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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070050#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>
Arjan van de Ven0b950672006-01-11 13:16:10 +010056#include <linux/mutex.h>
Dan Williams2955b472012-07-09 19:33:25 -070057#include <linux/async.h>
Martin K. Petersen3c6bdae2012-09-18 12:19:30 -040058#include <asm/unaligned.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
60#include <scsi/scsi.h>
61#include <scsi/scsi_cmnd.h>
62#include <scsi/scsi_dbg.h>
63#include <scsi/scsi_device.h>
Linus Torvalds7b3d9542008-01-06 10:17:12 -080064#include <scsi/scsi_driver.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070065#include <scsi/scsi_eh.h>
66#include <scsi/scsi_host.h>
67#include <scsi/scsi_tcq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
69#include "scsi_priv.h"
70#include "scsi_logging.h"
71
Kei Tokunagabf816232010-04-01 20:41:40 +090072#define CREATE_TRACE_POINTS
73#include <trace/events/scsi.h>
74
Adrian Bunk52c1da32005-06-23 22:05:33 -070075static void scsi_done(struct scsi_cmnd *cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
77/*
78 * Definitions and constants.
79 */
80
81#define MIN_RESET_DELAY (2*HZ)
82
83/* Do not call reset on error if we just did a reset within 15 sec. */
84#define MIN_RESET_PERIOD (15*HZ)
85
86/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 * Note - the initial logging level can be set here to log events at boot time.
88 * After the system is up, you may enable logging via the /proc interface.
89 */
90unsigned int scsi_logging_level;
91#if defined(CONFIG_SCSI_LOGGING)
92EXPORT_SYMBOL(scsi_logging_level);
93#endif
94
James Bottomleyea80dad2012-06-06 14:54:13 +090095/* sd, scsi core and power management need to coordinate flushing async actions */
Dan Williams2955b472012-07-09 19:33:25 -070096ASYNC_DOMAIN(scsi_sd_probe_domain);
Dan Williamsa7a20d12012-03-22 17:05:11 -070097EXPORT_SYMBOL(scsi_sd_probe_domain);
Dan Williamsa7a20d12012-03-22 17:05:11 -070098
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -060099/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
100 * You may not alter any existing entry (although adding new ones is
101 * encouraged once assigned by ANSI/INCITS T10
102 */
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600103static const char *const scsi_device_types[] = {
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600104 "Direct-Access ",
105 "Sequential-Access",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 "Printer ",
107 "Processor ",
108 "WORM ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600109 "CD-ROM ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 "Scanner ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600111 "Optical Device ",
112 "Medium Changer ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 "Communications ",
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600114 "ASC IT8 ",
115 "ASC IT8 ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 "RAID ",
117 "Enclosure ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600118 "Direct-Access-RBC",
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600119 "Optical card ",
120 "Bridge controller",
121 "Object storage ",
122 "Automation/Drive ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123};
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600124
Rob Landleyeb448202007-11-03 13:30:39 -0500125/**
126 * scsi_device_type - Return 17 char string indicating device type.
127 * @type: type number to look up
128 */
129
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600130const char * scsi_device_type(unsigned type)
131{
132 if (type == 0x1e)
133 return "Well-known LUN ";
134 if (type == 0x1f)
135 return "No Device ";
Eric Sesterhenn80c6e3c2006-09-26 13:22:13 +0200136 if (type >= ARRAY_SIZE(scsi_device_types))
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600137 return "Unknown ";
138 return scsi_device_types[type];
139}
140
141EXPORT_SYMBOL(scsi_device_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143struct scsi_host_cmd_pool {
James Bottomley5b7f1682008-01-20 09:28:24 -0600144 struct kmem_cache *cmd_slab;
145 struct kmem_cache *sense_slab;
146 unsigned int users;
147 char *cmd_name;
148 char *sense_name;
149 unsigned int slab_flags;
150 gfp_t gfp_mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151};
152
153static struct scsi_host_cmd_pool scsi_cmd_pool = {
James Bottomley5b7f1682008-01-20 09:28:24 -0600154 .cmd_name = "scsi_cmd_cache",
155 .sense_name = "scsi_sense_cache",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 .slab_flags = SLAB_HWCACHE_ALIGN,
157};
158
159static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
James Bottomley5b7f1682008-01-20 09:28:24 -0600160 .cmd_name = "scsi_cmd_cache(DMA)",
161 .sense_name = "scsi_sense_cache(DMA)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
163 .gfp_mask = __GFP_DMA,
164};
165
Arjan van de Ven0b950672006-01-11 13:16:10 +0100166static DEFINE_MUTEX(host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167
Rob Landleyeb448202007-11-03 13:30:39 -0500168/**
James Bottomleye507e302008-03-13 11:16:33 -0500169 * scsi_pool_alloc_command - internal function to get a fully allocated command
170 * @pool: slab pool to allocate the command from
171 * @gfp_mask: mask for the allocation
172 *
173 * Returns a fully allocated command (with the allied sense buffer) or
174 * NULL on failure
175 */
176static struct scsi_cmnd *
177scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
178{
179 struct scsi_cmnd *cmd;
180
Wei Yongjunebef2642009-03-04 12:06:13 -0800181 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
James Bottomleye507e302008-03-13 11:16:33 -0500182 if (!cmd)
183 return NULL;
184
James Bottomleye507e302008-03-13 11:16:33 -0500185 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
186 gfp_mask | pool->gfp_mask);
187 if (!cmd->sense_buffer) {
188 kmem_cache_free(pool->cmd_slab, cmd);
189 return NULL;
190 }
191
192 return cmd;
193}
194
195/**
196 * scsi_pool_free_command - internal function to release a command
197 * @pool: slab pool to allocate the command from
198 * @cmd: command to release
199 *
200 * the command must previously have been allocated by
201 * scsi_pool_alloc_command.
