 goto done;
1605
1606 }
1607
1608 trace_scsi_dispatch_cmd_start(cmd);
1609 rtn = host->hostt->queuecommand(host, cmd);
1610 if (rtn) {
1611 atomic_dec(&cmd->device->iorequest_cnt);
1612 trace_scsi_dispatch_cmd_error(cmd, rtn);
1613 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1614 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1615 rtn = SCSI_MLQUEUE_HOST_BUSY;
1616
1617 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1618 "queuecommand : request rejected\n"));
1619 }
1620
1621 return rtn;
1622 done:
1623 scsi_done(cmd);
1624 return 0;
1625 }
1626
1627 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
scsi_mq_inline_sgl_size(struct Scsi_Host * shost)1628 static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1629 {
1630 return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1631 sizeof(struct scatterlist);
1632 }
1633
scsi_prepare_cmd(struct request * req)1634 static blk_status_t scsi_prepare_cmd(struct request *req)
1635 {
1636 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1637 struct scsi_device *sdev = req->q->queuedata;
1638 struct Scsi_Host *shost = sdev->host;
1639 bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1640 struct scatterlist *sg;
1641
1642 scsi_init_command(sdev, cmd);
1643
1644 cmd->eh_eflags = 0;
1645 cmd->prot_type = 0;
1646 cmd->prot_flags = 0;
1647 cmd->submitter = 0;
1648 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1649 cmd->underflow = 0;
1650 cmd->transfersize = 0;
1651 cmd->host_scribble = NULL;
1652 cmd->result = 0;
1653 cmd->extra_len = 0;
1654 cmd->state = 0;
1655 if (in_flight)
1656 __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1657
1658 /*
1659 * Only clear the driver-private command data if the LLD does not supply
1660 * a function to initialize that data.
1661 */
1662 if (!shost->hostt->init_cmd_priv)
1663 memset(cmd + 1, 0, shost->hostt->cmd_size);
1664
1665 cmd->prot_op = SCSI_PROT_NORMAL;
1666 if (blk_rq_bytes(req))
1667 cmd->sc_data_direction = rq_dma_dir(req);
1668 else
1669 cmd->sc_data_direction = DMA_NONE;
1670
1671 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1672 cmd->sdb.table.sgl = sg;
1673
1674 if (scsi_host_get_prot(shost)) {
1675 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1676
1677 cmd->prot_sdb->table.sgl =
1678 (struct scatterlist *)(cmd->prot_sdb + 1);
1679 }
1680
1681 /*
1682 * Special handling for passthrough commands, which don't go to the ULP
1683 * at all:
1684 */
1685 if (blk_rq_is_passthrough(req))
1686 return scsi_setup_scsi_cmnd(sdev, req);
1687
1688 if (sdev->handler && sdev->handler->prep_fn) {
1689 blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1690
1691 if (ret != BLK_STS_OK)
1692 return ret;
1693 }
1694
1695 /* Usually overridden by the ULP */
1696 cmd->allowed = 0;
1697 memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1698 return scsi_cmd_to_driver(cmd)->init_command(cmd);
1699 }
1700
scsi_done_internal(struct scsi_cmnd * cmd,bool complete_directly)1701 static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly)
1702 {
1703 struct request *req = scsi_cmd_to_rq(cmd);
1704
1705 switch (cmd->submitter) {
1706 case SUBMITTED_BY_BLOCK_LAYER:
1707 break;
1708 case SUBMITTED_BY_SCSI_ERROR_HANDLER:
1709 return scsi_eh_done(cmd);
1710 case SUBMITTED_BY_SCSI_RESET_IOCTL:
1711 return;
1712 }
1713
1714 if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q)))
1715 return;
1716 if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1717 return;
1718 trace_scsi_dispatch_cmd_done(cmd);
1719
1720 if (complete_directly)
1721 blk_mq_complete_request_direct(req, scsi_complete);
1722 else
1723 blk_mq_complete_request(req);
1724 }
1725
scsi_done(struct scsi_cmnd * cmd)1726 void scsi_done(struct scsi_cmnd *cmd)
1727 {
1728 scsi_done_internal(cmd, false);
1729 }
1730 EXPORT_SYMBOL(scsi_done);
1731
scsi_done_direct(struct scsi_cmnd * cmd)1732 void scsi_done_direct(struct scsi_cmnd *cmd)
1733 {
1734 scsi_done_internal(cmd, true);
1735 }
1736 EXPORT_SYMBOL(scsi_done_direct);
1737
scsi_mq_put_budget(struct request_queue * q,int budget_token)1738 static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1739 {
1740 struct scsi_device *sdev = q->queuedata;
1741
1742 sbitmap_put(&sdev->budget_map, budget_token);
1743 }
1744
1745 /*
1746 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
1747 * not change behaviour from the previous unplug mechanism, experimentation
1748 * may prove this needs changing.
1749 */
1750 #define SCSI_QUEUE_DELAY 3
1751
scsi_mq_get_budget(struct request_queue * q)1752 static int scsi_mq_get_budget(struct request_queue *q)
1753 {
1754 struct scsi_device *sdev = q->queuedata;
1755 int token = scsi_dev_queue_ready(q, sdev);
1756
1757 if (token >= 0)
1758 return token;
1759
1760 atomic_inc(&sdev->restarts);
1761
1762 /*
1763 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1764 * .restarts must be incremented before .device_busy is read because the
1765 * code in scsi_run_queue_async() depends on the order of these operations.
1766 */
1767 smp_mb__after_atomic();
1768
1769 /*
1770 * If all in-flight requests originated from this LUN are completed
1771 * before reading .device_busy, sdev->device_busy will be observed as
1772 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1773 * soon. Otherwise, completion of one of these requests will observe
1774 * the .restarts flag, and the request queue will be run for handling
1775 * this request, see scsi_end_request().
1776 */
1777 if (unlikely(scsi_device_busy(sdev) == 0 &&
1778 !scsi_device_blocked(sdev)))
1779 blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1780 return -1;
1781 }
1782
scsi_mq_set_rq_budget_token(struct request * req,int token)1783 static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1784 {
1785 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1786
1787 cmd->budget_token = token;
1788 }
1789
scsi_mq_get_rq_budget_token(struct request * req)1790 static int scsi_mq_get_rq_budget_token(struct request *req)
1791 {
1792 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1793
1794 return cmd->budget_token;
1795 }
1796
scsi_queue_rq(struct blk_mq_hw_ctx * hctx,const struct blk_mq_queue_data * bd)1797 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1798 const struct blk_mq_queue_data *bd)
1799 {
1800 struct request *req = bd->rq;
1801 struct request_queue *q = req->q;
1802 struct scsi_device *sdev = q->queuedata;
1803 struct Scsi_Host *shost = sdev->host;
1804 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1805 blk_status_t ret;
1806 int reason;
1807
1808 WARN_ON_ONCE(cmd->budget_token < 0);
1809
1810 /*
1811 * If the device is not in running state we will reject some or all
1812 * commands.
