blob: 1c08f6164658155d370735e35cfbdf6b22ae7713 [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
Adrian Bunk52c1da32005-06-23 22:05:33 -070070static void scsi_done(struct scsi_cmnd *cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
72/*
73 * Definitions and constants.
74 */
75
76#define MIN_RESET_DELAY (2*HZ)
77
78/* Do not call reset on error if we just did a reset within 15 sec. */
79#define MIN_RESET_PERIOD (15*HZ)
80
81/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 * Note - the initial logging level can be set here to log events at boot time.
83 * After the system is up, you may enable logging via the /proc interface.
84 */
85unsigned int scsi_logging_level;
86#if defined(CONFIG_SCSI_LOGGING)
87EXPORT_SYMBOL(scsi_logging_level);
88#endif
89
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -060090/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
91 * You may not alter any existing entry (although adding new ones is
92 * encouraged once assigned by ANSI/INCITS T10
93 */
Matthew Wilcox4ff36712006-07-04 12:15:20 -060094static const char *const scsi_device_types[] = {
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -060095 "Direct-Access ",
96 "Sequential-Access",
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 "Printer ",
98 "Processor ",
99 "WORM ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600100 "CD-ROM ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 "Scanner ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600102 "Optical Device ",
103 "Medium Changer ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 "Communications ",
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600105 "ASC IT8 ",
106 "ASC IT8 ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 "RAID ",
108 "Enclosure ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600109 "Direct-Access-RBC",
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600110 "Optical card ",
111 "Bridge controller",
112 "Object storage ",
113 "Automation/Drive ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114};
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600115
Rob Landleyeb448202007-11-03 13:30:39 -0500116/**
117 * scsi_device_type - Return 17 char string indicating device type.
118 * @type: type number to look up
119 */
120
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600121const char * scsi_device_type(unsigned type)
122{
123 if (type == 0x1e)
124 return "Well-known LUN ";
125 if (type == 0x1f)
126 return "No Device ";
Eric Sesterhenn80c6e3c2006-09-26 13:22:13 +0200127 if (type >= ARRAY_SIZE(scsi_device_types))
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600128 return "Unknown ";
129 return scsi_device_types[type];
130}
131
132EXPORT_SYMBOL(scsi_device_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134struct scsi_host_cmd_pool {
James Bottomley5b7f1682008-01-20 09:28:24 -0600135 struct kmem_cache *cmd_slab;
136 struct kmem_cache *sense_slab;
137 unsigned int users;
138 char *cmd_name;
139 char *sense_name;
140 unsigned int slab_flags;
141 gfp_t gfp_mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142};
143
144static struct scsi_host_cmd_pool scsi_cmd_pool = {
James Bottomley5b7f1682008-01-20 09:28:24 -0600145 .cmd_name = "scsi_cmd_cache",
146 .sense_name = "scsi_sense_cache",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 .slab_flags = SLAB_HWCACHE_ALIGN,
148};
149
150static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
James Bottomley5b7f1682008-01-20 09:28:24 -0600151 .cmd_name = "scsi_cmd_cache(DMA)",
152 .sense_name = "scsi_sense_cache(DMA)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
154 .gfp_mask = __GFP_DMA,
155};
156
Arjan van de Ven0b950672006-01-11 13:16:10 +0100157static DEFINE_MUTEX(host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
Rob Landleyeb448202007-11-03 13:30:39 -0500159/**
James Bottomleye507e302008-03-13 11:16:33 -0500160 * scsi_pool_alloc_command - internal function to get a fully allocated command
161 * @pool: slab pool to allocate the command from
162 * @gfp_mask: mask for the allocation
163 *
164 * Returns a fully allocated command (with the allied sense buffer) or
165 * NULL on failure
166 */
167static struct scsi_cmnd *
168scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
169{
170 struct scsi_cmnd *cmd;
171
Wei Yongjunebef2642009-03-04 12:06:13 -0800172 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
James Bottomleye507e302008-03-13 11:16:33 -0500173 if (!cmd)
174 return NULL;
175
James Bottomleye507e302008-03-13 11:16:33 -0500176 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
177 gfp_mask | pool->gfp_mask);
178 if (!cmd->sense_buffer) {
179 kmem_cache_free(pool->cmd_slab, cmd);
180 return NULL;
181 }
182
183 return cmd;
184}
185
186/**
187 * scsi_pool_free_command - internal function to release a command
188 * @pool: slab pool to allocate the command from
189 * @cmd: command to release
190 *
191 * the command must previously have been allocated by
192 * scsi_pool_alloc_command.
193 */
194static void
195scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
196 struct scsi_cmnd *cmd)
197{
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400198 if (cmd->prot_sdb)
199 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
200
James Bottomleye507e302008-03-13 11:16:33 -0500201 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
202 kmem_cache_free(pool->cmd_slab, cmd);
203}
204
205/**
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400206 * scsi_host_alloc_command - internal function to allocate command
207 * @shost: SCSI host whose pool to allocate from
208 * @gfp_mask: mask for the allocation
209 *
210 * Returns a fully allocated command with sense buffer and protection
211 * data buffer (where applicable) or NULL on failure
212 */
213static struct scsi_cmnd *
214scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
215{
216 struct scsi_cmnd *cmd;
217
218 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
219 if (!cmd)
220 return NULL;
221
222 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
223 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
224
225 if (!cmd->prot_sdb) {
226 scsi_pool_free_command(shost->cmd_pool, cmd);
227 return NULL;
228 }
229 }
230
231 return cmd;
232}
233
234/**
Rob Landleyeb448202007-11-03 13:30:39 -0500235 * __scsi_get_command - Allocate a struct scsi_cmnd
236 * @shost: host to transmit command
237 * @gfp_mask: allocation mask
238 *
239 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
240 * host's free_list if necessary.
