blob: ad0ed212db4ad094441f7a5656639e989c980738 [file] [log] [blame]
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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
58#include <scsi/scsi.h>
59#include <scsi/scsi_cmnd.h>
60#include <scsi/scsi_dbg.h>
61#include <scsi/scsi_device.h>
Linus Torvalds7b3d9542008-01-06 10:17:12 -080062#include <scsi/scsi_driver.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070063#include <scsi/scsi_eh.h>
64#include <scsi/scsi_host.h>
65#include <scsi/scsi_tcq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67#include "scsi_priv.h"
68#include "scsi_logging.h"
69
Kei Tokunagabf816232010-04-01 20:41:40 +090070#define CREATE_TRACE_POINTS
71#include <trace/events/scsi.h>
72
Adrian Bunk52c1da32005-06-23 22:05:33 -070073static void scsi_done(struct scsi_cmnd *cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
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/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 * 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
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -060093/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
94 * You may not alter any existing entry (although adding new ones is
95 * encouraged once assigned by ANSI/INCITS T10
96 */
Matthew Wilcox4ff36712006-07-04 12:15:20 -060097static const char *const scsi_device_types[] = {
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -060098 "Direct-Access ",
99 "Sequential-Access",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 "Printer ",
101 "Processor ",
102 "WORM ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600103 "CD-ROM ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 "Scanner ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600105 "Optical Device ",
106 "Medium Changer ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 "Communications ",
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600108 "ASC IT8 ",
109 "ASC IT8 ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 "RAID ",
111 "Enclosure ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600112 "Direct-Access-RBC",
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600113 "Optical card ",
114 "Bridge controller",
115 "Object storage ",
116 "Automation/Drive ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117};
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600118
Rob Landleyeb448202007-11-03 13:30:39 -0500119/**
120 * scsi_device_type - Return 17 char string indicating device type.
121 * @type: type number to look up
122 */
123
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600124const char * scsi_device_type(unsigned type)
125{
126 if (type == 0x1e)
127 return "Well-known LUN ";
128 if (type == 0x1f)
129 return "No Device ";
Eric Sesterhenn80c6e3c2006-09-26 13:22:13 +0200130 if (type >= ARRAY_SIZE(scsi_device_types))
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600131 return "Unknown ";
132 return scsi_device_types[type];
133}
134
135EXPORT_SYMBOL(scsi_device_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137struct scsi_host_cmd_pool {
James Bottomley5b7f1682008-01-20 09:28:24 -0600138 struct kmem_cache *cmd_slab;
139 struct kmem_cache *sense_slab;
140 unsigned int users;
141 char *cmd_name;
142 char *sense_name;
143 unsigned int slab_flags;
144 gfp_t gfp_mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145};
146
147static struct scsi_host_cmd_pool scsi_cmd_pool = {
James Bottomley5b7f1682008-01-20 09:28:24 -0600148 .cmd_name = "scsi_cmd_cache",
149 .sense_name = "scsi_sense_cache",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 .slab_flags = SLAB_HWCACHE_ALIGN,
151};
152
153static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
James Bottomley5b7f1682008-01-20 09:28:24 -0600154 .cmd_name = "scsi_cmd_cache(DMA)",
155 .sense_name = "scsi_sense_cache(DMA)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
157 .gfp_mask = __GFP_DMA,
158};
159
Arjan van de Ven0b950672006-01-11 13:16:10 +0100160static DEFINE_MUTEX(host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
Rob Landleyeb448202007-11-03 13:30:39 -0500162/**
James Bottomleye507e302008-03-13 11:16:33 -0500163 * scsi_pool_alloc_command - internal function to get a fully allocated command
164 * @pool: slab pool to allocate the command from
165 * @gfp_mask: mask for the allocation
166 *
167 * Returns a fully allocated command (with the allied sense buffer) or
168 * NULL on failure
169 */
170static struct scsi_cmnd *
171scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
172{
173 struct scsi_cmnd *cmd;
174
Wei Yongjunebef2642009-03-04 12:06:13 -0800175 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
James Bottomleye507e302008-03-13 11:16:33 -0500176 if (!cmd)
177 return NULL;
178
James Bottomleye507e302008-03-13 11:16:33 -0500179 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
180 gfp_mask | pool->gfp_mask);
181 if (!cmd->sense_buffer) {
182 kmem_cache_free(pool->cmd_slab, cmd);
183 return NULL;
184 }
185
186 return cmd;
187}
188
189/**
190 * scsi_pool_free_command - internal function to release a command
191 * @pool: slab pool to allocate the command from
192 * @cmd: command to release
193 *
194 * the command must previously have been allocated by
195 * scsi_pool_alloc_command.
196 */
197static void
198scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
199 struct scsi_cmnd *cmd)
200{
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400201 if (cmd->prot_sdb)
202 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
203
James Bottomleye507e302008-03-13 11:16:33 -0500204 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
205 kmem_cache_free(pool->cmd_slab, cmd);
206}
207
208/**
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400209 * scsi_host_alloc_command - internal function to allocate command
210 * @shost: SCSI host whose pool to allocate from
211 * @gfp_mask: mask for the allocation
212 *
213 * Returns a fully allocated command with sense buffer and protection
214 * data buffer (where applicable) or NULL on failure
215 */
216static struct scsi_cmnd *
217scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
218{
219 struct scsi_cmnd *cmd;
220
221 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
222 if (!cmd)
223 return NULL;
224
225 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
226 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
227
228 if (!cmd->prot_sdb) {
229 scsi_pool_free_command(shost->cmd_pool, cmd);
230 return NULL;
231 }
232 }
233
234 return cmd;
235}
236
237/**
Rob Landleyeb448202007-11-03 13:30:39 -0500238 * __scsi_get_command - Allocate a struct scsi_cmnd
239 * @shost: host to transmit command
240 * @gfp_mask: allocation mask
241 *
242 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
243 * host's free_list if necessary.