1813 */
1814 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1815 ret = scsi_device_state_check(sdev, req);
1816 if (ret != BLK_STS_OK)
1817 goto out_put_budget;
1818 }
1819
1820 ret = BLK_STS_RESOURCE;
1821 if (!scsi_target_queue_ready(shost, sdev))
1822 goto out_put_budget;
1823 if (unlikely(scsi_host_in_recovery(shost))) {
1824 if (cmd->flags & SCMD_FAIL_IF_RECOVERING)
1825 ret = BLK_STS_OFFLINE;
1826 goto out_dec_target_busy;
1827 }
1828 if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1829 goto out_dec_target_busy;
1830
1831 if (!(req->rq_flags & RQF_DONTPREP)) {
1832 ret = scsi_prepare_cmd(req);
1833 if (ret != BLK_STS_OK)
1834 goto out_dec_host_busy;
1835 req->rq_flags |= RQF_DONTPREP;
1836 } else {
1837 clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1838 }
1839
1840 cmd->flags &= SCMD_PRESERVED_FLAGS;
1841 if (sdev->simple_tags)
1842 cmd->flags |= SCMD_TAGGED;
1843 if (bd->last)
1844 cmd->flags |= SCMD_LAST;
1845
1846 scsi_set_resid(cmd, 0);
1847 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1848 cmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
1849
1850 blk_mq_start_request(req);
1851 reason = scsi_dispatch_cmd(cmd);
1852 if (reason) {
1853 scsi_set_blocked(cmd, reason);
1854 ret = BLK_STS_RESOURCE;
1855 goto out_dec_host_busy;
1856 }
1857
1858 return BLK_STS_OK;
1859
1860 out_dec_host_busy:
1861 scsi_dec_host_busy(shost, cmd);
1862 out_dec_target_busy:
1863 if (scsi_target(sdev)->can_queue > 0)
1864 atomic_dec(&scsi_target(sdev)->target_busy);
1865 out_put_budget:
1866 scsi_mq_put_budget(q, cmd->budget_token);
1867 cmd->budget_token = -1;
1868 switch (ret) {
1869 case BLK_STS_OK:
1870 break;
1871 case BLK_STS_RESOURCE:
1872 if (scsi_device_blocked(sdev))
1873 ret = BLK_STS_DEV_RESOURCE;
1874 break;
1875 case BLK_STS_AGAIN:
1876 cmd->result = DID_BUS_BUSY << 16;
1877 if (req->rq_flags & RQF_DONTPREP)
1878 scsi_mq_uninit_cmd(cmd);
1879 break;
1880 default:
1881 if (unlikely(!scsi_device_online(sdev)))
1882 cmd->result = DID_NO_CONNECT << 16;
1883 else
1884 cmd->result = DID_ERROR << 16;
1885 /*
1886 * Make sure to release all allocated resources when
1887 * we hit an error, as we will never see this command
1888 * again.
1889 */
1890 if (req->rq_flags & RQF_DONTPREP)
1891 scsi_mq_uninit_cmd(cmd);
1892 scsi_run_queue_async(sdev);
1893 break;
1894 }
1895 return ret;
1896 }
1897
scsi_mq_init_request(struct blk_mq_tag_set * set,struct request * rq,unsigned int hctx_idx,unsigned int numa_node)1898 static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1899 unsigned int hctx_idx, unsigned int numa_node)
1900 {
1901 struct Scsi_Host *shost = set->driver_data;
1902 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1903 struct scatterlist *sg;
1904 int ret = 0;
1905
1906 cmd->sense_buffer =
1907 kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node);
1908 if (!cmd->sense_buffer)
1909 return -ENOMEM;
1910
1911 if (scsi_host_get_prot(shost)) {
1912 sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1913 shost->hostt->cmd_size;
1914 cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1915 }
1916
1917 if (shost->hostt->init_cmd_priv) {
1918 ret = shost->hostt->init_cmd_priv(shost, cmd);
1919 if (ret < 0)
1920 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1921 }
1922
1923 return ret;
1924 }
1925
scsi_mq_exit_request(struct blk_mq_tag_set * set,struct request * rq,unsigned int hctx_idx)1926 static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1927 unsigned int hctx_idx)
1928 {
1929 struct Scsi_Host *shost = set->driver_data;
1930 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1931
1932 if (shost->hostt->exit_cmd_priv)
1933 shost->hostt->exit_cmd_priv(shost, cmd);
1934 kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1935 }
1936
1937
scsi_mq_poll(struct blk_mq_hw_ctx * hctx,struct io_comp_batch * iob)1938 static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1939 {
1940 struct Scsi_Host *shost = hctx->driver_data;
1941
1942 if (shost->hostt->mq_poll)
1943 return shost->hostt->mq_poll(shost, hctx->queue_num);
1944
1945 return 0;
1946 }
1947
scsi_init_hctx(struct blk_mq_hw_ctx * hctx,void * data,unsigned int hctx_idx)1948 static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
1949 unsigned int hctx_idx)
1950 {
1951 struct Scsi_Host *shost = data;
1952
1953 hctx->driver_data = shost;
1954 return 0;
1955 }
1956
scsi_map_queues(struct blk_mq_tag_set * set)1957 static void scsi_map_queues(struct blk_mq_tag_set *set)
1958 {
1959 struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1960
1961 if (shost->hostt->map_queues)
1962 return shost->hostt->map_queues(shost);
1963 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1964 }
1965
scsi_init_limits(struct Scsi_Host * shost,struct queue_limits * lim)1966 void scsi_init_limits(struct Scsi_Host *shost, struct queue_limits *lim)
1967 {
1968 struct device *dev = shost->dma_dev;
1969
1970 memset(lim, 0, sizeof(*lim));
1971 lim->max_segments =
1972 min_t(unsigned short, shost->sg_tablesize, SG_MAX_SEGMENTS);
1973
1974 if (scsi_host_prot_dma(shost)) {
1975 shost->sg_prot_tablesize =
1976 min_not_zero(shost->sg_prot_tablesize,
1977 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1978 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1979 lim->max_integrity_segments = shost->sg_prot_tablesize;
1980 }
1981
1982 lim->max_hw_sectors = shost->max_sectors;
1983 lim->seg_boundary_mask = shost->dma_boundary;
1984 lim->max_segment_size = shost->max_segment_size;
1985 lim->virt_boundary_mask = shost->virt_boundary_mask;
1986 lim->dma_alignment = max_t(unsigned int,
1987 shost->dma_alignment, dma_get_cache_alignment() - 1);
1988
1989 if (shost->no_highmem)
1990 lim->bounce = BLK_BOUNCE_HIGH;
1991
1992 dma_set_seg_boundary(dev, shost->dma_boundary);
1993 dma_set_max_seg_size(dev, shost->max_segment_size);
1994 }
1995 EXPORT_SYMBOL_GPL(scsi_init_limits);
1996
1997 static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1998 .get_budget = scsi_mq_get_budget,
1999 .put_budget = scsi_mq_put_budget,
2000 .queue_rq = scsi_queue_rq,
2001 .complete = scsi_complete,
2002 .timeout = scsi_timeout,
2003 #ifdef CONFIG_BLK_DEBUG_FS
2004 .show_rq = scsi_show_rq,
2005 #endif
2006 .init_request = scsi_mq_init_request,
2007 .exit_request = scsi_mq_exit_request,
2008 .cleanup_rq = scsi_cleanup_rq,
2009 .busy = scsi_mq_lld_busy,
2010 .map_queues = scsi_map_queues,
2011 .init_hctx = scsi_init_hctx,
2012 .poll = scsi_mq_poll,
2013 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
2014 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
2015 };
2016
2017
scsi_commit_rqs(struct blk_mq_hw_ctx * hctx)2018 static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
2019 {
2020 struct Scsi_Host *shost = hctx->driver_data;
2021
2022 shost->hostt->commit_rqs(shost, hctx->queue_num);
2023 }
2024
2025 static const struct blk_mq_ops scsi_mq_ops = {
2026 .get_budget = scsi_mq_get_budget,
2027 .put_budget = scsi_mq_put_budget,
2028 .queue_rq = scsi_queue_rq,
2029 .commit_rqs = scsi_commit_rqs,
2030 .complete = scsi_complete,
2031 .timeout = scsi_timeout,
2032 #ifdef CONFIG_BLK_DEBUG_FS
2033 .show_rq = scsi_show_rq,
2034 #endif
2035 .init_request = scsi_mq_init_request,
2036 .exit_request = scsi_mq_exit_request,
2037 .cleanup_rq = scsi_cleanup_rq,
2038 .busy = scsi_mq_lld_busy,
2039 .map_queues = scsi_map_queues,
2040 .init_hctx = scsi_init_hctx,
2041 .poll = scsi_mq_poll,
2042 .set_rq_budget_token = scsi_mq_set_rq_budget_token,
2043 .get_rq_budget_token = scsi_mq_get_rq_budget_token,
2044 };
2045
scsi_mq_setup_tags(struct Scsi_Host * shost)2046 int scsi_mq_setup_tags(struct Scsi_Host *shost)
2047 {
2048 unsigned int cmd_size, sgl_size;
2049 struct blk_mq_tag_set *tag_set = &shost->tag_set;
2050
2051 sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
2052 scsi_mq_inline_sgl_size(shost));
2053 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2054 if (scsi_host_get_prot(shost))
2055 cmd_size += sizeof(struct scsi_data_buffer) +
2056 sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
2057
2058 memset(tag_set, 0, sizeof(*tag_set));
2059 if (shost->hostt->commit_rqs)
2060 tag_set->ops = &scsi_mq_ops;
2061 else
2062 tag_set->ops = &scsi_mq_ops_no_commit;
2063 tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
2064 tag_set->nr_maps = shost->nr_maps ? : 1;
2065 tag_set->queue_depth = shost->can_queue;
2066 tag_set->cmd_size = cmd_size;
2067 tag_set->numa_node = dev_to_node(shost->dma_dev);
2068 tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
2069 tag_set->flags |=
2070 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
2071 if (shost->queuecommand_may_block)
2072 tag_set->flags |= BLK_MQ_F_BLOCKING;
2073 tag_set->driver_data = shost;
2074 if (shost->host_tagset)
2075 tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
2076
2077 return blk_mq_alloc_tag_set(tag_set);
2078 }
2079
scsi_mq_free_tags(struct kref * kref)2080 void scsi_mq_free_tags(struct kref *kref)
2081 {
2082 struct Scsi_Host *shost = container_of(kref, typeof(*shost),
2083 tagset_refcnt);
2084
2085 blk_mq_free_tag_set(&shost->tag_set);
2086 complete(&shost->tagset_freed);
2087 }
2088
2089 /**
2090 * scsi_device_from_queue - return sdev associated with a request_queue
2091 * @q: The request queue to return the sdev from
2092 *
2093 * Return the sdev associated with a request queue or NULL if the
2094 * request_queue does not reference a SCSI device.
