blob: cbcd3f681b62103d3871dd5816b918f30880b7a6 [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
172 cmd = kmem_cache_alloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
173 if (!cmd)
174 return NULL;
175
176 memset(cmd, 0, sizeof(*cmd));
177
178 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
179 gfp_mask | pool->gfp_mask);
180 if (!cmd->sense_buffer) {
181 kmem_cache_free(pool->cmd_slab, cmd);
182 return NULL;
183 }
184
185 return cmd;
186}
187
188/**
189 * scsi_pool_free_command - internal function to release a command
190 * @pool: slab pool to allocate the command from
191 * @cmd: command to release
192 *
193 * the command must previously have been allocated by
194 * scsi_pool_alloc_command.
195 */
196static void
197scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
198 struct scsi_cmnd *cmd)
199{
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400200 if (cmd->prot_sdb)
201 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
202
James Bottomleye507e302008-03-13 11:16:33 -0500203 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
204 kmem_cache_free(pool->cmd_slab, cmd);
205}
206
207/**
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400208 * scsi_host_alloc_command - internal function to allocate command
209 * @shost: SCSI host whose pool to allocate from
210 * @gfp_mask: mask for the allocation
211 *
212 * Returns a fully allocated command with sense buffer and protection
213 * data buffer (where applicable) or NULL on failure
214 */
215static struct scsi_cmnd *
216scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
217{
218 struct scsi_cmnd *cmd;
219
220 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
221 if (!cmd)
222 return NULL;
223
224 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
225 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
226
227 if (!cmd->prot_sdb) {
228 scsi_pool_free_command(shost->cmd_pool, cmd);
229 return NULL;
230 }
231 }
232
233 return cmd;
234}
235
236/**
Rob Landleyeb448202007-11-03 13:30:39 -0500237 * __scsi_get_command - Allocate a struct scsi_cmnd
238 * @shost: host to transmit command
239 * @gfp_mask: allocation mask
240 *
241 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
242 * host's free_list if necessary.
243 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900244struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245{
246 struct scsi_cmnd *cmd;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900247 unsigned char *buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400249 cmd = scsi_host_alloc_command(shost, gfp_mask);
Hugh Dickins164fc5d2008-04-06 23:56:57 +0100250
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 if (unlikely(!cmd)) {
252 unsigned long flags;
253
254 spin_lock_irqsave(&shost->free_list_lock, flags);
255 if (likely(!list_empty(&shost->free_list))) {
256 cmd = list_entry(shost->free_list.next,
257 struct scsi_cmnd, list);
258 list_del_init(&cmd->list);
259 }
260 spin_unlock_irqrestore(&shost->free_list_lock, flags);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900261
262 if (cmd) {
263 buf = cmd->sense_buffer;
264 memset(cmd, 0, sizeof(*cmd));
265 cmd->sense_buffer = buf;
266 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 }
268
269 return cmd;
270}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900271EXPORT_SYMBOL_GPL(__scsi_get_command);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272
Rob Landleyeb448202007-11-03 13:30:39 -0500273/**
274 * scsi_get_command - Allocate and setup a scsi command block
275 * @dev: parent scsi device
276 * @gfp_mask: allocator flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 *
278 * Returns: The allocated scsi command structure.
279 */
Al Viroc53033f2005-10-21 03:22:08 -0400280struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281{
282 struct scsi_cmnd *cmd;
283
284 /* Bail if we can't get a reference to the device */
285 if (!get_device(&dev->sdev_gendev))
286 return NULL;
287
288 cmd = __scsi_get_command(dev->host, gfp_mask);
289
290 if (likely(cmd != NULL)) {
291 unsigned long flags;
292
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 cmd->device = dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 INIT_LIST_HEAD(&cmd->list);
295 spin_lock_irqsave(&dev->list_lock, flags);
296 list_add_tail(&cmd->list, &dev->cmd_list);
297 spin_unlock_irqrestore(&dev->list_lock, flags);
Matthew Dobson79e448b2005-11-21 21:32:29 -0800298 cmd->jiffies_at_alloc = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 } else
300 put_device(&dev->sdev_gendev);
301
302 return cmd;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900303}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304EXPORT_SYMBOL(scsi_get_command);
305
Rob Landleyeb448202007-11-03 13:30:39 -0500306/**
307 * __scsi_put_command - Free a struct scsi_cmnd
308 * @shost: dev->host
309 * @cmd: Command to free
310 * @dev: parent scsi device
311 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900312void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
313 struct device *dev)
314{
315 unsigned long flags;
316
317 /* changing locks here, don't need to restore the irq state */
318 spin_lock_irqsave(&shost->free_list_lock, flags);
319 if (unlikely(list_empty(&shost->free_list))) {
320 list_add(&cmd->list, &shost->free_list);
321 cmd = NULL;
322 }
323 spin_unlock_irqrestore(&shost->free_list_lock, flags);
324
James Bottomleye507e302008-03-13 11:16:33 -0500325 if (likely(cmd != NULL))
326 scsi_pool_free_command(shost->cmd_pool, cmd);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900327
328 put_device(dev);
329}
330EXPORT_SYMBOL(__scsi_put_command);
331
Rob Landleyeb448202007-11-03 13:30:39 -0500332/**
333 * scsi_put_command - Free a scsi command block
334 * @cmd: command block to free
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 *
336 * Returns: Nothing.
