blob: 110e776d1a078cbd24cfdb795f7fec16cf95f1c3 [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{
200 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
201 kmem_cache_free(pool->cmd_slab, cmd);
202}
203
204/**
Rob Landleyeb448202007-11-03 13:30:39 -0500205 * __scsi_get_command - Allocate a struct scsi_cmnd
206 * @shost: host to transmit command
207 * @gfp_mask: allocation mask
208 *
209 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
210 * host's free_list if necessary.
211 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900212struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213{
214 struct scsi_cmnd *cmd;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900215 unsigned char *buf;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
James Bottomleye507e302008-03-13 11:16:33 -0500217 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
Hugh Dickins164fc5d2008-04-06 23:56:57 +0100218
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 if (unlikely(!cmd)) {
220 unsigned long flags;
221
222 spin_lock_irqsave(&shost->free_list_lock, flags);
223 if (likely(!list_empty(&shost->free_list))) {
224 cmd = list_entry(shost->free_list.next,
225 struct scsi_cmnd, list);
226 list_del_init(&cmd->list);
227 }
228 spin_unlock_irqrestore(&shost->free_list_lock, flags);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900229
230 if (cmd) {
231 buf = cmd->sense_buffer;
232 memset(cmd, 0, sizeof(*cmd));
233 cmd->sense_buffer = buf;
234 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 }
236
237 return cmd;
238}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900239EXPORT_SYMBOL_GPL(__scsi_get_command);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240
Rob Landleyeb448202007-11-03 13:30:39 -0500241/**
242 * scsi_get_command - Allocate and setup a scsi command block
243 * @dev: parent scsi device
244 * @gfp_mask: allocator flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 *
246 * Returns: The allocated scsi command structure.
247 */
Al Viroc53033f2005-10-21 03:22:08 -0400248struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249{
250 struct scsi_cmnd *cmd;
251
252 /* Bail if we can't get a reference to the device */
253 if (!get_device(&dev->sdev_gendev))
254 return NULL;
255
256 cmd = __scsi_get_command(dev->host, gfp_mask);
257
258 if (likely(cmd != NULL)) {
259 unsigned long flags;
260
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 cmd->device = dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 init_timer(&cmd->eh_timeout);
263 INIT_LIST_HEAD(&cmd->list);
264 spin_lock_irqsave(&dev->list_lock, flags);
265 list_add_tail(&cmd->list, &dev->cmd_list);
266 spin_unlock_irqrestore(&dev->list_lock, flags);
Matthew Dobson79e448b2005-11-21 21:32:29 -0800267 cmd->jiffies_at_alloc = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 } else
269 put_device(&dev->sdev_gendev);
270
271 return cmd;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900272}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273EXPORT_SYMBOL(scsi_get_command);
274
Rob Landleyeb448202007-11-03 13:30:39 -0500275/**
276 * __scsi_put_command - Free a struct scsi_cmnd
277 * @shost: dev->host
278 * @cmd: Command to free
279 * @dev: parent scsi device
280 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900281void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
282 struct device *dev)
283{
284 unsigned long flags;
285
286 /* changing locks here, don't need to restore the irq state */
287 spin_lock_irqsave(&shost->free_list_lock, flags);
288 if (unlikely(list_empty(&shost->free_list))) {
289 list_add(&cmd->list, &shost->free_list);
290 cmd = NULL;
291 }
292 spin_unlock_irqrestore(&shost->free_list_lock, flags);
293
James Bottomleye507e302008-03-13 11:16:33 -0500294 if (likely(cmd != NULL))
295 scsi_pool_free_command(shost->cmd_pool, cmd);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900296
297 put_device(dev);
298}
299EXPORT_SYMBOL(__scsi_put_command);
300
Rob Landleyeb448202007-11-03 13:30:39 -0500301/**
302 * scsi_put_command - Free a scsi command block
303 * @cmd: command block to free
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 *
305 * Returns: Nothing.