244 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900245struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246{
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400247 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
Hugh Dickins164fc5d2008-04-06 23:56:57 +0100248
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 if (unlikely(!cmd)) {
250 unsigned long flags;
251
252 spin_lock_irqsave(&shost->free_list_lock, flags);
253 if (likely(!list_empty(&shost->free_list))) {
254 cmd = list_entry(shost->free_list.next,
255 struct scsi_cmnd, list);
256 list_del_init(&cmd->list);
257 }
258 spin_unlock_irqrestore(&shost->free_list_lock, flags);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900259
260 if (cmd) {
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400261 void *buf, *prot;
262
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900263 buf = cmd->sense_buffer;
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400264 prot = cmd->prot_sdb;
265
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900266 memset(cmd, 0, sizeof(*cmd));
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400267
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900268 cmd->sense_buffer = buf;
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400269 cmd->prot_sdb = prot;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900270 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 }
272
273 return cmd;
274}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900275EXPORT_SYMBOL_GPL(__scsi_get_command);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276
Rob Landleyeb448202007-11-03 13:30:39 -0500277/**
278 * scsi_get_command - Allocate and setup a scsi command block
279 * @dev: parent scsi device
280 * @gfp_mask: allocator flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 *
282 * Returns: The allocated scsi command structure.
283 */
Al Viroc53033f2005-10-21 03:22:08 -0400284struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285{
286 struct scsi_cmnd *cmd;
287
288 /* Bail if we can't get a reference to the device */
289 if (!get_device(&dev->sdev_gendev))
290 return NULL;
291
292 cmd = __scsi_get_command(dev->host, gfp_mask);
293
294 if (likely(cmd != NULL)) {
295 unsigned long flags;
296
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 cmd->device = dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 INIT_LIST_HEAD(&cmd->list);
299 spin_lock_irqsave(&dev->list_lock, flags);
300 list_add_tail(&cmd->list, &dev->cmd_list);
301 spin_unlock_irqrestore(&dev->list_lock, flags);
Matthew Dobson79e448b2005-11-21 21:32:29 -0800302 cmd->jiffies_at_alloc = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 } else
304 put_device(&dev->sdev_gendev);
305
306 return cmd;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900307}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308EXPORT_SYMBOL(scsi_get_command);
309
Rob Landleyeb448202007-11-03 13:30:39 -0500310/**
311 * __scsi_put_command - Free a struct scsi_cmnd
312 * @shost: dev->host
313 * @cmd: Command to free
314 * @dev: parent scsi device
315 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900316void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
317 struct device *dev)
318{
319 unsigned long flags;
320
321 /* changing locks here, don't need to restore the irq state */
322 spin_lock_irqsave(&shost->free_list_lock, flags);
323 if (unlikely(list_empty(&shost->free_list))) {
324 list_add(&cmd->list, &shost->free_list);
325 cmd = NULL;
326 }
327 spin_unlock_irqrestore(&shost->free_list_lock, flags);
328
James Bottomleye507e302008-03-13 11:16:33 -0500329 if (likely(cmd != NULL))
330 scsi_pool_free_command(shost->cmd_pool, cmd);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900331
332 put_device(dev);
333}
334EXPORT_SYMBOL(__scsi_put_command);
335
Rob Landleyeb448202007-11-03 13:30:39 -0500336/**
337 * scsi_put_command - Free a scsi command block
338 * @cmd: command block to free
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 *
340 * Returns: Nothing.
341 *
342 * Notes: The command must not belong to any lists.
343 */
344void scsi_put_command(struct scsi_cmnd *cmd)
345{
346 struct scsi_device *sdev = cmd->device;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 unsigned long flags;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900348
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 /* serious error if the command hasn't come from a device list */
350 spin_lock_irqsave(&cmd->device->list_lock, flags);
351 BUG_ON(list_empty(&cmd->list));
352 list_del_init(&cmd->list);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900353 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900355 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356}
357EXPORT_SYMBOL(scsi_put_command);
358
James Bottomley1c353f72008-03-13 11:19:36 -0500359static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360{
James Bottomley1c353f72008-03-13 11:19:36 -0500361 struct scsi_host_cmd_pool *retval = NULL, *pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 /*
363 * Select a command slab for this host and create it if not
Rob Landleyeb448202007-11-03 13:30:39 -0500364 * yet existent.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 */
Arjan van de Ven0b950672006-01-11 13:16:10 +0100366 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500367 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
368 &scsi_cmd_pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 if (!pool->users) {
James Bottomley5b7f1682008-01-20 09:28:24 -0600370 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
371 sizeof(struct scsi_cmnd), 0,
372 pool->slab_flags, NULL);
373 if (!pool->cmd_slab)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 goto fail;
James Bottomley5b7f1682008-01-20 09:28:24 -0600375
376 pool->sense_slab = kmem_cache_create(pool->sense_name,
377 SCSI_SENSE_BUFFERSIZE, 0,
378 pool->slab_flags, NULL);
379 if (!pool->sense_slab) {
380 kmem_cache_destroy(pool->cmd_slab);
381 goto fail;
382 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 }
384
385 pool->users++;
James Bottomley1c353f72008-03-13 11:19:36 -0500386 retval = pool;
387 fail:
Arjan van de Ven0b950672006-01-11 13:16:10 +0100388 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500389 return retval;
390}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391
James Bottomley1c353f72008-03-13 11:19:36 -0500392static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
393{
394 struct scsi_host_cmd_pool *pool;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900395
FUJITA Tomonori166a7282008-01-08 07:59:05 +0900396 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500397 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
398 &scsi_cmd_pool;
399 /*
400 * This may happen if a driver has a mismatched get and put
401 * of the command pool; the driver should be implicated in
402 * the stack trace
403 */
404 BUG_ON(pool->users == 0);
405
James Bottomley5b7f1682008-01-20 09:28:24 -0600406 if (!--pool->users) {
407 kmem_cache_destroy(pool->cmd_slab);
408 kmem_cache_destroy(pool->sense_slab);
409 }
Arjan van de Ven0b950672006-01-11 13:16:10 +0100410 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500411}
412
413/**
414 * scsi_allocate_command - get a fully allocated SCSI command
415 * @gfp_mask: allocation mask
416 *
417 * This function is for use outside of the normal host based pools.
