blob: b6e03074cb8f9bff620f47b8838e0345d16f1c2c [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{
244 struct scsi_cmnd *cmd;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900245 unsigned char *buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400247 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) {
261 buf = cmd->sense_buffer;
262 memset(cmd, 0, sizeof(*cmd));
263 cmd->sense_buffer = buf;
264 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 }
266
267 return cmd;
268}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900269EXPORT_SYMBOL_GPL(__scsi_get_command);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270
Rob Landleyeb448202007-11-03 13:30:39 -0500271/**
272 * scsi_get_command - Allocate and setup a scsi command block
273 * @dev: parent scsi device
274 * @gfp_mask: allocator flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 *
276 * Returns: The allocated scsi command structure.
277 */
Al Viroc53033f2005-10-21 03:22:08 -0400278struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279{
280 struct scsi_cmnd *cmd;
281
282 /* Bail if we can't get a reference to the device */
283 if (!get_device(&dev->sdev_gendev))
284 return NULL;
285
286 cmd = __scsi_get_command(dev->host, gfp_mask);
287
288 if (likely(cmd != NULL)) {
289 unsigned long flags;
290
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 cmd->device = dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 INIT_LIST_HEAD(&cmd->list);
293 spin_lock_irqsave(&dev->list_lock, flags);
294 list_add_tail(&cmd->list, &dev->cmd_list);
295 spin_unlock_irqrestore(&dev->list_lock, flags);
Matthew Dobson79e448b2005-11-21 21:32:29 -0800296 cmd->jiffies_at_alloc = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 } else
298 put_device(&dev->sdev_gendev);
299
300 return cmd;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900301}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302EXPORT_SYMBOL(scsi_get_command);
303
Rob Landleyeb448202007-11-03 13:30:39 -0500304/**
305 * __scsi_put_command - Free a struct scsi_cmnd
306 * @shost: dev->host
307 * @cmd: Command to free
308 * @dev: parent scsi device
309 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900310void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
311 struct device *dev)
312{
313 unsigned long flags;
314
315 /* changing locks here, don't need to restore the irq state */
316 spin_lock_irqsave(&shost->free_list_lock, flags);
317 if (unlikely(list_empty(&shost->free_list))) {
318 list_add(&cmd->list, &shost->free_list);
319 cmd = NULL;
320 }
321 spin_unlock_irqrestore(&shost->free_list_lock, flags);
322
James Bottomleye507e302008-03-13 11:16:33 -0500323 if (likely(cmd != NULL))
324 scsi_pool_free_command(shost->cmd_pool, cmd);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900325
326 put_device(dev);
327}
328EXPORT_SYMBOL(__scsi_put_command);
329
Rob Landleyeb448202007-11-03 13:30:39 -0500330/**
331 * scsi_put_command - Free a scsi command block
332 * @cmd: command block to free
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 *
334 * Returns: Nothing.
335 *
336 * Notes: The command must not belong to any lists.
337 */
338void scsi_put_command(struct scsi_cmnd *cmd)
339{
340 struct scsi_device *sdev = cmd->device;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 unsigned long flags;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900342
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 /* serious error if the command hasn't come from a device list */
344 spin_lock_irqsave(&cmd->device->list_lock, flags);
345 BUG_ON(list_empty(&cmd->list));
346 list_del_init(&cmd->list);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900347 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900349 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350}
351EXPORT_SYMBOL(scsi_put_command);
352
James Bottomley1c353f72008-03-13 11:19:36 -0500353static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354{
James Bottomley1c353f72008-03-13 11:19:36 -0500355 struct scsi_host_cmd_pool *retval = NULL, *pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 /*
357 * Select a command slab for this host and create it if not
Rob Landleyeb448202007-11-03 13:30:39 -0500358 * yet existent.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 */
Arjan van de Ven0b950672006-01-11 13:16:10 +0100360 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500361 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
362 &scsi_cmd_pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 if (!pool->users) {
James Bottomley5b7f1682008-01-20 09:28:24 -0600364 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
365 sizeof(struct scsi_cmnd), 0,
366 pool->slab_flags, NULL);
367 if (!pool->cmd_slab)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 goto fail;
James Bottomley5b7f1682008-01-20 09:28:24 -0600369
370 pool->sense_slab = kmem_cache_create(pool->sense_name,
371 SCSI_SENSE_BUFFERSIZE, 0,
372 pool->slab_flags, NULL);
373 if (!pool->sense_slab) {
374 kmem_cache_destroy(pool->cmd_slab);
375 goto fail;
376 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 }
378
379 pool->users++;
James Bottomley1c353f72008-03-13 11:19:36 -0500380 retval = pool;
381 fail:
Arjan van de Ven0b950672006-01-11 13:16:10 +0100382 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500383 return retval;
384}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385
James Bottomley1c353f72008-03-13 11:19:36 -0500386static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
387{
388 struct scsi_host_cmd_pool *pool;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900389
FUJITA Tomonori166a7282008-01-08 07:59:05 +0900390 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500391 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
392 &scsi_cmd_pool;
393 /*
394 * This may happen if a driver has a mismatched get and put
395 * of the command pool; the driver should be implicated in
396 * the stack trace
397 */
398 BUG_ON(pool->users == 0);
399
James Bottomley5b7f1682008-01-20 09:28:24 -0600400 if (!--pool->users) {
401 kmem_cache_destroy(pool->cmd_slab);
402 kmem_cache_destroy(pool->sense_slab);
403 }
Arjan van de Ven0b950672006-01-11 13:16:10 +0100404 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500405}
406
407/**
408 * scsi_allocate_command - get a fully allocated SCSI command
409 * @gfp_mask: allocation mask
410 *
411 * This function is for use outside of the normal host based pools.