241 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900242struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243{
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400244 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
Hugh Dickins164fc5d2008-04-06 23:56:57 +0100245
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 if (unlikely(!cmd)) {
247 unsigned long flags;
248
249 spin_lock_irqsave(&shost->free_list_lock, flags);
250 if (likely(!list_empty(&shost->free_list))) {
251 cmd = list_entry(shost->free_list.next,
252 struct scsi_cmnd, list);
253 list_del_init(&cmd->list);
254 }
255 spin_unlock_irqrestore(&shost->free_list_lock, flags);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900256
257 if (cmd) {
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400258 void *buf, *prot;
259
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900260 buf = cmd->sense_buffer;
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400261 prot = cmd->prot_sdb;
262
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900263 memset(cmd, 0, sizeof(*cmd));
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400264
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900265 cmd->sense_buffer = buf;
Martin K. Petersenb4c25542009-09-18 17:33:01 -0400266 cmd->prot_sdb = prot;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900267 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 }
269
270 return cmd;
271}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900272EXPORT_SYMBOL_GPL(__scsi_get_command);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273
Rob Landleyeb448202007-11-03 13:30:39 -0500274/**
275 * scsi_get_command - Allocate and setup a scsi command block
276 * @dev: parent scsi device
277 * @gfp_mask: allocator flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 *
279 * Returns: The allocated scsi command structure.
280 */
Al Viroc53033f2005-10-21 03:22:08 -0400281struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282{
283 struct scsi_cmnd *cmd;
284
285 /* Bail if we can't get a reference to the device */
286 if (!get_device(&dev->sdev_gendev))
287 return NULL;
288
289 cmd = __scsi_get_command(dev->host, gfp_mask);
290
291 if (likely(cmd != NULL)) {
292 unsigned long flags;
293
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 cmd->device = dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 INIT_LIST_HEAD(&cmd->list);
296 spin_lock_irqsave(&dev->list_lock, flags);
297 list_add_tail(&cmd->list, &dev->cmd_list);
298 spin_unlock_irqrestore(&dev->list_lock, flags);
Matthew Dobson79e448b2005-11-21 21:32:29 -0800299 cmd->jiffies_at_alloc = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 } else
301 put_device(&dev->sdev_gendev);
302
303 return cmd;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900304}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305EXPORT_SYMBOL(scsi_get_command);
306
Rob Landleyeb448202007-11-03 13:30:39 -0500307/**
308 * __scsi_put_command - Free a struct scsi_cmnd
309 * @shost: dev->host
310 * @cmd: Command to free
311 * @dev: parent scsi device
312 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900313void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
314 struct device *dev)
315{
316 unsigned long flags;
317
318 /* changing locks here, don't need to restore the irq state */
319 spin_lock_irqsave(&shost->free_list_lock, flags);
320 if (unlikely(list_empty(&shost->free_list))) {
321 list_add(&cmd->list, &shost->free_list);
322 cmd = NULL;
323 }
324 spin_unlock_irqrestore(&shost->free_list_lock, flags);
325
James Bottomleye507e302008-03-13 11:16:33 -0500326 if (likely(cmd != NULL))
327 scsi_pool_free_command(shost->cmd_pool, cmd);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900328
329 put_device(dev);
330}
331EXPORT_SYMBOL(__scsi_put_command);
332
Rob Landleyeb448202007-11-03 13:30:39 -0500333/**
334 * scsi_put_command - Free a scsi command block
335 * @cmd: command block to free
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 *
337 * Returns: Nothing.
338 *
339 * Notes: The command must not belong to any lists.
340 */
341void scsi_put_command(struct scsi_cmnd *cmd)
342{
343 struct scsi_device *sdev = cmd->device;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 unsigned long flags;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900345
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 /* serious error if the command hasn't come from a device list */
347 spin_lock_irqsave(&cmd->device->list_lock, flags);
348 BUG_ON(list_empty(&cmd->list));
349 list_del_init(&cmd->list);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900350 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900352 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353}
354EXPORT_SYMBOL(scsi_put_command);
355
James Bottomley1c353f72008-03-13 11:19:36 -0500356static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357{
James Bottomley1c353f72008-03-13 11:19:36 -0500358 struct scsi_host_cmd_pool *retval = NULL, *pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 /*
360 * Select a command slab for this host and create it if not
Rob Landleyeb448202007-11-03 13:30:39 -0500361 * yet existent.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 */
Arjan van de Ven0b950672006-01-11 13:16:10 +0100363 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500364 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
365 &scsi_cmd_pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 if (!pool->users) {
James Bottomley5b7f1682008-01-20 09:28:24 -0600367 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
368 sizeof(struct scsi_cmnd), 0,
369 pool->slab_flags, NULL);
370 if (!pool->cmd_slab)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 goto fail;
James Bottomley5b7f1682008-01-20 09:28:24 -0600372
373 pool->sense_slab = kmem_cache_create(pool->sense_name,
374 SCSI_SENSE_BUFFERSIZE, 0,
375 pool->slab_flags, NULL);
376 if (!pool->sense_slab) {
377 kmem_cache_destroy(pool->cmd_slab);
378 goto fail;
379 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 }
381
382 pool->users++;
James Bottomley1c353f72008-03-13 11:19:36 -0500383 retval = pool;
384 fail:
Arjan van de Ven0b950672006-01-11 13:16:10 +0100385 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500386 return retval;
387}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388
James Bottomley1c353f72008-03-13 11:19:36 -0500389static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
390{
391 struct scsi_host_cmd_pool *pool;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900392
FUJITA Tomonori166a7282008-01-08 07:59:05 +0900393 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500394 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
395 &scsi_cmd_pool;
396 /*
397 * This may happen if a driver has a mismatched get and put
398 * of the command pool; the driver should be implicated in
399 * the stack trace
400 */
401 BUG_ON(pool->users == 0);
402
James Bottomley5b7f1682008-01-20 09:28:24 -0600403 if (!--pool->users) {
404 kmem_cache_destroy(pool->cmd_slab);
405 kmem_cache_destroy(pool->sense_slab);
406 }
Arjan van de Ven0b950672006-01-11 13:16:10 +0100407 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500408}
409
410/**
411 * scsi_allocate_command - get a fully allocated SCSI command
412 * @gfp_mask: allocation mask
413 *
414 * This function is for use outside of the normal host based pools.