418 * It allocates the relevant command and takes an additional reference
419 * on the pool it used. This function *must* be paired with
420 * scsi_free_command which also has the identical mask, otherwise the
421 * free pool counts will eventually go wrong and you'll trigger a bug.
422 *
423 * This function should *only* be used by drivers that need a static
424 * command allocation at start of day for internal functions.
425 */
426struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
427{
428 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
429
430 if (!pool)
431 return NULL;
432
433 return scsi_pool_alloc_command(pool, gfp_mask);
434}
435EXPORT_SYMBOL(scsi_allocate_command);
436
437/**
438 * scsi_free_command - free a command allocated by scsi_allocate_command
439 * @gfp_mask: mask used in the original allocation
440 * @cmd: command to free
441 *
442 * Note: using the original allocation mask is vital because that's
443 * what determines which command pool we use to free the command. Any
444 * mismatch will cause the system to BUG eventually.
445 */
446void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
447{
448 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
449
450 /*
451 * this could trigger if the mask to scsi_allocate_command
452 * doesn't match this mask. Otherwise we're guaranteed that this
453 * succeeds because scsi_allocate_command must have taken a reference
454 * on the pool
455 */
456 BUG_ON(!pool);
457
458 scsi_pool_free_command(pool, cmd);
459 /*
460 * scsi_put_host_cmd_pool is called twice; once to release the
461 * reference we took above, and once to release the reference
462 * originally taken by scsi_allocate_command
463 */
464 scsi_put_host_cmd_pool(gfp_mask);
465 scsi_put_host_cmd_pool(gfp_mask);
466}
467EXPORT_SYMBOL(scsi_free_command);
468
469/**
470 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
471 * @shost: host to allocate the freelist for.
472 *
473 * Description: The command freelist protects against system-wide out of memory
474 * deadlock by preallocating one SCSI command structure for each host, so the
475 * system can always write to a swap file on a device associated with that host.
476 *
477 * Returns: Nothing.
478 */
479int scsi_setup_command_freelist(struct Scsi_Host *shost)
480{
481 struct scsi_cmnd *cmd;
482 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
483
484 spin_lock_init(&shost->free_list_lock);
485 INIT_LIST_HEAD(&shost->free_list);
486
487 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
488
489 if (!shost->cmd_pool)
490 return -ENOMEM;
491
492 /*
493 * Get one backup command for this host.
494 */
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400495 cmd = scsi_host_alloc_command(shost, gfp_mask);
James Bottomley1c353f72008-03-13 11:19:36 -0500496 if (!cmd) {
497 scsi_put_host_cmd_pool(gfp_mask);
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400498 shost->cmd_pool = NULL;
James Bottomley1c353f72008-03-13 11:19:36 -0500499 return -ENOMEM;
500 }
501 list_add(&cmd->list, &shost->free_list);
502 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503}
504
Rob Landleyeb448202007-11-03 13:30:39 -0500505/**
506 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
507 * @shost: host whose freelist is going to be destroyed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 */
509void scsi_destroy_command_freelist(struct Scsi_Host *shost)
510{
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400511 /*
512 * If cmd_pool is NULL the free list was not initialized, so
513 * do not attempt to release resources.
514 */
515 if (!shost->cmd_pool)
516 return;
517
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 while (!list_empty(&shost->free_list)) {
519 struct scsi_cmnd *cmd;
520
521 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
522 list_del_init(&cmd->list);
James Bottomleye507e302008-03-13 11:16:33 -0500523 scsi_pool_free_command(shost->cmd_pool, cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 }
James Bottomley1c353f72008-03-13 11:19:36 -0500525 shost->cmd_pool = NULL;
526 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900527}
528
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529#ifdef CONFIG_SCSI_LOGGING
530void scsi_log_send(struct scsi_cmnd *cmd)
531{
532 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533
534 /*
535 * If ML QUEUE log level is greater than or equal to:
536 *
537 * 1: nothing (match completion)
538 *
539 * 2: log opcode + command of all commands
540 *
541 * 3: same as 2 plus dump cmd address
542 *
543 * 4: same as 3 plus dump extra junk
544 */
545 if (unlikely(scsi_logging_level)) {
546 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
547 SCSI_LOG_MLQUEUE_BITS);
548 if (level > 1) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500549 scmd_printk(KERN_INFO, cmd, "Send: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 if (level > 2)
551 printk("0x%p ", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500552 printk("\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 scsi_print_command(cmd);
554 if (level > 3) {
555 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800556 " queuecommand 0x%p\n",
Boaz Harrosha73e45b2007-07-04 21:26:01 +0300557 scsi_sglist(cmd), scsi_bufflen(cmd),
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500558 cmd->device->host->hostt->queuecommand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559
560 }
561 }
562 }
563}
564
565void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
566{
567 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568
569 /*
570 * If ML COMPLETE log level is greater than or equal to:
571 *
572 * 1: log disposition, result, opcode + command, and conditionally
573 * sense data for failures or non SUCCESS dispositions.
574 *
575 * 2: same as 1 but for all command completions.
