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1/*
2 * scsi.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
4 * Copyright (C) 2002, 2003 Christoph Hellwig
5 *
6 * generic mid-level SCSI driver
7 * Initial versions: Drew Eckhardt
8 * Subsequent revisions: Eric Youngdale
9 *
10 * <drew@colorado.edu>
11 *
12 * Bug correction thanks go to :
13 * Rik Faith <faith@cs.unc.edu>
14 * Tommy Thorn <tthorn>
15 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
16 *
17 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
18 * add scatter-gather, multiple outstanding request, and other
19 * enhancements.
20 *
21 * Native multichannel, wide scsi, /proc/scsi and hot plugging
22 * support added by Michael Neuffer <mike@i-connect.net>
23 *
24 * Added request_module("scsi_hostadapter") for kerneld:
25 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
26 * Bjorn Ekwall <bj0rn@blox.se>
27 * (changed to kmod)
28 *
29 * Major improvements to the timeout, abort, and reset processing,
30 * as well as performance modifications for large queue depths by
31 * Leonard N. Zubkoff <lnz@dandelion.com>
32 *
33 * Converted cli() code to spinlocks, Ingo Molnar
34 *
35 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
36 *
37 * out_of_space hacks, D. Gilbert (dpg) 990608
38 */
39
40#include <linux/module.h>
41#include <linux/moduleparam.h>
42#include <linux/kernel.h>
43#include <linux/timer.h>
44#include <linux/string.h>
45#include <linux/slab.h>
46#include <linux/blkdev.h>
47#include <linux/delay.h>
48#include <linux/init.h>
49#include <linux/completion.h>
50#include <linux/unistd.h>
51#include <linux/spinlock.h>
52#include <linux/kmod.h>
53#include <linux/interrupt.h>
54#include <linux/notifier.h>
55#include <linux/cpu.h>
56#include <linux/mutex.h>
57#include <linux/async.h>
58#include <asm/unaligned.h>
59
60#include <scsi/scsi.h>
61#include <scsi/scsi_cmnd.h>
62#include <scsi/scsi_dbg.h>
63#include <scsi/scsi_device.h>
64#include <scsi/scsi_driver.h>
65#include <scsi/scsi_eh.h>
66#include <scsi/scsi_host.h>
67#include <scsi/scsi_tcq.h>
68
69#include "scsi_priv.h"
70#include "scsi_logging.h"
71
72#define CREATE_TRACE_POINTS
73#include <trace/events/scsi.h>
74
75/*
76 * Definitions and constants.
77 */
78
79/*
80 * Note - the initial logging level can be set here to log events at boot time.
81 * After the system is up, you may enable logging via the /proc interface.
82 */
83unsigned int scsi_logging_level;
84#if defined(CONFIG_SCSI_LOGGING)
85EXPORT_SYMBOL(scsi_logging_level);
86#endif
87
88/* sd, scsi core and power management need to coordinate flushing async actions */
89ASYNC_DOMAIN(scsi_sd_probe_domain);
90EXPORT_SYMBOL(scsi_sd_probe_domain);
91
92/*
93 * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of
94 * asynchronous system resume operations. It is marked 'exclusive' to avoid
95 * being included in the async_synchronize_full() that is invoked by
96 * dpm_resume()
97 */
98ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
99EXPORT_SYMBOL(scsi_sd_pm_domain);
100
101struct scsi_host_cmd_pool {
102 struct kmem_cache *cmd_slab;
103 struct kmem_cache *sense_slab;
104 unsigned int users;
105 char *cmd_name;
106 char *sense_name;
107 unsigned int slab_flags;
108 gfp_t gfp_mask;
109};
110
111static struct scsi_host_cmd_pool scsi_cmd_pool = {
112 .cmd_name = "scsi_cmd_cache",
113 .sense_name = "scsi_sense_cache",
114 .slab_flags = SLAB_HWCACHE_ALIGN,
115};
116
117static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
118 .cmd_name = "scsi_cmd_cache(DMA)",
119 .sense_name = "scsi_sense_cache(DMA)",
120 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
121 .gfp_mask = __GFP_DMA,
122};
123
124static DEFINE_MUTEX(host_cmd_pool_mutex);
125
126/**
127 * scsi_host_free_command - internal function to release a command
128 * @shost: host to free the command for
129 * @cmd: command to release
130 *
131 * the command must previously have been allocated by
132 * scsi_host_alloc_command.
133 */
134static void
135scsi_host_free_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
136{
137 struct scsi_host_cmd_pool *pool = shost->cmd_pool;
138
139 if (cmd->prot_sdb)
140 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
141 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
142 kmem_cache_free(pool->cmd_slab, cmd);
143}
144
145/**
146 * scsi_host_alloc_command - internal function to allocate command
147 * @shost: SCSI host whose pool to allocate from
148 * @gfp_mask: mask for the allocation
149 *
150 * Returns a fully allocated command with sense buffer and protection
151 * data buffer (where applicable) or NULL on failure
152 */
153static struct scsi_cmnd *
154scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
155{
156 struct scsi_host_cmd_pool *pool = shost->cmd_pool;
157 struct scsi_cmnd *cmd;
158
159 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
160 if (!cmd)
161 goto fail;
162
163 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
164 gfp_mask | pool->gfp_mask);
165 if (!cmd->sense_buffer)
166 goto fail_free_cmd;
167
168 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
169 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
170 if (!cmd->prot_sdb)
171 goto fail_free_sense;
172 }
173
174 return cmd;
175
176fail_free_sense:
177 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
178fail_free_cmd:
179 kmem_cache_free(pool->cmd_slab, cmd);
180fail:
181 return NULL;
182}
183
184/**
185 * __scsi_get_command - Allocate a struct scsi_cmnd
186 * @shost: host to transmit command
187 * @gfp_mask: allocation mask
188 *
189 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
190 * host's free_list if necessary.
191 */
192static struct scsi_cmnd *
193__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
194{
195 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
196
197 if (unlikely(!cmd)) {
198 unsigned long flags;
199
200 spin_lock_irqsave(&shost->free_list_lock, flags);
201 if (likely(!list_empty(&shost->free_list))) {
202 cmd = list_entry(shost->free_list.next,
203 struct scsi_cmnd, list);
204 list_del_init(&cmd->list);
205 }
206 spin_unlock_irqrestore(&shost->free_list_lock, flags);
207
208 if (cmd) {
209 void *buf, *prot;
210
211 buf = cmd->sense_buffer;
212 prot = cmd->prot_sdb;
213
214 memset(cmd, 0, sizeof(*cmd));
215
216 cmd->sense_buffer = buf;
217 cmd->prot_sdb = prot;
218 }
219 }
220
221 return cmd;
222}
223
224/**
225 * scsi_get_command - Allocate and setup a scsi command block
226 * @dev: parent scsi device
227 * @gfp_mask: allocator flags
228 *
229 * Returns: The allocated scsi command structure.
230 */
231struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
232{
233 struct scsi_cmnd *cmd = __scsi_get_command(dev->host, gfp_mask);
234 unsigned long flags;
235
236 if (unlikely(cmd == NULL))
237 return NULL;
238
239 cmd->device = dev;
240 INIT_LIST_HEAD(&cmd->list);
241 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
242 spin_lock_irqsave(&dev->list_lock, flags);
243 list_add_tail(&cmd->list, &dev->cmd_list);
244 spin_unlock_irqrestore(&dev->list_lock, flags);
245 cmd->jiffies_at_alloc = jiffies;
246 return cmd;
247}
248
249/**
250 * __scsi_put_command - Free a struct scsi_cmnd
251 * @shost: dev->host
252 * @cmd: Command to free
253 */
254static void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
255{
256 unsigned long flags;
257
258 if (unlikely(list_empty(&shost->free_list))) {
259 spin_lock_irqsave(&shost->free_list_lock, flags);
260 if (list_empty(&shost->free_list)) {
261 list_add(&cmd->list, &shost->free_list);
262 cmd = NULL;
263 }
264 spin_unlock_irqrestore(&shost->free_list_lock, flags);
265 }
266
267 if (likely(cmd != NULL))
268 scsi_host_free_command(shost, cmd);
269}
270
271/**
272 * scsi_put_command - Free a scsi command block
273 * @cmd: command block to free
274 *
275 * Returns: Nothing.
276 *
277 * Notes: The command must not belong to any lists.
278 */
279void scsi_put_command(struct scsi_cmnd *cmd)
280{
281 unsigned long flags;
282
283 /* serious error if the command hasn't come from a device list */
284 spin_lock_irqsave(&cmd->device->list_lock, flags);
285 BUG_ON(list_empty(&cmd->list));
286 list_del_init(&cmd->list);
287 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
288
289 BUG_ON(delayed_work_pending(&cmd->abort_work));
290
291 __scsi_put_command(cmd->device->host, cmd);
292}
293
294static struct scsi_host_cmd_pool *
295scsi_find_host_cmd_pool(struct Scsi_Host *shost)
296{
297 if (shost->hostt->cmd_size)
298 return shost->hostt->cmd_pool;
299 if (shost->unchecked_isa_dma)
300 return &scsi_cmd_dma_pool;
301 return &scsi_cmd_pool;
302}
303
304static void
305scsi_free_host_cmd_pool(struct scsi_host_cmd_pool *pool)
306{
307 kfree(pool->sense_name);
308 kfree(pool->cmd_name);
309 kfree(pool);
310}
311
312static struct scsi_host_cmd_pool *
313scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
314{
315 struct scsi_host_template *hostt = shost->hostt;
316 struct scsi_host_cmd_pool *pool;
317
318 pool = kzalloc(sizeof(*pool), GFP_KERNEL);
319 if (!pool)
320 return NULL;
321
322 pool->cmd_name = kasprintf(GFP_KERNEL, "%s_cmd", hostt->proc_name);
323 pool->sense_name = kasprintf(GFP_KERNEL, "%s_sense", hostt->proc_name);
324 if (!pool->cmd_name || !pool->sense_name) {
325 scsi_free_host_cmd_pool(pool);
326 return NULL;
327 }
328
329 pool->slab_flags = SLAB_HWCACHE_ALIGN;
330 if (shost->unchecked_isa_dma) {
331 pool->slab_flags |= SLAB_CACHE_DMA;
332 pool->gfp_mask = __GFP_DMA;
333 }
334
335 if (hostt->cmd_size)
336 hostt->cmd_pool = pool;
337
338 return pool;
339}
340
341static struct scsi_host_cmd_pool *
342scsi_get_host_cmd_pool(struct Scsi_Host *shost)
343{
344 struct scsi_host_template *hostt = shost->hostt;
345 struct scsi_host_cmd_pool *retval = NULL, *pool;
346 size_t cmd_size = sizeof(struct scsi_cmnd) + hostt->cmd_size;
347
348 /*
349 * Select a command slab for this host and create it if not
350 * yet existent.