202 */
203static void
204scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
205 struct scsi_cmnd *cmd)
206{
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400207 if (cmd->prot_sdb)
208 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
209
James Bottomleye507e302008-03-13 11:16:33 -0500210 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
211 kmem_cache_free(pool->cmd_slab, cmd);
212}
213
214/**
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400215 * scsi_host_alloc_command - internal function to allocate command
216 * @shost: SCSI host whose pool to allocate from
217 * @gfp_mask: mask for the allocation
218 *
219 * Returns a fully allocated command with sense buffer and protection
220 * data buffer (where applicable) or NULL on failure
221 */
222static struct scsi_cmnd *
223scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
224{
225 struct scsi_cmnd *cmd;
226
227 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
228 if (!cmd)
229 return NULL;
230
231 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
232 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
233
234 if (!cmd->prot_sdb) {
235 scsi_pool_free_command(shost->cmd_pool, cmd);
236 return NULL;
237 }
238 }
239
240 return cmd;
241}
242
243/**
Rob Landleyeb448202007-11-03 13:30:39 -0500244 * __scsi_get_command - Allocate a struct scsi_cmnd
245 * @shost: host to transmit command
246 * @gfp_mask: allocation mask
247 *
248 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
249 * host's free_list if necessary.
250 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900251struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252{
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400253 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
Hugh Dickins164fc5d2008-04-06 23:56:57 +0100254
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 if (unlikely(!cmd)) {
256 unsigned long flags;
257
258 spin_lock_irqsave(&shost->free_list_lock, flags);
259 if (likely(!list_empty(&shost->free_list))) {
260 cmd = list_entry(shost->free_list.next,
261 struct scsi_cmnd, list);
262 list_del_init(&cmd->list);
263 }
264 spin_unlock_irqrestore(&shost->free_list_lock, flags);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900265
266 if (cmd) {
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400267 void *buf, *prot;
268
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900269 buf = cmd->sense_buffer;
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400270 prot = cmd->prot_sdb;
271
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900272 memset(cmd, 0, sizeof(*cmd));
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400273
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900274 cmd->sense_buffer = buf;
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400275 cmd->prot_sdb = prot;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900276 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 }
278
279 return cmd;
280}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900281EXPORT_SYMBOL_GPL(__scsi_get_command);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282
Rob Landleyeb448202007-11-03 13:30:39 -0500283/**
284 * scsi_get_command - Allocate and setup a scsi command block
285 * @dev: parent scsi device
286 * @gfp_mask: allocator flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 *
288 * Returns: The allocated scsi command structure.
289 */
Al Viroc53033f2005-10-21 03:22:08 -0400290struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291{
292 struct scsi_cmnd *cmd;
293
294 /* Bail if we can't get a reference to the device */
295 if (!get_device(&dev->sdev_gendev))
296 return NULL;
297
298 cmd = __scsi_get_command(dev->host, gfp_mask);
299
300 if (likely(cmd != NULL)) {
301 unsigned long flags;
302
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 cmd->device = dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 INIT_LIST_HEAD(&cmd->list);
305 spin_lock_irqsave(&dev->list_lock, flags);
306 list_add_tail(&cmd->list, &dev->cmd_list);
307 spin_unlock_irqrestore(&dev->list_lock, flags);
Matthew Dobson79e448b2005-11-21 21:32:29 -0800308 cmd->jiffies_at_alloc = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 } else
310 put_device(&dev->sdev_gendev);
311
312 return cmd;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900313}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314EXPORT_SYMBOL(scsi_get_command);
315
Rob Landleyeb448202007-11-03 13:30:39 -0500316/**
317 * __scsi_put_command - Free a struct scsi_cmnd
318 * @shost: dev->host
319 * @cmd: Command to free
320 * @dev: parent scsi device
321 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900322void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
323 struct device *dev)
324{
325 unsigned long flags;
326
327 /* changing locks here, don't need to restore the irq state */
328 spin_lock_irqsave(&shost->free_list_lock, flags);
329 if (unlikely(list_empty(&shost->free_list))) {
330 list_add(&cmd->list, &shost->free_list);
331 cmd = NULL;
332 }
333 spin_unlock_irqrestore(&shost->free_list_lock, flags);
334
James Bottomleye507e302008-03-13 11:16:33 -0500335 if (likely(cmd != NULL))
336 scsi_pool_free_command(shost->cmd_pool, cmd);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900337
338 put_device(dev);
339}
340EXPORT_SYMBOL(__scsi_put_command);
341
Rob Landleyeb448202007-11-03 13:30:39 -0500342/**
343 * scsi_put_command - Free a scsi command block
344 * @cmd: command block to free
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 *
346 * Returns: Nothing.
347 *
348 * Notes: The command must not belong to any lists.
349 */
350void scsi_put_command(struct scsi_cmnd *cmd)
351{
352 struct scsi_device *sdev = cmd->device;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 unsigned long flags;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900354
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 /* serious error if the command hasn't come from a device list */
356 spin_lock_irqsave(&cmd->device->list_lock, flags);
357 BUG_ON(list_empty(&cmd->list));
358 list_del_init(&cmd->list);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900359 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900361 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362}
363EXPORT_SYMBOL(scsi_put_command);
364
James Bottomley1c353f72008-03-13 11:19:36 -0500365static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366{
James Bottomley1c353f72008-03-13 11:19:36 -0500367 struct scsi_host_cmd_pool *retval = NULL, *pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 /*
369 * Select a command slab for this host and create it if not
Rob Landleyeb448202007-11-03 13:30:39 -0500370 * yet existent.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 */
Arjan van de Ven0b950672006-01-11 13:16:10 +0100372 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500373 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
374 &scsi_cmd_pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 if (!pool->users) {
James Bottomley5b7f1682008-01-20 09:28:24 -0600376 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
377 sizeof(struct scsi_cmnd), 0,
378 pool->slab_flags, NULL);
379 if (!pool->cmd_slab)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 goto fail;
James Bottomley5b7f1682008-01-20 09:28:24 -0600381
382 pool->sense_slab = kmem_cache_create(pool->sense_name,
383 SCSI_SENSE_BUFFERSIZE, 0,
384 pool->slab_flags, NULL);
385 if (!pool->sense_slab) {
386 kmem_cache_destroy(pool->cmd_slab);
387 goto fail;
388 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 }
390
391 pool->users++;
James Bottomley1c353f72008-03-13 11:19:36 -0500392 retval = pool;
393 fail:
Arjan van de Ven0b950672006-01-11 13:16:10 +0100394 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500395 return retval;
396}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397
James Bottomley1c353f72008-03-13 11:19:36 -0500398static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
399{
400 struct scsi_host_cmd_pool *pool;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900401
FUJITA Tomonori166a7282008-01-08 07:59:05 +0900402 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500403 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
404 &scsi_cmd_pool;
405 /*
406 * This may happen if a driver has a mismatched get and put
407 * of the command pool; the driver should be implicated in
408 * the stack trace
409 */
410 BUG_ON(pool->users == 0);
411
James Bottomley5b7f1682008-01-20 09:28:24 -0600412 if (!--pool->users) {
413 kmem_cache_destroy(pool->cmd_slab);
414 kmem_cache_destroy(pool->sense_slab);
415 }
Arjan van de Ven0b950672006-01-11 13:16:10 +0100416 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500417}
418
419/**
420 * scsi_allocate_command - get a fully allocated SCSI command
421 * @gfp_mask: allocation mask
422 *
423 * This function is for use outside of the normal host based pools.