337 *
338 * Notes: The command must not belong to any lists.
339 */
340void scsi_put_command(struct scsi_cmnd *cmd)
341{
342 struct scsi_device *sdev = cmd->device;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 unsigned long flags;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900344
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 /* serious error if the command hasn't come from a device list */
346 spin_lock_irqsave(&cmd->device->list_lock, flags);
347 BUG_ON(list_empty(&cmd->list));
348 list_del_init(&cmd->list);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900349 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900351 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352}
353EXPORT_SYMBOL(scsi_put_command);
354
James Bottomley1c353f72008-03-13 11:19:36 -0500355static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356{
James Bottomley1c353f72008-03-13 11:19:36 -0500357 struct scsi_host_cmd_pool *retval = NULL, *pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 /*
359 * Select a command slab for this host and create it if not
Rob Landleyeb448202007-11-03 13:30:39 -0500360 * yet existent.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 */
Arjan van de Ven0b950672006-01-11 13:16:10 +0100362 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500363 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
364 &scsi_cmd_pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 if (!pool->users) {
James Bottomley5b7f1682008-01-20 09:28:24 -0600366 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
367 sizeof(struct scsi_cmnd), 0,
368 pool->slab_flags, NULL);
369 if (!pool->cmd_slab)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 goto fail;
James Bottomley5b7f1682008-01-20 09:28:24 -0600371
372 pool->sense_slab = kmem_cache_create(pool->sense_name,
373 SCSI_SENSE_BUFFERSIZE, 0,
374 pool->slab_flags, NULL);
375 if (!pool->sense_slab) {
376 kmem_cache_destroy(pool->cmd_slab);
377 goto fail;
378 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 }
380
381 pool->users++;
James Bottomley1c353f72008-03-13 11:19:36 -0500382 retval = pool;
383 fail:
Arjan van de Ven0b950672006-01-11 13:16:10 +0100384 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500385 return retval;
386}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387
James Bottomley1c353f72008-03-13 11:19:36 -0500388static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
389{
390 struct scsi_host_cmd_pool *pool;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900391
FUJITA Tomonori166a7282008-01-08 07:59:05 +0900392 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500393 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
394 &scsi_cmd_pool;
395 /*
396 * This may happen if a driver has a mismatched get and put
397 * of the command pool; the driver should be implicated in
398 * the stack trace
399 */
400 BUG_ON(pool->users == 0);
401
James Bottomley5b7f1682008-01-20 09:28:24 -0600402 if (!--pool->users) {
403 kmem_cache_destroy(pool->cmd_slab);
404 kmem_cache_destroy(pool->sense_slab);
405 }
Arjan van de Ven0b950672006-01-11 13:16:10 +0100406 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500407}
408
409/**
410 * scsi_allocate_command - get a fully allocated SCSI command
411 * @gfp_mask: allocation mask
412 *
413 * This function is for use outside of the normal host based pools.
414 * It allocates the relevant command and takes an additional reference
415 * on the pool it used. This function *must* be paired with
416 * scsi_free_command which also has the identical mask, otherwise the
417 * free pool counts will eventually go wrong and you'll trigger a bug.
418 *
419 * This function should *only* be used by drivers that need a static
420 * command allocation at start of day for internal functions.
421 */
422struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
423{
424 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
425
426 if (!pool)
427 return NULL;
428
429 return scsi_pool_alloc_command(pool, gfp_mask);
430}
431EXPORT_SYMBOL(scsi_allocate_command);
432
433/**
434 * scsi_free_command - free a command allocated by scsi_allocate_command
435 * @gfp_mask: mask used in the original allocation
436 * @cmd: command to free
437 *
438 * Note: using the original allocation mask is vital because that's
439 * what determines which command pool we use to free the command. Any
440 * mismatch will cause the system to BUG eventually.
441 */
442void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
443{
444 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
445
446 /*
447 * this could trigger if the mask to scsi_allocate_command
448 * doesn't match this mask. Otherwise we're guaranteed that this
449 * succeeds because scsi_allocate_command must have taken a reference
450 * on the pool
451 */
452 BUG_ON(!pool);
453
454 scsi_pool_free_command(pool, cmd);
455 /*
456 * scsi_put_host_cmd_pool is called twice; once to release the
457 * reference we took above, and once to release the reference
458 * originally taken by scsi_allocate_command
459 */
460 scsi_put_host_cmd_pool(gfp_mask);
461 scsi_put_host_cmd_pool(gfp_mask);
462}
463EXPORT_SYMBOL(scsi_free_command);
464
465/**
466 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
467 * @shost: host to allocate the freelist for.