351 */
352 mutex_lock(&host_cmd_pool_mutex);
353 pool = scsi_find_host_cmd_pool(shost);
354 if (!pool) {
355 pool = scsi_alloc_host_cmd_pool(shost);
356 if (!pool)
357 goto out;
358 }
359
360 if (!pool->users) {
361 pool->cmd_slab = kmem_cache_create(pool->cmd_name, cmd_size, 0,
362 pool->slab_flags, NULL);
363 if (!pool->cmd_slab)
364 goto out_free_pool;
365
366 pool->sense_slab = kmem_cache_create(pool->sense_name,
367 SCSI_SENSE_BUFFERSIZE, 0,
368 pool->slab_flags, NULL);
369 if (!pool->sense_slab)
370 goto out_free_slab;
371 }
372
373 pool->users++;
374 retval = pool;
375out:
376 mutex_unlock(&host_cmd_pool_mutex);
377 return retval;
378
379out_free_slab:
380 kmem_cache_destroy(pool->cmd_slab);
381out_free_pool:
382 if (hostt->cmd_size) {
383 scsi_free_host_cmd_pool(pool);
384 hostt->cmd_pool = NULL;
385 }
386 goto out;
387}
388
389static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
390{
391 struct scsi_host_template *hostt = shost->hostt;
392 struct scsi_host_cmd_pool *pool;
393
394 mutex_lock(&host_cmd_pool_mutex);
395 pool = scsi_find_host_cmd_pool(shost);
396
397 /*
398 * This may happen if a driver has a mismatched get and put
399 * of the command pool; the driver should be implicated in
400 * the stack trace
401 */
402 BUG_ON(pool->users == 0);
403
404 if (!--pool->users) {
405 kmem_cache_destroy(pool->cmd_slab);
406 kmem_cache_destroy(pool->sense_slab);
407 if (hostt->cmd_size) {
408 scsi_free_host_cmd_pool(pool);
409 hostt->cmd_pool = NULL;
410 }
411 }
412 mutex_unlock(&host_cmd_pool_mutex);
413}
414
415/**
416 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
417 * @shost: host to allocate the freelist for.
418 *
419 * Description: The command freelist protects against system-wide out of memory
420 * deadlock by preallocating one SCSI command structure for each host, so the
421 * system can always write to a swap file on a device associated with that host.
422 *
423 * Returns: Nothing.
424 */
425int scsi_setup_command_freelist(struct Scsi_Host *shost)
426{
427 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
428 struct scsi_cmnd *cmd;
429
430 spin_lock_init(&shost->free_list_lock);
431 INIT_LIST_HEAD(&shost->free_list);
432
433 shost->cmd_pool = scsi_get_host_cmd_pool(shost);
434 if (!shost->cmd_pool)
435 return -ENOMEM;
436
437 /*
438 * Get one backup command for this host.
439 */
440 cmd = scsi_host_alloc_command(shost, gfp_mask);
441 if (!cmd) {
442 scsi_put_host_cmd_pool(shost);
443 shost->cmd_pool = NULL;
444 return -ENOMEM;
445 }
446 list_add(&cmd->list, &shost->free_list);
447 return 0;
448}
449
450/**
451 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
452 * @shost: host whose freelist is going to be destroyed
453 */
454void scsi_destroy_command_freelist(struct Scsi_Host *shost)
455{
456 /*
457 * If cmd_pool is NULL the free list was not initialized, so
458 * do not attempt to release resources.
459 */
460 if (!shost->cmd_pool)
461 return;
462
463 while (!list_empty(&shost->free_list)) {
464 struct scsi_cmnd *cmd;
465
466 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
467 list_del_init(&cmd->list);
468 scsi_host_free_command(shost, cmd);
469 }
470 shost->cmd_pool = NULL;
471 scsi_put_host_cmd_pool(shost);
472}
473
474#ifdef CONFIG_SCSI_LOGGING
475void scsi_log_send(struct scsi_cmnd *cmd)
476{
477 unsigned int level;
478
479 /*
480 * If ML QUEUE log level is greater than or equal to:
481 *
482 * 1: nothing (match completion)
483 *
484 * 2: log opcode + command of all commands + cmd address
485 *
486 * 3: same as 2
487 *
488 * 4: same as 3
489 */
490 if (unlikely(scsi_logging_level)) {
491 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
492 SCSI_LOG_MLQUEUE_BITS);
493 if (level > 1) {
494 scmd_printk(KERN_INFO, cmd,
495 "Send: scmd 0x%p\n", cmd);
496 scsi_print_command(cmd);
497 }
498 }
499}
500
501void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
502{
503 unsigned int level;
504
505 /*
506 * If ML COMPLETE log level is greater than or equal to:
507 *
508 * 1: log disposition, result, opcode + command, and conditionally
509 * sense data for failures or non SUCCESS dispositions.
510 *
511 * 2: same as 1 but for all command completions.
512 *
513 * 3: same as 2
514 *
515 * 4: same as 3 plus dump extra junk
516 */
517 if (unlikely(scsi_logging_level)) {
518 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
519 SCSI_LOG_MLCOMPLETE_BITS);
520 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
521 (level > 1)) {
522 scsi_print_result(cmd, "Done", disposition);
523 scsi_print_command(cmd);
524 if (status_byte(cmd->result) & CHECK_CONDITION)
525 scsi_print_sense(cmd);
526 if (level > 3)
527 scmd_printk(KERN_INFO, cmd,
528 "scsi host busy %d failed %d\n",
529 atomic_read(&cmd->device->host->host_busy),
530 cmd->device->host->host_failed);
531 }
532 }
533}
534#endif
535
536/**
537 * scsi_cmd_get_serial - Assign a serial number to a command
538 * @host: the scsi host
539 * @cmd: command to assign serial number to
540 *
541 * Description: a serial number identifies a request for error recovery
542 * and debugging purposes. Protected by the Host_Lock of host.
543 */
544void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
545{
546 cmd->serial_number = host->cmd_serial_number++;
547 if (cmd->serial_number == 0)
548 cmd->serial_number = host->cmd_serial_number++;
549}
550EXPORT_SYMBOL(scsi_cmd_get_serial);
551
552/**
553 * scsi_finish_command - cleanup and pass command back to upper layer
554 * @cmd: the command
555 *
556 * Description: Pass command off to upper layer for finishing of I/O
557 * request, waking processes that are waiting on results,
558 * etc.
559 */
560void scsi_finish_command(struct scsi_cmnd *cmd)
561{
562 struct scsi_device *sdev = cmd->device;
563 struct scsi_target *starget = scsi_target(sdev);
564 struct Scsi_Host *shost = sdev->host;
565 struct scsi_driver *drv;
566 unsigned int good_bytes;
567
568 scsi_device_unbusy(sdev);
569
570 /*
571 * Clear the flags that say that the device/target/host is no longer
572 * capable of accepting new commands.
573 */
574 if (atomic_read(&shost->host_blocked))
575 atomic_set(&shost->host_blocked, 0);
576 if (atomic_read(&starget->target_blocked))
577 atomic_set(&starget->target_blocked, 0);
578 if (atomic_read(&sdev->device_blocked))
579 atomic_set(&sdev->device_blocked, 0);
580
581 /*
582 * If we have valid sense information, then some kind of recovery
583 * must have taken place. Make a note of this.
584 */
585 if (SCSI_SENSE_VALID(cmd))
586 cmd->result |= (DRIVER_SENSE << 24);
587
588 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
589 "Notifying upper driver of completion "
590 "(result %x)\n", cmd->result));
591
592 good_bytes = scsi_bufflen(cmd);
593 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
594 int old_good_bytes = good_bytes;
595 drv = scsi_cmd_to_driver(cmd);
596 if (drv->done)
597 good_bytes = drv->done(cmd);
598 /*
599 * USB may not give sense identifying bad sector and
600 * simply return a residue instead, so subtract off the
601 * residue if drv->done() error processing indicates no
602 * change to the completion length.
603 */
604 if (good_bytes == old_good_bytes)
605 good_bytes -= scsi_get_resid(cmd);
606 }
607 scsi_io_completion(cmd, good_bytes);
608}
609
610/**
611 * scsi_change_queue_depth - change a device's queue depth
612 * @sdev: SCSI Device in question
613 * @depth: number of commands allowed to be queued to the driver
614 *
615 * Sets the device queue depth and returns the new value.
616 */
617int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
618{
619 if (depth > 0) {
620 sdev->queue_depth = depth;
621 wmb();
622 }
623
624 return sdev->queue_depth;
625}
626EXPORT_SYMBOL(scsi_change_queue_depth);
627
628/**
629 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
630 * @sdev: SCSI Device in question
631 * @depth: Current number of outstanding SCSI commands on this device,
632 * not counting the one returned as QUEUE_FULL.