306 *
307 * Notes: The command must not belong to any lists.
308 */
309void scsi_put_command(struct scsi_cmnd *cmd)
310{
311 struct scsi_device *sdev = cmd->device;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 unsigned long flags;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900313
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 /* serious error if the command hasn't come from a device list */
315 spin_lock_irqsave(&cmd->device->list_lock, flags);
316 BUG_ON(list_empty(&cmd->list));
317 list_del_init(&cmd->list);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900318 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900320 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321}
322EXPORT_SYMBOL(scsi_put_command);
323
James Bottomley1c353f72008-03-13 11:19:36 -0500324static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325{
James Bottomley1c353f72008-03-13 11:19:36 -0500326 struct scsi_host_cmd_pool *retval = NULL, *pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 /*
328 * Select a command slab for this host and create it if not
Rob Landleyeb448202007-11-03 13:30:39 -0500329 * yet existent.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 */
Arjan van de Ven0b950672006-01-11 13:16:10 +0100331 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500332 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
333 &scsi_cmd_pool;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 if (!pool->users) {
James Bottomley5b7f1682008-01-20 09:28:24 -0600335 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
336 sizeof(struct scsi_cmnd), 0,
337 pool->slab_flags, NULL);
338 if (!pool->cmd_slab)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 goto fail;
James Bottomley5b7f1682008-01-20 09:28:24 -0600340
341 pool->sense_slab = kmem_cache_create(pool->sense_name,
342 SCSI_SENSE_BUFFERSIZE, 0,
343 pool->slab_flags, NULL);
344 if (!pool->sense_slab) {
345 kmem_cache_destroy(pool->cmd_slab);
346 goto fail;
347 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 }
349
350 pool->users++;
James Bottomley1c353f72008-03-13 11:19:36 -0500351 retval = pool;
352 fail:
Arjan van de Ven0b950672006-01-11 13:16:10 +0100353 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500354 return retval;
355}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356
James Bottomley1c353f72008-03-13 11:19:36 -0500357static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
358{
359 struct scsi_host_cmd_pool *pool;
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900360
FUJITA Tomonori166a7282008-01-08 07:59:05 +0900361 mutex_lock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500362 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
363 &scsi_cmd_pool;
364 /*
365 * This may happen if a driver has a mismatched get and put
366 * of the command pool; the driver should be implicated in
367 * the stack trace
368 */
369 BUG_ON(pool->users == 0);
370
James Bottomley5b7f1682008-01-20 09:28:24 -0600371 if (!--pool->users) {
372 kmem_cache_destroy(pool->cmd_slab);
373 kmem_cache_destroy(pool->sense_slab);
374 }
Arjan van de Ven0b950672006-01-11 13:16:10 +0100375 mutex_unlock(&host_cmd_pool_mutex);
James Bottomley1c353f72008-03-13 11:19:36 -0500376}
377
378/**
379 * scsi_allocate_command - get a fully allocated SCSI command
380 * @gfp_mask: allocation mask
381 *
382 * This function is for use outside of the normal host based pools.
383 * It allocates the relevant command and takes an additional reference
384 * on the pool it used. This function *must* be paired with
385 * scsi_free_command which also has the identical mask, otherwise the
386 * free pool counts will eventually go wrong and you'll trigger a bug.
387 *
388 * This function should *only* be used by drivers that need a static
389 * command allocation at start of day for internal functions.
390 */
391struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
392{
393 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
394
395 if (!pool)
396 return NULL;
397
398 return scsi_pool_alloc_command(pool, gfp_mask);
399}
400EXPORT_SYMBOL(scsi_allocate_command);
401
402/**
403 * scsi_free_command - free a command allocated by scsi_allocate_command
404 * @gfp_mask: mask used in the original allocation
405 * @cmd: command to free
406 *
407 * Note: using the original allocation mask is vital because that's
408 * what determines which command pool we use to free the command. Any
409 * mismatch will cause the system to BUG eventually.