412 * It allocates the relevant command and takes an additional reference
413 * on the pool it used. This function *must* be paired with
414 * scsi_free_command which also has the identical mask, otherwise the
415 * free pool counts will eventually go wrong and you'll trigger a bug.
416 *
417 * This function should *only* be used by drivers that need a static
418 * command allocation at start of day for internal functions.
419 */
420struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
421{
422 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
423
424 if (!pool)
425 return NULL;
426
427 return scsi_pool_alloc_command(pool, gfp_mask);
428}
429EXPORT_SYMBOL(scsi_allocate_command);
430
431/**
432 * scsi_free_command - free a command allocated by scsi_allocate_command
433 * @gfp_mask: mask used in the original allocation
434 * @cmd: command to free
435 *
436 * Note: using the original allocation mask is vital because that's
437 * what determines which command pool we use to free the command. Any
438 * mismatch will cause the system to BUG eventually.
439 */
440void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
441{
442 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
443
444 /*
445 * this could trigger if the mask to scsi_allocate_command
446 * doesn't match this mask. Otherwise we're guaranteed that this
447 * succeeds because scsi_allocate_command must have taken a reference
448 * on the pool
449 */
450 BUG_ON(!pool);
451
452 scsi_pool_free_command(pool, cmd);
453 /*
454 * scsi_put_host_cmd_pool is called twice; once to release the
455 * reference we took above, and once to release the reference
456 * originally taken by scsi_allocate_command
457 */
458 scsi_put_host_cmd_pool(gfp_mask);
459 scsi_put_host_cmd_pool(gfp_mask);
460}
461EXPORT_SYMBOL(scsi_free_command);
462
463/**
464 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
465 * @shost: host to allocate the freelist for.
466 *
467 * Description: The command freelist protects against system-wide out of memory
468 * deadlock by preallocating one SCSI command structure for each host, so the
469 * system can always write to a swap file on a device associated with that host.
470 *
471 * Returns: Nothing.
472 */
473int scsi_setup_command_freelist(struct Scsi_Host *shost)
474{
475 struct scsi_cmnd *cmd;
476 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
477
478 spin_lock_init(&shost->free_list_lock);
479 INIT_LIST_HEAD(&shost->free_list);
480
481 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
482
483 if (!shost->cmd_pool)
484 return -ENOMEM;
485
486 /*
487 * Get one backup command for this host.
488 */
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400489 cmd = scsi_host_alloc_command(shost, gfp_mask);
James Bottomley1c353f72008-03-13 11:19:36 -0500490 if (!cmd) {
491 scsi_put_host_cmd_pool(gfp_mask);
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400492 shost->cmd_pool = NULL;
James Bottomley1c353f72008-03-13 11:19:36 -0500493 return -ENOMEM;
494 }
495 list_add(&cmd->list, &shost->free_list);
496 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497}
498
Rob Landleyeb448202007-11-03 13:30:39 -0500499/**
500 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
501 * @shost: host whose freelist is going to be destroyed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 */
503void scsi_destroy_command_freelist(struct Scsi_Host *shost)
504{
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400505 /*
506 * If cmd_pool is NULL the free list was not initialized, so
507 * do not attempt to release resources.
508 */
509 if (!shost->cmd_pool)
510 return;
511
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 while (!list_empty(&shost->free_list)) {
513 struct scsi_cmnd *cmd;
514
515 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
516 list_del_init(&cmd->list);
James Bottomleye507e302008-03-13 11:16:33 -0500517 scsi_pool_free_command(shost->cmd_pool, cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 }
James Bottomley1c353f72008-03-13 11:19:36 -0500519 shost->cmd_pool = NULL;
520 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900521}
522
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523#ifdef CONFIG_SCSI_LOGGING
524void scsi_log_send(struct scsi_cmnd *cmd)
525{
526 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
528 /*
529 * If ML QUEUE log level is greater than or equal to:
530 *
531 * 1: nothing (match completion)
532 *
533 * 2: log opcode + command of all commands
534 *
535 * 3: same as 2 plus dump cmd address
536 *
537 * 4: same as 3 plus dump extra junk
538 */
539 if (unlikely(scsi_logging_level)) {
540 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
541 SCSI_LOG_MLQUEUE_BITS);
542 if (level > 1) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500543 scmd_printk(KERN_INFO, cmd, "Send: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 if (level > 2)
545 printk("0x%p ", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500546 printk("\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 scsi_print_command(cmd);
548 if (level > 3) {
549 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800550 " queuecommand 0x%p\n",
Boaz Harrosha73e45b2007-07-04 21:26:01 +0300551 scsi_sglist(cmd), scsi_bufflen(cmd),
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500552 cmd->device->host->hostt->queuecommand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553
554 }
555 }
556 }
557}
558
559void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
560{
561 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562
563 /*
564 * If ML COMPLETE log level is greater than or equal to:
565 *
566 * 1: log disposition, result, opcode + command, and conditionally
567 * sense data for failures or non SUCCESS dispositions.