424 * It allocates the relevant command and takes an additional reference
425 * on the pool it used. This function *must* be paired with
426 * scsi_free_command which also has the identical mask, otherwise the
427 * free pool counts will eventually go wrong and you'll trigger a bug.
428 *
429 * This function should *only* be used by drivers that need a static
430 * command allocation at start of day for internal functions.
431 */
432struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
433{
434 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
435
436 if (!pool)
437 return NULL;
438
439 return scsi_pool_alloc_command(pool, gfp_mask);
440}
441EXPORT_SYMBOL(scsi_allocate_command);
442
443/**
444 * scsi_free_command - free a command allocated by scsi_allocate_command
445 * @gfp_mask: mask used in the original allocation
446 * @cmd: command to free
447 *
448 * Note: using the original allocation mask is vital because that's
449 * what determines which command pool we use to free the command. Any
450 * mismatch will cause the system to BUG eventually.
451 */
452void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
453{
454 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
455
456 /*
457 * this could trigger if the mask to scsi_allocate_command
458 * doesn't match this mask. Otherwise we're guaranteed that this
459 * succeeds because scsi_allocate_command must have taken a reference
460 * on the pool
461 */
462 BUG_ON(!pool);
463
464 scsi_pool_free_command(pool, cmd);
465 /*
466 * scsi_put_host_cmd_pool is called twice; once to release the
467 * reference we took above, and once to release the reference
468 * originally taken by scsi_allocate_command
469 */
470 scsi_put_host_cmd_pool(gfp_mask);
471 scsi_put_host_cmd_pool(gfp_mask);
472}
473EXPORT_SYMBOL(scsi_free_command);
474
475/**
476 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
477 * @shost: host to allocate the freelist for.
478 *
479 * Description: The command freelist protects against system-wide out of memory
480 * deadlock by preallocating one SCSI command structure for each host, so the
481 * system can always write to a swap file on a device associated with that host.
482 *
483 * Returns: Nothing.
484 */
485int scsi_setup_command_freelist(struct Scsi_Host *shost)
486{
487 struct scsi_cmnd *cmd;
488 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
489
490 spin_lock_init(&shost->free_list_lock);
491 INIT_LIST_HEAD(&shost->free_list);
492
493 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
494
495 if (!shost->cmd_pool)
496 return -ENOMEM;
497
498 /*
499 * Get one backup command for this host.
500 */
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400501 cmd = scsi_host_alloc_command(shost, gfp_mask);
James Bottomley1c353f72008-03-13 11:19:36 -0500502 if (!cmd) {
503 scsi_put_host_cmd_pool(gfp_mask);
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400504 shost->cmd_pool = NULL;
James Bottomley1c353f72008-03-13 11:19:36 -0500505 return -ENOMEM;
506 }
507 list_add(&cmd->list, &shost->free_list);
508 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509}
510
Rob Landleyeb448202007-11-03 13:30:39 -0500511/**
512 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
513 * @shost: host whose freelist is going to be destroyed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 */
515void scsi_destroy_command_freelist(struct Scsi_Host *shost)
516{
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400517 /*
518 * If cmd_pool is NULL the free list was not initialized, so
519 * do not attempt to release resources.
520 */
521 if (!shost->cmd_pool)
522 return;
523
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 while (!list_empty(&shost->free_list)) {
525 struct scsi_cmnd *cmd;
526
527 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
528 list_del_init(&cmd->list);
James Bottomleye507e302008-03-13 11:16:33 -0500529 scsi_pool_free_command(shost->cmd_pool, cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 }
James Bottomley1c353f72008-03-13 11:19:36 -0500531 shost->cmd_pool = NULL;
532 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900533}
534
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535#ifdef CONFIG_SCSI_LOGGING
536void scsi_log_send(struct scsi_cmnd *cmd)
537{
538 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539
540 /*
541 * If ML QUEUE log level is greater than or equal to:
542 *
543 * 1: nothing (match completion)
544 *
545 * 2: log opcode + command of all commands
546 *
547 * 3: same as 2 plus dump cmd address
548 *
549 * 4: same as 3 plus dump extra junk
550 */
551 if (unlikely(scsi_logging_level)) {
552 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
553 SCSI_LOG_MLQUEUE_BITS);
554 if (level > 1) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500555 scmd_printk(KERN_INFO, cmd, "Send: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 if (level > 2)
557 printk("0x%p ", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500558 printk("\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 scsi_print_command(cmd);
560 if (level > 3) {
561 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800562 " queuecommand 0x%p\n",
Boaz Harrosha73e45b2007-07-04 21:26:01 +0300563 scsi_sglist(cmd), scsi_bufflen(cmd),
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500564 cmd->device->host->hostt->queuecommand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565
566 }
567 }
568 }
569}
570
571void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
572{
573 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
575 /*
576 * If ML COMPLETE log level is greater than or equal to:
577 *
578 * 1: log disposition, result, opcode + command, and conditionally
579 * sense data for failures or non SUCCESS dispositions.