468 *
469 * Description: The command freelist protects against system-wide out of memory
470 * deadlock by preallocating one SCSI command structure for each host, so the
471 * system can always write to a swap file on a device associated with that host.
472 *
473 * Returns: Nothing.
474 */
475int scsi_setup_command_freelist(struct Scsi_Host *shost)
476{
477 struct scsi_cmnd *cmd;
478 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
479
480 spin_lock_init(&shost->free_list_lock);
481 INIT_LIST_HEAD(&shost->free_list);
482
483 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
484
485 if (!shost->cmd_pool)
486 return -ENOMEM;
487
488 /*
489 * Get one backup command for this host.
490 */
Martin K. Petersen7027ad72008-07-17 17:08:48 -0400491 cmd = scsi_host_alloc_command(shost, gfp_mask);
James Bottomley1c353f72008-03-13 11:19:36 -0500492 if (!cmd) {
493 scsi_put_host_cmd_pool(gfp_mask);
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400494 shost->cmd_pool = NULL;
James Bottomley1c353f72008-03-13 11:19:36 -0500495 return -ENOMEM;
496 }
497 list_add(&cmd->list, &shost->free_list);
498 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499}
500
Rob Landleyeb448202007-11-03 13:30:39 -0500501/**
502 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
503 * @shost: host whose freelist is going to be destroyed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 */
505void scsi_destroy_command_freelist(struct Scsi_Host *shost)
506{
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400507 /*
508 * If cmd_pool is NULL the free list was not initialized, so
509 * do not attempt to release resources.
510 */
511 if (!shost->cmd_pool)
512 return;
513
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 while (!list_empty(&shost->free_list)) {
515 struct scsi_cmnd *cmd;
516
517 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
518 list_del_init(&cmd->list);
James Bottomleye507e302008-03-13 11:16:33 -0500519 scsi_pool_free_command(shost->cmd_pool, cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 }
James Bottomley1c353f72008-03-13 11:19:36 -0500521 shost->cmd_pool = NULL;
522 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900523}
524
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525#ifdef CONFIG_SCSI_LOGGING
526void scsi_log_send(struct scsi_cmnd *cmd)
527{
528 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529
530 /*
531 * If ML QUEUE log level is greater than or equal to:
532 *
533 * 1: nothing (match completion)
534 *
535 * 2: log opcode + command of all commands
536 *
537 * 3: same as 2 plus dump cmd address
538 *
539 * 4: same as 3 plus dump extra junk
540 */
541 if (unlikely(scsi_logging_level)) {
542 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
543 SCSI_LOG_MLQUEUE_BITS);
544 if (level > 1) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500545 scmd_printk(KERN_INFO, cmd, "Send: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 if (level > 2)
547 printk("0x%p ", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500548 printk("\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 scsi_print_command(cmd);
550 if (level > 3) {
551 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800552 " queuecommand 0x%p\n",
Boaz Harrosha73e45b2007-07-04 21:26:01 +0300553 scsi_sglist(cmd), scsi_bufflen(cmd),
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500554 cmd->device->host->hostt->queuecommand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555
556 }
557 }
558 }
559}
560
561void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
562{
563 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564
565 /*
566 * If ML COMPLETE log level is greater than or equal to:
567 *
568 * 1: log disposition, result, opcode + command, and conditionally
569 * sense data for failures or non SUCCESS dispositions.
570 *
571 * 2: same as 1 but for all command completions.
572 *
573 * 3: same as 2 plus dump cmd address
574 *
575 * 4: same as 3 plus dump extra junk
576 */
577 if (unlikely(scsi_logging_level)) {
578 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
579 SCSI_LOG_MLCOMPLETE_BITS);
580 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
581 (level > 1)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500582 scmd_printk(KERN_INFO, cmd, "Done: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 if (level > 2)
584 printk("0x%p ", cmd);
585 /*
586 * Dump truncated values, so we usually fit within
587 * 80 chars.
588 */
589 switch (disposition) {
590 case SUCCESS:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500591 printk("SUCCESS\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 break;
593 case NEEDS_RETRY:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500594 printk("RETRY\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 break;
596 case ADD_TO_MLQUEUE:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500597 printk("MLQUEUE\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 break;
599 case FAILED:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500600 printk("FAILED\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 break;
602 case TIMEOUT_ERROR:
603 /*
604 * If called via scsi_times_out.