568 *
569 * 2: same as 1 but for all command completions.
570 *
571 * 3: same as 2 plus dump cmd address
572 *
573 * 4: same as 3 plus dump extra junk
574 */
575 if (unlikely(scsi_logging_level)) {
576 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
577 SCSI_LOG_MLCOMPLETE_BITS);
578 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
579 (level > 1)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500580 scmd_printk(KERN_INFO, cmd, "Done: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 if (level > 2)
582 printk("0x%p ", cmd);
583 /*
584 * Dump truncated values, so we usually fit within
585 * 80 chars.
586 */
587 switch (disposition) {
588 case SUCCESS:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500589 printk("SUCCESS\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 break;
591 case NEEDS_RETRY:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500592 printk("RETRY\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 break;
594 case ADD_TO_MLQUEUE:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500595 printk("MLQUEUE\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 break;
597 case FAILED:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500598 printk("FAILED\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 break;
600 case TIMEOUT_ERROR:
601 /*
602 * If called via scsi_times_out.
603 */
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500604 printk("TIMEOUT\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 break;
606 default:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500607 printk("UNKNOWN\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 }
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500609 scsi_print_result(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 scsi_print_command(cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500611 if (status_byte(cmd->result) & CHECK_CONDITION)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 scsi_print_sense("", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500613 if (level > 3)
614 scmd_printk(KERN_INFO, cmd,
615 "scsi host busy %d failed %d\n",
616 cmd->device->host->host_busy,
617 cmd->device->host->host_failed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 }
619 }
620}
621#endif
622
Rob Landleyeb448202007-11-03 13:30:39 -0500623/**
624 * scsi_cmd_get_serial - Assign a serial number to a command
625 * @host: the scsi host
626 * @cmd: command to assign serial number to
627 *
628 * Description: a serial number identifies a request for error recovery
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 * and debugging purposes. Protected by the Host_Lock of host.
630 */
631static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
632{
633 cmd->serial_number = host->cmd_serial_number++;
634 if (cmd->serial_number == 0)
635 cmd->serial_number = host->cmd_serial_number++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636}
637
Rob Landleyeb448202007-11-03 13:30:39 -0500638/**
639 * scsi_dispatch_command - Dispatch a command to the low-level driver.
640 * @cmd: command block we are dispatching.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 *
Rob Landleyeb448202007-11-03 13:30:39 -0500642 * Return: nonzero return request was rejected and device's queue needs to be
643 * plugged.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 */
645int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
646{
647 struct Scsi_Host *host = cmd->device->host;
648 unsigned long flags = 0;
649 unsigned long timeout;
650 int rtn = 0;
651
Jens Axboe242f9dc2008-09-14 05:55:09 -0700652 atomic_inc(&cmd->device->iorequest_cnt);
653
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 /* check if the device is still usable */
655 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
656 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
657 * returns an immediate error upwards, and signals
658 * that the device is no longer present */
659 cmd->result = DID_NO_CONNECT << 16;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700660 scsi_done(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 /* return 0 (because the command has been processed) */
662 goto out;
663 }
664
James Bottomley0f1d87a2008-08-22 16:43:59 -0500665 /* Check to see if the scsi lld made this device blocked. */
666 if (unlikely(scsi_device_blocked(cmd->device))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 /*
James Bottomley0f1d87a2008-08-22 16:43:59 -0500668 * in blocked state, the command is just put back on
669 * the device queue. The suspend state has already
670 * blocked the queue so future requests should not
671 * occur until the device transitions out of the
672 * suspend state.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 */
Jens Axboe242f9dc2008-09-14 05:55:09 -0700674
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
676
677 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
678
679 /*
680 * NOTE: rtn is still zero here because we don't need the
681 * queue to be plugged on return (it's already stopped)
682 */
683 goto out;
684 }
685
686 /*
687 * If SCSI-2 or lower, store the LUN value in cmnd.
688 */
James Bottomley4d7db042006-03-31 20:07:45 -0600689 if (cmd->device->scsi_level <= SCSI_2 &&
690 cmd->device->scsi_level != SCSI_UNKNOWN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
692 (cmd->device->lun << 5 & 0xe0);
693 }
694
695 /*
696 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
697 * we can avoid the drive not being ready.