580 *
581 * 2: same as 1 but for all command completions.
582 *
583 * 3: same as 2 plus dump cmd address
584 *
585 * 4: same as 3 plus dump extra junk
586 */
587 if (unlikely(scsi_logging_level)) {
588 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
589 SCSI_LOG_MLCOMPLETE_BITS);
590 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
591 (level > 1)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500592 scmd_printk(KERN_INFO, cmd, "Done: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 if (level > 2)
594 printk("0x%p ", cmd);
595 /*
596 * Dump truncated values, so we usually fit within
597 * 80 chars.
598 */
599 switch (disposition) {
600 case SUCCESS:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500601 printk("SUCCESS\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 break;
603 case NEEDS_RETRY:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500604 printk("RETRY\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 break;
606 case ADD_TO_MLQUEUE:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500607 printk("MLQUEUE\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 break;
609 case FAILED:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500610 printk("FAILED\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 break;
612 case TIMEOUT_ERROR:
613 /*
614 * If called via scsi_times_out.
615 */
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500616 printk("TIMEOUT\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 break;
618 default:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500619 printk("UNKNOWN\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 }
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500621 scsi_print_result(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 scsi_print_command(cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500623 if (status_byte(cmd->result) & CHECK_CONDITION)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 scsi_print_sense("", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500625 if (level > 3)
626 scmd_printk(KERN_INFO, cmd,
627 "scsi host busy %d failed %d\n",
628 cmd->device->host->host_busy,
629 cmd->device->host->host_failed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 }
631 }
632}
633#endif
634
Rob Landleyeb448202007-11-03 13:30:39 -0500635/**
636 * scsi_cmd_get_serial - Assign a serial number to a command
637 * @host: the scsi host
638 * @cmd: command to assign serial number to
639 *
640 * Description: a serial number identifies a request for error recovery
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 * and debugging purposes. Protected by the Host_Lock of host.
642 */
Jeff Garzikf2812332010-11-16 02:10:29 -0500643void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644{
645 cmd->serial_number = host->cmd_serial_number++;
646 if (cmd->serial_number == 0)
647 cmd->serial_number = host->cmd_serial_number++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648}
Jeff Garzikf2812332010-11-16 02:10:29 -0500649EXPORT_SYMBOL(scsi_cmd_get_serial);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650
Rob Landleyeb448202007-11-03 13:30:39 -0500651/**
652 * scsi_dispatch_command - Dispatch a command to the low-level driver.
653 * @cmd: command block we are dispatching.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 *
Rob Landleyeb448202007-11-03 13:30:39 -0500655 * Return: nonzero return request was rejected and device's queue needs to be
656 * plugged.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 */
658int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
659{
660 struct Scsi_Host *host = cmd->device->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 unsigned long timeout;
662 int rtn = 0;
663
Jens Axboe242f9dc2008-09-14 05:55:09 -0700664 atomic_inc(&cmd->device->iorequest_cnt);
665
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 /* check if the device is still usable */
667 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
668 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
669 * returns an immediate error upwards, and signals
670 * that the device is no longer present */
671 cmd->result = DID_NO_CONNECT << 16;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700672 scsi_done(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 /* return 0 (because the command has been processed) */
674 goto out;
675 }
676
James Bottomley0f1d87a2008-08-22 16:43:59 -0500677 /* Check to see if the scsi lld made this device blocked. */
678 if (unlikely(scsi_device_blocked(cmd->device))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 /*
James Bottomley0f1d87a2008-08-22 16:43:59 -0500680 * in blocked state, the command is just put back on
681 * the device queue. The suspend state has already
682 * blocked the queue so future requests should not
683 * occur until the device transitions out of the
684 * suspend state.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 */
Jens Axboe242f9dc2008-09-14 05:55:09 -0700686
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
688
689 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
690
691 /*
692 * NOTE: rtn is still zero here because we don't need the
693 * queue to be plugged on return (it's already stopped)
694 */
695 goto out;
696 }
697
698 /*
699 * If SCSI-2 or lower, store the LUN value in cmnd.
700 */
James Bottomley4d7db042006-03-31 20:07:45 -0600701 if (cmd->device->scsi_level <= SCSI_2 &&
702 cmd->device->scsi_level != SCSI_UNKNOWN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
704 (cmd->device->lun << 5 & 0xe0);
705 }
706
707 /*
708 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
709 * we can avoid the drive not being ready.
710 */
711 timeout = host->last_reset + MIN_RESET_DELAY;
712
713 if (host->resetting && time_before(jiffies, timeout)) {
714 int ticks_remaining = timeout - jiffies;
715 /*
716 * NOTE: This may be executed from within an interrupt
717 * handler! This is bad, but for now, it'll do. The irq
718 * level of the interrupt handler has been masked out by the
719 * platform dependent interrupt handling code already, so the
720 * sti() here will not cause another call to the SCSI host's
721 * interrupt handler (assuming there is one irq-level per
722 * host).
723 */
724 while (--ticks_remaining >= 0)
725 mdelay(1 + 999 / HZ);
726 host->resetting = 0;
727 }
728
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 scsi_log_send(cmd);
730
731 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 * Before we queue this command, check if the command
733 * length exceeds what the host adapter can handle.
734 */
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300735 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 SCSI_LOG_MLQUEUE(3,
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300737 printk("queuecommand : command too long. "
738 "cdb_size=%d host->max_cmd_len=%d\n",
739 cmd->cmd_len, cmd->device->host->max_cmd_len));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 cmd->result = (DID_ABORT << 16);
741
742 scsi_done(cmd);
743 goto out;
744 }
745
Mike Andersond2c9d9e2005-06-16 11:13:42 -0700746 if (unlikely(host->shost_state == SHOST_DEL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 cmd->result = (DID_NO_CONNECT << 16);
748 scsi_done(cmd);
749 } else {
Kei Tokunagabf816232010-04-01 20:41:40 +0900750 trace_scsi_dispatch_cmd_start(cmd);
Jeff Garzikf2812332010-11-16 02:10:29 -0500751 cmd->scsi_done = scsi_done;
752 rtn = host->hostt->queuecommand(host, cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 }
Jeff Garzikf2812332010-11-16 02:10:29 -0500754
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755 if (rtn) {
Kei Tokunagabf816232010-04-01 20:41:40 +0900756 trace_scsi_dispatch_cmd_error(cmd, rtn);
Mike Christief0c0a372008-08-17 15:24:38 -0500757 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
758 rtn != SCSI_MLQUEUE_TARGET_BUSY)
759 rtn = SCSI_MLQUEUE_HOST_BUSY;
760
761 scsi_queue_insert(cmd, rtn);
762
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 SCSI_LOG_MLQUEUE(3,
764 printk("queuecommand : request rejected\n"));
765 }
766
767 out:
768 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
769 return rtn;
770}
771
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772/**
773 * scsi_done - Enqueue the finished SCSI command into the done queue.