415 * It allocates the relevant command and takes an additional reference
416 * on the pool it used. This function *must* be paired with
417 * scsi_free_command which also has the identical mask, otherwise the
418 * free pool counts will eventually go wrong and you'll trigger a bug.
419 *
420 * This function should *only* be used by drivers that need a static
421 * command allocation at start of day for internal functions.
422 */
423struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
424{
425 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
426
427 if (!pool)
428 return NULL;
429
430 return scsi_pool_alloc_command(pool, gfp_mask);
431}
432EXPORT_SYMBOL(scsi_allocate_command);
433
434/**
435 * scsi_free_command - free a command allocated by scsi_allocate_command
436 * @gfp_mask: mask used in the original allocation
437 * @cmd: command to free
438 *
439 * Note: using the original allocation mask is vital because that's
440 * what determines which command pool we use to free the command. Any
441 * mismatch will cause the system to BUG eventually.
442 */
443void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
444{
445 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
446
447 /*
448 * this could trigger if the mask to scsi_allocate_command
449 * doesn't match this mask. Otherwise we're guaranteed that this
450 * succeeds because scsi_allocate_command must have taken a reference
451 * on the pool
452 */
453 BUG_ON(!pool);
454
455 scsi_pool_free_command(pool, cmd);
456 /*
457 * scsi_put_host_cmd_pool is called twice; once to release the
458 * reference we took above, and once to release the reference
459 * originally taken by scsi_allocate_command
460 */
461 scsi_put_host_cmd_pool(gfp_mask);
462 scsi_put_host_cmd_pool(gfp_mask);
463}
464EXPORT_SYMBOL(scsi_free_command);
465
466/**
467 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
468 * @shost: host to allocate the freelist for.
469 *
470 * Description: The command freelist protects against system-wide out of memory
471 * deadlock by preallocating one SCSI command structure for each host, so the
472 * system can always write to a swap file on a device associated with that host.
473 *
474 * Returns: Nothing.
475 */
476int scsi_setup_command_freelist(struct Scsi_Host *shost)
477{
478 struct scsi_cmnd *cmd;
479 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
480
481 spin_lock_init(&shost->free_list_lock);
482 INIT_LIST_HEAD(&shost->free_list);
483
484 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
485
486 if (!shost->cmd_pool)
487 return -ENOMEM;
488
489 /*
490 * Get one backup command for this host.
491 */
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400492 cmd = scsi_host_alloc_command(shost, gfp_mask);
James Bottomley1c353f72008-03-13 11:19:36 -0500493 if (!cmd) {
494 scsi_put_host_cmd_pool(gfp_mask);
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400495 shost->cmd_pool = NULL;
James Bottomley1c353f72008-03-13 11:19:36 -0500496 return -ENOMEM;
497 }
498 list_add(&cmd->list, &shost->free_list);
499 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500}
501
Rob Landleyeb448202007-11-03 13:30:39 -0500502/**
503 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
504 * @shost: host whose freelist is going to be destroyed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 */
506void scsi_destroy_command_freelist(struct Scsi_Host *shost)
507{
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400508 /*
509 * If cmd_pool is NULL the free list was not initialized, so
510 * do not attempt to release resources.
511 */
512 if (!shost->cmd_pool)
513 return;
514
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 while (!list_empty(&shost->free_list)) {
516 struct scsi_cmnd *cmd;
517
518 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
519 list_del_init(&cmd->list);
James Bottomleye507e302008-03-13 11:16:33 -0500520 scsi_pool_free_command(shost->cmd_pool, cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 }
James Bottomley1c353f72008-03-13 11:19:36 -0500522 shost->cmd_pool = NULL;
523 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900524}
525
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526#ifdef CONFIG_SCSI_LOGGING
527void scsi_log_send(struct scsi_cmnd *cmd)
528{
529 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530
531 /*
532 * If ML QUEUE log level is greater than or equal to:
533 *
534 * 1: nothing (match completion)
535 *
536 * 2: log opcode + command of all commands
537 *
538 * 3: same as 2 plus dump cmd address
539 *
540 * 4: same as 3 plus dump extra junk
541 */
542 if (unlikely(scsi_logging_level)) {
543 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
544 SCSI_LOG_MLQUEUE_BITS);
545 if (level > 1) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500546 scmd_printk(KERN_INFO, cmd, "Send: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 if (level > 2)
548 printk("0x%p ", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500549 printk("\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 scsi_print_command(cmd);
551 if (level > 3) {
552 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800553 " queuecommand 0x%p\n",
Boaz Harrosha73e45b2007-07-04 21:26:01 +0300554 scsi_sglist(cmd), scsi_bufflen(cmd),
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500555 cmd->device->host->hostt->queuecommand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556
557 }
558 }
559 }
560}
561
562void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
563{
564 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565
566 /*
567 * If ML COMPLETE log level is greater than or equal to:
568 *
569 * 1: log disposition, result, opcode + command, and conditionally
570 * sense data for failures or non SUCCESS dispositions.