698 */
699 timeout = host->last_reset + MIN_RESET_DELAY;
700
701 if (host->resetting && time_before(jiffies, timeout)) {
702 int ticks_remaining = timeout - jiffies;
703 /*
704 * NOTE: This may be executed from within an interrupt
705 * handler! This is bad, but for now, it'll do. The irq
706 * level of the interrupt handler has been masked out by the
707 * platform dependent interrupt handling code already, so the
708 * sti() here will not cause another call to the SCSI host's
709 * interrupt handler (assuming there is one irq-level per
710 * host).
711 */
712 while (--ticks_remaining >= 0)
713 mdelay(1 + 999 / HZ);
714 host->resetting = 0;
715 }
716
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 scsi_log_send(cmd);
718
719 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 * Before we queue this command, check if the command
721 * length exceeds what the host adapter can handle.
722 */
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300723 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 SCSI_LOG_MLQUEUE(3,
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300725 printk("queuecommand : command too long. "
726 "cdb_size=%d host->max_cmd_len=%d\n",
727 cmd->cmd_len, cmd->device->host->max_cmd_len));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 cmd->result = (DID_ABORT << 16);
729
730 scsi_done(cmd);
731 goto out;
732 }
733
734 spin_lock_irqsave(host->host_lock, flags);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700735 /*
736 * AK: unlikely race here: for some reason the timer could
737 * expire before the serial number is set up below.
738 *
739 * TODO: kill serial or move to blk layer
740 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 scsi_cmd_get_serial(host, cmd);
742
Mike Andersond2c9d9e2005-06-16 11:13:42 -0700743 if (unlikely(host->shost_state == SHOST_DEL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 cmd->result = (DID_NO_CONNECT << 16);
745 scsi_done(cmd);
746 } else {
747 rtn = host->hostt->queuecommand(cmd, scsi_done);
748 }
749 spin_unlock_irqrestore(host->host_lock, flags);
750 if (rtn) {
Mike Christief0c0a372008-08-17 15:24:38 -0500751 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
752 rtn != SCSI_MLQUEUE_TARGET_BUSY)
753 rtn = SCSI_MLQUEUE_HOST_BUSY;
754
755 scsi_queue_insert(cmd, rtn);
756
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 SCSI_LOG_MLQUEUE(3,
758 printk("queuecommand : request rejected\n"));
759 }
760
761 out:
762 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
763 return rtn;
764}
765
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766/**
767 * scsi_done - Enqueue the finished SCSI command into the done queue.
768 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
769 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
770 *
Rob Landleyeb448202007-11-03 13:30:39 -0500771 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
772 * which regains ownership of the SCSI command (de facto) from a LLDD, and
773 * enqueues the command to the done queue for further processing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 *
775 * This is the producer of the done queue who enqueues at the tail.
776 *
777 * This function is interrupt context safe.
778 */
Adrian Bunk52c1da32005-06-23 22:05:33 -0700779static void scsi_done(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780{
Jens Axboe242f9dc2008-09-14 05:55:09 -0700781 blk_complete_request(cmd->request);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782}
783
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800784/* Move this to a header if it becomes more generally useful */
785static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
786{
787 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
788}
789
Rob Landleyeb448202007-11-03 13:30:39 -0500790/**
791 * scsi_finish_command - cleanup and pass command back to upper layer
792 * @cmd: the command
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 *
Rob Landleyeb448202007-11-03 13:30:39 -0500794 * Description: Pass command off to upper layer for finishing of I/O
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 * request, waking processes that are waiting on results,
796 * etc.
797 */
798void scsi_finish_command(struct scsi_cmnd *cmd)
799{
800 struct scsi_device *sdev = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -0500801 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 struct Scsi_Host *shost = sdev->host;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800803 struct scsi_driver *drv;
804 unsigned int good_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805
806 scsi_device_unbusy(sdev);
807
808 /*
809 * Clear the flags which say that the device/host is no longer
810 * capable of accepting new commands. These are set in scsi_queue.c
811 * for both the queue full condition on a device, and for a
812 * host full condition on the host.
813 *
814 * XXX(hch): What about locking?
815 */
816 shost->host_blocked = 0;
Mike Christief0c0a372008-08-17 15:24:38 -0500817 starget->target_blocked = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 sdev->device_blocked = 0;
819
820 /*
821 * If we have valid sense information, then some kind of recovery
822 * must have taken place. Make a note of this.
823 */
824 if (SCSI_SENSE_VALID(cmd))
825 cmd->result |= (DRIVER_SENSE << 24);
826
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400827 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
828 "Notifying upper driver of completion "
829 "(result %x)\n", cmd->result));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830
FUJITA Tomonorif18573a2008-04-11 12:56:52 +0200831 good_bytes = scsi_bufflen(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800832 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
James Bottomley427e59f2008-03-08 18:24:17 -0600833 int old_good_bytes = good_bytes;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800834 drv = scsi_cmd_to_driver(cmd);
835 if (drv->done)
836 good_bytes = drv->done(cmd);
James Bottomley427e59f2008-03-08 18:24:17 -0600837 /*
838 * USB may not give sense identifying bad sector and
839 * simply return a residue instead, so subtract off the
840 * residue if drv->done() error processing indicates no
841 * change to the completion length.