633 *
634 * Description: This function will track successive QUEUE_FULL events on a
635 * specific SCSI device to determine if and when there is a
636 * need to adjust the queue depth on the device.
637 *
638 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
639 * -1 - Drop back to untagged operation using host->cmd_per_lun
640 * as the untagged command depth
641 *
642 * Lock Status: None held on entry
643 *
644 * Notes: Low level drivers may call this at any time and we will do
645 * "The Right Thing." We are interrupt context safe.
646 */
647int scsi_track_queue_full(struct scsi_device *sdev, int depth)
648{
649
650 /*
651 * Don't let QUEUE_FULLs on the same
652 * jiffies count, they could all be from
653 * same event.
654 */
655 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
656 return 0;
657
658 sdev->last_queue_full_time = jiffies;
659 if (sdev->last_queue_full_depth != depth) {
660 sdev->last_queue_full_count = 1;
661 sdev->last_queue_full_depth = depth;
662 } else {
663 sdev->last_queue_full_count++;
664 }
665
666 if (sdev->last_queue_full_count <= 10)
667 return 0;
668
669 return scsi_change_queue_depth(sdev, depth);
670}
671EXPORT_SYMBOL(scsi_track_queue_full);
672
673/**
674 * scsi_vpd_inquiry - Request a device provide us with a VPD page
675 * @sdev: The device to ask
676 * @buffer: Where to put the result
677 * @page: Which Vital Product Data to return
678 * @len: The length of the buffer
679 *
680 * This is an internal helper function. You probably want to use
681 * scsi_get_vpd_page instead.
682 *
683 * Returns size of the vpd page on success or a negative error number.
684 */
685static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
686 u8 page, unsigned len)
687{
688 int result;
689 unsigned char cmd[16];
690
691 if (len < 4)
692 return -EINVAL;
693
694 cmd[0] = INQUIRY;
695 cmd[1] = 1; /* EVPD */
696 cmd[2] = page;
697 cmd[3] = len >> 8;
698 cmd[4] = len & 0xff;
699 cmd[5] = 0; /* Control byte */
700
701 /*
702 * I'm not convinced we need to try quite this hard to get VPD, but
703 * all the existing users tried this hard.
704 */
705 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
706 len, NULL, 30 * HZ, 3, NULL);
707 if (result)
708 return -EIO;
709
710 /* Sanity check that we got the page back that we asked for */
711 if (buffer[1] != page)
712 return -EIO;
713
714 return get_unaligned_be16(&buffer[2]) + 4;
715}
716
717/**
718 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
719 * @sdev: The device to ask
720 * @page: Which Vital Product Data to return
721 * @buf: where to store the VPD
722 * @buf_len: number of bytes in the VPD buffer area
723 *
724 * SCSI devices may optionally supply Vital Product Data. Each 'page'
725 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
726 * If the device supports this VPD page, this routine returns a pointer
727 * to a buffer containing the data from that page. The caller is
728 * responsible for calling kfree() on this pointer when it is no longer
729 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
730 */
731int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
732 int buf_len)
733{
734 int i, result;
735
736 if (sdev->skip_vpd_pages)
737 goto fail;
738
739 /* Ask for all the pages supported by this device */
740 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
741 if (result < 4)
742 goto fail;
743
744 /* If the user actually wanted this page, we can skip the rest */
745 if (page == 0)
746 return 0;
747
748 for (i = 4; i < min(result, buf_len); i++)
749 if (buf[i] == page)
750 goto found;
751
752 if (i < result && i >= buf_len)
753 /* ran off the end of the buffer, give us benefit of doubt */
754 goto found;
755 /* The device claims it doesn't support the requested page */
756 goto fail;
757
758 found:
759 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
760 if (result < 0)
761 goto fail;
762
763 return 0;
764
765 fail:
766 return -EINVAL;
767}
768EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
769
770/**
771 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
772 * @sdev: The device to ask
773 *
774 * Attach the 'Device Identification' VPD page (0x83) and the
775 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
776 * structure. This information can be used to identify the device
777 * uniquely.
778 */
779void scsi_attach_vpd(struct scsi_device *sdev)
780{
781 int result, i;
782 int vpd_len = SCSI_VPD_PG_LEN;
783 int pg80_supported = 0;
784 int pg83_supported = 0;
785 unsigned char __rcu *vpd_buf, *orig_vpd_buf = NULL;
786
787 if (!scsi_device_supports_vpd(sdev))
788 return;
789
790retry_pg0:
791 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
792 if (!vpd_buf)
793 return;
794
795 /* Ask for all the pages supported by this device */
796 result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);
797 if (result < 0) {
798 kfree(vpd_buf);
799 return;
800 }
801 if (result > vpd_len) {
802 vpd_len = result;
803 kfree(vpd_buf);
804 goto retry_pg0;
805 }
806
807 for (i = 4; i < result; i++) {
808 if (vpd_buf[i] == 0x80)
809 pg80_supported = 1;
810 if (vpd_buf[i] == 0x83)
811 pg83_supported = 1;
812 }
813 kfree(vpd_buf);
814 vpd_len = SCSI_VPD_PG_LEN;
815
816 if (pg80_supported) {
817retry_pg80:
818 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
819 if (!vpd_buf)
820 return;
821
822 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);
823 if (result < 0) {
824 kfree(vpd_buf);
825 return;
826 }
827 if (result > vpd_len) {
828 vpd_len = result;
829 kfree(vpd_buf);
830 goto retry_pg80;
831 }
832 mutex_lock(&sdev->inquiry_mutex);
833 orig_vpd_buf = sdev->vpd_pg80;
834 sdev->vpd_pg80_len = result;
835 rcu_assign_pointer(sdev->vpd_pg80, vpd_buf);
836 mutex_unlock(&sdev->inquiry_mutex);
837 synchronize_rcu();
838 if (orig_vpd_buf) {
839 kfree(orig_vpd_buf);
840 orig_vpd_buf = NULL;
841 }
842 vpd_len = SCSI_VPD_PG_LEN;
843 }
844
845 if (pg83_supported) {
846retry_pg83:
847 vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
848 if (!vpd_buf)
849 return;
850
851 result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);
852 if (result < 0) {
853 kfree(vpd_buf);
854 return;
855 }
856 if (result > vpd_len) {
857 vpd_len = result;
858 kfree(vpd_buf);
859 goto retry_pg83;
860 }
861 mutex_lock(&sdev->inquiry_mutex);
862 orig_vpd_buf = sdev->vpd_pg83;
863 sdev->vpd_pg83_len = result;
864 rcu_assign_pointer(sdev->vpd_pg83, vpd_buf);
865 mutex_unlock(&sdev->inquiry_mutex);
866 synchronize_rcu();
867 if (orig_vpd_buf)
868 kfree(orig_vpd_buf);
869 }
870}
871
872/**
873 * scsi_report_opcode - Find out if a given command opcode is supported
874 * @sdev: scsi device to query
875 * @buffer: scratch buffer (must be at least 20 bytes long)
876 * @len: length of buffer
877 * @opcode: opcode for command to look up
878 *
879 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
880 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
881 * unsupported and 1 if the device claims to support the command.
882 */
883int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
884 unsigned int len, unsigned char opcode)
885{
886 unsigned char cmd[16];
887 struct scsi_sense_hdr sshdr;
888 int result;
889
890 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
891 return -EINVAL;
892
893 memset(cmd, 0, 16);
894 cmd[0] = MAINTENANCE_IN;
895 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
896 cmd[2] = 1; /* One command format */
897 cmd[3] = opcode;
898 put_unaligned_be32(len, &cmd[6]);
899 memset(buffer, 0, len);
900
901 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
902 &sshdr, 30 * HZ, 3, NULL);
903
904 if (result && scsi_sense_valid(&sshdr) &&
905 sshdr.sense_key == ILLEGAL_REQUEST &&
906 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
907 return -EINVAL;
908
909 if ((buffer[1] & 3) == 3) /* Command supported */
910 return 1;
911
912 return 0;
913}
914EXPORT_SYMBOL(scsi_report_opcode);
915
916/**
917 * scsi_device_get - get an additional reference to a scsi_device
918 * @sdev: device to get a reference to
919 *
920 * Description: Gets a reference to the scsi_device and increments the use count
921 * of the underlying LLDD module. You must hold host_lock of the
922 * parent Scsi_Host or already have a reference when calling this.
923 *
924 * This will fail if a device is deleted or cancelled, or when the LLD module
925 * is in the process of being unloaded.
926 */
927int scsi_device_get(struct scsi_device *sdev)
928{
929 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
930 goto fail;
931 if (!get_device(&sdev->sdev_gendev))
932 goto fail;
933 if (!try_module_get(sdev->host->hostt->module))
934 goto fail_put_device;
935 return 0;
936
937fail_put_device:
938 put_device(&sdev->sdev_gendev);
939fail:
940 return -ENXIO;
941}
942EXPORT_SYMBOL(scsi_device_get);
943
944/**
945 * scsi_device_put - release a reference to a scsi_device
946 * @sdev: device to release a reference on.
947 *
948 * Description: Release a reference to the scsi_device and decrements the use
949 * count of the underlying LLDD module. The device is freed once the last
950 * user vanishes.
951 */
952void scsi_device_put(struct scsi_device *sdev)
953{
954 module_put(sdev->host->hostt->module);
955 put_device(&sdev->sdev_gendev);
956}
957EXPORT_SYMBOL(scsi_device_put);
958
959/* helper for shost_for_each_device, see that for documentation */
960struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
961 struct scsi_device *prev)
962{
963 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
964 struct scsi_device *next = NULL;
965 unsigned long flags;
966
967 spin_lock_irqsave(shost->host_lock, flags);
968 while (list->next != &shost->__devices) {
969 next = list_entry(list->next, struct scsi_device, siblings);
970 /* skip devices that we can't get a reference to */
971 if (!scsi_device_get(next))
972 break;
973 next = NULL;
974 list = list->next;
975 }
976 spin_unlock_irqrestore(shost->host_lock, flags);
977
978 if (prev)
979 scsi_device_put(prev);
980 return next;
981}
982EXPORT_SYMBOL(__scsi_iterate_devices);
983
984/**
985 * starget_for_each_device - helper to walk all devices of a target
986 * @starget: target whose devices we want to iterate over.