2095 */
scsi_device_from_queue(struct request_queue * q)2096 struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2097 {
2098 struct scsi_device *sdev = NULL;
2099
2100 if (q->mq_ops == &scsi_mq_ops_no_commit ||
2101 q->mq_ops == &scsi_mq_ops)
2102 sdev = q->queuedata;
2103 if (!sdev || !get_device(&sdev->sdev_gendev))
2104 sdev = NULL;
2105
2106 return sdev;
2107 }
2108 /*
2109 * pktcdvd should have been integrated into the SCSI layers, but for historical
2110 * reasons like the old IDE driver it isn't. This export allows it to safely
2111 * probe if a given device is a SCSI one and only attach to that.
2112 */
2113 #ifdef CONFIG_CDROM_PKTCDVD_MODULE
2114 EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2115 #endif
2116
2117 /**
2118 * scsi_block_requests - Utility function used by low-level drivers to prevent
2119 * further commands from being queued to the device.
2120 * @shost: host in question
2121 *
2122 * There is no timer nor any other means by which the requests get unblocked
2123 * other than the low-level driver calling scsi_unblock_requests().
2124 */
scsi_block_requests(struct Scsi_Host * shost)2125 void scsi_block_requests(struct Scsi_Host *shost)
2126 {
2127 shost->host_self_blocked = 1;
2128 }
2129 EXPORT_SYMBOL(scsi_block_requests);
2130
2131 /**
2132 * scsi_unblock_requests - Utility function used by low-level drivers to allow
2133 * further commands to be queued to the device.
2134 * @shost: host in question
2135 *
2136 * There is no timer nor any other means by which the requests get unblocked
2137 * other than the low-level driver calling scsi_unblock_requests(). This is done
2138 * as an API function so that changes to the internals of the scsi mid-layer
2139 * won't require wholesale changes to drivers that use this feature.
2140 */
scsi_unblock_requests(struct Scsi_Host * shost)2141 void scsi_unblock_requests(struct Scsi_Host *shost)
2142 {
2143 shost->host_self_blocked = 0;
2144 scsi_run_host_queues(shost);
2145 }
2146 EXPORT_SYMBOL(scsi_unblock_requests);
2147
scsi_exit_queue(void)2148 void scsi_exit_queue(void)
2149 {
2150 kmem_cache_destroy(scsi_sense_cache);
2151 }
2152
2153 /**
2154 * scsi_mode_select - issue a mode select
2155 * @sdev: SCSI device to be queried
2156 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2157 * @sp: Save page bit (0 == don't save, 1 == save)
2158 * @buffer: request buffer (may not be smaller than eight bytes)
2159 * @len: length of request buffer.
2160 * @timeout: command timeout
2161 * @retries: number of retries before failing
2162 * @data: returns a structure abstracting the mode header data
2163 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2164 * must be SCSI_SENSE_BUFFERSIZE big.
2165 *
2166 * Returns zero if successful; negative error number or scsi
2167 * status on error
2168 *
2169 */
scsi_mode_select(struct scsi_device * sdev,int pf,int sp,unsigned char * buffer,int len,int timeout,int retries,struct scsi_mode_data * data,struct scsi_sense_hdr * sshdr)2170 int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
2171 unsigned char *buffer, int len, int timeout, int retries,
2172 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2173 {
2174 unsigned char cmd[10];
2175 unsigned char *real_buffer;
2176 const struct scsi_exec_args exec_args = {
2177 .sshdr = sshdr,
2178 };
2179 int ret;
2180
2181 memset(cmd, 0, sizeof(cmd));
2182 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2183
2184 /*
2185 * Use MODE SELECT(10) if the device asked for it or if the mode page
2186 * and the mode select header cannot fit within the maximumm 255 bytes
2187 * of the MODE SELECT(6) command.
2188 */
2189 if (sdev->use_10_for_ms ||
2190 len + 4 > 255 ||
2191 data->block_descriptor_length > 255) {
2192 if (len > 65535 - 8)
2193 return -EINVAL;
2194 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2195 if (!real_buffer)
2196 return -ENOMEM;
2197 memcpy(real_buffer + 8, buffer, len);
2198 len += 8;
2199 real_buffer[0] = 0;
2200 real_buffer[1] = 0;
2201 real_buffer[2] = data->medium_type;
2202 real_buffer[3] = data->device_specific;
2203 real_buffer[4] = data->longlba ? 0x01 : 0;
2204 real_buffer[5] = 0;
2205 put_unaligned_be16(data->block_descriptor_length,
2206 &real_buffer[6]);
2207
2208 cmd[0] = MODE_SELECT_10;
2209 put_unaligned_be16(len, &cmd[7]);
2210 } else {
2211 if (data->longlba)
2212 return -EINVAL;
2213
2214 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2215 if (!real_buffer)
2216 return -ENOMEM;
2217 memcpy(real_buffer + 4, buffer, len);
2218 len += 4;
2219 real_buffer[0] = 0;
2220 real_buffer[1] = data->medium_type;
2221 real_buffer[2] = data->device_specific;
2222 real_buffer[3] = data->block_descriptor_length;
2223
2224 cmd[0] = MODE_SELECT;
2225 cmd[4] = len;
2226 }
2227
2228 ret = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_OUT, real_buffer, len,
2229 timeout, retries, &exec_args);
2230 kfree(real_buffer);
2231 return ret;
2232 }
2233 EXPORT_SYMBOL_GPL(scsi_mode_select);
2234
2235 /**
2236 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2237 * @sdev: SCSI device to be queried
2238 * @dbd: set to prevent mode sense from returning block descriptors
2239 * @modepage: mode page being requested
2240 * @subpage: sub-page of the mode page being requested
2241 * @buffer: request buffer (may not be smaller than eight bytes)
2242 * @len: length of request buffer.
2243 * @timeout: command timeout
2244 * @retries: number of retries before failing
2245 * @data: returns a structure abstracting the mode header data
2246 * @sshdr: place to put sense data (or NULL if no sense to be collected).
2247 * must be SCSI_SENSE_BUFFERSIZE big.