842 */
843 if (good_bytes == old_good_bytes)
844 good_bytes -= scsi_get_resid(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800845 }
846 scsi_io_completion(cmd, good_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847}
848EXPORT_SYMBOL(scsi_finish_command);
849
Rob Landleyeb448202007-11-03 13:30:39 -0500850/**
851 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
852 * @sdev: SCSI Device in question
853 * @tagged: Do we use tagged queueing (non-0) or do we treat
854 * this device as an untagged device (0)
855 * @tags: Number of tags allowed if tagged queueing enabled,
856 * or number of commands the low level driver can
857 * queue up in non-tagged mode (as per cmd_per_lun).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 *
859 * Returns: Nothing
860 *
861 * Lock Status: None held on entry
862 *
863 * Notes: Low level drivers may call this at any time and we will do
864 * the right thing depending on whether or not the device is
865 * currently active and whether or not it even has the
866 * command blocks built yet.
867 */
868void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
869{
870 unsigned long flags;
871
872 /*
873 * refuse to set tagged depth to an unworkable size
874 */
875 if (tags <= 0)
876 return;
877
878 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
879
Mike Christie885ace92008-07-11 19:50:32 -0500880 /*
881 * Check to see if the queue is managed by the block layer.
882 * If it is, and we fail to adjust the depth, exit.
883 *
884 * Do not resize the tag map if it is a host wide share bqt,
885 * because the size should be the hosts's can_queue. If there
886 * is more IO than the LLD's can_queue (so there are not enuogh
887 * tags) request_fn's host queue ready check will handle it.
888 */
889 if (!sdev->host->bqt) {
890 if (blk_queue_tagged(sdev->request_queue) &&
891 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
892 goto out;
893 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894
895 sdev->queue_depth = tags;
896 switch (tagged) {
897 case MSG_ORDERED_TAG:
898 sdev->ordered_tags = 1;
899 sdev->simple_tags = 1;
900 break;
901 case MSG_SIMPLE_TAG:
902 sdev->ordered_tags = 0;
903 sdev->simple_tags = 1;
904 break;
905 default:
James Bottomley9ccfc752005-10-02 11:45:08 -0500906 sdev_printk(KERN_WARNING, sdev,
907 "scsi_adjust_queue_depth, bad queue type, "
908 "disabled\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909 case 0:
910 sdev->ordered_tags = sdev->simple_tags = 0;
911 sdev->queue_depth = tags;
912 break;
913 }
914 out:
915 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
916}
917EXPORT_SYMBOL(scsi_adjust_queue_depth);
918
Rob Landleyeb448202007-11-03 13:30:39 -0500919/**
920 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
921 * @sdev: SCSI Device in question
922 * @depth: Current number of outstanding SCSI commands on this device,
923 * not counting the one returned as QUEUE_FULL.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924 *
Rob Landleyeb448202007-11-03 13:30:39 -0500925 * Description: This function will track successive QUEUE_FULL events on a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 * specific SCSI device to determine if and when there is a
927 * need to adjust the queue depth on the device.
928 *
Rob Landleyeb448202007-11-03 13:30:39 -0500929 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 * -1 - Drop back to untagged operation using host->cmd_per_lun
931 * as the untagged command depth
932 *
933 * Lock Status: None held on entry
934 *
935 * Notes: Low level drivers may call this at any time and we will do
936 * "The Right Thing." We are interrupt context safe.
937 */
938int scsi_track_queue_full(struct scsi_device *sdev, int depth)
939{
940 if ((jiffies >> 4) == sdev->last_queue_full_time)
941 return 0;
942
943 sdev->last_queue_full_time = (jiffies >> 4);
944 if (sdev->last_queue_full_depth != depth) {
945 sdev->last_queue_full_count = 1;
946 sdev->last_queue_full_depth = depth;
947 } else {
948 sdev->last_queue_full_count++;
949 }
950
951 if (sdev->last_queue_full_count <= 10)
952 return 0;
953 if (sdev->last_queue_full_depth < 8) {
954 /* Drop back to untagged */
955 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
956 return -1;
957 }
958
959 if (sdev->ordered_tags)
960 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
961 else
962 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
963 return depth;
964}
965EXPORT_SYMBOL(scsi_track_queue_full);
966
967/**
Matthew Wilcox881a2562008-12-31 13:12:46 -0500968 * scsi_vpd_inquiry - Request a device provide us with a VPD page
969 * @sdev: The device to ask
970 * @buffer: Where to put the result
971 * @page: Which Vital Product Data to return
972 * @len: The length of the buffer
973 *
974 * This is an internal helper function. You probably want to use
975 * scsi_get_vpd_page instead.