774 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
775 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
776 *
Rob Landleyeb448202007-11-03 13:30:39 -0500777 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
778 * which regains ownership of the SCSI command (de facto) from a LLDD, and
779 * enqueues the command to the done queue for further processing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 *
781 * This is the producer of the done queue who enqueues at the tail.
782 *
783 * This function is interrupt context safe.
784 */
Adrian Bunk52c1da32005-06-23 22:05:33 -0700785static void scsi_done(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786{
Kei Tokunagabf816232010-04-01 20:41:40 +0900787 trace_scsi_dispatch_cmd_done(cmd);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700788 blk_complete_request(cmd->request);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789}
790
Rob Landleyeb448202007-11-03 13:30:39 -0500791/**
792 * scsi_finish_command - cleanup and pass command back to upper layer
793 * @cmd: the command
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 *
Rob Landleyeb448202007-11-03 13:30:39 -0500795 * Description: Pass command off to upper layer for finishing of I/O
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 * request, waking processes that are waiting on results,
797 * etc.
798 */
799void scsi_finish_command(struct scsi_cmnd *cmd)
800{
801 struct scsi_device *sdev = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -0500802 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 struct Scsi_Host *shost = sdev->host;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800804 struct scsi_driver *drv;
805 unsigned int good_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806
807 scsi_device_unbusy(sdev);
808
809 /*
810 * Clear the flags which say that the device/host is no longer
811 * capable of accepting new commands. These are set in scsi_queue.c
812 * for both the queue full condition on a device, and for a
813 * host full condition on the host.
814 *
815 * XXX(hch): What about locking?
816 */
817 shost->host_blocked = 0;
Mike Christief0c0a372008-08-17 15:24:38 -0500818 starget->target_blocked = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819 sdev->device_blocked = 0;
820
821 /*
822 * If we have valid sense information, then some kind of recovery
823 * must have taken place. Make a note of this.
824 */
825 if (SCSI_SENSE_VALID(cmd))
826 cmd->result |= (DRIVER_SENSE << 24);
827
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400828 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
829 "Notifying upper driver of completion "
830 "(result %x)\n", cmd->result));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831
FUJITA Tomonorif18573a2008-04-11 12:56:52 +0200832 good_bytes = scsi_bufflen(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800833 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
James Bottomley427e59f2008-03-08 18:24:17 -0600834 int old_good_bytes = good_bytes;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800835 drv = scsi_cmd_to_driver(cmd);
836 if (drv->done)
837 good_bytes = drv->done(cmd);
James Bottomley427e59f2008-03-08 18:24:17 -0600838 /*
839 * USB may not give sense identifying bad sector and
840 * simply return a residue instead, so subtract off the
841 * residue if drv->done() error processing indicates no
842 * change to the completion length.
843 */
844 if (good_bytes == old_good_bytes)
845 good_bytes -= scsi_get_resid(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800846 }
847 scsi_io_completion(cmd, good_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848}
849EXPORT_SYMBOL(scsi_finish_command);
850
Rob Landleyeb448202007-11-03 13:30:39 -0500851/**
852 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
853 * @sdev: SCSI Device in question
854 * @tagged: Do we use tagged queueing (non-0) or do we treat
855 * this device as an untagged device (0)
856 * @tags: Number of tags allowed if tagged queueing enabled,
857 * or number of commands the low level driver can
858 * queue up in non-tagged mode (as per cmd_per_lun).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 *
860 * Returns: Nothing
861 *
862 * Lock Status: None held on entry
863 *
864 * Notes: Low level drivers may call this at any time and we will do
865 * the right thing depending on whether or not the device is
866 * currently active and whether or not it even has the
867 * command blocks built yet.
868 */
869void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
870{
871 unsigned long flags;
872
873 /*
874 * refuse to set tagged depth to an unworkable size
875 */
876 if (tags <= 0)
877 return;
878
879 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
880
Mike Christie885ace92008-07-11 19:50:32 -0500881 /*
882 * Check to see if the queue is managed by the block layer.
883 * If it is, and we fail to adjust the depth, exit.
884 *
885 * Do not resize the tag map if it is a host wide share bqt,
886 * because the size should be the hosts's can_queue. If there
887 * is more IO than the LLD's can_queue (so there are not enuogh
888 * tags) request_fn's host queue ready check will handle it.
889 */
890 if (!sdev->host->bqt) {
891 if (blk_queue_tagged(sdev->request_queue) &&
892 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
893 goto out;
894 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895
896 sdev->queue_depth = tags;
897 switch (tagged) {
898 case MSG_ORDERED_TAG:
899 sdev->ordered_tags = 1;
900 sdev->simple_tags = 1;
901 break;
902 case MSG_SIMPLE_TAG:
903 sdev->ordered_tags = 0;
904 sdev->simple_tags = 1;
905 break;
906 default:
James Bottomley9ccfc752005-10-02 11:45:08 -0500907 sdev_printk(KERN_WARNING, sdev,
908 "scsi_adjust_queue_depth, bad queue type, "
909 "disabled\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 case 0:
911 sdev->ordered_tags = sdev->simple_tags = 0;
912 sdev->queue_depth = tags;
913 break;
914 }
915 out:
916 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
917}
918EXPORT_SYMBOL(scsi_adjust_queue_depth);
919
Rob Landleyeb448202007-11-03 13:30:39 -0500920/**
921 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
922 * @sdev: SCSI Device in question
923 * @depth: Current number of outstanding SCSI commands on this device,
924 * not counting the one returned as QUEUE_FULL.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925 *
Rob Landleyeb448202007-11-03 13:30:39 -0500926 * Description: This function will track successive QUEUE_FULL events on a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 * specific SCSI device to determine if and when there is a
928 * need to adjust the queue depth on the device.