2248 *
2249 * Returns zero if successful, or a negative error number on failure
2250 */
2251 int
scsi_mode_sense(struct scsi_device * sdev,int dbd,int modepage,int subpage,unsigned char * buffer,int len,int timeout,int retries,struct scsi_mode_data * data,struct scsi_sense_hdr * sshdr)2252 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage,
2253 unsigned char *buffer, int len, int timeout, int retries,
2254 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2255 {
2256 unsigned char cmd[12];
2257 int use_10_for_ms;
2258 int header_length;
2259 int result;
2260 struct scsi_sense_hdr my_sshdr;
2261 struct scsi_failure failure_defs[] = {
2262 {
2263 .sense = UNIT_ATTENTION,
2264 .asc = SCMD_FAILURE_ASC_ANY,
2265 .ascq = SCMD_FAILURE_ASCQ_ANY,
2266 .allowed = retries,
2267 .result = SAM_STAT_CHECK_CONDITION,
2268 },
2269 {}
2270 };
2271 struct scsi_failures failures = {
2272 .failure_definitions = failure_defs,
2273 };
2274 const struct scsi_exec_args exec_args = {
2275 /* caller might not be interested in sense, but we need it */
2276 .sshdr = sshdr ? : &my_sshdr,
2277 .failures = &failures,
2278 };
2279
2280 memset(data, 0, sizeof(*data));
2281 memset(&cmd[0], 0, 12);
2282
2283 dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2284 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2285 cmd[2] = modepage;
2286 cmd[3] = subpage;
2287
2288 sshdr = exec_args.sshdr;
2289
2290 retry:
2291 use_10_for_ms = sdev->use_10_for_ms || len > 255;
2292
2293 if (use_10_for_ms) {
2294 if (len < 8 || len > 65535)
2295 return -EINVAL;
2296
2297 cmd[0] = MODE_SENSE_10;
2298 put_unaligned_be16(len, &cmd[7]);
2299 header_length = 8;
2300 } else {
2301 if (len < 4)
2302 return -EINVAL;
2303
2304 cmd[0] = MODE_SENSE;
2305 cmd[4] = len;
2306 header_length = 4;
2307 }
2308
2309 memset(buffer, 0, len);
2310
2311 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
2312 timeout, retries, &exec_args);
2313 if (result < 0)
2314 return result;
2315
2316 /* This code looks awful: what it's doing is making sure an
2317 * ILLEGAL REQUEST sense return identifies the actual command
2318 * byte as the problem. MODE_SENSE commands can return
2319 * ILLEGAL REQUEST if the code page isn't supported */
2320
2321 if (!scsi_status_is_good(result)) {
2322 if (scsi_sense_valid(sshdr)) {
2323 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2324 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2325 /*
2326 * Invalid command operation code: retry using
2327 * MODE SENSE(6) if this was a MODE SENSE(10)
2328 * request, except if the request mode page is
2329 * too large for MODE SENSE single byte
2330 * allocation length field.
2331 */
2332 if (use_10_for_ms) {
2333 if (len > 255)
2334 return -EIO;
2335 sdev->use_10_for_ms = 0;
2336 goto retry;
2337 }
2338 }
2339 }
2340 return -EIO;
2341 }
2342 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2343 (modepage == 6 || modepage == 8))) {
2344 /* Initio breakage? */
2345 header_length = 0;
2346 data->length = 13;
2347 data->medium_type = 0;
2348 data->device_specific = 0;
2349 data->longlba = 0;
2350 data->block_descriptor_length = 0;
2351 } else if (use_10_for_ms) {
2352 data->length = get_unaligned_be16(&buffer[0]) + 2;
2353 data->medium_type = buffer[2];
2354 data->device_specific = buffer[3];
2355 data->longlba = buffer[4] & 0x01;
2356 data->block_descriptor_length = get_unaligned_be16(&buffer[6]);
2357 } else {
2358 data->length = buffer[0] + 1;
2359 data->medium_type = buffer[1];
2360 data->device_specific = buffer[2];
2361 data->block_descriptor_length = buffer[3];
2362 }
2363 data->header_length = header_length;
2364
2365 return 0;
2366 }
2367 EXPORT_SYMBOL(scsi_mode_sense);
2368
2369 /**
2370 * scsi_test_unit_ready - test if unit is ready
2371 * @sdev: scsi device to change the state of.
2372 * @timeout: command timeout
2373 * @retries: number of retries before failing
2374 * @sshdr: outpout pointer for decoded sense information.
2375 *
2376 * Returns zero if unsuccessful or an error if TUR failed. For
2377 * removable media, UNIT_ATTENTION sets ->changed flag.
2378 **/
2379 int
scsi_test_unit_ready(struct scsi_device * sdev,int timeout,int retries,struct scsi_sense_hdr * sshdr)2380 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2381 struct scsi_sense_hdr *sshdr)
2382 {
2383 char cmd[] = {
2384 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2385 };
2386 const struct scsi_exec_args exec_args = {
2387 .sshdr = sshdr,
2388 };
2389 int result;
2390
2391 /* try to eat the UNIT_ATTENTION if there are enough retries */
2392 do {
2393 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, NULL, 0,
2394 timeout, 1, &exec_args);
2395 if (sdev->removable && result > 0 && scsi_sense_valid(sshdr) &&
2396 sshdr->sense_key == UNIT_ATTENTION)
2397 sdev->changed = 1;
2398 } while (result > 0 && scsi_sense_valid(sshdr) &&
2399 sshdr->sense_key == UNIT_ATTENTION && --retries);
2400
2401 return result;
2402 }
2403 EXPORT_SYMBOL(scsi_test_unit_ready);
2404
2405 /**
2406 * scsi_device_set_state - Take the given device through the device state model.
2407 * @sdev: scsi device to change the state of.
2408 * @state: state to change to.
2409 *
2410 * Returns zero if successful or an error if the requested
2411 * transition is illegal.
2412 */
2413 int
scsi_device_set_state(struct scsi_device * sdev,enum scsi_device_state state)2414 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2415 {
2416 enum scsi_device_state oldstate = sdev->sdev_state;
2417
2418 if (state == oldstate)
2419 return 0;
2420
2421 switch (state) {
2422 case SDEV_CREATED:
2423 switch (oldstate) {
2424 case SDEV_CREATED_BLOCK:
2425 break;
2426 default:
2427 goto illegal;
2428 }
2429 break;
2430
2431 case SDEV_RUNNING:
2432 switch (oldstate) {
2433 case SDEV_CREATED:
2434 case SDEV_OFFLINE:
2435 case SDEV_TRANSPORT_OFFLINE:
2436 case SDEV_QUIESCE:
2437 case SDEV_BLOCK:
2438 break;
2439 default:
2440 goto illegal;
2441 }
2442 break;
2443
2444 case SDEV_QUIESCE:
2445 switch (oldstate) {
2446 case SDEV_RUNNING:
2447 case SDEV_OFFLINE:
2448 case SDEV_TRANSPORT_OFFLINE:
2449 break;
2450 default:
2451 goto illegal;
2452 }
2453 break;
2454
2455 case SDEV_OFFLINE:
2456 case SDEV_TRANSPORT_OFFLINE:
2457 switch (oldstate) {
2458 case SDEV_CREATED:
2459 case SDEV_RUNNING:
2460 case SDEV_QUIESCE:
2461 case SDEV_BLOCK:
2462 break;
2463 default:
2464 goto illegal;
2465 }
2466 break;
2467
2468 case SDEV_BLOCK:
2469 switch (oldstate) {
2470 case SDEV_RUNNING:
2471 case SDEV_CREATED_BLOCK:
2472 case SDEV_QUIESCE:
2473 case SDEV_OFFLINE:
2474 break;
2475 default:
2476 goto illegal;
2477 }
2478 break;
2479
2480 case SDEV_CREATED_BLOCK:
2481 switch (oldstate) {
2482 case SDEV_CREATED:
2483 break;
2484 default:
2485 goto illegal;
2486 }
2487 break;
2488
2489 case SDEV_CANCEL:
2490 switch (oldstate) {
2491 case SDEV_CREATED:
2492 case SDEV_RUNNING:
2493 case SDEV_QUIESCE:
2494 case SDEV_OFFLINE:
2495 case SDEV_TRANSPORT_OFFLINE:
2496 break;
2497 default:
2498 goto illegal;
2499 }
2500 break;
2501
2502 case SDEV_DEL:
2503 switch (oldstate) {
2504 case SDEV_CREATED:
2505 case SDEV_RUNNING:
2506 case SDEV_OFFLINE:
2507 case SDEV_TRANSPORT_OFFLINE:
2508 case SDEV_CANCEL:
2509 case SDEV_BLOCK:
2510 case SDEV_CREATED_BLOCK:
2511 break;
2512 default:
2513 goto illegal;
2514 }
2515 break;
2516
2517 }
2518 sdev->offline_already = false;
2519 sdev->sdev_state = state;
2520 return 0;
2521
2522 illegal:
2523 SCSI_LOG_ERROR_RECOVERY(1,
2524 sdev_printk(KERN_ERR, sdev,
2525 "Illegal state transition %s->%s",
2526 scsi_device_state_name(oldstate),
2527 scsi_device_state_name(state))
2528 );
2529 return -EINVAL;
2530 }
2531 EXPORT_SYMBOL(scsi_device_set_state);
2532
2533 /**
2534 * scsi_evt_emit - emit a single SCSI device uevent
2535 * @sdev: associated SCSI device
2536 * @evt: event to emit
2537 *
2538 * Send a single uevent (scsi_event) to the associated scsi_device.