571 *
572 * 2: same as 1 but for all command completions.
573 *
574 * 3: same as 2 plus dump cmd address
575 *
576 * 4: same as 3 plus dump extra junk
577 */
578 if (unlikely(scsi_logging_level)) {
579 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
580 SCSI_LOG_MLCOMPLETE_BITS);
581 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
582 (level > 1)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500583 scmd_printk(KERN_INFO, cmd, "Done: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 if (level > 2)
585 printk("0x%p ", cmd);
586 /*
587 * Dump truncated values, so we usually fit within
588 * 80 chars.
589 */
590 switch (disposition) {
591 case SUCCESS:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500592 printk("SUCCESS\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 break;
594 case NEEDS_RETRY:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500595 printk("RETRY\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 break;
597 case ADD_TO_MLQUEUE:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500598 printk("MLQUEUE\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 break;
600 case FAILED:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500601 printk("FAILED\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 break;
603 case TIMEOUT_ERROR:
604 /*
605 * If called via scsi_times_out.
606 */
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500607 printk("TIMEOUT\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 break;
609 default:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500610 printk("UNKNOWN\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 }
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500612 scsi_print_result(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 scsi_print_command(cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500614 if (status_byte(cmd->result) & CHECK_CONDITION)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 scsi_print_sense("", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500616 if (level > 3)
617 scmd_printk(KERN_INFO, cmd,
618 "scsi host busy %d failed %d\n",
619 cmd->device->host->host_busy,
620 cmd->device->host->host_failed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 }
622 }
623}
624#endif
625
Rob Landleyeb448202007-11-03 13:30:39 -0500626/**
627 * scsi_cmd_get_serial - Assign a serial number to a command
628 * @host: the scsi host
629 * @cmd: command to assign serial number to
630 *
631 * Description: a serial number identifies a request for error recovery
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 * and debugging purposes. Protected by the Host_Lock of host.
633 */
634static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
635{
636 cmd->serial_number = host->cmd_serial_number++;
637 if (cmd->serial_number == 0)
638 cmd->serial_number = host->cmd_serial_number++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639}
640
Rob Landleyeb448202007-11-03 13:30:39 -0500641/**
642 * scsi_dispatch_command - Dispatch a command to the low-level driver.
643 * @cmd: command block we are dispatching.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 *
Rob Landleyeb448202007-11-03 13:30:39 -0500645 * Return: nonzero return request was rejected and device's queue needs to be
646 * plugged.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 */
648int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
649{
650 struct Scsi_Host *host = cmd->device->host;
651 unsigned long flags = 0;
652 unsigned long timeout;
653 int rtn = 0;
654
Jens Axboe242f9dc2008-09-14 05:55:09 -0700655 atomic_inc(&cmd->device->iorequest_cnt);
656
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 /* check if the device is still usable */
658 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
659 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
660 * returns an immediate error upwards, and signals
661 * that the device is no longer present */
662 cmd->result = DID_NO_CONNECT << 16;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700663 scsi_done(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 /* return 0 (because the command has been processed) */
665 goto out;
666 }
667
James Bottomley0f1d87a2008-08-22 16:43:59 -0500668 /* Check to see if the scsi lld made this device blocked. */
669 if (unlikely(scsi_device_blocked(cmd->device))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 /*
James Bottomley0f1d87a2008-08-22 16:43:59 -0500671 * in blocked state, the command is just put back on
672 * the device queue. The suspend state has already
673 * blocked the queue so future requests should not
674 * occur until the device transitions out of the
675 * suspend state.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 */
Jens Axboe242f9dc2008-09-14 05:55:09 -0700677
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
679
680 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
681
682 /*
683 * NOTE: rtn is still zero here because we don't need the
684 * queue to be plugged on return (it's already stopped)
685 */
686 goto out;
687 }
688
689 /*
690 * If SCSI-2 or lower, store the LUN value in cmnd.
691 */
James Bottomley4d7db042006-03-31 20:07:45 -0600692 if (cmd->device->scsi_level <= SCSI_2 &&
693 cmd->device->scsi_level != SCSI_UNKNOWN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
695 (cmd->device->lun << 5 & 0xe0);
696 }
697
698 /*
699 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
700 * we can avoid the drive not being ready.
701 */
702 timeout = host->last_reset + MIN_RESET_DELAY;
703
704 if (host->resetting && time_before(jiffies, timeout)) {
705 int ticks_remaining = timeout - jiffies;
706 /*
707 * NOTE: This may be executed from within an interrupt
708 * handler! This is bad, but for now, it'll do. The irq
709 * level of the interrupt handler has been masked out by the
710 * platform dependent interrupt handling code already, so the
711 * sti() here will not cause another call to the SCSI host's
712 * interrupt handler (assuming there is one irq-level per
713 * host).
714 */
715 while (--ticks_remaining >= 0)
716 mdelay(1 + 999 / HZ);
717 host->resetting = 0;
718 }
719
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 scsi_log_send(cmd);
721
722 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 * Before we queue this command, check if the command
724 * length exceeds what the host adapter can handle.
725 */
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300726 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 SCSI_LOG_MLQUEUE(3,
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300728 printk("queuecommand : command too long. "
729 "cdb_size=%d host->max_cmd_len=%d\n",
730 cmd->cmd_len, cmd->device->host->max_cmd_len));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 cmd->result = (DID_ABORT << 16);
732
733 scsi_done(cmd);
734 goto out;
735 }
736
737 spin_lock_irqsave(host->host_lock, flags);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700738 /*
739 * AK: unlikely race here: for some reason the timer could
740 * expire before the serial number is set up below.