929 *
Rob Landleyeb448202007-11-03 13:30:39 -0500930 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 * -1 - Drop back to untagged operation using host->cmd_per_lun
932 * as the untagged command depth
933 *
934 * Lock Status: None held on entry
935 *
936 * Notes: Low level drivers may call this at any time and we will do
937 * "The Right Thing." We are interrupt context safe.
938 */
939int scsi_track_queue_full(struct scsi_device *sdev, int depth)
940{
Vasu Dev4a840672009-10-22 15:46:33 -0700941
942 /*
943 * Don't let QUEUE_FULLs on the same
944 * jiffies count, they could all be from
945 * same event.
946 */
947 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948 return 0;
949
Vasu Dev4a840672009-10-22 15:46:33 -0700950 sdev->last_queue_full_time = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 if (sdev->last_queue_full_depth != depth) {
952 sdev->last_queue_full_count = 1;
953 sdev->last_queue_full_depth = depth;
954 } else {
955 sdev->last_queue_full_count++;
956 }
957
958 if (sdev->last_queue_full_count <= 10)
959 return 0;
960 if (sdev->last_queue_full_depth < 8) {
961 /* Drop back to untagged */
962 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
963 return -1;
964 }
965
966 if (sdev->ordered_tags)
967 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
968 else
969 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
970 return depth;
971}
972EXPORT_SYMBOL(scsi_track_queue_full);
973
974/**
Matthew Wilcox881a2562008-12-31 13:12:46 -0500975 * scsi_vpd_inquiry - Request a device provide us with a VPD page
976 * @sdev: The device to ask
977 * @buffer: Where to put the result
978 * @page: Which Vital Product Data to return
979 * @len: The length of the buffer
980 *
981 * This is an internal helper function. You probably want to use
982 * scsi_get_vpd_page instead.
983 *
984 * Returns 0 on success or a negative error number.
985 */
986static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
987 u8 page, unsigned len)
988{
989 int result;
990 unsigned char cmd[16];
991
992 cmd[0] = INQUIRY;
993 cmd[1] = 1; /* EVPD */
994 cmd[2] = page;
995 cmd[3] = len >> 8;
996 cmd[4] = len & 0xff;
997 cmd[5] = 0; /* Control byte */
998
999 /*
1000 * I'm not convinced we need to try quite this hard to get VPD, but
1001 * all the existing users tried this hard.
1002 */
1003 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
James Bottomley95a36392009-08-11 10:59:09 -05001004 len, NULL, 30 * HZ, 3, NULL);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001005 if (result)
1006 return result;
1007
1008 /* Sanity check that we got the page back that we asked for */
1009 if (buffer[1] != page)
1010 return -EIO;
1011
1012 return 0;
1013}
1014
1015/**
1016 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1017 * @sdev: The device to ask
1018 * @page: Which Vital Product Data to return
Randy Dunlap786f8ba2010-02-28 17:32:45 -08001019 * @buf: where to store the VPD
1020 * @buf_len: number of bytes in the VPD buffer area
Matthew Wilcox881a2562008-12-31 13:12:46 -05001021 *
1022 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1023 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1024 * If the device supports this VPD page, this routine returns a pointer
1025 * to a buffer containing the data from that page. The caller is
1026 * responsible for calling kfree() on this pointer when it is no longer
1027 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1028 */
James Bottomleye3deec02009-11-03 12:33:07 -06001029int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1030 int buf_len)
Matthew Wilcox881a2562008-12-31 13:12:46 -05001031{
1032 int i, result;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001033
1034 /* Ask for all the pages supported by this device */
James Bottomleye3deec02009-11-03 12:33:07 -06001035 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001036 if (result)
1037 goto fail;
1038
1039 /* If the user actually wanted this page, we can skip the rest */
1040 if (page == 0)
Martin K. Petersen16d3ea22010-09-10 01:20:27 -04001041 return 0;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001042
James Bottomleye3deec02009-11-03 12:33:07 -06001043 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
Matthew Wilcox881a2562008-12-31 13:12:46 -05001044 if (buf[i + 4] == page)
1045 goto found;
James Bottomleye3deec02009-11-03 12:33:07 -06001046
Martin K. Petersen16d3ea22010-09-10 01:20:27 -04001047 if (i < buf[3] && i >= buf_len - 4)
James Bottomleye3deec02009-11-03 12:33:07 -06001048 /* ran off the end of the buffer, give us benefit of doubt */
1049 goto found;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001050 /* The device claims it doesn't support the requested page */
1051 goto fail;
1052
1053 found:
James Bottomleye3deec02009-11-03 12:33:07 -06001054 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001055 if (result)
1056 goto fail;
1057
James Bottomleye3deec02009-11-03 12:33:07 -06001058 return 0;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001059
1060 fail:
James Bottomleye3deec02009-11-03 12:33:07 -06001061 return -EINVAL;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001062}
1063EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1064
1065/**
Martin K. Petersen3c6bdae2012-09-18 12:19:30 -04001066 * scsi_report_opcode - Find out if a given command opcode is supported
1067 * @sdev: scsi device to query
1068 * @buffer: scratch buffer (must be at least 20 bytes long)
1069 * @len: length of buffer
1070 * @opcode: opcode for command to look up
1071 *
1072 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
1073 * opcode. Returns 0 if RSOC fails or if the command opcode is
1074 * unsupported. Returns 1 if the device claims to support the command.