605 */
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500606 printk("TIMEOUT\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 break;
608 default:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500609 printk("UNKNOWN\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 }
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500611 scsi_print_result(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 scsi_print_command(cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500613 if (status_byte(cmd->result) & CHECK_CONDITION)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 scsi_print_sense("", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500615 if (level > 3)
616 scmd_printk(KERN_INFO, cmd,
617 "scsi host busy %d failed %d\n",
618 cmd->device->host->host_busy,
619 cmd->device->host->host_failed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 }
621 }
622}
623#endif
624
Rob Landleyeb448202007-11-03 13:30:39 -0500625/**
626 * scsi_cmd_get_serial - Assign a serial number to a command
627 * @host: the scsi host
628 * @cmd: command to assign serial number to
629 *
630 * Description: a serial number identifies a request for error recovery
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 * and debugging purposes. Protected by the Host_Lock of host.
632 */
633static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
634{
635 cmd->serial_number = host->cmd_serial_number++;
636 if (cmd->serial_number == 0)
637 cmd->serial_number = host->cmd_serial_number++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638}
639
Rob Landleyeb448202007-11-03 13:30:39 -0500640/**
641 * scsi_dispatch_command - Dispatch a command to the low-level driver.
642 * @cmd: command block we are dispatching.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 *
Rob Landleyeb448202007-11-03 13:30:39 -0500644 * Return: nonzero return request was rejected and device's queue needs to be
645 * plugged.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 */
647int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
648{
649 struct Scsi_Host *host = cmd->device->host;
650 unsigned long flags = 0;
651 unsigned long timeout;
652 int rtn = 0;
653
Jens Axboe242f9dc2008-09-14 05:55:09 -0700654 atomic_inc(&cmd->device->iorequest_cnt);
655
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 /* check if the device is still usable */
657 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
658 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
659 * returns an immediate error upwards, and signals
660 * that the device is no longer present */
661 cmd->result = DID_NO_CONNECT << 16;
Jens Axboe242f9dc2008-09-14 05:55:09 -0700662 scsi_done(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 /* return 0 (because the command has been processed) */
664 goto out;
665 }
666
James Bottomley0f1d87a2008-08-22 16:43:59 -0500667 /* Check to see if the scsi lld made this device blocked. */
668 if (unlikely(scsi_device_blocked(cmd->device))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 /*
James Bottomley0f1d87a2008-08-22 16:43:59 -0500670 * in blocked state, the command is just put back on
671 * the device queue. The suspend state has already
672 * blocked the queue so future requests should not
673 * occur until the device transitions out of the
674 * suspend state.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 */
Jens Axboe242f9dc2008-09-14 05:55:09 -0700676
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
678
679 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
680
681 /*
682 * NOTE: rtn is still zero here because we don't need the
683 * queue to be plugged on return (it's already stopped)
684 */
685 goto out;
686 }
687
688 /*
689 * If SCSI-2 or lower, store the LUN value in cmnd.
690 */
James Bottomley4d7db042006-03-31 20:07:45 -0600691 if (cmd->device->scsi_level <= SCSI_2 &&
692 cmd->device->scsi_level != SCSI_UNKNOWN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
694 (cmd->device->lun << 5 & 0xe0);
695 }
696
697 /*
698 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
699 * we can avoid the drive not being ready.
700 */
701 timeout = host->last_reset + MIN_RESET_DELAY;
702
703 if (host->resetting && time_before(jiffies, timeout)) {
704 int ticks_remaining = timeout - jiffies;
705 /*
706 * NOTE: This may be executed from within an interrupt
707 * handler! This is bad, but for now, it'll do. The irq
708 * level of the interrupt handler has been masked out by the
709 * platform dependent interrupt handling code already, so the
710 * sti() here will not cause another call to the SCSI host's
711 * interrupt handler (assuming there is one irq-level per
712 * host).
713 */
714 while (--ticks_remaining >= 0)
715 mdelay(1 + 999 / HZ);
716 host->resetting = 0;
717 }
718
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 scsi_log_send(cmd);
720
721 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 * Before we queue this command, check if the command
723 * length exceeds what the host adapter can handle.
724 */
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300725 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 SCSI_LOG_MLQUEUE(3,
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300727 printk("queuecommand : command too long. "
728 "cdb_size=%d host->max_cmd_len=%d\n",
729 cmd->cmd_len, cmd->device->host->max_cmd_len));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 cmd->result = (DID_ABORT << 16);
731
732 scsi_done(cmd);
733 goto out;
734 }
735
736 spin_lock_irqsave(host->host_lock, flags);
Jens Axboe242f9dc2008-09-14 05:55:09 -0700737 /*
738 * AK: unlikely race here: for some reason the timer could
739 * expire before the serial number is set up below.