410 */
411void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
412{
413 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
414
415 /*
416 * this could trigger if the mask to scsi_allocate_command
417 * doesn't match this mask. Otherwise we're guaranteed that this
418 * succeeds because scsi_allocate_command must have taken a reference
419 * on the pool
420 */
421 BUG_ON(!pool);
422
423 scsi_pool_free_command(pool, cmd);
424 /*
425 * scsi_put_host_cmd_pool is called twice; once to release the
426 * reference we took above, and once to release the reference
427 * originally taken by scsi_allocate_command
428 */
429 scsi_put_host_cmd_pool(gfp_mask);
430 scsi_put_host_cmd_pool(gfp_mask);
431}
432EXPORT_SYMBOL(scsi_free_command);
433
434/**
435 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
436 * @shost: host to allocate the freelist for.
437 *
438 * Description: The command freelist protects against system-wide out of memory
439 * deadlock by preallocating one SCSI command structure for each host, so the
440 * system can always write to a swap file on a device associated with that host.
441 *
442 * Returns: Nothing.
443 */
444int scsi_setup_command_freelist(struct Scsi_Host *shost)
445{
446 struct scsi_cmnd *cmd;
447 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
448
449 spin_lock_init(&shost->free_list_lock);
450 INIT_LIST_HEAD(&shost->free_list);
451
452 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
453
454 if (!shost->cmd_pool)
455 return -ENOMEM;
456
457 /*
458 * Get one backup command for this host.
459 */
460 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
461 if (!cmd) {
462 scsi_put_host_cmd_pool(gfp_mask);
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400463 shost->cmd_pool = NULL;
James Bottomley1c353f72008-03-13 11:19:36 -0500464 return -ENOMEM;
465 }
466 list_add(&cmd->list, &shost->free_list);
467 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468}
469
Rob Landleyeb448202007-11-03 13:30:39 -0500470/**
471 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
472 * @shost: host whose freelist is going to be destroyed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 */
474void scsi_destroy_command_freelist(struct Scsi_Host *shost)
475{
Alan D. Brunelle61d74162008-04-29 16:12:51 -0400476 /*
477 * If cmd_pool is NULL the free list was not initialized, so
478 * do not attempt to release resources.
479 */
480 if (!shost->cmd_pool)
481 return;
482
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 while (!list_empty(&shost->free_list)) {
484 struct scsi_cmnd *cmd;
485
486 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
487 list_del_init(&cmd->list);
James Bottomleye507e302008-03-13 11:16:33 -0500488 scsi_pool_free_command(shost->cmd_pool, cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 }
James Bottomley1c353f72008-03-13 11:19:36 -0500490 shost->cmd_pool = NULL;
491 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
FUJITA Tomonoride25deb2008-01-16 13:32:17 +0900492}
493
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494#ifdef CONFIG_SCSI_LOGGING
495void scsi_log_send(struct scsi_cmnd *cmd)
496{
497 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498
499 /*
500 * If ML QUEUE log level is greater than or equal to:
501 *
502 * 1: nothing (match completion)
503 *
504 * 2: log opcode + command of all commands
505 *
506 * 3: same as 2 plus dump cmd address
507 *
508 * 4: same as 3 plus dump extra junk
509 */
510 if (unlikely(scsi_logging_level)) {
511 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
512 SCSI_LOG_MLQUEUE_BITS);
513 if (level > 1) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500514 scmd_printk(KERN_INFO, cmd, "Send: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 if (level > 2)
516 printk("0x%p ", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500517 printk("\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 scsi_print_command(cmd);
519 if (level > 3) {
520 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800521 " queuecommand 0x%p\n",
Boaz Harrosha73e45b2007-07-04 21:26:01 +0300522 scsi_sglist(cmd), scsi_bufflen(cmd),
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500523 cmd->device->host->hostt->queuecommand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524
525 }
526 }
527 }
528}
529
530void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
531{
532 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533
534 /*
535 * If ML COMPLETE log level is greater than or equal to:
536 *
537 * 1: log disposition, result, opcode + command, and conditionally
538 * sense data for failures or non SUCCESS dispositions.