2539 */
scsi_evt_emit(struct scsi_device * sdev,struct scsi_event * evt)2540 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2541 {
2542 int idx = 0;
2543 char *envp[3];
2544
2545 switch (evt->evt_type) {
2546 case SDEV_EVT_MEDIA_CHANGE:
2547 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2548 break;
2549 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2550 scsi_rescan_device(sdev);
2551 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2552 break;
2553 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2554 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2555 break;
2556 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2557 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2558 break;
2559 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2560 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2561 break;
2562 case SDEV_EVT_LUN_CHANGE_REPORTED:
2563 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2564 break;
2565 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2566 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2567 break;
2568 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2569 envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2570 break;
2571 default:
2572 /* do nothing */
2573 break;
2574 }
2575
2576 envp[idx++] = NULL;
2577
2578 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2579 }
2580
2581 /**
2582 * scsi_evt_thread - send a uevent for each scsi event
2583 * @work: work struct for scsi_device
2584 *
2585 * Dispatch queued events to their associated scsi_device kobjects
2586 * as uevents.
2587 */
scsi_evt_thread(struct work_struct * work)2588 void scsi_evt_thread(struct work_struct *work)
2589 {
2590 struct scsi_device *sdev;
2591 enum scsi_device_event evt_type;
2592 LIST_HEAD(event_list);
2593
2594 sdev = container_of(work, struct scsi_device, event_work);
2595
2596 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2597 if (test_and_clear_bit(evt_type, sdev->pending_events))
2598 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2599
2600 while (1) {
2601 struct scsi_event *evt;
2602 struct list_head *this, *tmp;
2603 unsigned long flags;
2604
2605 spin_lock_irqsave(&sdev->list_lock, flags);
2606 list_splice_init(&sdev->event_list, &event_list);
2607 spin_unlock_irqrestore(&sdev->list_lock, flags);
2608
2609 if (list_empty(&event_list))
2610 break;
2611
2612 list_for_each_safe(this, tmp, &event_list) {
2613 evt = list_entry(this, struct scsi_event, node);
2614 list_del(&evt->node);
2615 scsi_evt_emit(sdev, evt);
2616 kfree(evt);
2617 }
2618 }
2619 }
2620
2621 /**
2622 * sdev_evt_send - send asserted event to uevent thread
2623 * @sdev: scsi_device event occurred on
2624 * @evt: event to send
2625 *
2626 * Assert scsi device event asynchronously.
2627 */
sdev_evt_send(struct scsi_device * sdev,struct scsi_event * evt)2628 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2629 {
2630 unsigned long flags;
2631
2632 #if 0
2633 /* FIXME: currently this check eliminates all media change events
2634 * for polled devices. Need to update to discriminate between AN
2635 * and polled events */
2636 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2637 kfree(evt);
2638 return;
2639 }
2640 #endif
2641
2642 spin_lock_irqsave(&sdev->list_lock, flags);
2643 list_add_tail(&evt->node, &sdev->event_list);
2644 schedule_work(&sdev->event_work);
2645 spin_unlock_irqrestore(&sdev->list_lock, flags);
2646 }
2647 EXPORT_SYMBOL_GPL(sdev_evt_send);
2648
2649 /**
2650 * sdev_evt_alloc - allocate a new scsi event
2651 * @evt_type: type of event to allocate
2652 * @gfpflags: GFP flags for allocation
2653 *
2654 * Allocates and returns a new scsi_event.
2655 */
sdev_evt_alloc(enum scsi_device_event evt_type,gfp_t gfpflags)2656 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2657 gfp_t gfpflags)
2658 {
2659 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2660 if (!evt)
2661 return NULL;
2662
2663 evt->evt_type = evt_type;
2664 INIT_LIST_HEAD(&evt->node);
2665
2666 /* evt_type-specific initialization, if any */
2667 switch (evt_type) {
2668 case SDEV_EVT_MEDIA_CHANGE:
2669 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2670 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2671 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2672 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2673 case SDEV_EVT_LUN_CHANGE_REPORTED:
2674 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2675 case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2676 default:
2677 /* do nothing */
2678 break;
2679 }
2680
2681 return evt;
2682 }
2683 EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2684
2685 /**
2686 * sdev_evt_send_simple - send asserted event to uevent thread
2687 * @sdev: scsi_device event occurred on
2688 * @evt_type: type of event to send
2689 * @gfpflags: GFP flags for allocation
2690 *
2691 * Assert scsi device event asynchronously, given an event type.
2692 */
sdev_evt_send_simple(struct scsi_device * sdev,enum scsi_device_event evt_type,gfp_t gfpflags)2693 void sdev_evt_send_simple(struct scsi_device *sdev,
2694 enum scsi_device_event evt_type, gfp_t gfpflags)
2695 {
2696 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2697 if (!evt) {
2698 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2699 evt_type);
2700 return;
2701 }
2702
2703 sdev_evt_send(sdev, evt);
2704 }
2705 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2706
2707 /**
2708 * scsi_device_quiesce - Block all commands except power management.
2709 * @sdev: scsi device to quiesce.
2710 *
2711 * This works by trying to transition to the SDEV_QUIESCE state
2712 * (which must be a legal transition). When the device is in this
2713 * state, only power management requests will be accepted, all others will
2714 * be deferred.
2715 *
2716 * Must be called with user context, may sleep.
2717 *
2718 * Returns zero if unsuccessful or an error if not.
2719 */
2720 int
scsi_device_quiesce(struct scsi_device * sdev)2721 scsi_device_quiesce(struct scsi_device *sdev)
2722 {
2723 struct request_queue *q = sdev->request_queue;
2724 int err;
2725
2726 /*
2727 * It is allowed to call scsi_device_quiesce() multiple times from
2728 * the same context but concurrent scsi_device_quiesce() calls are
2729 * not allowed.
2730 */
2731 WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2732
2733 if (sdev->quiesced_by == current)
2734 return 0;
2735
2736 blk_set_pm_only(q);
2737
2738 blk_mq_freeze_queue(q);
2739 /*
2740 * Ensure that the effect of blk_set_pm_only() will be visible
2741 * for percpu_ref_tryget() callers that occur after the queue
2742 * unfreeze even if the queue was already frozen before this function
2743 * was called. See also https://lwn.net/Articles/573497/.