576 *
577 * 3: same as 2 plus dump cmd address
578 *
579 * 4: same as 3 plus dump extra junk
580 */
581 if (unlikely(scsi_logging_level)) {
582 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
583 SCSI_LOG_MLCOMPLETE_BITS);
584 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
585 (level > 1)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500586 scmd_printk(KERN_INFO, cmd, "Done: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 if (level > 2)
588 printk("0x%p ", cmd);
589 /*
590 * Dump truncated values, so we usually fit within
591 * 80 chars.
592 */
593 switch (disposition) {
594 case SUCCESS:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500595 printk("SUCCESS\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 break;
597 case NEEDS_RETRY:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500598 printk("RETRY\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 break;
600 case ADD_TO_MLQUEUE:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500601 printk("MLQUEUE\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 break;
603 case FAILED:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500604 printk("FAILED\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 break;
606 case TIMEOUT_ERROR:
607 /*
608 * If called via scsi_times_out.
609 */
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500610 printk("TIMEOUT\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 break;
612 default:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500613 printk("UNKNOWN\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 }
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500615 scsi_print_result(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 scsi_print_command(cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500617 if (status_byte(cmd->result) & CHECK_CONDITION)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 scsi_print_sense("", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500619 if (level > 3)
620 scmd_printk(KERN_INFO, cmd,
621 "scsi host busy %d failed %d\n",
622 cmd->device->host->host_busy,
623 cmd->device->host->host_failed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 }
625 }
626}
627#endif
628
Rob Landleyeb448202007-11-03 13:30:39 -0500629/**
630 * scsi_cmd_get_serial - Assign a serial number to a command
631 * @host: the scsi host
632 * @cmd: command to assign serial number to
633 *
634 * Description: a serial number identifies a request for error recovery
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 * and debugging purposes. Protected by the Host_Lock of host.
636 */
637static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
638{
639 cmd->serial_number = host->cmd_serial_number++;
640 if (cmd->serial_number == 0)
641 cmd->serial_number = host->cmd_serial_number++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642}
643
Rob Landleyeb448202007-11-03 13:30:39 -0500644/**
645 * scsi_dispatch_command - Dispatch a command to the low-level driver.
646 * @cmd: command block we are dispatching.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 *
Rob Landleyeb448202007-11-03 13:30:39 -0500648 * Return: nonzero return request was rejected and device's queue needs to be
649 * plugged.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 */
651int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
652{
653 struct Scsi_Host *host = cmd->device->host;
654 unsigned long flags = 0;
655 unsigned long timeout;
656 int rtn = 0;
657
Jens Axboe242f9dc2008-09-14 05:55:09 -0700658 atomic_inc(&cmd->device->iorequest_cnt);
659
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 /* check if the device is still usable */
661 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
662 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
663 * returns an immediate error upwards, and signals
664 * that the device is no longer present */
665 cmd->result = DID_NO_CONNECT << 16;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700666 scsi_done(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 /* return 0 (because the command has been processed) */
668 goto out;
669 }
670
James Bottomley0f1d87a2008-08-22 16:43:59 -0500671 /* Check to see if the scsi lld made this device blocked. */
672 if (unlikely(scsi_device_blocked(cmd->device))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 /*
James Bottomley0f1d87a2008-08-22 16:43:59 -0500674 * in blocked state, the command is just put back on
675 * the device queue. The suspend state has already
676 * blocked the queue so future requests should not
677 * occur until the device transitions out of the
678 * suspend state.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 */
Jens Axboe242f9dc2008-09-14 05:55:09 -0700680
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
682
683 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
684
685 /*
686 * NOTE: rtn is still zero here because we don't need the
687 * queue to be plugged on return (it's already stopped)
688 */
689 goto out;
690 }
691
692 /*
693 * If SCSI-2 or lower, store the LUN value in cmnd.
694 */
James Bottomley4d7db042006-03-31 20:07:45 -0600695 if (cmd->device->scsi_level <= SCSI_2 &&
696 cmd->device->scsi_level != SCSI_UNKNOWN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
698 (cmd->device->lun << 5 & 0xe0);
699 }
700
701 /*
702 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
703 * we can avoid the drive not being ready.
704 */
705 timeout = host->last_reset + MIN_RESET_DELAY;
706
707 if (host->resetting && time_before(jiffies, timeout)) {
708 int ticks_remaining = timeout - jiffies;
709 /*
710 * NOTE: This may be executed from within an interrupt
711 * handler! This is bad, but for now, it'll do. The irq
712 * level of the interrupt handler has been masked out by the
713 * platform dependent interrupt handling code already, so the
714 * sti() here will not cause another call to the SCSI host's
715 * interrupt handler (assuming there is one irq-level per
716 * host).
717 */
718 while (--ticks_remaining >= 0)
719 mdelay(1 + 999 / HZ);
720 host->resetting = 0;
721 }
722
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 scsi_log_send(cmd);
724
725 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 * Before we queue this command, check if the command
727 * length exceeds what the host adapter can handle.
728 */
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300729 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 SCSI_LOG_MLQUEUE(3,
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300731 printk("queuecommand : command too long. "
732 "cdb_size=%d host->max_cmd_len=%d\n",
733 cmd->cmd_len, cmd->device->host->max_cmd_len));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 cmd->result = (DID_ABORT << 16);
735
736 scsi_done(cmd);
737 goto out;
738 }
739
740 spin_lock_irqsave(host->host_lock, flags);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700741 /*
742 * AK: unlikely race here: for some reason the timer could
743 * expire before the serial number is set up below.