976 *
977 * Returns 0 on success or a negative error number.
978 */
979static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
980 u8 page, unsigned len)
981{
982 int result;
983 unsigned char cmd[16];
984
985 cmd[0] = INQUIRY;
986 cmd[1] = 1; /* EVPD */
987 cmd[2] = page;
988 cmd[3] = len >> 8;
989 cmd[4] = len & 0xff;
990 cmd[5] = 0; /* Control byte */
991
992 /*
993 * I'm not convinced we need to try quite this hard to get VPD, but
994 * all the existing users tried this hard.
995 */
996 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
James Bottomley95a36392009-08-11 10:59:09 -0500997 len, NULL, 30 * HZ, 3, NULL);
Matthew Wilcox881a2562008-12-31 13:12:46 -0500998 if (result)
999 return result;
1000
1001 /* Sanity check that we got the page back that we asked for */
1002 if (buffer[1] != page)
1003 return -EIO;
1004
1005 return 0;
1006}
1007
1008/**
1009 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1010 * @sdev: The device to ask
1011 * @page: Which Vital Product Data to return
1012 *
1013 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1014 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1015 * If the device supports this VPD page, this routine returns a pointer
1016 * to a buffer containing the data from that page. The caller is
1017 * responsible for calling kfree() on this pointer when it is no longer
1018 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1019 */
1020unsigned char *scsi_get_vpd_page(struct scsi_device *sdev, u8 page)
1021{
1022 int i, result;
1023 unsigned int len;
James Bottomley95a36392009-08-11 10:59:09 -05001024 const unsigned int init_vpd_len = 255;
1025 unsigned char *buf = kmalloc(init_vpd_len, GFP_KERNEL);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001026
1027 if (!buf)
1028 return NULL;
1029
1030 /* Ask for all the pages supported by this device */
James Bottomley95a36392009-08-11 10:59:09 -05001031 result = scsi_vpd_inquiry(sdev, buf, 0, init_vpd_len);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001032 if (result)
1033 goto fail;
1034
1035 /* If the user actually wanted this page, we can skip the rest */
1036 if (page == 0)
1037 return buf;
1038
1039 for (i = 0; i < buf[3]; i++)
1040 if (buf[i + 4] == page)
1041 goto found;
1042 /* The device claims it doesn't support the requested page */
1043 goto fail;
1044
1045 found:
1046 result = scsi_vpd_inquiry(sdev, buf, page, 255);
1047 if (result)
1048 goto fail;
1049
1050 /*
1051 * Some pages are longer than 255 bytes. The actual length of
1052 * the page is returned in the header.
1053 */
James Bottomley95a36392009-08-11 10:59:09 -05001054 len = ((buf[2] << 8) | buf[3]) + 4;
1055 if (len <= init_vpd_len)
Matthew Wilcox881a2562008-12-31 13:12:46 -05001056 return buf;
1057
1058 kfree(buf);
James Bottomley95a36392009-08-11 10:59:09 -05001059 buf = kmalloc(len, GFP_KERNEL);
Matthew Wilcox881a2562008-12-31 13:12:46 -05001060 result = scsi_vpd_inquiry(sdev, buf, page, len);
1061 if (result)
1062 goto fail;
1063
1064 return buf;
1065
1066 fail:
1067 kfree(buf);
1068 return NULL;
1069}
1070EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1071
1072/**
Rob Landleyeb448202007-11-03 13:30:39 -05001073 * scsi_device_get - get an additional reference to a scsi_device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 * @sdev: device to get a reference to
1075 *
Rob Landleyeb448202007-11-03 13:30:39 -05001076 * Description: Gets a reference to the scsi_device and increments the use count
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 * of the underlying LLDD module. You must hold host_lock of the
1078 * parent Scsi_Host or already have a reference when calling this.
1079 */
1080int scsi_device_get(struct scsi_device *sdev)
1081{
James Bottomley85b6c722006-08-31 18:15:22 -04001082 if (sdev->sdev_state == SDEV_DEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 return -ENXIO;
1084 if (!get_device(&sdev->sdev_gendev))
1085 return -ENXIO;
James Bottomley85b6c722006-08-31 18:15:22 -04001086 /* We can fail this if we're doing SCSI operations
1087 * from module exit (like cache flush) */
1088 try_module_get(sdev->host->hostt->module);
1089
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 return 0;
1091}
1092EXPORT_SYMBOL(scsi_device_get);
1093
1094/**
1095 * scsi_device_put - release a reference to a scsi_device
1096 * @sdev: device to release a reference on.
1097 *
Rob Landleyeb448202007-11-03 13:30:39 -05001098 * Description: Release a reference to the scsi_device and decrements the use
1099 * count of the underlying LLDD module. The device is freed once the last
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100 * user vanishes.