741 *
742 * TODO: kill serial or move to blk layer
743 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 scsi_cmd_get_serial(host, cmd);
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 {
750 rtn = host->hostt->queuecommand(cmd, scsi_done);
751 }
752 spin_unlock_irqrestore(host->host_lock, flags);
753 if (rtn) {
Mike Christief0c0a372008-08-17 15:24:38 -0500754 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
755 rtn != SCSI_MLQUEUE_TARGET_BUSY)
756 rtn = SCSI_MLQUEUE_HOST_BUSY;
757
758 scsi_queue_insert(cmd, rtn);
759
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 SCSI_LOG_MLQUEUE(3,
761 printk("queuecommand : request rejected\n"));
762 }
763
764 out:
765 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
766 return rtn;
767}
768
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769/**
770 * scsi_done - Enqueue the finished SCSI command into the done queue.
771 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
772 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
773 *
Rob Landleyeb448202007-11-03 13:30:39 -0500774 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
775 * which regains ownership of the SCSI command (de facto) from a LLDD, and
776 * enqueues the command to the done queue for further processing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 *
778 * This is the producer of the done queue who enqueues at the tail.
779 *
780 * This function is interrupt context safe.
781 */
Adrian Bunk52c1da32005-06-23 22:05:33 -0700782static void scsi_done(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783{
Jens Axboe242f9dc2008-09-14 05:55:09 -0700784 blk_complete_request(cmd->request);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785}
786
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800787/* Move this to a header if it becomes more generally useful */
788static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
789{
790 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
791}
792
Rob Landleyeb448202007-11-03 13:30:39 -0500793/**
794 * scsi_finish_command - cleanup and pass command back to upper layer
795 * @cmd: the command
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 *
Rob Landleyeb448202007-11-03 13:30:39 -0500797 * Description: Pass command off to upper layer for finishing of I/O
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 * request, waking processes that are waiting on results,
799 * etc.
800 */
801void scsi_finish_command(struct scsi_cmnd *cmd)
802{
803 struct scsi_device *sdev = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -0500804 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 struct Scsi_Host *shost = sdev->host;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800806 struct scsi_driver *drv;
807 unsigned int good_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808
809 scsi_device_unbusy(sdev);
810
811 /*
812 * Clear the flags which say that the device/host is no longer
813 * capable of accepting new commands. These are set in scsi_queue.c
814 * for both the queue full condition on a device, and for a
815 * host full condition on the host.
816 *
817 * XXX(hch): What about locking?
818 */
819 shost->host_blocked = 0;
Mike Christief0c0a372008-08-17 15:24:38 -0500820 starget->target_blocked = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 sdev->device_blocked = 0;
822
823 /*
824 * If we have valid sense information, then some kind of recovery
825 * must have taken place. Make a note of this.
826 */
827 if (SCSI_SENSE_VALID(cmd))
828 cmd->result |= (DRIVER_SENSE << 24);
829
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400830 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
831 "Notifying upper driver of completion "
832 "(result %x)\n", cmd->result));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833
FUJITA Tomonorif18573a2008-04-11 12:56:52 +0200834 good_bytes = scsi_bufflen(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800835 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
James Bottomley427e59f2008-03-08 18:24:17 -0600836 int old_good_bytes = good_bytes;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800837 drv = scsi_cmd_to_driver(cmd);
838 if (drv->done)
839 good_bytes = drv->done(cmd);
James Bottomley427e59f2008-03-08 18:24:17 -0600840 /*
841 * USB may not give sense identifying bad sector and
842 * simply return a residue instead, so subtract off the
843 * residue if drv->done() error processing indicates no
844 * change to the completion length.
845 */
846 if (good_bytes == old_good_bytes)
847 good_bytes -= scsi_get_resid(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800848 }
849 scsi_io_completion(cmd, good_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850}
851EXPORT_SYMBOL(scsi_finish_command);
852
Rob Landleyeb448202007-11-03 13:30:39 -0500853/**
854 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
855 * @sdev: SCSI Device in question
856 * @tagged: Do we use tagged queueing (non-0) or do we treat
857 * this device as an untagged device (0)
858 * @tags: Number of tags allowed if tagged queueing enabled,
859 * or number of commands the low level driver can
860 * queue up in non-tagged mode (as per cmd_per_lun).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 *
862 * Returns: Nothing
863 *
864 * Lock Status: None held on entry
865 *
866 * Notes: Low level drivers may call this at any time and we will do
867 * the right thing depending on whether or not the device is
868 * currently active and whether or not it even has the
869 * command blocks built yet.
870 */
871void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
872{
873 unsigned long flags;
874
875 /*
876 * refuse to set tagged depth to an unworkable size
877 */
878 if (tags <= 0)
879 return;
880
881 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
882
Mike Christie885ace92008-07-11 19:50:32 -0500883 /*
884 * Check to see if the queue is managed by the block layer.
885 * If it is, and we fail to adjust the depth, exit.
886 *
887 * Do not resize the tag map if it is a host wide share bqt,
888 * because the size should be the hosts's can_queue. If there
889 * is more IO than the LLD's can_queue (so there are not enuogh
890 * tags) request_fn's host queue ready check will handle it.