987 * @data: Opaque passed to each function call.
988 * @fn: Function to call on each device
989 *
990 * This traverses over each device of @starget. The devices have
991 * a reference that must be released by scsi_host_put when breaking
992 * out of the loop.
993 */
994void starget_for_each_device(struct scsi_target *starget, void *data,
995 void (*fn)(struct scsi_device *, void *))
996{
997 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
998 struct scsi_device *sdev;
999
1000 shost_for_each_device(sdev, shost) {
1001 if ((sdev->channel == starget->channel) &&
1002 (sdev->id == starget->id))
1003 fn(sdev, data);
1004 }
1005}
1006EXPORT_SYMBOL(starget_for_each_device);
1007
1008/**
1009 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1010 * @starget: target whose devices we want to iterate over.
1011 * @data: parameter for callback @fn()
1012 * @fn: callback function that is invoked for each device
1013 *
1014 * This traverses over each device of @starget. It does _not_
1015 * take a reference on the scsi_device, so the whole loop must be
1016 * protected by shost->host_lock.
1017 *
1018 * Note: The only reason why drivers would want to use this is because
1019 * they need to access the device list in irq context. Otherwise you
1020 * really want to use starget_for_each_device instead.
1021 **/
1022void __starget_for_each_device(struct scsi_target *starget, void *data,
1023 void (*fn)(struct scsi_device *, void *))
1024{
1025 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1026 struct scsi_device *sdev;
1027
1028 __shost_for_each_device(sdev, shost) {
1029 if ((sdev->channel == starget->channel) &&
1030 (sdev->id == starget->id))
1031 fn(sdev, data);
1032 }
1033}
1034EXPORT_SYMBOL(__starget_for_each_device);
1035
1036/**
1037 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1038 * @starget: SCSI target pointer
1039 * @lun: SCSI Logical Unit Number
1040 *
1041 * Description: Looks up the scsi_device with the specified @lun for a given
1042 * @starget. The returned scsi_device does not have an additional
1043 * reference. You must hold the host's host_lock over this call and
1044 * any access to the returned scsi_device. A scsi_device in state
1045 * SDEV_DEL is skipped.
1046 *
1047 * Note: The only reason why drivers should use this is because
1048 * they need to access the device list in irq context. Otherwise you
1049 * really want to use scsi_device_lookup_by_target instead.
1050 **/
1051struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1052 u64 lun)
1053{
1054 struct scsi_device *sdev;
1055
1056 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1057 if (sdev->sdev_state == SDEV_DEL)
1058 continue;
1059 if (sdev->lun ==lun)
1060 return sdev;
1061 }
1062
1063 return NULL;
1064}
1065EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1066
1067/**
1068 * scsi_device_lookup_by_target - find a device given the target
1069 * @starget: SCSI target pointer
1070 * @lun: SCSI Logical Unit Number
1071 *
1072 * Description: Looks up the scsi_device with the specified @lun for a given
1073 * @starget. The returned scsi_device has an additional reference that
1074 * needs to be released with scsi_device_put once you're done with it.
1075 **/
1076struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1077 u64 lun)
1078{
1079 struct scsi_device *sdev;
1080 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1081 unsigned long flags;
1082
1083 spin_lock_irqsave(shost->host_lock, flags);
1084 sdev = __scsi_device_lookup_by_target(starget, lun);
1085 if (sdev && scsi_device_get(sdev))
1086 sdev = NULL;
1087 spin_unlock_irqrestore(shost->host_lock, flags);
1088
1089 return sdev;
1090}
1091EXPORT_SYMBOL(scsi_device_lookup_by_target);
1092
1093/**
1094 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1095 * @shost: SCSI host pointer
1096 * @channel: SCSI channel (zero if only one channel)
1097 * @id: SCSI target number (physical unit number)
1098 * @lun: SCSI Logical Unit Number
1099 *
1100 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1101 * for a given host. The returned scsi_device does not have an additional
1102 * reference. You must hold the host's host_lock over this call and any access
1103 * to the returned scsi_device.
1104 *
1105 * Note: The only reason why drivers would want to use this is because
1106 * they need to access the device list in irq context. Otherwise you
1107 * really want to use scsi_device_lookup instead.
1108 **/
1109struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1110 uint channel, uint id, u64 lun)
1111{
1112 struct scsi_device *sdev;
1113
1114 list_for_each_entry(sdev, &shost->__devices, siblings) {
1115 if (sdev->channel == channel && sdev->id == id &&
1116 sdev->lun ==lun)
1117 return sdev;
1118 }
1119
1120 return NULL;
1121}
1122EXPORT_SYMBOL(__scsi_device_lookup);
1123
1124/**
1125 * scsi_device_lookup - find a device given the host
1126 * @shost: SCSI host pointer
1127 * @channel: SCSI channel (zero if only one channel)
1128 * @id: SCSI target number (physical unit number)
1129 * @lun: SCSI Logical Unit Number
1130 *
1131 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1132 * for a given host. The returned scsi_device has an additional reference that
1133 * needs to be released with scsi_device_put once you're done with it.
1134 **/
1135struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1136 uint channel, uint id, u64 lun)
1137{
1138 struct scsi_device *sdev;
1139 unsigned long flags;
1140
1141 spin_lock_irqsave(shost->host_lock, flags);
1142 sdev = __scsi_device_lookup(shost, channel, id, lun);
1143 if (sdev && scsi_device_get(sdev))
1144 sdev = NULL;
1145 spin_unlock_irqrestore(shost->host_lock, flags);
1146
1147 return sdev;
1148}
1149EXPORT_SYMBOL(scsi_device_lookup);
1150
1151MODULE_DESCRIPTION("SCSI core");
1152MODULE_LICENSE("GPL");
1153
1154module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1155MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1156
1157#ifdef CONFIG_SCSI_MQ_DEFAULT
1158bool scsi_use_blk_mq = true;
1159#else
1160bool scsi_use_blk_mq = false;
1161#endif
1162module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
1163
1164static int __init init_scsi(void)
1165{
1166 int error;
1167
1168 error = scsi_init_queue();
1169 if (error)
1170 return error;
1171 error = scsi_init_procfs();
1172 if (error)
1173 goto cleanup_queue;
1174 error = scsi_init_devinfo();
1175 if (error)
1176 goto cleanup_procfs;
1177 error = scsi_init_hosts();
1178 if (error)
1179 goto cleanup_devlist;
1180 error = scsi_init_sysctl();
1181 if (error)
1182 goto cleanup_hosts;
1183 error = scsi_sysfs_register();
1184 if (error)
1185 goto cleanup_sysctl;
1186
1187 scsi_netlink_init();
1188
1189 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1190 return 0;
1191
1192cleanup_sysctl:
1193 scsi_exit_sysctl();
1194cleanup_hosts:
1195 scsi_exit_hosts();
1196cleanup_devlist:
1197 scsi_exit_devinfo();
1198cleanup_procfs:
1199 scsi_exit_procfs();
1200cleanup_queue:
1201 scsi_exit_queue();
1202 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1203 -error);
1204 return error;
1205}
1206
1207static void __exit exit_scsi(void)
1208{
1209 scsi_netlink_exit();
1210 scsi_sysfs_unregister();
1211 scsi_exit_sysctl();
1212 scsi_exit_hosts();
1213 scsi_exit_devinfo();
1214 scsi_exit_procfs();
1215 scsi_exit_queue();
1216 async_unregister_domain(&scsi_sd_probe_domain);
1217}
1218
1219subsys_initcall(init_scsi);
1220module_exit(exit_scsi);
1/*
2 * scsi.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
4 * Copyright (C) 2002, 2003 Christoph Hellwig
5 *
6 * generic mid-level SCSI driver
7 * Initial versions: Drew Eckhardt
8 * Subsequent revisions: Eric Youngdale
9 *
10 * <drew@colorado.edu>
11 *
12 * Bug correction thanks go to :
13 * Rik Faith <faith@cs.unc.edu>
14 * Tommy Thorn <tthorn>
15 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
16 *
17 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
18 * add scatter-gather, multiple outstanding request, and other
19 * enhancements.
20 *
21 * Native multichannel, wide scsi, /proc/scsi and hot plugging
22 * support added by Michael Neuffer <mike@i-connect.net>
23 *
24 * Added request_module("scsi_hostadapter") for kerneld:
25 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
26 * Bjorn Ekwall <bj0rn@blox.se>
27 * (changed to kmod)
28 *
29 * Major improvements to the timeout, abort, and reset processing,
30 * as well as performance modifications for large queue depths by
31 * Leonard N. Zubkoff <lnz@dandelion.com>
32 *
33 * Converted cli() code to spinlocks, Ingo Molnar
34 *
35 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
36 *
37 * out_of_space hacks, D. Gilbert (dpg) 990608
38 */
39
40#include <linux/module.h>
41#include <linux/moduleparam.h>
42#include <linux/kernel.h>
43#include <linux/timer.h>
44#include <linux/string.h>
45#include <linux/slab.h>
46#include <linux/blkdev.h>
47#include <linux/delay.h>
48#include <linux/init.h>
49#include <linux/completion.h>
50#include <linux/unistd.h>
51#include <linux/spinlock.h>
52#include <linux/kmod.h>
53#include <linux/interrupt.h>
54#include <linux/notifier.h>
55#include <linux/cpu.h>
56#include <linux/mutex.h>
57
58#include <scsi/scsi.h>
59#include <scsi/scsi_cmnd.h>
60#include <scsi/scsi_dbg.h>
61#include <scsi/scsi_device.h>
62#include <scsi/scsi_driver.h>
63#include <scsi/scsi_eh.h>
64#include <scsi/scsi_host.h>
65#include <scsi/scsi_tcq.h>
66
67#include "scsi_priv.h"
68#include "scsi_logging.h"
69
70#define CREATE_TRACE_POINTS
71#include <trace/events/scsi.h>
72
73static void scsi_done(struct scsi_cmnd *cmd);
74
75/*
76 * Definitions and constants.
