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