891 */
892 if (!sdev->host->bqt) {
893 if (blk_queue_tagged(sdev->request_queue) &&
894 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
895 goto out;
896 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897
898 sdev->queue_depth = tags;
899 switch (tagged) {
900 case MSG_ORDERED_TAG:
901 sdev->ordered_tags = 1;
902 sdev->simple_tags = 1;
903 break;
904 case MSG_SIMPLE_TAG:
905 sdev->ordered_tags = 0;
906 sdev->simple_tags = 1;
907 break;
908 default:
James Bottomley9ccfc752005-10-02 11:45:08 -0500909 sdev_printk(KERN_WARNING, sdev,
910 "scsi_adjust_queue_depth, bad queue type, "
911 "disabled\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 case 0:
913 sdev->ordered_tags = sdev->simple_tags = 0;
914 sdev->queue_depth = tags;
915 break;
916 }
917 out:
918 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
919}
920EXPORT_SYMBOL(scsi_adjust_queue_depth);
921
Rob Landleyeb448202007-11-03 13:30:39 -0500922/**
923 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
924 * @sdev: SCSI Device in question
925 * @depth: Current number of outstanding SCSI commands on this device,
926 * not counting the one returned as QUEUE_FULL.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 *
Rob Landleyeb448202007-11-03 13:30:39 -0500928 * Description: This function will track successive QUEUE_FULL events on a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 * specific SCSI device to determine if and when there is a
930 * need to adjust the queue depth on the device.
931 *
Rob Landleyeb448202007-11-03 13:30:39 -0500932 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 * -1 - Drop back to untagged operation using host->cmd_per_lun
934 * as the untagged command depth
935 *
936 * Lock Status: None held on entry
937 *
938 * Notes: Low level drivers may call this at any time and we will do
939 * "The Right Thing." We are interrupt context safe.
940 */
941int scsi_track_queue_full(struct scsi_device *sdev, int depth)
942{
Vasu Dev4a840672009-10-22 15:46:33 -0700943
944 /*
945 * Don't let QUEUE_FULLs on the same
946 * jiffies count, they could all be from
947 * same event.
948 */
949 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950 return 0;
951
Vasu Dev4a840672009-10-22 15:46:33 -0700952 sdev->last_queue_full_time = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953 if (sdev->last_queue_full_depth != depth) {
954 sdev->last_queue_full_count = 1;
955 sdev->last_queue_full_depth = depth;
956 } else {
957 sdev->last_queue_full_count++;
958 }
959
960 if (sdev->last_queue_full_count <= 10)
961 return 0;
962 if (sdev->last_queue_full_depth < 8) {
963 /* Drop back to untagged */
964 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
965 return -1;
966 }
967
968 if (sdev->ordered_tags)
969 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
970 else
971 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
972 return depth;
973}
974EXPORT_SYMBOL(scsi_track_queue_full);
975
976/**
Matthew Wilcox881a2562008-12-31 13:12:46 -0500977 * scsi_vpd_inquiry - Request a device provide us with a VPD page
978 * @sdev: The device to ask
979 * @buffer: Where to put the result
980 * @page: Which Vital Product Data to return
981 * @len: The length of the buffer
982 *
983 * This is an internal helper function. You probably want to use
984 * scsi_get_vpd_page instead.
985 *
986 * Returns 0 on success or a negative error number.
987 */
988static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
989 u8 page, unsigned len)
990{
991 int result;
992 unsigned char cmd[16];
993
994 cmd[0] = INQUIRY;
995 cmd[1] = 1; /* EVPD */
996 cmd[2] = page;
997 cmd[3] = len >> 8;
998 cmd[4] = len & 0xff;
999 cmd[5] = 0; /* Control byte */
1000
1001 /*
1002 * I'm not convinced we need to try quite this hard to get VPD, but
1003 * all the existing users tried this hard.
1004 */
1005 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
James Bottomley95a36392009-08-11 10:59:09 -05001006 len, NULL, 30 * HZ, 3, NULL);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001007 if (result)
1008 return result;
1009
1010 /* Sanity check that we got the page back that we asked for */
1011 if (buffer[1] != page)
1012 return -EIO;
1013
1014 return 0;
1015}
1016
1017/**
1018 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1019 * @sdev: The device to ask
1020 * @page: Which Vital Product Data to return
Randy Dunlap786f8ba2010-02-28 17:32:45 -08001021 * @buf: where to store the VPD
1022 * @buf_len: number of bytes in the VPD buffer area
Matthew Wilcox881a2562008-12-31 13:12:46 -05001023 *
1024 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1025 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1026 * If the device supports this VPD page, this routine returns a pointer
1027 * to a buffer containing the data from that page. The caller is
1028 * responsible for calling kfree() on this pointer when it is no longer
1029 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1030 */
James Bottomleye3deec02009-11-03 12:33:07 -06001031int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1032 int buf_len)
Matthew Wilcox881a2562008-12-31 13:12:46 -05001033{
1034 int i, result;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001035
1036 /* Ask for all the pages supported by this device */
James Bottomleye3deec02009-11-03 12:33:07 -06001037 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001038 if (result)
1039 goto fail;
1040
1041 /* If the user actually wanted this page, we can skip the rest */
1042 if (page == 0)
James Bottomleye3deec02009-11-03 12:33:07 -06001043 return -EINVAL;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001044
James Bottomleye3deec02009-11-03 12:33:07 -06001045 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
Matthew Wilcox881a2562008-12-31 13:12:46 -05001046 if (buf[i + 4] == page)
1047 goto found;
James Bottomleye3deec02009-11-03 12:33:07 -06001048
1049 if (i < buf[3] && i > buf_len)
1050 /* ran off the end of the buffer, give us benefit of doubt */
1051 goto found;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001052 /* The device claims it doesn't support the requested page */
1053 goto fail;
1054
1055 found:
James Bottomleye3deec02009-11-03 12:33:07 -06001056 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001057 if (result)
1058 goto fail;
1059
James Bottomleye3deec02009-11-03 12:33:07 -06001060 return 0;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001061
1062 fail:
James Bottomleye3deec02009-11-03 12:33:07 -06001063 return -EINVAL;
Matthew Wilcox881a2562008-12-31 13:12:46 -05001064}
1065EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1066
1067/**
Rob Landleyeb448202007-11-03 13:30:39 -05001068 * scsi_device_get - get an additional reference to a scsi_device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 * @sdev: device to get a reference to
1070 *
Rob Landleyeb448202007-11-03 13:30:39 -05001071 * Description: Gets a reference to the scsi_device and increments the use count
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072 * of the underlying LLDD module. You must hold host_lock of the
1073 * parent Scsi_Host or already have a reference when calling this.