740 *
741 * TODO: kill serial or move to blk layer
742 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 scsi_cmd_get_serial(host, cmd);
744
Mike Andersond2c9d9e2005-06-16 11:13:42 -0700745 if (unlikely(host->shost_state == SHOST_DEL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 cmd->result = (DID_NO_CONNECT << 16);
747 scsi_done(cmd);
748 } else {
749 rtn = host->hostt->queuecommand(cmd, scsi_done);
750 }
751 spin_unlock_irqrestore(host->host_lock, flags);
752 if (rtn) {
Mike Christief0c0a372008-08-17 15:24:38 -0500753 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
754 rtn != SCSI_MLQUEUE_TARGET_BUSY)
755 rtn = SCSI_MLQUEUE_HOST_BUSY;
756
757 scsi_queue_insert(cmd, rtn);
758
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 SCSI_LOG_MLQUEUE(3,
760 printk("queuecommand : request rejected\n"));
761 }
762
763 out:
764 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
765 return rtn;
766}
767
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768/**
769 * scsi_done - Enqueue the finished SCSI command into the done queue.
770 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
771 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
772 *
Rob Landleyeb448202007-11-03 13:30:39 -0500773 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
774 * which regains ownership of the SCSI command (de facto) from a LLDD, and
775 * enqueues the command to the done queue for further processing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 *
777 * This is the producer of the done queue who enqueues at the tail.
778 *
779 * This function is interrupt context safe.
780 */
Adrian Bunk52c1da32005-06-23 22:05:33 -0700781static void scsi_done(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782{
Jens Axboe242f9dc2008-09-14 05:55:09 -0700783 blk_complete_request(cmd->request);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784}
785
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800786/* Move this to a header if it becomes more generally useful */
787static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
788{
789 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
790}
791
Rob Landleyeb448202007-11-03 13:30:39 -0500792/**
793 * scsi_finish_command - cleanup and pass command back to upper layer
794 * @cmd: the command
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 *
Rob Landleyeb448202007-11-03 13:30:39 -0500796 * Description: Pass command off to upper layer for finishing of I/O
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 * request, waking processes that are waiting on results,
798 * etc.
799 */
800void scsi_finish_command(struct scsi_cmnd *cmd)
801{
802 struct scsi_device *sdev = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -0500803 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 struct Scsi_Host *shost = sdev->host;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800805 struct scsi_driver *drv;
806 unsigned int good_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807
808 scsi_device_unbusy(sdev);
809
810 /*
811 * Clear the flags which say that the device/host is no longer
812 * capable of accepting new commands. These are set in scsi_queue.c
813 * for both the queue full condition on a device, and for a
814 * host full condition on the host.
815 *
816 * XXX(hch): What about locking?
817 */
818 shost->host_blocked = 0;
Mike Christief0c0a372008-08-17 15:24:38 -0500819 starget->target_blocked = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 sdev->device_blocked = 0;
821
822 /*
823 * If we have valid sense information, then some kind of recovery
824 * must have taken place. Make a note of this.
825 */
826 if (SCSI_SENSE_VALID(cmd))
827 cmd->result |= (DRIVER_SENSE << 24);
828
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400829 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
830 "Notifying upper driver of completion "
831 "(result %x)\n", cmd->result));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832
FUJITA Tomonorif18573a2008-04-11 12:56:52 +0200833 good_bytes = scsi_bufflen(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800834 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
James Bottomley427e59f2008-03-08 18:24:17 -0600835 int old_good_bytes = good_bytes;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800836 drv = scsi_cmd_to_driver(cmd);
837 if (drv->done)
838 good_bytes = drv->done(cmd);
James Bottomley427e59f2008-03-08 18:24:17 -0600839 /*
840 * USB may not give sense identifying bad sector and
841 * simply return a residue instead, so subtract off the
842 * residue if drv->done() error processing indicates no
843 * change to the completion length.
844 */
845 if (good_bytes == old_good_bytes)
846 good_bytes -= scsi_get_resid(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800847 }
848 scsi_io_completion(cmd, good_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849}
850EXPORT_SYMBOL(scsi_finish_command);
851
Rob Landleyeb448202007-11-03 13:30:39 -0500852/**
853 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
854 * @sdev: SCSI Device in question
855 * @tagged: Do we use tagged queueing (non-0) or do we treat
856 * this device as an untagged device (0)
857 * @tags: Number of tags allowed if tagged queueing enabled,
858 * or number of commands the low level driver can
859 * queue up in non-tagged mode (as per cmd_per_lun).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860 *
861 * Returns: Nothing
862 *
863 * Lock Status: None held on entry
864 *
865 * Notes: Low level drivers may call this at any time and we will do
866 * the right thing depending on whether or not the device is
867 * currently active and whether or not it even has the
868 * command blocks built yet.