744 *
745 * TODO: kill serial or move to blk layer
746 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 scsi_cmd_get_serial(host, cmd);
748
Mike Andersond2c9d9e2005-06-16 11:13:42 -0700749 if (unlikely(host->shost_state == SHOST_DEL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 cmd->result = (DID_NO_CONNECT << 16);
751 scsi_done(cmd);
752 } else {
Kei Tokunagabf816232010-04-01 20:41:40 +0900753 trace_scsi_dispatch_cmd_start(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 rtn = host->hostt->queuecommand(cmd, scsi_done);
755 }
756 spin_unlock_irqrestore(host->host_lock, flags);
757 if (rtn) {
Kei Tokunagabf816232010-04-01 20:41:40 +0900758 trace_scsi_dispatch_cmd_error(cmd, rtn);
Mike Christief0c0a372008-08-17 15:24:38 -0500759 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
760 rtn != SCSI_MLQUEUE_TARGET_BUSY)
761 rtn = SCSI_MLQUEUE_HOST_BUSY;
762
763 scsi_queue_insert(cmd, rtn);
764
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 SCSI_LOG_MLQUEUE(3,
766 printk("queuecommand : request rejected\n"));
767 }
768
769 out:
770 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
771 return rtn;
772}
773
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774/**
775 * scsi_done - Enqueue the finished SCSI command into the done queue.
776 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
777 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
778 *
Rob Landleyeb448202007-11-03 13:30:39 -0500779 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
780 * which regains ownership of the SCSI command (de facto) from a LLDD, and
781 * enqueues the command to the done queue for further processing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 *
783 * This is the producer of the done queue who enqueues at the tail.
784 *
785 * This function is interrupt context safe.
786 */
Adrian Bunk52c1da32005-06-23 22:05:33 -0700787static void scsi_done(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788{
Kei Tokunagabf816232010-04-01 20:41:40 +0900789 trace_scsi_dispatch_cmd_done(cmd);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700790 blk_complete_request(cmd->request);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791}
792
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800793/* Move this to a header if it becomes more generally useful */
794static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
795{
796 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
797}
798
Rob Landleyeb448202007-11-03 13:30:39 -0500799/**
800 * scsi_finish_command - cleanup and pass command back to upper layer
801 * @cmd: the command
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 *
Rob Landleyeb448202007-11-03 13:30:39 -0500803 * Description: Pass command off to upper layer for finishing of I/O
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 * request, waking processes that are waiting on results,
805 * etc.
806 */
807void scsi_finish_command(struct scsi_cmnd *cmd)
808{
809 struct scsi_device *sdev = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -0500810 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 struct Scsi_Host *shost = sdev->host;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800812 struct scsi_driver *drv;
813 unsigned int good_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814
815 scsi_device_unbusy(sdev);
816
817 /*
818 * Clear the flags which say that the device/host is no longer
819 * capable of accepting new commands. These are set in scsi_queue.c
820 * for both the queue full condition on a device, and for a
821 * host full condition on the host.
822 *
823 * XXX(hch): What about locking?
824 */
825 shost->host_blocked = 0;
Mike Christief0c0a372008-08-17 15:24:38 -0500826 starget->target_blocked = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 sdev->device_blocked = 0;
828
829 /*
830 * If we have valid sense information, then some kind of recovery
831 * must have taken place. Make a note of this.
832 */
833 if (SCSI_SENSE_VALID(cmd))
834 cmd->result |= (DRIVER_SENSE << 24);
835
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400836 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
837 "Notifying upper driver of completion "
838 "(result %x)\n", cmd->result));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839
FUJITA Tomonorif18573a2008-04-11 12:56:52 +0200840 good_bytes = scsi_bufflen(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800841 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
James Bottomley427e59f2008-03-08 18:24:17 -0600842 int old_good_bytes = good_bytes;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800843 drv = scsi_cmd_to_driver(cmd);
844 if (drv->done)
845 good_bytes = drv->done(cmd);
James Bottomley427e59f2008-03-08 18:24:17 -0600846 /*
847 * USB may not give sense identifying bad sector and
848 * simply return a residue instead, so subtract off the
849 * residue if drv->done() error processing indicates no
850 * change to the completion length.
851 */
852 if (good_bytes == old_good_bytes)
853 good_bytes -= scsi_get_resid(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800854 }
855 scsi_io_completion(cmd, good_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856}
857EXPORT_SYMBOL(scsi_finish_command);
858
Rob Landleyeb448202007-11-03 13:30:39 -0500859/**
860 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
861 * @sdev: SCSI Device in question
862 * @tagged: Do we use tagged queueing (non-0) or do we treat
863 * this device as an untagged device (0)
864 * @tags: Number of tags allowed if tagged queueing enabled,
865 * or number of commands the low level driver can
866 * queue up in non-tagged mode (as per cmd_per_lun).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 *
868 * Returns: Nothing
869 *
870 * Lock Status: None held on entry
871 *
872 * Notes: Low level drivers may call this at any time and we will do
873 * the right thing depending on whether or not the device is
874 * currently active and whether or not it even has the
875 * command blocks built yet.
876 */
877void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
878{
879 unsigned long flags;
880
881 /*
882 * refuse to set tagged depth to an unworkable size
883 */
884 if (tags <= 0)
885 return;
886
887 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
888
Mike Christie885ace92008-07-11 19:50:32 -0500889 /*
890 * Check to see if the queue is managed by the block layer.
891 * If it is, and we fail to adjust the depth, exit.
892 *
893 * Do not resize the tag map if it is a host wide share bqt,
894 * because the size should be the hosts's can_queue. If there
895 * is more IO than the LLD's can_queue (so there are not enuogh
896 * tags) request_fn's host queue ready check will handle it.