1075 */
1076int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
1077 unsigned int len, unsigned char opcode)
1078{
1079 unsigned char cmd[16];
1080 struct scsi_sense_hdr sshdr;
1081 int result;
1082
1083 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
1084 return 0;
1085
1086 memset(cmd, 0, 16);
1087 cmd[0] = MAINTENANCE_IN;
1088 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
1089 cmd[2] = 1; /* One command format */
1090 cmd[3] = opcode;
1091 put_unaligned_be32(len, &cmd[6]);
1092 memset(buffer, 0, len);
1093
1094 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
1095 &sshdr, 30 * HZ, 3, NULL);
1096
1097 if (result && scsi_sense_valid(&sshdr) &&
1098 sshdr.sense_key == ILLEGAL_REQUEST &&
1099 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
1100 return 0;
1101
1102 if ((buffer[1] & 3) == 3) /* Command supported */
1103 return 1;
1104
1105 return 0;
1106}
1107EXPORT_SYMBOL(scsi_report_opcode);
1108
1109/**
Rob Landleyeb448202007-11-03 13:30:39 -05001110 * scsi_device_get - get an additional reference to a scsi_device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111 * @sdev: device to get a reference to
1112 *
Rob Landleyeb448202007-11-03 13:30:39 -05001113 * Description: Gets a reference to the scsi_device and increments the use count
Linus Torvalds1da177e2005-04-16 15:20:36 -07001114 * of the underlying LLDD module. You must hold host_lock of the
1115 * parent Scsi_Host or already have a reference when calling this.
1116 */
1117int scsi_device_get(struct scsi_device *sdev)
1118{
James Bottomley85b6c722006-08-31 18:15:22 -04001119 if (sdev->sdev_state == SDEV_DEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120 return -ENXIO;
1121 if (!get_device(&sdev->sdev_gendev))
1122 return -ENXIO;
James Bottomley85b6c722006-08-31 18:15:22 -04001123 /* We can fail this if we're doing SCSI operations
1124 * from module exit (like cache flush) */
1125 try_module_get(sdev->host->hostt->module);
1126
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127 return 0;
1128}
1129EXPORT_SYMBOL(scsi_device_get);
1130
1131/**
1132 * scsi_device_put - release a reference to a scsi_device
1133 * @sdev: device to release a reference on.
1134 *
Rob Landleyeb448202007-11-03 13:30:39 -05001135 * Description: Release a reference to the scsi_device and decrements the use
1136 * count of the underlying LLDD module. The device is freed once the last
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137 * user vanishes.
1138 */
1139void scsi_device_put(struct scsi_device *sdev)
1140{
Ingo Molnar504fb372006-11-09 10:09:35 +01001141#ifdef CONFIG_MODULE_UNLOAD
James Bottomleyf479ab82006-09-06 09:00:29 -05001142 struct module *module = sdev->host->hostt->module;
1143
James Bottomley85b6c722006-08-31 18:15:22 -04001144 /* The module refcount will be zero if scsi_device_get()
1145 * was called from a module removal routine */
James Bottomleyf479ab82006-09-06 09:00:29 -05001146 if (module && module_refcount(module) != 0)
1147 module_put(module);
Daniel Walkera506b442006-09-09 09:31:03 -07001148#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 put_device(&sdev->sdev_gendev);
1150}
1151EXPORT_SYMBOL(scsi_device_put);
1152
Rob Landleyeb448202007-11-03 13:30:39 -05001153/* helper for shost_for_each_device, see that for documentation */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1155 struct scsi_device *prev)
1156{
1157 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1158 struct scsi_device *next = NULL;
1159 unsigned long flags;
1160
1161 spin_lock_irqsave(shost->host_lock, flags);
1162 while (list->next != &shost->__devices) {
1163 next = list_entry(list->next, struct scsi_device, siblings);
1164 /* skip devices that we can't get a reference to */
1165 if (!scsi_device_get(next))
1166 break;
1167 next = NULL;
1168 list = list->next;
1169 }
1170 spin_unlock_irqrestore(shost->host_lock, flags);
1171
1172 if (prev)
1173 scsi_device_put(prev);
1174 return next;
1175}
1176EXPORT_SYMBOL(__scsi_iterate_devices);
1177
1178/**
1179 * starget_for_each_device - helper to walk all devices of a target
1180 * @starget: target whose devices we want to iterate over.
Rob Landleyeb448202007-11-03 13:30:39 -05001181 * @data: Opaque passed to each function call.
1182 * @fn: Function to call on each device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001183 *
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001184 * This traverses over each device of @starget. The devices have
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185 * a reference that must be released by scsi_host_put when breaking
1186 * out of the loop.
1187 */
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001188void starget_for_each_device(struct scsi_target *starget, void *data,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 void (*fn)(struct scsi_device *, void *))
1190{
1191 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1192 struct scsi_device *sdev;
1193
1194 shost_for_each_device(sdev, shost) {
1195 if ((sdev->channel == starget->channel) &&
1196 (sdev->id == starget->id))
1197 fn(sdev, data);
1198 }
1199}
1200EXPORT_SYMBOL(starget_for_each_device);
1201
1202/**
Randy Dunlap14f501a2008-02-03 15:06:36 -08001203 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001204 * @starget: target whose devices we want to iterate over.
Randy Dunlap14f501a2008-02-03 15:06:36 -08001205 * @data: parameter for callback @fn()
1206 * @fn: callback function that is invoked for each device
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001207 *
1208 * This traverses over each device of @starget. It does _not_
1209 * take a reference on the scsi_device, so the whole loop must be
1210 * protected by shost->host_lock.
1211 *
1212 * Note: The only reason why drivers would want to use this is because
1213 * they need to access the device list in irq context. Otherwise you
1214 * really want to use starget_for_each_device instead.
1215 **/
1216void __starget_for_each_device(struct scsi_target *starget, void *data,
1217 void (*fn)(struct scsi_device *, void *))
1218{
1219 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1220 struct scsi_device *sdev;
1221
1222 __shost_for_each_device(sdev, shost) {
1223 if ((sdev->channel == starget->channel) &&
1224 (sdev->id == starget->id))
1225 fn(sdev, data);
1226 }
1227}
1228EXPORT_SYMBOL(__starget_for_each_device);
1229
1230/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1232 * @starget: SCSI target pointer
1233 * @lun: SCSI Logical Unit Number
1234 *
Rob Landleyeb448202007-11-03 13:30:39 -05001235 * Description: Looks up the scsi_device with the specified @lun for a given
1236 * @starget. The returned scsi_device does not have an additional
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 * reference. You must hold the host's host_lock over this call and
Hannes Reinecke32aeef62009-01-13 16:50:37 +01001238 * any access to the returned scsi_device. A scsi_device in state
1239 * SDEV_DEL is skipped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 *
Randy Dunlapdc8875e2007-11-15 15:42:30 -08001241 * Note: The only reason why drivers should use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001242 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 * really want to use scsi_device_lookup_by_target instead.