869 */
870void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
871{
872 unsigned long flags;
873
874 /*
875 * refuse to set tagged depth to an unworkable size
876 */
877 if (tags <= 0)
878 return;
879
880 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
881
Mike Christie885ace92008-07-11 19:50:32 -0500882 /*
883 * Check to see if the queue is managed by the block layer.
884 * If it is, and we fail to adjust the depth, exit.
885 *
886 * Do not resize the tag map if it is a host wide share bqt,
887 * because the size should be the hosts's can_queue. If there
888 * is more IO than the LLD's can_queue (so there are not enuogh
889 * tags) request_fn's host queue ready check will handle it.
890 */
891 if (!sdev->host->bqt) {
892 if (blk_queue_tagged(sdev->request_queue) &&
893 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
894 goto out;
895 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896
897 sdev->queue_depth = tags;
898 switch (tagged) {
899 case MSG_ORDERED_TAG:
900 sdev->ordered_tags = 1;
901 sdev->simple_tags = 1;
902 break;
903 case MSG_SIMPLE_TAG:
904 sdev->ordered_tags = 0;
905 sdev->simple_tags = 1;
906 break;
907 default:
James Bottomley9ccfc752005-10-02 11:45:08 -0500908 sdev_printk(KERN_WARNING, sdev,
909 "scsi_adjust_queue_depth, bad queue type, "
910 "disabled\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 case 0:
912 sdev->ordered_tags = sdev->simple_tags = 0;
913 sdev->queue_depth = tags;
914 break;
915 }
916 out:
917 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
918}
919EXPORT_SYMBOL(scsi_adjust_queue_depth);
920
Rob Landleyeb448202007-11-03 13:30:39 -0500921/**
922 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
923 * @sdev: SCSI Device in question
924 * @depth: Current number of outstanding SCSI commands on this device,
925 * not counting the one returned as QUEUE_FULL.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 *
Rob Landleyeb448202007-11-03 13:30:39 -0500927 * Description: This function will track successive QUEUE_FULL events on a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928 * specific SCSI device to determine if and when there is a
929 * need to adjust the queue depth on the device.
930 *
Rob Landleyeb448202007-11-03 13:30:39 -0500931 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 * -1 - Drop back to untagged operation using host->cmd_per_lun
933 * as the untagged command depth
934 *
935 * Lock Status: None held on entry
936 *
937 * Notes: Low level drivers may call this at any time and we will do
938 * "The Right Thing." We are interrupt context safe.
939 */
940int scsi_track_queue_full(struct scsi_device *sdev, int depth)
941{
942 if ((jiffies >> 4) == sdev->last_queue_full_time)
943 return 0;
944
945 sdev->last_queue_full_time = (jiffies >> 4);
946 if (sdev->last_queue_full_depth != depth) {
947 sdev->last_queue_full_count = 1;
948 sdev->last_queue_full_depth = depth;
949 } else {
950 sdev->last_queue_full_count++;
951 }
952
953 if (sdev->last_queue_full_count <= 10)
954 return 0;
955 if (sdev->last_queue_full_depth < 8) {
956 /* Drop back to untagged */
957 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
958 return -1;
959 }
960
961 if (sdev->ordered_tags)
962 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
963 else
964 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
965 return depth;
966}
967EXPORT_SYMBOL(scsi_track_queue_full);
968
969/**
Rob Landleyeb448202007-11-03 13:30:39 -0500970 * scsi_device_get - get an additional reference to a scsi_device
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971 * @sdev: device to get a reference to
972 *
Rob Landleyeb448202007-11-03 13:30:39 -0500973 * Description: Gets a reference to the scsi_device and increments the use count
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974 * of the underlying LLDD module. You must hold host_lock of the
975 * parent Scsi_Host or already have a reference when calling this.
976 */
977int scsi_device_get(struct scsi_device *sdev)
978{
James Bottomley85b6c722006-08-31 18:15:22 -0400979 if (sdev->sdev_state == SDEV_DEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 return -ENXIO;
981 if (!get_device(&sdev->sdev_gendev))
982 return -ENXIO;
James Bottomley85b6c722006-08-31 18:15:22 -0400983 /* We can fail this if we're doing SCSI operations
984 * from module exit (like cache flush) */
985 try_module_get(sdev->host->hostt->module);
986
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 return 0;
988}
989EXPORT_SYMBOL(scsi_device_get);
990
991/**
992 * scsi_device_put - release a reference to a scsi_device
993 * @sdev: device to release a reference on.
994 *
Rob Landleyeb448202007-11-03 13:30:39 -0500995 * Description: Release a reference to the scsi_device and decrements the use
996 * count of the underlying LLDD module. The device is freed once the last
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 * user vanishes.