77 */
78
79#define MIN_RESET_DELAY (2*HZ)
80
81/* Do not call reset on error if we just did a reset within 15 sec. */
82#define MIN_RESET_PERIOD (15*HZ)
83
84/*
85 * Note - the initial logging level can be set here to log events at boot time.
86 * After the system is up, you may enable logging via the /proc interface.
87 */
88unsigned int scsi_logging_level;
89#if defined(CONFIG_SCSI_LOGGING)
90EXPORT_SYMBOL(scsi_logging_level);
91#endif
92
93/* sd, scsi core and power management need to coordinate flushing async actions */
94LIST_HEAD(scsi_sd_probe_domain);
95EXPORT_SYMBOL(scsi_sd_probe_domain);
96
97/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
98 * You may not alter any existing entry (although adding new ones is
99 * encouraged once assigned by ANSI/INCITS T10
100 */
101static const char *const scsi_device_types[] = {
102 "Direct-Access ",
103 "Sequential-Access",
104 "Printer ",
105 "Processor ",
106 "WORM ",
107 "CD-ROM ",
108 "Scanner ",
109 "Optical Device ",
110 "Medium Changer ",
111 "Communications ",
112 "ASC IT8 ",
113 "ASC IT8 ",
114 "RAID ",
115 "Enclosure ",
116 "Direct-Access-RBC",
117 "Optical card ",
118 "Bridge controller",
119 "Object storage ",
120 "Automation/Drive ",
121};
122
123/**
124 * scsi_device_type - Return 17 char string indicating device type.
125 * @type: type number to look up
126 */
127
128const char * scsi_device_type(unsigned type)
129{
130 if (type == 0x1e)
131 return "Well-known LUN ";
132 if (type == 0x1f)
133 return "No Device ";
134 if (type >= ARRAY_SIZE(scsi_device_types))
135 return "Unknown ";
136 return scsi_device_types[type];
137}
138
139EXPORT_SYMBOL(scsi_device_type);
140
141struct scsi_host_cmd_pool {
142 struct kmem_cache *cmd_slab;
143 struct kmem_cache *sense_slab;
144 unsigned int users;
145 char *cmd_name;
146 char *sense_name;
147 unsigned int slab_flags;
148 gfp_t gfp_mask;
149};
150
151static struct scsi_host_cmd_pool scsi_cmd_pool = {
152 .cmd_name = "scsi_cmd_cache",
153 .sense_name = "scsi_sense_cache",
154 .slab_flags = SLAB_HWCACHE_ALIGN,
155};
156
157static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
158 .cmd_name = "scsi_cmd_cache(DMA)",
159 .sense_name = "scsi_sense_cache(DMA)",
160 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
161 .gfp_mask = __GFP_DMA,
162};
163
164static DEFINE_MUTEX(host_cmd_pool_mutex);
165
166/**
167 * scsi_pool_alloc_command - internal function to get a fully allocated command
168 * @pool: slab pool to allocate the command from
169 * @gfp_mask: mask for the allocation
170 *
171 * Returns a fully allocated command (with the allied sense buffer) or
172 * NULL on failure
173 */
174static struct scsi_cmnd *
175scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
176{
177 struct scsi_cmnd *cmd;
178
179 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
180 if (!cmd)
181 return NULL;
182
183 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
184 gfp_mask | pool->gfp_mask);
185 if (!cmd->sense_buffer) {
186 kmem_cache_free(pool->cmd_slab, cmd);
187 return NULL;
188 }
189
190 return cmd;
191}
192
193/**
194 * scsi_pool_free_command - internal function to release a command
195 * @pool: slab pool to allocate the command from
196 * @cmd: command to release
197 *
198 * the command must previously have been allocated by
199 * scsi_pool_alloc_command.
200 */
201static void
202scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
203 struct scsi_cmnd *cmd)
204{
205 if (cmd->prot_sdb)
206 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
207
208 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
209 kmem_cache_free(pool->cmd_slab, cmd);
210}
211
212/**
213 * scsi_host_alloc_command - internal function to allocate command
214 * @shost: SCSI host whose pool to allocate from
215 * @gfp_mask: mask for the allocation
216 *
217 * Returns a fully allocated command with sense buffer and protection
218 * data buffer (where applicable) or NULL on failure
219 */
220static struct scsi_cmnd *
221scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
222{
223 struct scsi_cmnd *cmd;
224
225 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
226 if (!cmd)
227 return NULL;
228
229 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
230 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
231
232 if (!cmd->prot_sdb) {
233 scsi_pool_free_command(shost->cmd_pool, cmd);
234 return NULL;
235 }
236 }
237
238 return cmd;
239}
240
241/**
242 * __scsi_get_command - Allocate a struct scsi_cmnd
243 * @shost: host to transmit command
244 * @gfp_mask: allocation mask
245 *
246 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
247 * host's free_list if necessary.
248 */
249struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
250{
251 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
252
253 if (unlikely(!cmd)) {
254 unsigned long flags;
255
256 spin_lock_irqsave(&shost->free_list_lock, flags);
257 if (likely(!list_empty(&shost->free_list))) {
258 cmd = list_entry(shost->free_list.next,
259 struct scsi_cmnd, list);
260 list_del_init(&cmd->list);
261 }
262 spin_unlock_irqrestore(&shost->free_list_lock, flags);
263
264 if (cmd) {
265 void *buf, *prot;
266
267 buf = cmd->sense_buffer;
268 prot = cmd->prot_sdb;
269
270 memset(cmd, 0, sizeof(*cmd));
271
272 cmd->sense_buffer = buf;
273 cmd->prot_sdb = prot;
274 }
275 }
276
277 return cmd;
278}
279EXPORT_SYMBOL_GPL(__scsi_get_command);
280
281/**
282 * scsi_get_command - Allocate and setup a scsi command block
283 * @dev: parent scsi device
284 * @gfp_mask: allocator flags
285 *
286 * Returns: The allocated scsi command structure.
287 */
288struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
289{
290 struct scsi_cmnd *cmd;
291
292 /* Bail if we can't get a reference to the device */
293 if (!get_device(&dev->sdev_gendev))
294 return NULL;
295
296 cmd = __scsi_get_command(dev->host, gfp_mask);
297
298 if (likely(cmd != NULL)) {
299 unsigned long flags;
300
301 cmd->device = dev;
302 INIT_LIST_HEAD(&cmd->list);
303 spin_lock_irqsave(&dev->list_lock, flags);
304 list_add_tail(&cmd->list, &dev->cmd_list);
305 spin_unlock_irqrestore(&dev->list_lock, flags);
306 cmd->jiffies_at_alloc = jiffies;
307 } else
308 put_device(&dev->sdev_gendev);
309
310 return cmd;
311}
312EXPORT_SYMBOL(scsi_get_command);
313
314/**
315 * __scsi_put_command - Free a struct scsi_cmnd
316 * @shost: dev->host
317 * @cmd: Command to free
318 * @dev: parent scsi device
319 */
320void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
321 struct device *dev)
322{
323 unsigned long flags;
324
325 /* changing locks here, don't need to restore the irq state */
326 spin_lock_irqsave(&shost->free_list_lock, flags);
327 if (unlikely(list_empty(&shost->free_list))) {
328 list_add(&cmd->list, &shost->free_list);
329 cmd = NULL;
330 }
331 spin_unlock_irqrestore(&shost->free_list_lock, flags);
332
333 if (likely(cmd != NULL))
334 scsi_pool_free_command(shost->cmd_pool, cmd);
335
336 put_device(dev);
337}
338EXPORT_SYMBOL(__scsi_put_command);
339
340/**
341 * scsi_put_command - Free a scsi command block
342 * @cmd: command block to free
343 *
344 * Returns: Nothing.
345 *
346 * Notes: The command must not belong to any lists.
347 */
348void scsi_put_command(struct scsi_cmnd *cmd)
349{
350 struct scsi_device *sdev = cmd->device;
351 unsigned long flags;
352
353 /* serious error if the command hasn't come from a device list */
354 spin_lock_irqsave(&cmd->device->list_lock, flags);
355 BUG_ON(list_empty(&cmd->list));
356 list_del_init(&cmd->list);
357 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
358
359 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
360}
361EXPORT_SYMBOL(scsi_put_command);
362
363static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
364{
365 struct scsi_host_cmd_pool *retval = NULL, *pool;
366 /*
367 * Select a command slab for this host and create it if not
368 * yet existent.
369 */
370 mutex_lock(&host_cmd_pool_mutex);
371 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
372 &scsi_cmd_pool;
373 if (!pool->users) {
374 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
375 sizeof(struct scsi_cmnd), 0,
376 pool->slab_flags, NULL);
377 if (!pool->cmd_slab)
378 goto fail;
379
380 pool->sense_slab = kmem_cache_create(pool->sense_name,
381 SCSI_SENSE_BUFFERSIZE, 0,
382 pool->slab_flags, NULL);
383 if (!pool->sense_slab) {
384 kmem_cache_destroy(pool->cmd_slab);
385 goto fail;
386 }
387 }
388
389 pool->users++;
390 retval = pool;
391 fail:
392 mutex_unlock(&host_cmd_pool_mutex);
393 return retval;
394}
395
396static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
397{
398 struct scsi_host_cmd_pool *pool;
399
400 mutex_lock(&host_cmd_pool_mutex);
401 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
402 &scsi_cmd_pool;
403 /*
404 * This may happen if a driver has a mismatched get and put
405 * of the command pool; the driver should be implicated in
406 * the stack trace
407 */
408 BUG_ON(pool->users == 0);
409
410 if (!--pool->users) {
411 kmem_cache_destroy(pool->cmd_slab);
412 kmem_cache_destroy(pool->sense_slab);
413 }
414 mutex_unlock(&host_cmd_pool_mutex);
415}
416
417/**
418 * scsi_allocate_command - get a fully allocated SCSI command
419 * @gfp_mask: allocation mask
420 *
421 * This function is for use outside of the normal host based pools.