539 *
540 * 2: same as 1 but for all command completions.
541 *
542 * 3: same as 2 plus dump cmd address
543 *
544 * 4: same as 3 plus dump extra junk
545 */
546 if (unlikely(scsi_logging_level)) {
547 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
548 SCSI_LOG_MLCOMPLETE_BITS);
549 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
550 (level > 1)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500551 scmd_printk(KERN_INFO, cmd, "Done: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 if (level > 2)
553 printk("0x%p ", cmd);
554 /*
555 * Dump truncated values, so we usually fit within
556 * 80 chars.
557 */
558 switch (disposition) {
559 case SUCCESS:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500560 printk("SUCCESS\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 break;
562 case NEEDS_RETRY:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500563 printk("RETRY\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 break;
565 case ADD_TO_MLQUEUE:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500566 printk("MLQUEUE\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 break;
568 case FAILED:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500569 printk("FAILED\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 break;
571 case TIMEOUT_ERROR:
572 /*
573 * If called via scsi_times_out.
574 */
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500575 printk("TIMEOUT\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 break;
577 default:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500578 printk("UNKNOWN\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 }
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500580 scsi_print_result(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 scsi_print_command(cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500582 if (status_byte(cmd->result) & CHECK_CONDITION)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 scsi_print_sense("", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500584 if (level > 3)
585 scmd_printk(KERN_INFO, cmd,
586 "scsi host busy %d failed %d\n",
587 cmd->device->host->host_busy,
588 cmd->device->host->host_failed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 }
590 }
591}
592#endif
593
Rob Landleyeb448202007-11-03 13:30:39 -0500594/**
595 * scsi_cmd_get_serial - Assign a serial number to a command
596 * @host: the scsi host
597 * @cmd: command to assign serial number to
598 *
599 * Description: a serial number identifies a request for error recovery
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 * and debugging purposes. Protected by the Host_Lock of host.
601 */
602static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
603{
604 cmd->serial_number = host->cmd_serial_number++;
605 if (cmd->serial_number == 0)
606 cmd->serial_number = host->cmd_serial_number++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607}
608
Rob Landleyeb448202007-11-03 13:30:39 -0500609/**
610 * scsi_dispatch_command - Dispatch a command to the low-level driver.
611 * @cmd: command block we are dispatching.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 *
Rob Landleyeb448202007-11-03 13:30:39 -0500613 * Return: nonzero return request was rejected and device's queue needs to be
614 * plugged.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 */
616int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
617{
618 struct Scsi_Host *host = cmd->device->host;
619 unsigned long flags = 0;
620 unsigned long timeout;
621 int rtn = 0;
622
623 /* check if the device is still usable */
624 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
625 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
626 * returns an immediate error upwards, and signals
627 * that the device is no longer present */
628 cmd->result = DID_NO_CONNECT << 16;
629 atomic_inc(&cmd->device->iorequest_cnt);
Mike Christie69b52892005-05-01 14:47:15 -0500630 __scsi_done(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 /* return 0 (because the command has been processed) */
632 goto out;
633 }
634
635 /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
636 if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) {
637 /*
638 * in SDEV_BLOCK, the command is just put back on the device
639 * queue. The suspend state has already blocked the queue so
640 * future requests should not occur until the device
641 * transitions out of the suspend state.
642 */
643 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
644
645 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
646
647 /*
648 * NOTE: rtn is still zero here because we don't need the
649 * queue to be plugged on return (it's already stopped)
650 */
651 goto out;
652 }
653
654 /*
655 * If SCSI-2 or lower, store the LUN value in cmnd.