2744 */
2745 synchronize_rcu();
2746 blk_mq_unfreeze_queue(q);
2747
2748 mutex_lock(&sdev->state_mutex);
2749 err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2750 if (err == 0)
2751 sdev->quiesced_by = current;
2752 else
2753 blk_clear_pm_only(q);
2754 mutex_unlock(&sdev->state_mutex);
2755
2756 return err;
2757 }
2758 EXPORT_SYMBOL(scsi_device_quiesce);
2759
2760 /**
2761 * scsi_device_resume - Restart user issued commands to a quiesced device.
2762 * @sdev: scsi device to resume.
2763 *
2764 * Moves the device from quiesced back to running and restarts the
2765 * queues.
2766 *
2767 * Must be called with user context, may sleep.
2768 */
scsi_device_resume(struct scsi_device * sdev)2769 void scsi_device_resume(struct scsi_device *sdev)
2770 {
2771 /* check if the device state was mutated prior to resume, and if
2772 * so assume the state is being managed elsewhere (for example
2773 * device deleted during suspend)
2774 */
2775 mutex_lock(&sdev->state_mutex);
2776 if (sdev->sdev_state == SDEV_QUIESCE)
2777 scsi_device_set_state(sdev, SDEV_RUNNING);
2778 if (sdev->quiesced_by) {
2779 sdev->quiesced_by = NULL;
2780 blk_clear_pm_only(sdev->request_queue);
2781 }
2782 mutex_unlock(&sdev->state_mutex);
2783 }
2784 EXPORT_SYMBOL(scsi_device_resume);
2785
2786 static void
device_quiesce_fn(struct scsi_device * sdev,void * data)2787 device_quiesce_fn(struct scsi_device *sdev, void *data)
2788 {
2789 scsi_device_quiesce(sdev);
2790 }
2791
2792 void
scsi_target_quiesce(struct scsi_target * starget)2793 scsi_target_quiesce(struct scsi_target *starget)
2794 {
2795 starget_for_each_device(starget, NULL, device_quiesce_fn);
2796 }
2797 EXPORT_SYMBOL(scsi_target_quiesce);
2798
2799 static void
device_resume_fn(struct scsi_device * sdev,void * data)2800 device_resume_fn(struct scsi_device *sdev, void *data)
2801 {
2802 scsi_device_resume(sdev);
2803 }
2804
2805 void
scsi_target_resume(struct scsi_target * starget)2806 scsi_target_resume(struct scsi_target *starget)
2807 {
2808 starget_for_each_device(starget, NULL, device_resume_fn);
2809 }
2810 EXPORT_SYMBOL(scsi_target_resume);
2811
__scsi_internal_device_block_nowait(struct scsi_device * sdev)2812 static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
2813 {
2814 if (scsi_device_set_state(sdev, SDEV_BLOCK))
2815 return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2816
2817 return 0;
2818 }
2819
scsi_start_queue(struct scsi_device * sdev)2820 void scsi_start_queue(struct scsi_device *sdev)
2821 {
2822 if (cmpxchg(&sdev->queue_stopped, 1, 0))
2823 blk_mq_unquiesce_queue(sdev->request_queue);
2824 }
2825
scsi_stop_queue(struct scsi_device * sdev)2826 static void scsi_stop_queue(struct scsi_device *sdev)
2827 {
2828 /*
2829 * The atomic variable of ->queue_stopped covers that
2830 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue.
2831 *
2832 * The caller needs to wait until quiesce is done.
2833 */
2834 if (!cmpxchg(&sdev->queue_stopped, 0, 1))
2835 blk_mq_quiesce_queue_nowait(sdev->request_queue);
2836 }
2837
2838 /**
2839 * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2840 * @sdev: device to block
2841 *
2842 * Pause SCSI command processing on the specified device. Does not sleep.
2843 *
2844 * Returns zero if successful or a negative error code upon failure.
2845 *
2846 * Notes:
2847 * This routine transitions the device to the SDEV_BLOCK state (which must be
2848 * a legal transition). When the device is in this state, command processing
2849 * is paused until the device leaves the SDEV_BLOCK state. See also
2850 * scsi_internal_device_unblock_nowait().
2851 */
scsi_internal_device_block_nowait(struct scsi_device * sdev)2852 int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2853 {
2854 int ret = __scsi_internal_device_block_nowait(sdev);
2855
2856 /*
2857 * The device has transitioned to SDEV_BLOCK. Stop the
2858 * block layer from calling the midlayer with this device's
2859 * request queue.
2860 */
2861 if (!ret)
2862 scsi_stop_queue(sdev);
2863 return ret;
2864 }
2865 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2866
2867 /**
2868 * scsi_device_block - try to transition to the SDEV_BLOCK state
2869 * @sdev: device to block
2870 * @data: dummy argument, ignored
2871 *
2872 * Pause SCSI command processing on the specified device. Callers must wait
2873 * until all ongoing scsi_queue_rq() calls have finished after this function
2874 * returns.
2875 *
2876 * Note:
2877 * This routine transitions the device to the SDEV_BLOCK state (which must be
2878 * a legal transition). When the device is in this state, command processing
2879 * is paused until the device leaves the SDEV_BLOCK state. See also
2880 * scsi_internal_device_unblock().
2881 */
scsi_device_block(struct scsi_device * sdev,void * data)2882 static void scsi_device_block(struct scsi_device *sdev, void *data)
2883 {
2884 int err;
2885 enum scsi_device_state state;
2886
2887 mutex_lock(&sdev->state_mutex);
2888 err = __scsi_internal_device_block_nowait(sdev);
2889 state = sdev->sdev_state;
2890 if (err == 0)
2891 /*
2892 * scsi_stop_queue() must be called with the state_mutex
2893 * held. Otherwise a simultaneous scsi_start_queue() call
2894 * might unquiesce the queue before we quiesce it.
2895 */
2896 scsi_stop_queue(sdev);
2897
2898 mutex_unlock(&sdev->state_mutex);
2899
2900 WARN_ONCE(err, "%s: failed to block %s in state %d\n",
2901 __func__, dev_name(&sdev->sdev_gendev), state);
2902 }
2903
2904 /**
2905 * scsi_internal_device_unblock_nowait - resume a device after a block request
2906 * @sdev: device to resume
2907 * @new_state: state to set the device to after unblocking
2908 *
2909 * Restart the device queue for a previously suspended SCSI device. Does not
2910 * sleep.
2911 *
2912 * Returns zero if successful or a negative error code upon failure.
2913 *
2914 * Notes:
2915 * This routine transitions the device to the SDEV_RUNNING state or to one of
2916 * the offline states (which must be a legal transition) allowing the midlayer
2917 * to goose the queue for this device.
2918 */
scsi_internal_device_unblock_nowait(struct scsi_device * sdev,enum scsi_device_state new_state)2919 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2920 enum scsi_device_state new_state)
2921 {
2922 switch (new_state) {
2923 case SDEV_RUNNING:
2924 case SDEV_TRANSPORT_OFFLINE:
2925 break;
2926 default:
2927 return -EINVAL;
2928 }
2929
2930 /*
2931 * Try to transition the scsi device to SDEV_RUNNING or one of the
2932 * offlined states and goose the device queue if successful.
2933 */
2934 switch (sdev->sdev_state) {
2935 case SDEV_BLOCK:
2936 case SDEV_TRANSPORT_OFFLINE:
2937 sdev->sdev_state = new_state;
2938 break;
2939 case SDEV_CREATED_BLOCK:
2940 if (new_state == SDEV_TRANSPORT_OFFLINE ||
2941 new_state == SDEV_OFFLINE)
2942 sdev->sdev_state = new_state;
2943 else
2944 sdev->sdev_state = SDEV_CREATED;
2945 break;
2946 case SDEV_CANCEL:
2947 case SDEV_OFFLINE:
2948 break;
2949 default:
2950 return -EINVAL;
2951 }
2952 scsi_start_queue(sdev);
2953
2954 return 0;
2955 }
2956 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2957
2958 /**
2959 * scsi_internal_device_unblock - resume a device after a block request
2960 * @sdev: device to resume
2961 * @new_state: state to set the device to after unblocking
2962 *
2963 * Restart the device queue for a previously suspended SCSI device. May sleep.