998 */
999void scsi_device_put(struct scsi_device *sdev)
1000{
Ingo Molnar504fb372006-11-09 10:09:35 +01001001#ifdef CONFIG_MODULE_UNLOAD
James Bottomleyf479ab82006-09-06 09:00:29 -05001002 struct module *module = sdev->host->hostt->module;
1003
James Bottomley85b6c722006-08-31 18:15:22 -04001004 /* The module refcount will be zero if scsi_device_get()
1005 * was called from a module removal routine */
James Bottomleyf479ab82006-09-06 09:00:29 -05001006 if (module && module_refcount(module) != 0)
1007 module_put(module);
Daniel Walkera506b442006-09-09 09:31:03 -07001008#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 put_device(&sdev->sdev_gendev);
1010}
1011EXPORT_SYMBOL(scsi_device_put);
1012
Rob Landleyeb448202007-11-03 13:30:39 -05001013/* helper for shost_for_each_device, see that for documentation */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1015 struct scsi_device *prev)
1016{
1017 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1018 struct scsi_device *next = NULL;
1019 unsigned long flags;
1020
1021 spin_lock_irqsave(shost->host_lock, flags);
1022 while (list->next != &shost->__devices) {
1023 next = list_entry(list->next, struct scsi_device, siblings);
1024 /* skip devices that we can't get a reference to */
1025 if (!scsi_device_get(next))
1026 break;
1027 next = NULL;
1028 list = list->next;
1029 }
1030 spin_unlock_irqrestore(shost->host_lock, flags);
1031
1032 if (prev)
1033 scsi_device_put(prev);
1034 return next;
1035}
1036EXPORT_SYMBOL(__scsi_iterate_devices);
1037
1038/**
1039 * starget_for_each_device - helper to walk all devices of a target
1040 * @starget: target whose devices we want to iterate over.
Rob Landleyeb448202007-11-03 13:30:39 -05001041 * @data: Opaque passed to each function call.
1042 * @fn: Function to call on each device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 *
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001044 * This traverses over each device of @starget. The devices have
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045 * a reference that must be released by scsi_host_put when breaking
1046 * out of the loop.
1047 */
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001048void starget_for_each_device(struct scsi_target *starget, void *data,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049 void (*fn)(struct scsi_device *, void *))
1050{
1051 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1052 struct scsi_device *sdev;
1053
1054 shost_for_each_device(sdev, shost) {
1055 if ((sdev->channel == starget->channel) &&
1056 (sdev->id == starget->id))
1057 fn(sdev, data);
1058 }
1059}
1060EXPORT_SYMBOL(starget_for_each_device);
1061
1062/**
Randy Dunlap14f501a2008-02-03 15:06:36 -08001063 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001064 * @starget: target whose devices we want to iterate over.
Randy Dunlap14f501a2008-02-03 15:06:36 -08001065 * @data: parameter for callback @fn()
1066 * @fn: callback function that is invoked for each device
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001067 *
1068 * This traverses over each device of @starget. It does _not_
1069 * take a reference on the scsi_device, so the whole loop must be
1070 * protected by shost->host_lock.
1071 *
1072 * Note: The only reason why drivers would want to use this is because
1073 * they need to access the device list in irq context. Otherwise you
1074 * really want to use starget_for_each_device instead.
1075 **/
1076void __starget_for_each_device(struct scsi_target *starget, void *data,
1077 void (*fn)(struct scsi_device *, void *))
1078{
1079 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1080 struct scsi_device *sdev;
1081
1082 __shost_for_each_device(sdev, shost) {
1083 if ((sdev->channel == starget->channel) &&
1084 (sdev->id == starget->id))
1085 fn(sdev, data);
1086 }
1087}
1088EXPORT_SYMBOL(__starget_for_each_device);
1089
1090/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1092 * @starget: SCSI target pointer
1093 * @lun: SCSI Logical Unit Number
1094 *
Rob Landleyeb448202007-11-03 13:30:39 -05001095 * Description: Looks up the scsi_device with the specified @lun for a given
1096 * @starget. The returned scsi_device does not have an additional
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097 * reference. You must hold the host's host_lock over this call and
Hannes Reinecke32aeef62009-01-13 16:50:37 +01001098 * any access to the returned scsi_device. A scsi_device in state
1099 * SDEV_DEL is skipped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100 *
Randy Dunlapdc8875e2007-11-15 15:42:30 -08001101 * Note: The only reason why drivers should use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001102 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103 * really want to use scsi_device_lookup_by_target instead.