1101 */
1102void scsi_device_put(struct scsi_device *sdev)
1103{
Ingo Molnar504fb372006-11-09 10:09:35 +01001104#ifdef CONFIG_MODULE_UNLOAD
James Bottomleyf479ab82006-09-06 09:00:29 -05001105 struct module *module = sdev->host->hostt->module;
1106
James Bottomley85b6c722006-08-31 18:15:22 -04001107 /* The module refcount will be zero if scsi_device_get()
1108 * was called from a module removal routine */
James Bottomleyf479ab82006-09-06 09:00:29 -05001109 if (module && module_refcount(module) != 0)
1110 module_put(module);
Daniel Walkera506b442006-09-09 09:31:03 -07001111#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112 put_device(&sdev->sdev_gendev);
1113}
1114EXPORT_SYMBOL(scsi_device_put);
1115
Rob Landleyeb448202007-11-03 13:30:39 -05001116/* helper for shost_for_each_device, see that for documentation */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1118 struct scsi_device *prev)
1119{
1120 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1121 struct scsi_device *next = NULL;
1122 unsigned long flags;
1123
1124 spin_lock_irqsave(shost->host_lock, flags);
1125 while (list->next != &shost->__devices) {
1126 next = list_entry(list->next, struct scsi_device, siblings);
1127 /* skip devices that we can't get a reference to */
1128 if (!scsi_device_get(next))
1129 break;
1130 next = NULL;
1131 list = list->next;
1132 }
1133 spin_unlock_irqrestore(shost->host_lock, flags);
1134
1135 if (prev)
1136 scsi_device_put(prev);
1137 return next;
1138}
1139EXPORT_SYMBOL(__scsi_iterate_devices);
1140
1141/**
1142 * starget_for_each_device - helper to walk all devices of a target
1143 * @starget: target whose devices we want to iterate over.
Rob Landleyeb448202007-11-03 13:30:39 -05001144 * @data: Opaque passed to each function call.
1145 * @fn: Function to call on each device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146 *
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001147 * This traverses over each device of @starget. The devices have
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148 * a reference that must be released by scsi_host_put when breaking
1149 * out of the loop.
1150 */
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001151void starget_for_each_device(struct scsi_target *starget, void *data,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 void (*fn)(struct scsi_device *, void *))
1153{
1154 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1155 struct scsi_device *sdev;
1156
1157 shost_for_each_device(sdev, shost) {
1158 if ((sdev->channel == starget->channel) &&
1159 (sdev->id == starget->id))
1160 fn(sdev, data);
1161 }
1162}
1163EXPORT_SYMBOL(starget_for_each_device);
1164
1165/**
Randy Dunlap14f501a2008-02-03 15:06:36 -08001166 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001167 * @starget: target whose devices we want to iterate over.
Randy Dunlap14f501a2008-02-03 15:06:36 -08001168 * @data: parameter for callback @fn()
1169 * @fn: callback function that is invoked for each device
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001170 *
1171 * This traverses over each device of @starget. It does _not_
1172 * take a reference on the scsi_device, so the whole loop must be
1173 * protected by shost->host_lock.
1174 *
1175 * Note: The only reason why drivers would want to use this is because
1176 * they need to access the device list in irq context. Otherwise you
1177 * really want to use starget_for_each_device instead.
1178 **/
1179void __starget_for_each_device(struct scsi_target *starget, void *data,
1180 void (*fn)(struct scsi_device *, void *))
1181{
1182 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1183 struct scsi_device *sdev;
1184
1185 __shost_for_each_device(sdev, shost) {
1186 if ((sdev->channel == starget->channel) &&
1187 (sdev->id == starget->id))
1188 fn(sdev, data);
1189 }
1190}
1191EXPORT_SYMBOL(__starget_for_each_device);
1192
1193/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1195 * @starget: SCSI target pointer
1196 * @lun: SCSI Logical Unit Number
1197 *
Rob Landleyeb448202007-11-03 13:30:39 -05001198 * Description: Looks up the scsi_device with the specified @lun for a given
1199 * @starget. The returned scsi_device does not have an additional
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 * reference. You must hold the host's host_lock over this call and
Hannes Reinecke32aeef62009-01-13 16:50:37 +01001201 * any access to the returned scsi_device. A scsi_device in state
1202 * SDEV_DEL is skipped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 *
Randy Dunlapdc8875e2007-11-15 15:42:30 -08001204 * Note: The only reason why drivers should use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001205 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 * really want to use scsi_device_lookup_by_target instead.