2964 *
2965 * Returns zero if successful or a negative error code upon failure.
2966 *
2967 * Notes:
2968 * This routine transitions the device to the SDEV_RUNNING state or to one of
2969 * the offline states (which must be a legal transition) allowing the midlayer
2970 * to goose the queue for this device.
2971 */
scsi_internal_device_unblock(struct scsi_device * sdev,enum scsi_device_state new_state)2972 static int scsi_internal_device_unblock(struct scsi_device *sdev,
2973 enum scsi_device_state new_state)
2974 {
2975 int ret;
2976
2977 mutex_lock(&sdev->state_mutex);
2978 ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2979 mutex_unlock(&sdev->state_mutex);
2980
2981 return ret;
2982 }
2983
2984 static int
target_block(struct device * dev,void * data)2985 target_block(struct device *dev, void *data)
2986 {
2987 if (scsi_is_target_device(dev))
2988 starget_for_each_device(to_scsi_target(dev), NULL,
2989 scsi_device_block);
2990 return 0;
2991 }
2992
2993 /**
2994 * scsi_block_targets - transition all SCSI child devices to SDEV_BLOCK state
2995 * @dev: a parent device of one or more scsi_target devices
2996 * @shost: the Scsi_Host to which this device belongs
2997 *
2998 * Iterate over all children of @dev, which should be scsi_target devices,
2999 * and switch all subordinate scsi devices to SDEV_BLOCK state. Wait for
3000 * ongoing scsi_queue_rq() calls to finish. May sleep.
3001 *
3002 * Note:
3003 * @dev must not itself be a scsi_target device.
3004 */
3005 void
scsi_block_targets(struct Scsi_Host * shost,struct device * dev)3006 scsi_block_targets(struct Scsi_Host *shost, struct device *dev)
3007 {
3008 WARN_ON_ONCE(scsi_is_target_device(dev));
3009 device_for_each_child(dev, NULL, target_block);
3010 blk_mq_wait_quiesce_done(&shost->tag_set);
3011 }
3012 EXPORT_SYMBOL_GPL(scsi_block_targets);
3013
3014 static void
device_unblock(struct scsi_device * sdev,void * data)3015 device_unblock(struct scsi_device *sdev, void *data)
3016 {
3017 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
3018 }
3019
3020 static int
target_unblock(struct device * dev,void * data)3021 target_unblock(struct device *dev, void *data)
3022 {
3023 if (scsi_is_target_device(dev))
3024 starget_for_each_device(to_scsi_target(dev), data,
3025 device_unblock);
3026 return 0;
3027 }
3028
3029 void
scsi_target_unblock(struct device * dev,enum scsi_device_state new_state)3030 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
3031 {
3032 if (scsi_is_target_device(dev))
3033 starget_for_each_device(to_scsi_target(dev), &new_state,
3034 device_unblock);
3035 else
3036 device_for_each_child(dev, &new_state, target_unblock);
3037 }
3038 EXPORT_SYMBOL_GPL(scsi_target_unblock);
3039
3040 /**
3041 * scsi_host_block - Try to transition all logical units to the SDEV_BLOCK state
3042 * @shost: device to block
3043 *
3044 * Pause SCSI command processing for all logical units associated with the SCSI
3045 * host and wait until pending scsi_queue_rq() calls have finished.
3046 *
3047 * Returns zero if successful or a negative error code upon failure.
3048 */
3049 int
scsi_host_block(struct Scsi_Host * shost)3050 scsi_host_block(struct Scsi_Host *shost)
3051 {
3052 struct scsi_device *sdev;
3053 int ret;
3054
3055 /*
3056 * Call scsi_internal_device_block_nowait so we can avoid
3057 * calling synchronize_rcu() for each LUN.
3058 */
3059 shost_for_each_device(sdev, shost) {
3060 mutex_lock(&sdev->state_mutex);
3061 ret = scsi_internal_device_block_nowait(sdev);
3062 mutex_unlock(&sdev->state_mutex);
3063 if (ret) {
3064 scsi_device_put(sdev);
3065 return ret;
3066 }
3067 }
3068
3069 /* Wait for ongoing scsi_queue_rq() calls to finish. */
3070 blk_mq_wait_quiesce_done(&shost->tag_set);
3071
3072 return 0;
3073 }
3074 EXPORT_SYMBOL_GPL(scsi_host_block);
3075
3076 int
scsi_host_unblock(struct Scsi_Host * shost,int new_state)3077 scsi_host_unblock(struct Scsi_Host *shost, int new_state)
3078 {
3079 struct scsi_device *sdev;
3080 int ret = 0;
3081
3082 shost_for_each_device(sdev, shost) {
3083 ret = scsi_internal_device_unblock(sdev, new_state);
3084 if (ret) {
3085 scsi_device_put(sdev);
3086 break;
3087 }
3088 }
3089 return ret;
3090 }
3091 EXPORT_SYMBOL_GPL(scsi_host_unblock);
3092
3093 /**
3094 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3095 * @sgl: scatter-gather list
3096 * @sg_count: number of segments in sg
3097 * @offset: offset in bytes into sg, on return offset into the mapped area
3098 * @len: bytes to map, on return number of bytes mapped
3099 *
3100 * Returns virtual address of the start of the mapped page
3101 */
scsi_kmap_atomic_sg(struct scatterlist * sgl,int sg_count,size_t * offset,size_t * len)3102 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3103 size_t *offset, size_t *len)
3104 {
3105 int i;
3106 size_t sg_len = 0, len_complete = 0;
3107 struct scatterlist *sg;
3108 struct page *page;
3109
3110 WARN_ON(!irqs_disabled());
3111
3112 for_each_sg(sgl, sg, sg_count, i) {
3113 len_complete = sg_len; /* Complete sg-entries */
3114 sg_len += sg->length;
3115 if (sg_len > *offset)
3116 break;
3117 }
3118
3119 if (unlikely(i == sg_count)) {
3120 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3121 "elements %d\n",
3122 __func__, sg_len, *offset, sg_count);
3123 WARN_ON(1);
3124 return NULL;
3125 }
3126
3127 /* Offset starting from the beginning of first page in this sg-entry */
3128 *offset = *offset - len_complete + sg->offset;
3129
3130 /* Assumption: contiguous pages can be accessed as "page + i" */
3131 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3132 *offset &= ~PAGE_MASK;
3133
3134 /* Bytes in this sg-entry from *offset to the end of the page */
3135 sg_len = PAGE_SIZE - *offset;
3136 if (*len > sg_len)
3137 *len = sg_len;
3138
3139 return kmap_atomic(page);
3140 }
3141 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3142
3143 /**
3144 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3145 * @virt: virtual address to be unmapped
3146 */
scsi_kunmap_atomic_sg(void * virt)3147 void scsi_kunmap_atomic_sg(void *virt)
3148 {
3149 kunmap_atomic(virt);
3150 }
3151 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3152
sdev_disable_disk_events(struct scsi_device * sdev)3153 void sdev_disable_disk_events(struct scsi_device *sdev)
3154 {
3155 atomic_inc(&sdev->disk_events_disable_depth);
3156 }
3157 EXPORT_SYMBOL(sdev_disable_disk_events);
3158
sdev_enable_disk_events(struct scsi_device * sdev)3159 void sdev_enable_disk_events(struct scsi_device *sdev)
3160 {
3161 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3162 return;
3163 atomic_dec(&sdev->disk_events_disable_depth);
3164 }
3165 EXPORT_SYMBOL(sdev_enable_disk_events);
3166
designator_prio(const unsigned char * d)3167 static unsigned char designator_prio(const unsigned char *d)
3168 {
3169 if (d[1] & 0x30)
3170 /* not associated with LUN */
3171 return 0;
3172
3173 if (d[3] == 0)
3174 /* invalid length */
3175 return 0;
3176
3177 /*
3178 * Order of preference for lun descriptor:
3179 * - SCSI name string
3180 * - NAA IEEE Registered Extended
3181 * - EUI-64 based 16-byte
3182 * - EUI-64 based 12-byte
3183 * - NAA IEEE Registered
3184 * - NAA IEEE Extended
3185 * - EUI-64 based 8-byte
3186 * - SCSI name string (truncated)
3187 * - T10 Vendor ID
3188 * as longer descriptors reduce the likelyhood
3189 * of identification clashes.