1104 **/
1105struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1106 uint lun)
1107{
1108 struct scsi_device *sdev;
1109
1110 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
Hannes Reinecke32aeef62009-01-13 16:50:37 +01001111 if (sdev->sdev_state == SDEV_DEL)
1112 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 if (sdev->lun ==lun)
1114 return sdev;
1115 }
1116
1117 return NULL;
1118}
1119EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1120
1121/**
1122 * scsi_device_lookup_by_target - find a device given the target
1123 * @starget: SCSI target pointer
1124 * @lun: SCSI Logical Unit Number
1125 *
Rob Landleyeb448202007-11-03 13:30:39 -05001126 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1127 * for a given host. The returned scsi_device has an additional reference that
1128 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001129 **/
1130struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1131 uint lun)
1132{
1133 struct scsi_device *sdev;
1134 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1135 unsigned long flags;
1136
1137 spin_lock_irqsave(shost->host_lock, flags);
1138 sdev = __scsi_device_lookup_by_target(starget, lun);
1139 if (sdev && scsi_device_get(sdev))
1140 sdev = NULL;
1141 spin_unlock_irqrestore(shost->host_lock, flags);
1142
1143 return sdev;
1144}
1145EXPORT_SYMBOL(scsi_device_lookup_by_target);
1146
1147/**
Rob Landleyeb448202007-11-03 13:30:39 -05001148 * __scsi_device_lookup - find a device given the host (UNLOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001149 * @shost: SCSI host pointer
1150 * @channel: SCSI channel (zero if only one channel)
Rob Landleyeb448202007-11-03 13:30:39 -05001151 * @id: SCSI target number (physical unit number)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 * @lun: SCSI Logical Unit Number
1153 *
Rob Landleyeb448202007-11-03 13:30:39 -05001154 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1155 * for a given host. The returned scsi_device does not have an additional
1156 * reference. You must hold the host's host_lock over this call and any access
1157 * to the returned scsi_device.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158 *
1159 * Note: The only reason why drivers would want to use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001160 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161 * really want to use scsi_device_lookup instead.
1162 **/
1163struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1164 uint channel, uint id, uint lun)
1165{
1166 struct scsi_device *sdev;
1167
1168 list_for_each_entry(sdev, &shost->__devices, siblings) {
1169 if (sdev->channel == channel && sdev->id == id &&
1170 sdev->lun ==lun)
1171 return sdev;
1172 }
1173
1174 return NULL;
1175}
1176EXPORT_SYMBOL(__scsi_device_lookup);
1177
1178/**
1179 * scsi_device_lookup - find a device given the host
1180 * @shost: SCSI host pointer
1181 * @channel: SCSI channel (zero if only one channel)
1182 * @id: SCSI target number (physical unit number)
1183 * @lun: SCSI Logical Unit Number
1184 *
Rob Landleyeb448202007-11-03 13:30:39 -05001185 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1186 * for a given host. The returned scsi_device has an additional reference that
1187 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188 **/
1189struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1190 uint channel, uint id, uint lun)
1191{
1192 struct scsi_device *sdev;
1193 unsigned long flags;
1194
1195 spin_lock_irqsave(shost->host_lock, flags);
1196 sdev = __scsi_device_lookup(shost, channel, id, lun);
1197 if (sdev && scsi_device_get(sdev))
1198 sdev = NULL;
1199 spin_unlock_irqrestore(shost->host_lock, flags);
1200
1201 return sdev;
1202}
1203EXPORT_SYMBOL(scsi_device_lookup);
1204
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205MODULE_DESCRIPTION("SCSI core");
1206MODULE_LICENSE("GPL");
1207
1208module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1209MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1210
1211static int __init init_scsi(void)
1212{
Jens Axboe9bf09c22006-09-30 20:31:11 +02001213 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214
1215 error = scsi_init_queue();
1216 if (error)
1217 return error;
1218 error = scsi_init_procfs();
1219 if (error)
1220 goto cleanup_queue;
1221 error = scsi_init_devinfo();
1222 if (error)
1223 goto cleanup_procfs;
1224 error = scsi_init_hosts();
1225 if (error)
1226 goto cleanup_devlist;
1227 error = scsi_init_sysctl();
1228 if (error)
1229 goto cleanup_hosts;
1230 error = scsi_sysfs_register();
1231 if (error)
1232 goto cleanup_sysctl;
1233
James Smart84314fd2006-08-18 17:30:09 -04001234 scsi_netlink_init();
1235
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1237 return 0;
1238
1239cleanup_sysctl:
1240 scsi_exit_sysctl();
1241cleanup_hosts:
1242 scsi_exit_hosts();
1243cleanup_devlist:
1244 scsi_exit_devinfo();
1245cleanup_procfs:
1246 scsi_exit_procfs();
1247cleanup_queue:
1248 scsi_exit_queue();
1249 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1250 -error);
1251 return error;
1252}
1253
1254static void __exit exit_scsi(void)
1255{
James Smart84314fd2006-08-18 17:30:09 -04001256 scsi_netlink_exit();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 scsi_sysfs_unregister();
1258 scsi_exit_sysctl();
1259 scsi_exit_hosts();
1260 scsi_exit_devinfo();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 scsi_exit_procfs();
1262 scsi_exit_queue();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263}
1264
1265subsys_initcall(init_scsi);
1266module_exit(exit_scsi);