656 */
James Bottomley4d7db042006-03-31 20:07:45 -0600657 if (cmd->device->scsi_level <= SCSI_2 &&
658 cmd->device->scsi_level != SCSI_UNKNOWN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
660 (cmd->device->lun << 5 & 0xe0);
661 }
662
663 /*
664 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
665 * we can avoid the drive not being ready.
666 */
667 timeout = host->last_reset + MIN_RESET_DELAY;
668
669 if (host->resetting && time_before(jiffies, timeout)) {
670 int ticks_remaining = timeout - jiffies;
671 /*
672 * NOTE: This may be executed from within an interrupt
673 * handler! This is bad, but for now, it'll do. The irq
674 * level of the interrupt handler has been masked out by the
675 * platform dependent interrupt handling code already, so the
676 * sti() here will not cause another call to the SCSI host's
677 * interrupt handler (assuming there is one irq-level per
678 * host).
679 */
680 while (--ticks_remaining >= 0)
681 mdelay(1 + 999 / HZ);
682 host->resetting = 0;
683 }
684
685 /*
686 * AK: unlikely race here: for some reason the timer could
687 * expire before the serial number is set up below.
688 */
689 scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
690
691 scsi_log_send(cmd);
692
693 /*
694 * We will use a queued command if possible, otherwise we will
695 * emulate the queuing and calling of completion function ourselves.
696 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 atomic_inc(&cmd->device->iorequest_cnt);
698
699 /*
700 * Before we queue this command, check if the command
701 * length exceeds what the host adapter can handle.
702 */
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300703 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 SCSI_LOG_MLQUEUE(3,
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300705 printk("queuecommand : command too long. "
706 "cdb_size=%d host->max_cmd_len=%d\n",
707 cmd->cmd_len, cmd->device->host->max_cmd_len));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 cmd->result = (DID_ABORT << 16);
709
710 scsi_done(cmd);
711 goto out;
712 }
713
714 spin_lock_irqsave(host->host_lock, flags);
715 scsi_cmd_get_serial(host, cmd);
716
Mike Andersond2c9d9e2005-06-16 11:13:42 -0700717 if (unlikely(host->shost_state == SHOST_DEL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 cmd->result = (DID_NO_CONNECT << 16);
719 scsi_done(cmd);
720 } else {
721 rtn = host->hostt->queuecommand(cmd, scsi_done);
722 }
723 spin_unlock_irqrestore(host->host_lock, flags);
724 if (rtn) {
Tejun Heo d8c37e72005-05-14 00:46:08 +0900725 if (scsi_delete_timer(cmd)) {
726 atomic_inc(&cmd->device->iodone_cnt);
727 scsi_queue_insert(cmd,
728 (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
729 rtn : SCSI_MLQUEUE_HOST_BUSY);
730 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 SCSI_LOG_MLQUEUE(3,
732 printk("queuecommand : request rejected\n"));
733 }
734
735 out:
736 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
737 return rtn;
738}
739
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740/**
Luben Tuikov89f48c42006-05-15 20:57:18 +0900741 * scsi_req_abort_cmd -- Request command recovery for the specified command
Rob Landleyeb448202007-11-03 13:30:39 -0500742 * @cmd: pointer to the SCSI command of interest
Luben Tuikov89f48c42006-05-15 20:57:18 +0900743 *
744 * This function requests that SCSI Core start recovery for the
745 * command by deleting the timer and adding the command to the eh
746 * queue. It can be called by either LLDDs or SCSI Core. LLDDs who
747 * implement their own error recovery MAY ignore the timeout event if
748 * they generated scsi_req_abort_cmd.
749 */
750void scsi_req_abort_cmd(struct scsi_cmnd *cmd)
751{
752 if (!scsi_delete_timer(cmd))
753 return;
754 scsi_times_out(cmd);
755}
756EXPORT_SYMBOL(scsi_req_abort_cmd);
757
758/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 * scsi_done - Enqueue the finished SCSI command into the done queue.