897 */
898 if (!sdev->host->bqt) {
899 if (blk_queue_tagged(sdev->request_queue) &&
900 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
901 goto out;
902 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903
904 sdev->queue_depth = tags;
905 switch (tagged) {
906 case MSG_ORDERED_TAG:
907 sdev->ordered_tags = 1;
908 sdev->simple_tags = 1;
909 break;
910 case MSG_SIMPLE_TAG:
911 sdev->ordered_tags = 0;
912 sdev->simple_tags = 1;
913 break;
914 default:
James Bottomley9ccfc752005-10-02 11:45:08 -0500915 sdev_printk(KERN_WARNING, sdev,
916 "scsi_adjust_queue_depth, bad queue type, "
917 "disabled\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 case 0:
919 sdev->ordered_tags = sdev->simple_tags = 0;
920 sdev->queue_depth = tags;
921 break;
922 }
923 out:
924 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
925}
926EXPORT_SYMBOL(scsi_adjust_queue_depth);
927
Rob Landleyeb448202007-11-03 13:30:39 -0500928/**
929 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
930 * @sdev: SCSI Device in question
931 * @depth: Current number of outstanding SCSI commands on this device,
932 * not counting the one returned as QUEUE_FULL.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 *
Rob Landleyeb448202007-11-03 13:30:39 -0500934 * Description: This function will track successive QUEUE_FULL events on a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 * specific SCSI device to determine if and when there is a
936 * need to adjust the queue depth on the device.
937 *
Rob Landleyeb448202007-11-03 13:30:39 -0500938 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939 * -1 - Drop back to untagged operation using host->cmd_per_lun
940 * as the untagged command depth
941 *
942 * Lock Status: None held on entry
943 *
944 * Notes: Low level drivers may call this at any time and we will do
945 * "The Right Thing." We are interrupt context safe.
946 */
947int scsi_track_queue_full(struct scsi_device *sdev, int depth)
948{
Vasu Dev4a840672009-10-22 15:46:33 -0700949
950 /*
951 * Don't let QUEUE_FULLs on the same
952 * jiffies count, they could all be from
953 * same event.
954 */
955 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956 return 0;
957
Vasu Dev4a840672009-10-22 15:46:33 -0700958 sdev->last_queue_full_time = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 if (sdev->last_queue_full_depth != depth) {
960 sdev->last_queue_full_count = 1;
961 sdev->last_queue_full_depth = depth;
962 } else {
963 sdev->last_queue_full_count++;
964 }
965
966 if (sdev->last_queue_full_count <= 10)
967 return 0;
968 if (sdev->last_queue_full_depth < 8) {
969 /* Drop back to untagged */
970 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
971 return -1;
972 }
973
974 if (sdev->ordered_tags)
975 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
976 else
977 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
978 return depth;
979}
980EXPORT_SYMBOL(scsi_track_queue_full);
981
982/**
Matthew Wilcox881a2562008-12-31 13:12:46 -0500983 * scsi_vpd_inquiry - Request a device provide us with a VPD page
984 * @sdev: The device to ask
985 * @buffer: Where to put the result
986 * @page: Which Vital Product Data to return
987 * @len: The length of the buffer
988 *
989 * This is an internal helper function. You probably want to use
990 * scsi_get_vpd_page instead.
991 *
992 * Returns 0 on success or a negative error number.
993 */
994static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
995 u8 page, unsigned len)
996{
997 int result;
998 unsigned char cmd[16];
999
1000 cmd[0] = INQUIRY;
1001 cmd[1] = 1; /* EVPD */
1002 cmd[2] = page;
1003 cmd[3] = len >> 8;
1004 cmd[4] = len & 0xff;
1005 cmd[5] = 0; /* Control byte */
1006
1007 /*
1008 * I'm not convinced we need to try quite this hard to get VPD, but
1009 * all the existing users tried this hard.
1010 */
1011 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
James Bottomley95a36392009-08-11 10:59:09 -05001012 len, NULL, 30 * HZ, 3, NULL);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001013 if (result)
1014 return result;
1015
1016 /* Sanity check that we got the page back that we asked for */
1017 if (buffer[1] != page)
1018 return -EIO;
1019
1020 return 0;
1021}
1022
1023/**
1024 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1025 * @sdev: The device to ask
1026 * @page: Which Vital Product Data to return
Randy Dunlap786f8ba2010-02-28 17:32:45 -08001027 * @buf: where to store the VPD
1028 * @buf_len: number of bytes in the VPD buffer area
Matthew Wilcox881a2562008-12-31 13:12:46 -05001029 *
1030 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1031 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1032 * If the device supports this VPD page, this routine returns a pointer
1033 * to a buffer containing the data from that page. The caller is
1034 * responsible for calling kfree() on this pointer when it is no longer
1035 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1036 */
James Bottomleye3deec02009-11-03 12:33:07 -06001037int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1038 int buf_len)
Matthew Wilcox881a2562008-12-31 13:12:46 -05001039{
1040 int i, result;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001041
1042 /* Ask for all the pages supported by this device */
James Bottomleye3deec02009-11-03 12:33:07 -06001043 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001044 if (result)
1045 goto fail;
1046
1047 /* If the user actually wanted this page, we can skip the rest */
1048 if (page == 0)
James Bottomleye3deec02009-11-03 12:33:07 -06001049 return -EINVAL;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001050
James Bottomleye3deec02009-11-03 12:33:07 -06001051 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
Matthew Wilcox881a2562008-12-31 13:12:46 -05001052 if (buf[i + 4] == page)
1053 goto found;
James Bottomleye3deec02009-11-03 12:33:07 -06001054
1055 if (i < buf[3] && i > buf_len)
1056 /* ran off the end of the buffer, give us benefit of doubt */
1057 goto found;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001058 /* The device claims it doesn't support the requested page */
1059 goto fail;
1060
1061 found:
James Bottomleye3deec02009-11-03 12:33:07 -06001062 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001063 if (result)
1064 goto fail;
1065
James Bottomleye3deec02009-11-03 12:33:07 -06001066 return 0;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001067
1068 fail:
James Bottomleye3deec02009-11-03 12:33:07 -06001069 return -EINVAL;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001070}
1071EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1072
1073/**
Rob Landleyeb448202007-11-03 13:30:39 -05001074 * scsi_device_get - get an additional reference to a scsi_device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001075 * @sdev: device to get a reference to
1076 *
Rob Landleyeb448202007-11-03 13:30:39 -05001077 * Description: Gets a reference to the scsi_device and increments the use count
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078 * of the underlying LLDD module. You must hold host_lock of the
1079 * parent Scsi_Host or already have a reference when calling this.