422 * It allocates the relevant command and takes an additional reference
423 * on the pool it used. This function *must* be paired with
424 * scsi_free_command which also has the identical mask, otherwise the
425 * free pool counts will eventually go wrong and you'll trigger a bug.
426 *
427 * This function should *only* be used by drivers that need a static
428 * command allocation at start of day for internal functions.
429 */
430struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
431{
432 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
433
434 if (!pool)
435 return NULL;
436
437 return scsi_pool_alloc_command(pool, gfp_mask);
438}
439EXPORT_SYMBOL(scsi_allocate_command);
440
441/**
442 * scsi_free_command - free a command allocated by scsi_allocate_command
443 * @gfp_mask: mask used in the original allocation
444 * @cmd: command to free
445 *
446 * Note: using the original allocation mask is vital because that's
447 * what determines which command pool we use to free the command. Any
448 * mismatch will cause the system to BUG eventually.
449 */
450void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
451{
452 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
453
454 /*
455 * this could trigger if the mask to scsi_allocate_command
456 * doesn't match this mask. Otherwise we're guaranteed that this
457 * succeeds because scsi_allocate_command must have taken a reference
458 * on the pool
459 */
460 BUG_ON(!pool);
461
462 scsi_pool_free_command(pool, cmd);
463 /*
464 * scsi_put_host_cmd_pool is called twice; once to release the
465 * reference we took above, and once to release the reference
466 * originally taken by scsi_allocate_command
467 */
468 scsi_put_host_cmd_pool(gfp_mask);
469 scsi_put_host_cmd_pool(gfp_mask);
470}
471EXPORT_SYMBOL(scsi_free_command);
472
473/**
474 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
475 * @shost: host to allocate the freelist for.
476 *
477 * Description: The command freelist protects against system-wide out of memory
478 * deadlock by preallocating one SCSI command structure for each host, so the
479 * system can always write to a swap file on a device associated with that host.
480 *
481 * Returns: Nothing.
482 */
483int scsi_setup_command_freelist(struct Scsi_Host *shost)
484{
485 struct scsi_cmnd *cmd;
486 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
487
488 spin_lock_init(&shost->free_list_lock);
489 INIT_LIST_HEAD(&shost->free_list);
490
491 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
492
493 if (!shost->cmd_pool)
494 return -ENOMEM;
495
496 /*
497 * Get one backup command for this host.
498 */
499 cmd = scsi_host_alloc_command(shost, gfp_mask);
500 if (!cmd) {
501 scsi_put_host_cmd_pool(gfp_mask);
502 shost->cmd_pool = NULL;
503 return -ENOMEM;
504 }
505 list_add(&cmd->list, &shost->free_list);
506 return 0;
507}
508
509/**
510 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
511 * @shost: host whose freelist is going to be destroyed
512 */
513void scsi_destroy_command_freelist(struct Scsi_Host *shost)
514{
515 /*
516 * If cmd_pool is NULL the free list was not initialized, so
517 * do not attempt to release resources.
518 */
519 if (!shost->cmd_pool)
520 return;
521
522 while (!list_empty(&shost->free_list)) {
523 struct scsi_cmnd *cmd;
524
525 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
526 list_del_init(&cmd->list);
527 scsi_pool_free_command(shost->cmd_pool, cmd);
528 }
529 shost->cmd_pool = NULL;
530 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
531}
532
533#ifdef CONFIG_SCSI_LOGGING
534void scsi_log_send(struct scsi_cmnd *cmd)
535{
536 unsigned int level;
537
538 /*
539 * If ML QUEUE log level is greater than or equal to:
540 *
541 * 1: nothing (match completion)
542 *
543 * 2: log opcode + command of all commands
544 *
545 * 3: same as 2 plus dump cmd address
546 *
547 * 4: same as 3 plus dump extra junk
548 */
549 if (unlikely(scsi_logging_level)) {
550 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
551 SCSI_LOG_MLQUEUE_BITS);
552 if (level > 1) {
553 scmd_printk(KERN_INFO, cmd, "Send: ");
554 if (level > 2)
555 printk("0x%p ", cmd);
556 printk("\n");
557 scsi_print_command(cmd);
558 if (level > 3) {
559 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
560 " queuecommand 0x%p\n",
561 scsi_sglist(cmd), scsi_bufflen(cmd),
562 cmd->device->host->hostt->queuecommand);
563
564 }
565 }
566 }
567}
568
569void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
570{
571 unsigned int level;
572
573 /*
574 * If ML COMPLETE log level is greater than or equal to:
575 *
576 * 1: log disposition, result, opcode + command, and conditionally
577 * sense data for failures or non SUCCESS dispositions.
578 *
579 * 2: same as 1 but for all command completions.
580 *
581 * 3: same as 2 plus dump cmd address
582 *
583 * 4: same as 3 plus dump extra junk
584 */
585 if (unlikely(scsi_logging_level)) {
586 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
587 SCSI_LOG_MLCOMPLETE_BITS);
588 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
589 (level > 1)) {
590 scmd_printk(KERN_INFO, cmd, "Done: ");
591 if (level > 2)
592 printk("0x%p ", cmd);
593 /*
594 * Dump truncated values, so we usually fit within
595 * 80 chars.
596 */
597 switch (disposition) {
598 case SUCCESS:
599 printk("SUCCESS\n");
600 break;
601 case NEEDS_RETRY:
602 printk("RETRY\n");
603 break;
604 case ADD_TO_MLQUEUE:
605 printk("MLQUEUE\n");
606 break;
607 case FAILED:
608 printk("FAILED\n");
609 break;
610 case TIMEOUT_ERROR:
611 /*
612 * If called via scsi_times_out.
613 */
614 printk("TIMEOUT\n");
615 break;
616 default:
617 printk("UNKNOWN\n");
618 }
619 scsi_print_result(cmd);
620 scsi_print_command(cmd);
621 if (status_byte(cmd->result) & CHECK_CONDITION)
622 scsi_print_sense("", cmd);
623 if (level > 3)
624 scmd_printk(KERN_INFO, cmd,
625 "scsi host busy %d failed %d\n",
626 cmd->device->host->host_busy,
627 cmd->device->host->host_failed);
628 }
629 }
630}
631#endif
632
633/**
634 * scsi_cmd_get_serial - Assign a serial number to a command
635 * @host: the scsi host
636 * @cmd: command to assign serial number to
637 *
638 * Description: a serial number identifies a request for error recovery
639 * and debugging purposes. Protected by the Host_Lock of host.
640 */
641void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
642{
643 cmd->serial_number = host->cmd_serial_number++;
644 if (cmd->serial_number == 0)
645 cmd->serial_number = host->cmd_serial_number++;
646}
647EXPORT_SYMBOL(scsi_cmd_get_serial);
648
649/**
650 * scsi_dispatch_command - Dispatch a command to the low-level driver.
651 * @cmd: command block we are dispatching.
652 *
653 * Return: nonzero return request was rejected and device's queue needs to be
654 * plugged.
655 */
656int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
657{
658 struct Scsi_Host *host = cmd->device->host;
659 unsigned long timeout;
660 int rtn = 0;
661
662 atomic_inc(&cmd->device->iorequest_cnt);
663
664 /* check if the device is still usable */
665 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
666 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
667 * returns an immediate error upwards, and signals
668 * that the device is no longer present */
669 cmd->result = DID_NO_CONNECT << 16;
670 scsi_done(cmd);
671 /* return 0 (because the command has been processed) */
672 goto out;
673 }
674
675 /* Check to see if the scsi lld made this device blocked. */
676 if (unlikely(scsi_device_blocked(cmd->device))) {
677 /*
678 * in blocked state, the command is just put back on
679 * the device queue. The suspend state has already
680 * blocked the queue so future requests should not
681 * occur until the device transitions out of the
682 * suspend state.
683 */
684
685 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
686
687 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
688
689 /*
690 * NOTE: rtn is still zero here because we don't need the
691 * queue to be plugged on return (it's already stopped)
692 */
693 goto out;
694 }
695
696 /*
697 * If SCSI-2 or lower, store the LUN value in cmnd.
698 */
699 if (cmd->device->scsi_level <= SCSI_2 &&
700 cmd->device->scsi_level != SCSI_UNKNOWN) {
701 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
702 (cmd->device->lun << 5 & 0xe0);
703 }
704
705 /*
706 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
707 * we can avoid the drive not being ready.
708 */
709 timeout = host->last_reset + MIN_RESET_DELAY;
710
711 if (host->resetting && time_before(jiffies, timeout)) {
712 int ticks_remaining = timeout - jiffies;
713 /*
714 * NOTE: This may be executed from within an interrupt
715 * handler! This is bad, but for now, it'll do. The irq
716 * level of the interrupt handler has been masked out by the
717 * platform dependent interrupt handling code already, so the
718 * sti() here will not cause another call to the SCSI host's
719 * interrupt handler (assuming there is one irq-level per
720 * host).
721 */
722 while (--ticks_remaining >= 0)
723 mdelay(1 + 999 / HZ);
724 host->resetting = 0;
725 }
726
727 scsi_log_send(cmd);
728
729 /*
730 * Before we queue this command, check if the command
731 * length exceeds what the host adapter can handle.