1074 */
1075int scsi_device_get(struct scsi_device *sdev)
1076{
James Bottomley85b6c722006-08-31 18:15:22 -04001077 if (sdev->sdev_state == SDEV_DEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078 return -ENXIO;
1079 if (!get_device(&sdev->sdev_gendev))
1080 return -ENXIO;
James Bottomley85b6c722006-08-31 18:15:22 -04001081 /* We can fail this if we're doing SCSI operations
1082 * from module exit (like cache flush) */
1083 try_module_get(sdev->host->hostt->module);
1084
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085 return 0;
1086}
1087EXPORT_SYMBOL(scsi_device_get);
1088
1089/**
1090 * scsi_device_put - release a reference to a scsi_device
1091 * @sdev: device to release a reference on.
1092 *
Rob Landleyeb448202007-11-03 13:30:39 -05001093 * Description: Release a reference to the scsi_device and decrements the use
1094 * count of the underlying LLDD module. The device is freed once the last
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095 * user vanishes.
1096 */
1097void scsi_device_put(struct scsi_device *sdev)
1098{
Ingo Molnar504fb372006-11-09 10:09:35 +01001099#ifdef CONFIG_MODULE_UNLOAD
James Bottomleyf479ab82006-09-06 09:00:29 -05001100 struct module *module = sdev->host->hostt->module;
1101
James Bottomley85b6c722006-08-31 18:15:22 -04001102 /* The module refcount will be zero if scsi_device_get()
1103 * was called from a module removal routine */
James Bottomleyf479ab82006-09-06 09:00:29 -05001104 if (module && module_refcount(module) != 0)
1105 module_put(module);
Daniel Walkera506b442006-09-09 09:31:03 -07001106#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107 put_device(&sdev->sdev_gendev);
1108}
1109EXPORT_SYMBOL(scsi_device_put);
1110
Rob Landleyeb448202007-11-03 13:30:39 -05001111/* helper for shost_for_each_device, see that for documentation */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1113 struct scsi_device *prev)
1114{
1115 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1116 struct scsi_device *next = NULL;
1117 unsigned long flags;
1118
1119 spin_lock_irqsave(shost->host_lock, flags);
1120 while (list->next != &shost->__devices) {
1121 next = list_entry(list->next, struct scsi_device, siblings);
1122 /* skip devices that we can't get a reference to */
1123 if (!scsi_device_get(next))
1124 break;
1125 next = NULL;
1126 list = list->next;
1127 }
1128 spin_unlock_irqrestore(shost->host_lock, flags);
1129
1130 if (prev)
1131 scsi_device_put(prev);
1132 return next;
1133}
1134EXPORT_SYMBOL(__scsi_iterate_devices);
1135
1136/**
1137 * starget_for_each_device - helper to walk all devices of a target
1138 * @starget: target whose devices we want to iterate over.
Rob Landleyeb448202007-11-03 13:30:39 -05001139 * @data: Opaque passed to each function call.
1140 * @fn: Function to call on each device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 *
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001142 * This traverses over each device of @starget. The devices have
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143 * a reference that must be released by scsi_host_put when breaking
1144 * out of the loop.
1145 */
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001146void starget_for_each_device(struct scsi_target *starget, void *data,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 void (*fn)(struct scsi_device *, void *))
1148{
1149 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1150 struct scsi_device *sdev;
1151
1152 shost_for_each_device(sdev, shost) {
1153 if ((sdev->channel == starget->channel) &&
1154 (sdev->id == starget->id))
1155 fn(sdev, data);
1156 }
1157}
1158EXPORT_SYMBOL(starget_for_each_device);
1159
1160/**
Randy Dunlap14f501a2008-02-03 15:06:36 -08001161 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001162 * @starget: target whose devices we want to iterate over.
Randy Dunlap14f501a2008-02-03 15:06:36 -08001163 * @data: parameter for callback @fn()
1164 * @fn: callback function that is invoked for each device
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001165 *
1166 * This traverses over each device of @starget. It does _not_
1167 * take a reference on the scsi_device, so the whole loop must be
1168 * protected by shost->host_lock.
1169 *
1170 * Note: The only reason why drivers would want to use this is because
1171 * they need to access the device list in irq context. Otherwise you
1172 * really want to use starget_for_each_device instead.
1173 **/
1174void __starget_for_each_device(struct scsi_target *starget, void *data,
1175 void (*fn)(struct scsi_device *, void *))
1176{
1177 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1178 struct scsi_device *sdev;
1179
1180 __shost_for_each_device(sdev, shost) {
1181 if ((sdev->channel == starget->channel) &&
1182 (sdev->id == starget->id))
1183 fn(sdev, data);
1184 }
1185}
1186EXPORT_SYMBOL(__starget_for_each_device);
1187
1188/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001189 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1190 * @starget: SCSI target pointer
1191 * @lun: SCSI Logical Unit Number
1192 *
Rob Landleyeb448202007-11-03 13:30:39 -05001193 * Description: Looks up the scsi_device with the specified @lun for a given
1194 * @starget. The returned scsi_device does not have an additional
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 * reference. You must hold the host's host_lock over this call and
Hannes Reinecke32aeef62009-01-13 16:50:37 +01001196 * any access to the returned scsi_device. A scsi_device in state
1197 * SDEV_DEL is skipped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198 *
Randy Dunlapdc8875e2007-11-15 15:42:30 -08001199 * Note: The only reason why drivers should use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001200 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201 * really want to use scsi_device_lookup_by_target instead.