1080 */
1081int scsi_device_get(struct scsi_device *sdev)
1082{
James Bottomley85b6c722006-08-31 18:15:22 -04001083 if (sdev->sdev_state == SDEV_DEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084 return -ENXIO;
1085 if (!get_device(&sdev->sdev_gendev))
1086 return -ENXIO;
James Bottomley85b6c722006-08-31 18:15:22 -04001087 /* We can fail this if we're doing SCSI operations
1088 * from module exit (like cache flush) */
1089 try_module_get(sdev->host->hostt->module);
1090
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091 return 0;
1092}
1093EXPORT_SYMBOL(scsi_device_get);
1094
1095/**
1096 * scsi_device_put - release a reference to a scsi_device
1097 * @sdev: device to release a reference on.
1098 *
Rob Landleyeb448202007-11-03 13:30:39 -05001099 * Description: Release a reference to the scsi_device and decrements the use
1100 * count of the underlying LLDD module. The device is freed once the last
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101 * user vanishes.
1102 */
1103void scsi_device_put(struct scsi_device *sdev)
1104{
Ingo Molnar504fb372006-11-09 10:09:35 +01001105#ifdef CONFIG_MODULE_UNLOAD
James Bottomleyf479ab82006-09-06 09:00:29 -05001106 struct module *module = sdev->host->hostt->module;
1107
James Bottomley85b6c722006-08-31 18:15:22 -04001108 /* The module refcount will be zero if scsi_device_get()
1109 * was called from a module removal routine */
James Bottomleyf479ab82006-09-06 09:00:29 -05001110 if (module && module_refcount(module) != 0)
1111 module_put(module);
Daniel Walkera506b442006-09-09 09:31:03 -07001112#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 put_device(&sdev->sdev_gendev);
1114}
1115EXPORT_SYMBOL(scsi_device_put);
1116
Rob Landleyeb448202007-11-03 13:30:39 -05001117/* helper for shost_for_each_device, see that for documentation */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1119 struct scsi_device *prev)
1120{
1121 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1122 struct scsi_device *next = NULL;
1123 unsigned long flags;
1124
1125 spin_lock_irqsave(shost->host_lock, flags);
1126 while (list->next != &shost->__devices) {
1127 next = list_entry(list->next, struct scsi_device, siblings);
1128 /* skip devices that we can't get a reference to */
1129 if (!scsi_device_get(next))
1130 break;
1131 next = NULL;
1132 list = list->next;
1133 }
1134 spin_unlock_irqrestore(shost->host_lock, flags);
1135
1136 if (prev)
1137 scsi_device_put(prev);
1138 return next;
1139}
1140EXPORT_SYMBOL(__scsi_iterate_devices);
1141
1142/**
1143 * starget_for_each_device - helper to walk all devices of a target
1144 * @starget: target whose devices we want to iterate over.
Rob Landleyeb448202007-11-03 13:30:39 -05001145 * @data: Opaque passed to each function call.
1146 * @fn: Function to call on each device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 *
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001148 * This traverses over each device of @starget. The devices have
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 * a reference that must be released by scsi_host_put when breaking
1150 * out of the loop.
1151 */
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001152void starget_for_each_device(struct scsi_target *starget, void *data,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 void (*fn)(struct scsi_device *, void *))
1154{
1155 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1156 struct scsi_device *sdev;
1157
1158 shost_for_each_device(sdev, shost) {
1159 if ((sdev->channel == starget->channel) &&
1160 (sdev->id == starget->id))
1161 fn(sdev, data);
1162 }
1163}
1164EXPORT_SYMBOL(starget_for_each_device);
1165
1166/**
Randy Dunlap14f501a2008-02-03 15:06:36 -08001167 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001168 * @starget: target whose devices we want to iterate over.
Randy Dunlap14f501a2008-02-03 15:06:36 -08001169 * @data: parameter for callback @fn()
1170 * @fn: callback function that is invoked for each device
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001171 *
1172 * This traverses over each device of @starget. It does _not_
1173 * take a reference on the scsi_device, so the whole loop must be
1174 * protected by shost->host_lock.
1175 *
1176 * Note: The only reason why drivers would want to use this is because
1177 * they need to access the device list in irq context. Otherwise you
1178 * really want to use starget_for_each_device instead.
1179 **/
1180void __starget_for_each_device(struct scsi_target *starget, void *data,
1181 void (*fn)(struct scsi_device *, void *))
1182{
1183 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1184 struct scsi_device *sdev;
1185
1186 __shost_for_each_device(sdev, shost) {
1187 if ((sdev->channel == starget->channel) &&
1188 (sdev->id == starget->id))
1189 fn(sdev, data);
1190 }
1191}
1192EXPORT_SYMBOL(__starget_for_each_device);
1193
1194/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1196 * @starget: SCSI target pointer
1197 * @lun: SCSI Logical Unit Number
1198 *
Rob Landleyeb448202007-11-03 13:30:39 -05001199 * Description: Looks up the scsi_device with the specified @lun for a given
1200 * @starget. The returned scsi_device does not have an additional
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 * reference. You must hold the host's host_lock over this call and
Hannes Reinecke32aeef62009-01-13 16:50:37 +01001202 * any access to the returned scsi_device. A scsi_device in state
1203 * SDEV_DEL is skipped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 *
Randy Dunlapdc8875e2007-11-15 15:42:30 -08001205 * Note: The only reason why drivers should use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001206 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 * really want to use scsi_device_lookup_by_target instead.