732 */
733 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
734 SCSI_LOG_MLQUEUE(3,
735 printk("queuecommand : command too long. "
736 "cdb_size=%d host->max_cmd_len=%d\n",
737 cmd->cmd_len, cmd->device->host->max_cmd_len));
738 cmd->result = (DID_ABORT << 16);
739
740 scsi_done(cmd);
741 goto out;
742 }
743
744 if (unlikely(host->shost_state == SHOST_DEL)) {
745 cmd->result = (DID_NO_CONNECT << 16);
746 scsi_done(cmd);
747 } else {
748 trace_scsi_dispatch_cmd_start(cmd);
749 cmd->scsi_done = scsi_done;
750 rtn = host->hostt->queuecommand(host, cmd);
751 }
752
753 if (rtn) {
754 trace_scsi_dispatch_cmd_error(cmd, rtn);
755 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
756 rtn != SCSI_MLQUEUE_TARGET_BUSY)
757 rtn = SCSI_MLQUEUE_HOST_BUSY;
758
759 scsi_queue_insert(cmd, rtn);
760
761 SCSI_LOG_MLQUEUE(3,
762 printk("queuecommand : request rejected\n"));
763 }
764
765 out:
766 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
767 return rtn;
768}
769
770/**
771 * scsi_done - Enqueue the finished SCSI command into the done queue.
772 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
773 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
774 *
775 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
776 * which regains ownership of the SCSI command (de facto) from a LLDD, and
777 * enqueues the command to the done queue for further processing.
778 *
779 * This is the producer of the done queue who enqueues at the tail.
780 *
781 * This function is interrupt context safe.
782 */
783static void scsi_done(struct scsi_cmnd *cmd)
784{
785 trace_scsi_dispatch_cmd_done(cmd);
786 blk_complete_request(cmd->request);
787}
788
789/**
790 * scsi_finish_command - cleanup and pass command back to upper layer
791 * @cmd: the command
792 *
793 * Description: Pass command off to upper layer for finishing of I/O
794 * request, waking processes that are waiting on results,
795 * etc.
796 */
797void scsi_finish_command(struct scsi_cmnd *cmd)
798{
799 struct scsi_device *sdev = cmd->device;
800 struct scsi_target *starget = scsi_target(sdev);
801 struct Scsi_Host *shost = sdev->host;
802 struct scsi_driver *drv;
803 unsigned int good_bytes;
804
805 scsi_device_unbusy(sdev);
806
807 /*
808 * Clear the flags which say that the device/host is no longer
809 * capable of accepting new commands. These are set in scsi_queue.c
810 * for both the queue full condition on a device, and for a
811 * host full condition on the host.
812 *
813 * XXX(hch): What about locking?
814 */
815 shost->host_blocked = 0;
816 starget->target_blocked = 0;
817 sdev->device_blocked = 0;
818
819 /*
820 * If we have valid sense information, then some kind of recovery
821 * must have taken place. Make a note of this.
822 */
823 if (SCSI_SENSE_VALID(cmd))
824 cmd->result |= (DRIVER_SENSE << 24);
825
826 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
827 "Notifying upper driver of completion "
828 "(result %x)\n", cmd->result));
829
830 good_bytes = scsi_bufflen(cmd);
831 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
832 int old_good_bytes = good_bytes;
833 drv = scsi_cmd_to_driver(cmd);
834 if (drv->done)
835 good_bytes = drv->done(cmd);
836 /*
837 * USB may not give sense identifying bad sector and
838 * simply return a residue instead, so subtract off the
839 * residue if drv->done() error processing indicates no
840 * change to the completion length.
841 */
842 if (good_bytes == old_good_bytes)
843 good_bytes -= scsi_get_resid(cmd);
844 }
845 scsi_io_completion(cmd, good_bytes);
846}
847EXPORT_SYMBOL(scsi_finish_command);
848
849/**
850 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
851 * @sdev: SCSI Device in question
852 * @tagged: Do we use tagged queueing (non-0) or do we treat
853 * this device as an untagged device (0)
854 * @tags: Number of tags allowed if tagged queueing enabled,
855 * or number of commands the low level driver can
856 * queue up in non-tagged mode (as per cmd_per_lun).
857 *
858 * Returns: Nothing
859 *
860 * Lock Status: None held on entry
861 *
862 * Notes: Low level drivers may call this at any time and we will do
863 * the right thing depending on whether or not the device is
864 * currently active and whether or not it even has the
865 * command blocks built yet.
866 */
867void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
868{
869 unsigned long flags;
870
871 /*
872 * refuse to set tagged depth to an unworkable size
873 */
874 if (tags <= 0)
875 return;
876
877 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
878
879 /*
880 * Check to see if the queue is managed by the block layer.
881 * If it is, and we fail to adjust the depth, exit.
882 *
883 * Do not resize the tag map if it is a host wide share bqt,
884 * because the size should be the hosts's can_queue. If there
885 * is more IO than the LLD's can_queue (so there are not enuogh
886 * tags) request_fn's host queue ready check will handle it.
887 */
888 if (!sdev->host->bqt) {
889 if (blk_queue_tagged(sdev->request_queue) &&
890 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
891 goto out;
892 }
893
894 sdev->queue_depth = tags;
895 switch (tagged) {
896 case MSG_ORDERED_TAG:
897 sdev->ordered_tags = 1;
898 sdev->simple_tags = 1;
899 break;
900 case MSG_SIMPLE_TAG:
901 sdev->ordered_tags = 0;
902 sdev->simple_tags = 1;
903 break;
904 default:
905 sdev_printk(KERN_WARNING, sdev,
906 "scsi_adjust_queue_depth, bad queue type, "
907 "disabled\n");
908 case 0:
909 sdev->ordered_tags = sdev->simple_tags = 0;
910 sdev->queue_depth = tags;
911 break;
912 }
913 out:
914 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
915}
916EXPORT_SYMBOL(scsi_adjust_queue_depth);
917
918/**
919 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
920 * @sdev: SCSI Device in question
921 * @depth: Current number of outstanding SCSI commands on this device,
922 * not counting the one returned as QUEUE_FULL.
923 *
924 * Description: This function will track successive QUEUE_FULL events on a
925 * specific SCSI device to determine if and when there is a
926 * need to adjust the queue depth on the device.
927 *
928 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
929 * -1 - Drop back to untagged operation using host->cmd_per_lun
930 * as the untagged command depth
931 *
932 * Lock Status: None held on entry
933 *
934 * Notes: Low level drivers may call this at any time and we will do
935 * "The Right Thing." We are interrupt context safe.
936 */
937int scsi_track_queue_full(struct scsi_device *sdev, int depth)
938{
939
940 /*
941 * Don't let QUEUE_FULLs on the same
942 * jiffies count, they could all be from
943 * same event.
944 */
945 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
946 return 0;
947
948 sdev->last_queue_full_time = jiffies;
949 if (sdev->last_queue_full_depth != depth) {
950 sdev->last_queue_full_count = 1;
951 sdev->last_queue_full_depth = depth;
952 } else {
953 sdev->last_queue_full_count++;
954 }
955
956 if (sdev->last_queue_full_count <= 10)
957 return 0;
958 if (sdev->last_queue_full_depth < 8) {
959 /* Drop back to untagged */
960 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
961 return -1;
962 }
963
964 if (sdev->ordered_tags)
965 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
966 else
967 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
968 return depth;
969}
970EXPORT_SYMBOL(scsi_track_queue_full);
971
972/**
973 * scsi_vpd_inquiry - Request a device provide us with a VPD page
974 * @sdev: The device to ask
975 * @buffer: Where to put the result
976 * @page: Which Vital Product Data to return
977 * @len: The length of the buffer
978 *
979 * This is an internal helper function. You probably want to use
980 * scsi_get_vpd_page instead.
981 *
982 * Returns 0 on success or a negative error number.
983 */
984static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
985 u8 page, unsigned len)
986{
987 int result;
988 unsigned char cmd[16];
989
990 cmd[0] = INQUIRY;
991 cmd[1] = 1; /* EVPD */
992 cmd[2] = page;
993 cmd[3] = len >> 8;
994 cmd[4] = len & 0xff;
995 cmd[5] = 0; /* Control byte */
996
997 /*
998 * I'm not convinced we need to try quite this hard to get VPD, but
999 * all the existing users tried this hard.
1000 */
1001 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
1002 len, NULL, 30 * HZ, 3, NULL);
1003 if (result)
1004 return result;
1005
1006 /* Sanity check that we got the page back that we asked for */
1007 if (buffer[1] != page)
1008 return -EIO;
1009
1010 return 0;
1011}
1012
1013/**
1014 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1015 * @sdev: The device to ask
1016 * @page: Which Vital Product Data to return
1017 * @buf: where to store the VPD
1018 * @buf_len: number of bytes in the VPD buffer area
1019 *
1020 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1021 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1022 * If the device supports this VPD page, this routine returns a pointer
1023 * to a buffer containing the data from that page. The caller is
1024 * responsible for calling kfree() on this pointer when it is no longer
1025 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1026 */
1027int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1028 int buf_len)
1029{
1030 int i, result;
1031
1032 /* Ask for all the pages supported by this device */
1033 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
1034 if (result)
1035 goto fail;
1036
1037 /* If the user actually wanted this page, we can skip the rest */
1038 if (page == 0)
1039 return 0;
1040
1041 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
1042 if (buf[i + 4] == page)
1043 goto found;
1044
1045 if (i < buf[3] && i >= buf_len - 4)
1046 /* ran off the end of the buffer, give us benefit of doubt */
1047 goto found;
1048 /* The device claims it doesn't support the requested page */
1049 goto fail;
1050
1051 found:
1052 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1053 if (result)
1054 goto fail;
1055
1056 return 0;
1057
1058 fail:
1059 return -EINVAL;
1060}
1061EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1062
1063/**
1064 * scsi_device_get - get an additional reference to a scsi_device
1065 * @sdev: device to get a reference to
1066 *
1067 * Description: Gets a reference to the scsi_device and increments the use count
1068 * of the underlying LLDD module. You must hold host_lock of the
1069 * parent Scsi_Host or already have a reference when calling this.