1244 **/
1245struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1246 uint lun)
1247{
1248 struct scsi_device *sdev;
1249
1250 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
Hannes Reinecke32aeef62009-01-13 16:50:37 +01001251 if (sdev->sdev_state == SDEV_DEL)
1252 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 if (sdev->lun ==lun)
1254 return sdev;
1255 }
1256
1257 return NULL;
1258}
1259EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1260
1261/**
1262 * scsi_device_lookup_by_target - find a device given the target
1263 * @starget: SCSI target pointer
1264 * @lun: SCSI Logical Unit Number
1265 *
Bartlomiej Zolnierkiewicz477e6082009-04-27 20:54:22 +02001266 * Description: Looks up the scsi_device with the specified @lun for a given
1267 * @starget. The returned scsi_device has an additional reference that
Rob Landleyeb448202007-11-03 13:30:39 -05001268 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 **/
1270struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1271 uint lun)
1272{
1273 struct scsi_device *sdev;
1274 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1275 unsigned long flags;
1276
1277 spin_lock_irqsave(shost->host_lock, flags);
1278 sdev = __scsi_device_lookup_by_target(starget, lun);
1279 if (sdev && scsi_device_get(sdev))
1280 sdev = NULL;
1281 spin_unlock_irqrestore(shost->host_lock, flags);
1282
1283 return sdev;
1284}
1285EXPORT_SYMBOL(scsi_device_lookup_by_target);
1286
1287/**
Rob Landleyeb448202007-11-03 13:30:39 -05001288 * __scsi_device_lookup - find a device given the host (UNLOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001289 * @shost: SCSI host pointer
1290 * @channel: SCSI channel (zero if only one channel)
Rob Landleyeb448202007-11-03 13:30:39 -05001291 * @id: SCSI target number (physical unit number)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 * @lun: SCSI Logical Unit Number
1293 *
Rob Landleyeb448202007-11-03 13:30:39 -05001294 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1295 * for a given host. The returned scsi_device does not have an additional
1296 * reference. You must hold the host's host_lock over this call and any access
1297 * to the returned scsi_device.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298 *
1299 * Note: The only reason why drivers would want to use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001300 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001301 * really want to use scsi_device_lookup instead.
1302 **/
1303struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1304 uint channel, uint id, uint lun)
1305{
1306 struct scsi_device *sdev;
1307
1308 list_for_each_entry(sdev, &shost->__devices, siblings) {
1309 if (sdev->channel == channel && sdev->id == id &&
1310 sdev->lun ==lun)
1311 return sdev;
1312 }
1313
1314 return NULL;
1315}
1316EXPORT_SYMBOL(__scsi_device_lookup);
1317
1318/**
1319 * scsi_device_lookup - find a device given the host
1320 * @shost: SCSI host pointer
1321 * @channel: SCSI channel (zero if only one channel)
1322 * @id: SCSI target number (physical unit number)
1323 * @lun: SCSI Logical Unit Number
1324 *
Rob Landleyeb448202007-11-03 13:30:39 -05001325 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1326 * for a given host. The returned scsi_device has an additional reference that
1327 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 **/
1329struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1330 uint channel, uint id, uint lun)
1331{
1332 struct scsi_device *sdev;
1333 unsigned long flags;
1334
1335 spin_lock_irqsave(shost->host_lock, flags);
1336 sdev = __scsi_device_lookup(shost, channel, id, lun);
1337 if (sdev && scsi_device_get(sdev))
1338 sdev = NULL;
1339 spin_unlock_irqrestore(shost->host_lock, flags);
1340
1341 return sdev;
1342}
1343EXPORT_SYMBOL(scsi_device_lookup);
1344
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345MODULE_DESCRIPTION("SCSI core");
1346MODULE_LICENSE("GPL");
1347
1348module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1349MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1350
1351static int __init init_scsi(void)
1352{
Jens Axboe9bf09c22006-09-30 20:31:11 +02001353 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354
1355 error = scsi_init_queue();
1356 if (error)
1357 return error;
1358 error = scsi_init_procfs();
1359 if (error)
1360 goto cleanup_queue;
1361 error = scsi_init_devinfo();
1362 if (error)
1363 goto cleanup_procfs;
1364 error = scsi_init_hosts();
1365 if (error)
1366 goto cleanup_devlist;
1367 error = scsi_init_sysctl();
1368 if (error)
1369 goto cleanup_hosts;
1370 error = scsi_sysfs_register();
1371 if (error)
1372 goto cleanup_sysctl;
1373
James Smart84314fd2006-08-18 17:30:09 -04001374 scsi_netlink_init();
1375
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1377 return 0;
1378
1379cleanup_sysctl:
1380 scsi_exit_sysctl();
1381cleanup_hosts:
1382 scsi_exit_hosts();
1383cleanup_devlist:
1384 scsi_exit_devinfo();
1385cleanup_procfs:
1386 scsi_exit_procfs();
1387cleanup_queue:
1388 scsi_exit_queue();
1389 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1390 -error);
1391 return error;
1392}
1393
1394static void __exit exit_scsi(void)
1395{
James Smart84314fd2006-08-18 17:30:09 -04001396 scsi_netlink_exit();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 scsi_sysfs_unregister();
1398 scsi_exit_sysctl();
1399 scsi_exit_hosts();
1400 scsi_exit_devinfo();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401 scsi_exit_procfs();
1402 scsi_exit_queue();
Dan Williamsa4683482012-07-09 19:33:30 -07001403 async_unregister_domain(&scsi_sd_probe_domain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404}
1405
1406subsys_initcall(init_scsi);
1407module_exit(exit_scsi);