760 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
761 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
762 *
Rob Landleyeb448202007-11-03 13:30:39 -0500763 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
764 * which regains ownership of the SCSI command (de facto) from a LLDD, and
765 * enqueues the command to the done queue for further processing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 *
767 * This is the producer of the done queue who enqueues at the tail.
768 *
769 * This function is interrupt context safe.
770 */
Adrian Bunk52c1da32005-06-23 22:05:33 -0700771static void scsi_done(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772{
773 /*
Rob Landleyeb448202007-11-03 13:30:39 -0500774 * We don't have to worry about this one timing out anymore.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 * If we are unable to remove the timer, then the command
776 * has already timed out. In which case, we have no choice but to
777 * let the timeout function run, as we have no idea where in fact
778 * that function could really be. It might be on another processor,
779 * etc, etc.
780 */
781 if (!scsi_delete_timer(cmd))
782 return;
783 __scsi_done(cmd);
784}
785
786/* Private entry to scsi_done() to complete a command when the timer
787 * isn't running --- used by scsi_times_out */
788void __scsi_done(struct scsi_cmnd *cmd)
789{
Jens Axboe1aea6432006-01-09 16:03:03 +0100790 struct request *rq = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791
792 /*
793 * Set the serial numbers back to zero
794 */
795 cmd->serial_number = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796
797 atomic_inc(&cmd->device->iodone_cnt);
798 if (cmd->result)
799 atomic_inc(&cmd->device->ioerr_cnt);
800
Jens Axboe1aea6432006-01-09 16:03:03 +0100801 BUG_ON(!rq);
802
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 /*
Jens Axboe1aea6432006-01-09 16:03:03 +0100804 * The uptodate/nbytes values don't matter, as we allow partial
805 * completes and thus will check this in the softirq callback
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 */
Jens Axboe1aea6432006-01-09 16:03:03 +0100807 rq->completion_data = cmd;
808 blk_complete_request(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809}
810
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800811/* Move this to a header if it becomes more generally useful */
812static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
813{
814 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
815}
816
Rob Landleyeb448202007-11-03 13:30:39 -0500817/**
818 * scsi_finish_command - cleanup and pass command back to upper layer
819 * @cmd: the command
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 *
Rob Landleyeb448202007-11-03 13:30:39 -0500821 * Description: Pass command off to upper layer for finishing of I/O
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 * request, waking processes that are waiting on results,
823 * etc.
824 */
825void scsi_finish_command(struct scsi_cmnd *cmd)
826{
827 struct scsi_device *sdev = cmd->device;
828 struct Scsi_Host *shost = sdev->host;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800829 struct scsi_driver *drv;
830 unsigned int good_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831
832 scsi_device_unbusy(sdev);
833
834 /*
835 * Clear the flags which say that the device/host is no longer
836 * capable of accepting new commands. These are set in scsi_queue.c
837 * for both the queue full condition on a device, and for a
838 * host full condition on the host.
839 *
840 * XXX(hch): What about locking?
841 */
842 shost->host_blocked = 0;
843 sdev->device_blocked = 0;
844
845 /*
846 * If we have valid sense information, then some kind of recovery
847 * must have taken place. Make a note of this.
848 */
849 if (SCSI_SENSE_VALID(cmd))
850 cmd->result |= (DRIVER_SENSE << 24);
851
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400852 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
853 "Notifying upper driver of completion "
854 "(result %x)\n", cmd->result));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855
FUJITA Tomonorif18573a2008-04-11 12:56:52 +0200856 good_bytes = scsi_bufflen(cmd);
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800857 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
858 drv = scsi_cmd_to_driver(cmd);
859 if (drv->done)
860 good_bytes = drv->done(cmd);
861 }
862 scsi_io_completion(cmd, good_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863}
864EXPORT_SYMBOL(scsi_finish_command);
865
Rob Landleyeb448202007-11-03 13:30:39 -0500866/**
867 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
868 * @sdev: SCSI Device in question
869 * @tagged: Do we use tagged queueing (non-0) or do we treat
870 * this device as an untagged device (0)
871 * @tags: Number of tags allowed if tagged queueing enabled,
872 * or number of commands the low level driver can
873 * queue up in non-tagged mode (as per cmd_per_lun).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874 *
875 * Returns: Nothing
876 *
877 * Lock Status: None held on entry
878 *
879 * Notes: Low level drivers may call this at any time and we will do
880 * the right thing depending on whether or not the device is
881 * currently active and whether or not it even has the
882 * command blocks built yet.