1202 **/
1203struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1204 uint lun)
1205{
1206 struct scsi_device *sdev;
1207
1208 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
Hannes Reinecke32aeef62009-01-13 16:50:37 +01001209 if (sdev->sdev_state == SDEV_DEL)
1210 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211 if (sdev->lun ==lun)
1212 return sdev;
1213 }
1214
1215 return NULL;
1216}
1217EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1218
1219/**
1220 * scsi_device_lookup_by_target - find a device given the target
1221 * @starget: SCSI target pointer
1222 * @lun: SCSI Logical Unit Number
1223 *
Bartlomiej Zolnierkiewicz477e6082009-04-27 20:54:22 +02001224 * Description: Looks up the scsi_device with the specified @lun for a given
1225 * @starget. The returned scsi_device has an additional reference that
Rob Landleyeb448202007-11-03 13:30:39 -05001226 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227 **/
1228struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1229 uint lun)
1230{
1231 struct scsi_device *sdev;
1232 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1233 unsigned long flags;
1234
1235 spin_lock_irqsave(shost->host_lock, flags);
1236 sdev = __scsi_device_lookup_by_target(starget, lun);
1237 if (sdev && scsi_device_get(sdev))
1238 sdev = NULL;
1239 spin_unlock_irqrestore(shost->host_lock, flags);
1240
1241 return sdev;
1242}
1243EXPORT_SYMBOL(scsi_device_lookup_by_target);
1244
1245/**
Rob Landleyeb448202007-11-03 13:30:39 -05001246 * __scsi_device_lookup - find a device given the host (UNLOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247 * @shost: SCSI host pointer
1248 * @channel: SCSI channel (zero if only one channel)
Rob Landleyeb448202007-11-03 13:30:39 -05001249 * @id: SCSI target number (physical unit number)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250 * @lun: SCSI Logical Unit Number
1251 *
Rob Landleyeb448202007-11-03 13:30:39 -05001252 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1253 * for a given host. The returned scsi_device does not have an additional
1254 * reference. You must hold the host's host_lock over this call and any access
1255 * to the returned scsi_device.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 *
1257 * Note: The only reason why drivers would want to use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001258 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 * really want to use scsi_device_lookup instead.
1260 **/
1261struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1262 uint channel, uint id, uint lun)
1263{
1264 struct scsi_device *sdev;
1265
1266 list_for_each_entry(sdev, &shost->__devices, siblings) {
1267 if (sdev->channel == channel && sdev->id == id &&
1268 sdev->lun ==lun)
1269 return sdev;
1270 }
1271
1272 return NULL;
1273}
1274EXPORT_SYMBOL(__scsi_device_lookup);
1275
1276/**
1277 * scsi_device_lookup - find a device given the host
1278 * @shost: SCSI host pointer
1279 * @channel: SCSI channel (zero if only one channel)
1280 * @id: SCSI target number (physical unit number)
1281 * @lun: SCSI Logical Unit Number
1282 *
Rob Landleyeb448202007-11-03 13:30:39 -05001283 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1284 * for a given host. The returned scsi_device has an additional reference that
1285 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286 **/
1287struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1288 uint channel, uint id, uint lun)
1289{
1290 struct scsi_device *sdev;
1291 unsigned long flags;
1292
1293 spin_lock_irqsave(shost->host_lock, flags);
1294 sdev = __scsi_device_lookup(shost, channel, id, lun);
1295 if (sdev && scsi_device_get(sdev))
1296 sdev = NULL;
1297 spin_unlock_irqrestore(shost->host_lock, flags);
1298
1299 return sdev;
1300}
1301EXPORT_SYMBOL(scsi_device_lookup);
1302
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303MODULE_DESCRIPTION("SCSI core");
1304MODULE_LICENSE("GPL");
1305
1306module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1307MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1308
1309static int __init init_scsi(void)
1310{
Jens Axboe9bf09c22006-09-30 20:31:11 +02001311 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312
1313 error = scsi_init_queue();
1314 if (error)
1315 return error;
1316 error = scsi_init_procfs();
1317 if (error)
1318 goto cleanup_queue;
1319 error = scsi_init_devinfo();
1320 if (error)
1321 goto cleanup_procfs;
1322 error = scsi_init_hosts();
1323 if (error)
1324 goto cleanup_devlist;
1325 error = scsi_init_sysctl();
1326 if (error)
1327 goto cleanup_hosts;
1328 error = scsi_sysfs_register();
1329 if (error)
1330 goto cleanup_sysctl;
1331
James Smart84314fd2006-08-18 17:30:09 -04001332 scsi_netlink_init();
1333
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1335 return 0;
1336
1337cleanup_sysctl:
1338 scsi_exit_sysctl();
1339cleanup_hosts:
1340 scsi_exit_hosts();
1341cleanup_devlist:
1342 scsi_exit_devinfo();
1343cleanup_procfs:
1344 scsi_exit_procfs();
1345cleanup_queue:
1346 scsi_exit_queue();
1347 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1348 -error);
1349 return error;
1350}
1351
1352static void __exit exit_scsi(void)
1353{
James Smart84314fd2006-08-18 17:30:09 -04001354 scsi_netlink_exit();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355 scsi_sysfs_unregister();
1356 scsi_exit_sysctl();
1357 scsi_exit_hosts();
1358 scsi_exit_devinfo();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359 scsi_exit_procfs();
1360 scsi_exit_queue();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361}
1362
1363subsys_initcall(init_scsi);
1364module_exit(exit_scsi);