1070 */
1071int scsi_device_get(struct scsi_device *sdev)
1072{
1073 if (sdev->sdev_state == SDEV_DEL)
1074 return -ENXIO;
1075 if (!get_device(&sdev->sdev_gendev))
1076 return -ENXIO;
1077 /* We can fail this if we're doing SCSI operations
1078 * from module exit (like cache flush) */
1079 try_module_get(sdev->host->hostt->module);
1080
1081 return 0;
1082}
1083EXPORT_SYMBOL(scsi_device_get);
1084
1085/**
1086 * scsi_device_put - release a reference to a scsi_device
1087 * @sdev: device to release a reference on.
1088 *
1089 * Description: Release a reference to the scsi_device and decrements the use
1090 * count of the underlying LLDD module. The device is freed once the last
1091 * user vanishes.
1092 */
1093void scsi_device_put(struct scsi_device *sdev)
1094{
1095#ifdef CONFIG_MODULE_UNLOAD
1096 struct module *module = sdev->host->hostt->module;
1097
1098 /* The module refcount will be zero if scsi_device_get()
1099 * was called from a module removal routine */
1100 if (module && module_refcount(module) != 0)
1101 module_put(module);
1102#endif
1103 put_device(&sdev->sdev_gendev);
1104}
1105EXPORT_SYMBOL(scsi_device_put);
1106
1107/* helper for shost_for_each_device, see that for documentation */
1108struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1109 struct scsi_device *prev)
1110{
1111 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1112 struct scsi_device *next = NULL;
1113 unsigned long flags;
1114
1115 spin_lock_irqsave(shost->host_lock, flags);
1116 while (list->next != &shost->__devices) {
1117 next = list_entry(list->next, struct scsi_device, siblings);
1118 /* skip devices that we can't get a reference to */
1119 if (!scsi_device_get(next))
1120 break;
1121 next = NULL;
1122 list = list->next;
1123 }
1124 spin_unlock_irqrestore(shost->host_lock, flags);
1125
1126 if (prev)
1127 scsi_device_put(prev);
1128 return next;
1129}
1130EXPORT_SYMBOL(__scsi_iterate_devices);
1131
1132/**
1133 * starget_for_each_device - helper to walk all devices of a target
1134 * @starget: target whose devices we want to iterate over.
1135 * @data: Opaque passed to each function call.
1136 * @fn: Function to call on each device
1137 *
1138 * This traverses over each device of @starget. The devices have
1139 * a reference that must be released by scsi_host_put when breaking
1140 * out of the loop.
1141 */
1142void starget_for_each_device(struct scsi_target *starget, void *data,
1143 void (*fn)(struct scsi_device *, void *))
1144{
1145 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1146 struct scsi_device *sdev;
1147
1148 shost_for_each_device(sdev, shost) {
1149 if ((sdev->channel == starget->channel) &&
1150 (sdev->id == starget->id))
1151 fn(sdev, data);
1152 }
1153}
1154EXPORT_SYMBOL(starget_for_each_device);
1155
1156/**
1157 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1158 * @starget: target whose devices we want to iterate over.
1159 * @data: parameter for callback @fn()
1160 * @fn: callback function that is invoked for each device
1161 *
1162 * This traverses over each device of @starget. It does _not_
1163 * take a reference on the scsi_device, so the whole loop must be
1164 * protected by shost->host_lock.
1165 *
1166 * Note: The only reason why drivers would want to use this is because
1167 * they need to access the device list in irq context. Otherwise you
1168 * really want to use starget_for_each_device instead.
1169 **/
1170void __starget_for_each_device(struct scsi_target *starget, void *data,
1171 void (*fn)(struct scsi_device *, void *))
1172{
1173 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1174 struct scsi_device *sdev;
1175
1176 __shost_for_each_device(sdev, shost) {
1177 if ((sdev->channel == starget->channel) &&
1178 (sdev->id == starget->id))
1179 fn(sdev, data);
1180 }
1181}
1182EXPORT_SYMBOL(__starget_for_each_device);
1183
1184/**
1185 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1186 * @starget: SCSI target pointer
1187 * @lun: SCSI Logical Unit Number
1188 *
1189 * Description: Looks up the scsi_device with the specified @lun for a given
1190 * @starget. The returned scsi_device does not have an additional
1191 * reference. You must hold the host's host_lock over this call and
1192 * any access to the returned scsi_device. A scsi_device in state
1193 * SDEV_DEL is skipped.
1194 *
1195 * Note: The only reason why drivers should use this is because
1196 * they need to access the device list in irq context. Otherwise you
1197 * really want to use scsi_device_lookup_by_target instead.
1198 **/
1199struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1200 uint lun)
1201{
1202 struct scsi_device *sdev;
1203
1204 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1205 if (sdev->sdev_state == SDEV_DEL)
1206 continue;
1207 if (sdev->lun ==lun)
1208 return sdev;
1209 }
1210
1211 return NULL;
1212}
1213EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1214
1215/**
1216 * scsi_device_lookup_by_target - find a device given the target
1217 * @starget: SCSI target pointer
1218 * @lun: SCSI Logical Unit Number
1219 *
1220 * Description: Looks up the scsi_device with the specified @lun for a given
1221 * @starget. The returned scsi_device has an additional reference that
1222 * needs to be released with scsi_device_put once you're done with it.
1223 **/
1224struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1225 uint lun)
1226{
1227 struct scsi_device *sdev;
1228 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1229 unsigned long flags;
1230
1231 spin_lock_irqsave(shost->host_lock, flags);
1232 sdev = __scsi_device_lookup_by_target(starget, lun);
1233 if (sdev && scsi_device_get(sdev))
1234 sdev = NULL;
1235 spin_unlock_irqrestore(shost->host_lock, flags);
1236
1237 return sdev;
1238}
1239EXPORT_SYMBOL(scsi_device_lookup_by_target);
1240
1241/**
1242 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1243 * @shost: SCSI host pointer
1244 * @channel: SCSI channel (zero if only one channel)
1245 * @id: SCSI target number (physical unit number)
1246 * @lun: SCSI Logical Unit Number
1247 *
1248 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1249 * for a given host. The returned scsi_device does not have an additional
1250 * reference. You must hold the host's host_lock over this call and any access
1251 * to the returned scsi_device.
1252 *
1253 * Note: The only reason why drivers would want to use this is because
1254 * they need to access the device list in irq context. Otherwise you
1255 * really want to use scsi_device_lookup instead.
1256 **/
1257struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1258 uint channel, uint id, uint lun)
1259{
1260 struct scsi_device *sdev;
1261
1262 list_for_each_entry(sdev, &shost->__devices, siblings) {
1263 if (sdev->channel == channel && sdev->id == id &&
1264 sdev->lun ==lun)
1265 return sdev;
1266 }
1267
1268 return NULL;
1269}
1270EXPORT_SYMBOL(__scsi_device_lookup);
1271
1272/**
1273 * scsi_device_lookup - find a device given the host
1274 * @shost: SCSI host pointer
1275 * @channel: SCSI channel (zero if only one channel)
1276 * @id: SCSI target number (physical unit number)
1277 * @lun: SCSI Logical Unit Number
1278 *
1279 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1280 * for a given host. The returned scsi_device has an additional reference that
1281 * needs to be released with scsi_device_put once you're done with it.
1282 **/
1283struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1284 uint channel, uint id, uint lun)
1285{
1286 struct scsi_device *sdev;
1287 unsigned long flags;
1288
1289 spin_lock_irqsave(shost->host_lock, flags);
1290 sdev = __scsi_device_lookup(shost, channel, id, lun);
1291 if (sdev && scsi_device_get(sdev))
1292 sdev = NULL;
1293 spin_unlock_irqrestore(shost->host_lock, flags);
1294
1295 return sdev;
1296}
1297EXPORT_SYMBOL(scsi_device_lookup);
1298
1299MODULE_DESCRIPTION("SCSI core");
1300MODULE_LICENSE("GPL");
1301
1302module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1303MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1304
1305static int __init init_scsi(void)
1306{
1307 int error;
1308
1309 error = scsi_init_queue();
1310 if (error)
1311 return error;
1312 error = scsi_init_procfs();
1313 if (error)
1314 goto cleanup_queue;
1315 error = scsi_init_devinfo();
1316 if (error)
1317 goto cleanup_procfs;
1318 error = scsi_init_hosts();
1319 if (error)
1320 goto cleanup_devlist;
1321 error = scsi_init_sysctl();
1322 if (error)
1323 goto cleanup_hosts;
1324 error = scsi_sysfs_register();
1325 if (error)
1326 goto cleanup_sysctl;
1327
1328 scsi_netlink_init();
1329
1330 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1331 return 0;
1332
1333cleanup_sysctl:
1334 scsi_exit_sysctl();
1335cleanup_hosts:
1336 scsi_exit_hosts();
1337cleanup_devlist:
1338 scsi_exit_devinfo();
1339cleanup_procfs:
1340 scsi_exit_procfs();
1341cleanup_queue:
1342 scsi_exit_queue();
1343 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1344 -error);
1345 return error;
1346}
1347
1348static void __exit exit_scsi(void)
1349{
1350 scsi_netlink_exit();
1351 scsi_sysfs_unregister();
1352 scsi_exit_sysctl();
1353 scsi_exit_hosts();
1354 scsi_exit_devinfo();
1355 scsi_exit_procfs();
1356 scsi_exit_queue();
1357}
1358
1359subsys_initcall(init_scsi);
1360module_exit(exit_scsi);