1208 **/
1209struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1210 uint lun)
1211{
1212 struct scsi_device *sdev;
1213
1214 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
Hannes Reinecke32aeef62009-01-13 16:50:37 +01001215 if (sdev->sdev_state == SDEV_DEL)
1216 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 if (sdev->lun ==lun)
1218 return sdev;
1219 }
1220
1221 return NULL;
1222}
1223EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1224
1225/**
1226 * scsi_device_lookup_by_target - find a device given the target
1227 * @starget: SCSI target pointer
1228 * @lun: SCSI Logical Unit Number
1229 *
Bartlomiej Zolnierkiewicz477e6082009-04-27 20:54:22 +02001230 * Description: Looks up the scsi_device with the specified @lun for a given
1231 * @starget. The returned scsi_device has an additional reference that
Rob Landleyeb448202007-11-03 13:30:39 -05001232 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233 **/
1234struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1235 uint lun)
1236{
1237 struct scsi_device *sdev;
1238 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1239 unsigned long flags;
1240
1241 spin_lock_irqsave(shost->host_lock, flags);
1242 sdev = __scsi_device_lookup_by_target(starget, lun);
1243 if (sdev && scsi_device_get(sdev))
1244 sdev = NULL;
1245 spin_unlock_irqrestore(shost->host_lock, flags);
1246
1247 return sdev;
1248}
1249EXPORT_SYMBOL(scsi_device_lookup_by_target);
1250
1251/**
Rob Landleyeb448202007-11-03 13:30:39 -05001252 * __scsi_device_lookup - find a device given the host (UNLOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 * @shost: SCSI host pointer
1254 * @channel: SCSI channel (zero if only one channel)
Rob Landleyeb448202007-11-03 13:30:39 -05001255 * @id: SCSI target number (physical unit number)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 * @lun: SCSI Logical Unit Number
1257 *
Rob Landleyeb448202007-11-03 13:30:39 -05001258 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1259 * for a given host. The returned scsi_device does not have an additional
1260 * reference. You must hold the host's host_lock over this call and any access
1261 * to the returned scsi_device.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 *
1263 * Note: The only reason why drivers would want to use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001264 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 * really want to use scsi_device_lookup instead.
1266 **/
1267struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1268 uint channel, uint id, uint lun)
1269{
1270 struct scsi_device *sdev;
1271
1272 list_for_each_entry(sdev, &shost->__devices, siblings) {
1273 if (sdev->channel == channel && sdev->id == id &&
1274 sdev->lun ==lun)
1275 return sdev;
1276 }
1277
1278 return NULL;
1279}
1280EXPORT_SYMBOL(__scsi_device_lookup);
1281
1282/**
1283 * scsi_device_lookup - find a device given the host
1284 * @shost: SCSI host pointer
1285 * @channel: SCSI channel (zero if only one channel)
1286 * @id: SCSI target number (physical unit number)
1287 * @lun: SCSI Logical Unit Number
1288 *
Rob Landleyeb448202007-11-03 13:30:39 -05001289 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1290 * for a given host. The returned scsi_device has an additional reference that
1291 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 **/
1293struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1294 uint channel, uint id, uint lun)
1295{
1296 struct scsi_device *sdev;
1297 unsigned long flags;
1298
1299 spin_lock_irqsave(shost->host_lock, flags);
1300 sdev = __scsi_device_lookup(shost, channel, id, lun);
1301 if (sdev && scsi_device_get(sdev))
1302 sdev = NULL;
1303 spin_unlock_irqrestore(shost->host_lock, flags);
1304
1305 return sdev;
1306}
1307EXPORT_SYMBOL(scsi_device_lookup);
1308
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309MODULE_DESCRIPTION("SCSI core");
1310MODULE_LICENSE("GPL");
1311
1312module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1313MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1314
1315static int __init init_scsi(void)
1316{
Jens Axboe9bf09c22006-09-30 20:31:11 +02001317 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318
1319 error = scsi_init_queue();
1320 if (error)
1321 return error;
1322 error = scsi_init_procfs();
1323 if (error)
1324 goto cleanup_queue;
1325 error = scsi_init_devinfo();
1326 if (error)
1327 goto cleanup_procfs;
1328 error = scsi_init_hosts();
1329 if (error)
1330 goto cleanup_devlist;
1331 error = scsi_init_sysctl();
1332 if (error)
1333 goto cleanup_hosts;
1334 error = scsi_sysfs_register();
1335 if (error)
1336 goto cleanup_sysctl;
1337
James Smart84314fd2006-08-18 17:30:09 -04001338 scsi_netlink_init();
1339
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1341 return 0;
1342
1343cleanup_sysctl:
1344 scsi_exit_sysctl();
1345cleanup_hosts:
1346 scsi_exit_hosts();
1347cleanup_devlist:
1348 scsi_exit_devinfo();
1349cleanup_procfs:
1350 scsi_exit_procfs();
1351cleanup_queue:
1352 scsi_exit_queue();
1353 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1354 -error);
1355 return error;
1356}
1357
1358static void __exit exit_scsi(void)
1359{
James Smart84314fd2006-08-18 17:30:09 -04001360 scsi_netlink_exit();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361 scsi_sysfs_unregister();
1362 scsi_exit_sysctl();
1363 scsi_exit_hosts();
1364 scsi_exit_devinfo();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365 scsi_exit_procfs();
1366 scsi_exit_queue();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367}
1368
1369subsys_initcall(init_scsi);
1370module_exit(exit_scsi);