3190 */
3191
3192 switch (d[1] & 0xf) {
3193 case 8:
3194 /* SCSI name string, variable-length UTF-8 */
3195 return 9;
3196 case 3:
3197 switch (d[4] >> 4) {
3198 case 6:
3199 /* NAA registered extended */
3200 return 8;
3201 case 5:
3202 /* NAA registered */
3203 return 5;
3204 case 4:
3205 /* NAA extended */
3206 return 4;
3207 case 3:
3208 /* NAA locally assigned */
3209 return 1;
3210 default:
3211 break;
3212 }
3213 break;
3214 case 2:
3215 switch (d[3]) {
3216 case 16:
3217 /* EUI64-based, 16 byte */
3218 return 7;
3219 case 12:
3220 /* EUI64-based, 12 byte */
3221 return 6;
3222 case 8:
3223 /* EUI64-based, 8 byte */
3224 return 3;
3225 default:
3226 break;
3227 }
3228 break;
3229 case 1:
3230 /* T10 vendor ID */
3231 return 1;
3232 default:
3233 break;
3234 }
3235
3236 return 0;
3237 }
3238
3239 /**
3240 * scsi_vpd_lun_id - return a unique device identification
3241 * @sdev: SCSI device
3242 * @id: buffer for the identification
3243 * @id_len: length of the buffer
3244 *
3245 * Copies a unique device identification into @id based
3246 * on the information in the VPD page 0x83 of the device.
3247 * The string will be formatted as a SCSI name string.
3248 *
3249 * Returns the length of the identification or error on failure.
3250 * If the identifier is longer than the supplied buffer the actual
3251 * identifier length is returned and the buffer is not zero-padded.
3252 */
scsi_vpd_lun_id(struct scsi_device * sdev,char * id,size_t id_len)3253 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3254 {
3255 u8 cur_id_prio = 0;
3256 u8 cur_id_size = 0;
3257 const unsigned char *d, *cur_id_str;
3258 const struct scsi_vpd *vpd_pg83;
3259 int id_size = -EINVAL;
3260
3261 rcu_read_lock();
3262 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3263 if (!vpd_pg83) {
3264 rcu_read_unlock();
3265 return -ENXIO;
3266 }
3267
3268 /* The id string must be at least 20 bytes + terminating NULL byte */
3269 if (id_len < 21) {
3270 rcu_read_unlock();
3271 return -EINVAL;
3272 }
3273
3274 memset(id, 0, id_len);
3275 for (d = vpd_pg83->data + 4;
3276 d < vpd_pg83->data + vpd_pg83->len;
3277 d += d[3] + 4) {
3278 u8 prio = designator_prio(d);
3279
3280 if (prio == 0 || cur_id_prio > prio)
3281 continue;
3282
3283 switch (d[1] & 0xf) {
3284 case 0x1:
3285 /* T10 Vendor ID */
3286 if (cur_id_size > d[3])
3287 break;
3288 cur_id_prio = prio;
3289 cur_id_size = d[3];
3290 if (cur_id_size + 4 > id_len)
3291 cur_id_size = id_len - 4;
3292 cur_id_str = d + 4;
3293 id_size = snprintf(id, id_len, "t10.%*pE",
3294 cur_id_size, cur_id_str);
3295 break;
3296 case 0x2:
3297 /* EUI-64 */
3298 cur_id_prio = prio;
3299 cur_id_size = d[3];
3300 cur_id_str = d + 4;
3301 switch (cur_id_size) {
3302 case 8:
3303 id_size = snprintf(id, id_len,
3304 "eui.%8phN",
3305 cur_id_str);
3306 break;
3307 case 12:
3308 id_size = snprintf(id, id_len,
3309 "eui.%12phN",
3310 cur_id_str);
3311 break;
3312 case 16:
3313 id_size = snprintf(id, id_len,
3314 "eui.%16phN",
3315 cur_id_str);
3316 break;
3317 default:
3318 break;
3319 }
3320 break;
3321 case 0x3:
3322 /* NAA */
3323 cur_id_prio = prio;
3324 cur_id_size = d[3];
3325 cur_id_str = d + 4;
3326 switch (cur_id_size) {
3327 case 8:
3328 id_size = snprintf(id, id_len,
3329 "naa.%8phN",
3330 cur_id_str);
3331 break;
3332 case 16:
3333 id_size = snprintf(id, id_len,
3334 "naa.%16phN",
3335 cur_id_str);
3336 break;
3337 default:
3338 break;
3339 }
3340 break;
3341 case 0x8:
3342 /* SCSI name string */
3343 if (cur_id_size > d[3])
3344 break;
3345 /* Prefer others for truncated descriptor */
3346 if (d[3] > id_len) {
3347 prio = 2;
3348 if (cur_id_prio > prio)
3349 break;
3350 }
3351 cur_id_prio = prio;
3352 cur_id_size = id_size = d[3];
3353 cur_id_str = d + 4;
3354 if (cur_id_size >= id_len)
3355 cur_id_size = id_len - 1;
3356 memcpy(id, cur_id_str, cur_id_size);
3357 break;
3358 default:
3359 break;
3360 }
3361 }
3362 rcu_read_unlock();
3363
3364 return id_size;
3365 }
3366 EXPORT_SYMBOL(scsi_vpd_lun_id);
3367
3368 /*
3369 * scsi_vpd_tpg_id - return a target port group identifier
3370 * @sdev: SCSI device
3371 *
3372 * Returns the Target Port Group identifier from the information
3373 * froom VPD page 0x83 of the device.
3374 *
3375 * Returns the identifier or error on failure.
3376 */
scsi_vpd_tpg_id(struct scsi_device * sdev,int * rel_id)3377 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3378 {
3379 const unsigned char *d;
3380 const struct scsi_vpd *vpd_pg83;
3381 int group_id = -EAGAIN, rel_port = -1;
3382
3383 rcu_read_lock();
3384 vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3385 if (!vpd_pg83) {
3386 rcu_read_unlock();
3387 return -ENXIO;
3388 }
3389
3390 d = vpd_pg83->data + 4;
3391 while (d < vpd_pg83->data + vpd_pg83->len) {
3392 switch (d[1] & 0xf) {
3393 case 0x4:
3394 /* Relative target port */
3395 rel_port = get_unaligned_be16(&d[6]);
3396 break;
3397 case 0x5:
3398 /* Target port group */
3399 group_id = get_unaligned_be16(&d[6]);
3400 break;
3401 default:
3402 break;
3403 }
3404 d += d[3] + 4;
3405 }
3406 rcu_read_unlock();
3407
3408 if (group_id >= 0 && rel_id && rel_port != -1)
3409 *rel_id = rel_port;
3410
3411 return group_id;
3412 }
3413 EXPORT_SYMBOL(scsi_vpd_tpg_id);
3414
3415 /**
3416 * scsi_build_sense - build sense data for a command
3417 * @scmd: scsi command for which the sense should be formatted
3418 * @desc: Sense format (non-zero == descriptor format,
3419 * 0 == fixed format)
3420 * @key: Sense key
3421 * @asc: Additional sense code
3422 * @ascq: Additional sense code qualifier
3423 *
3424 **/
scsi_build_sense(struct scsi_cmnd * scmd,int desc,u8 key,u8 asc,u8 ascq)3425 void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3426 {
3427 scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3428 scmd->result = SAM_STAT_CHECK_CONDITION;
3429 }
3430 EXPORT_SYMBOL_GPL(scsi_build_sense);
3431
3432 #ifdef CONFIG_SCSI_LIB_KUNIT_TEST
3433 #include "scsi_lib_test.c"
3434 #endif
3435