1207 **/
1208struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1209 uint lun)
1210{
1211 struct scsi_device *sdev;
1212
1213 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
Hannes Reinecke32aeef62009-01-13 16:50:37 +01001214 if (sdev->sdev_state == SDEV_DEL)
1215 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216 if (sdev->lun ==lun)
1217 return sdev;
1218 }
1219
1220 return NULL;
1221}
1222EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1223
1224/**
1225 * scsi_device_lookup_by_target - find a device given the target
1226 * @starget: SCSI target pointer
1227 * @lun: SCSI Logical Unit Number
1228 *
Bartlomiej Zolnierkiewicz477e6082009-04-27 20:54:22 +02001229 * Description: Looks up the scsi_device with the specified @lun for a given
1230 * @starget. The returned scsi_device has an additional reference that
Rob Landleyeb448202007-11-03 13:30:39 -05001231 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232 **/
1233struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1234 uint lun)
1235{
1236 struct scsi_device *sdev;
1237 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1238 unsigned long flags;
1239
1240 spin_lock_irqsave(shost->host_lock, flags);
1241 sdev = __scsi_device_lookup_by_target(starget, lun);
1242 if (sdev && scsi_device_get(sdev))
1243 sdev = NULL;
1244 spin_unlock_irqrestore(shost->host_lock, flags);
1245
1246 return sdev;
1247}
1248EXPORT_SYMBOL(scsi_device_lookup_by_target);
1249
1250/**
Rob Landleyeb448202007-11-03 13:30:39 -05001251 * __scsi_device_lookup - find a device given the host (UNLOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001252 * @shost: SCSI host pointer
1253 * @channel: SCSI channel (zero if only one channel)
Rob Landleyeb448202007-11-03 13:30:39 -05001254 * @id: SCSI target number (physical unit number)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255 * @lun: SCSI Logical Unit Number
1256 *
Rob Landleyeb448202007-11-03 13:30:39 -05001257 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1258 * for a given host. The returned scsi_device does not have an additional
1259 * reference. You must hold the host's host_lock over this call and any access
1260 * to the returned scsi_device.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 *
1262 * Note: The only reason why drivers would want to use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001263 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264 * really want to use scsi_device_lookup instead.
1265 **/
1266struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1267 uint channel, uint id, uint lun)
1268{
1269 struct scsi_device *sdev;
1270
1271 list_for_each_entry(sdev, &shost->__devices, siblings) {
1272 if (sdev->channel == channel && sdev->id == id &&
1273 sdev->lun ==lun)
1274 return sdev;
1275 }
1276
1277 return NULL;
1278}
1279EXPORT_SYMBOL(__scsi_device_lookup);
1280
1281/**
1282 * scsi_device_lookup - find a device given the host
1283 * @shost: SCSI host pointer
1284 * @channel: SCSI channel (zero if only one channel)
1285 * @id: SCSI target number (physical unit number)
1286 * @lun: SCSI Logical Unit Number
1287 *
Rob Landleyeb448202007-11-03 13:30:39 -05001288 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1289 * for a given host. The returned scsi_device has an additional reference that
1290 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291 **/
1292struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1293 uint channel, uint id, uint lun)
1294{
1295 struct scsi_device *sdev;
1296 unsigned long flags;
1297
1298 spin_lock_irqsave(shost->host_lock, flags);
1299 sdev = __scsi_device_lookup(shost, channel, id, lun);
1300 if (sdev && scsi_device_get(sdev))
1301 sdev = NULL;
1302 spin_unlock_irqrestore(shost->host_lock, flags);
1303
1304 return sdev;
1305}
1306EXPORT_SYMBOL(scsi_device_lookup);
1307
Linus Torvalds1da177e2005-04-16 15:20:36 -07001308MODULE_DESCRIPTION("SCSI core");
1309MODULE_LICENSE("GPL");
1310
1311module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1312MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1313
1314static int __init init_scsi(void)
1315{
Jens Axboe9bf09c232006-09-30 20:31:11 +02001316 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317
1318 error = scsi_init_queue();
1319 if (error)
1320 return error;
1321 error = scsi_init_procfs();
1322 if (error)
1323 goto cleanup_queue;
1324 error = scsi_init_devinfo();
1325 if (error)
1326 goto cleanup_procfs;
1327 error = scsi_init_hosts();
1328 if (error)
1329 goto cleanup_devlist;
1330 error = scsi_init_sysctl();
1331 if (error)
1332 goto cleanup_hosts;
1333 error = scsi_sysfs_register();
1334 if (error)
1335 goto cleanup_sysctl;
1336
James Smart84314fd2006-08-18 17:30:09 -04001337 scsi_netlink_init();
1338
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1340 return 0;
1341
1342cleanup_sysctl:
1343 scsi_exit_sysctl();
1344cleanup_hosts:
1345 scsi_exit_hosts();
1346cleanup_devlist:
1347 scsi_exit_devinfo();
1348cleanup_procfs:
1349 scsi_exit_procfs();
1350cleanup_queue:
1351 scsi_exit_queue();
1352 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1353 -error);
1354 return error;
1355}
1356
1357static void __exit exit_scsi(void)
1358{
James Smart84314fd2006-08-18 17:30:09 -04001359 scsi_netlink_exit();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360 scsi_sysfs_unregister();
1361 scsi_exit_sysctl();
1362 scsi_exit_hosts();
1363 scsi_exit_devinfo();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001364 scsi_exit_procfs();
1365 scsi_exit_queue();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366}
1367
1368subsys_initcall(init_scsi);
1369module_exit(exit_scsi);