883 */
884void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
885{
886 unsigned long flags;
887
888 /*
889 * refuse to set tagged depth to an unworkable size
890 */
891 if (tags <= 0)
892 return;
893
894 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
895
Rob Landleyeb448202007-11-03 13:30:39 -0500896 /* Check to see if the queue is managed by the block layer.
897 * If it is, and we fail to adjust the depth, exit. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 if (blk_queue_tagged(sdev->request_queue) &&
899 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
900 goto out;
901
902 sdev->queue_depth = tags;
903 switch (tagged) {
904 case MSG_ORDERED_TAG:
905 sdev->ordered_tags = 1;
906 sdev->simple_tags = 1;
907 break;
908 case MSG_SIMPLE_TAG:
909 sdev->ordered_tags = 0;
910 sdev->simple_tags = 1;
911 break;
912 default:
James Bottomley9ccfc752005-10-02 11:45:08 -0500913 sdev_printk(KERN_WARNING, sdev,
914 "scsi_adjust_queue_depth, bad queue type, "
915 "disabled\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 case 0:
917 sdev->ordered_tags = sdev->simple_tags = 0;
918 sdev->queue_depth = tags;
919 break;
920 }
921 out:
922 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
923}
924EXPORT_SYMBOL(scsi_adjust_queue_depth);
925
Rob Landleyeb448202007-11-03 13:30:39 -0500926/**
927 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
928 * @sdev: SCSI Device in question
929 * @depth: Current number of outstanding SCSI commands on this device,
930 * not counting the one returned as QUEUE_FULL.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 *
Rob Landleyeb448202007-11-03 13:30:39 -0500932 * Description: This function will track successive QUEUE_FULL events on a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 * specific SCSI device to determine if and when there is a
934 * need to adjust the queue depth on the device.
935 *
Rob Landleyeb448202007-11-03 13:30:39 -0500936 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 * -1 - Drop back to untagged operation using host->cmd_per_lun
938 * as the untagged command depth
939 *
940 * Lock Status: None held on entry
941 *
942 * Notes: Low level drivers may call this at any time and we will do
943 * "The Right Thing." We are interrupt context safe.
944 */
945int scsi_track_queue_full(struct scsi_device *sdev, int depth)
946{
947 if ((jiffies >> 4) == sdev->last_queue_full_time)
948 return 0;
949
950 sdev->last_queue_full_time = (jiffies >> 4);
951 if (sdev->last_queue_full_depth != depth) {
952 sdev->last_queue_full_count = 1;
953 sdev->last_queue_full_depth = depth;
954 } else {
955 sdev->last_queue_full_count++;
956 }
957
958 if (sdev->last_queue_full_count <= 10)
959 return 0;
960 if (sdev->last_queue_full_depth < 8) {
961 /* Drop back to untagged */
962 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
963 return -1;
964 }
965
966 if (sdev->ordered_tags)
967 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
968 else
969 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
970 return depth;
971}
972EXPORT_SYMBOL(scsi_track_queue_full);
973
974/**
Rob Landleyeb448202007-11-03 13:30:39 -0500975 * scsi_device_get - get an additional reference to a scsi_device
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 * @sdev: device to get a reference to
977 *
Rob Landleyeb448202007-11-03 13:30:39 -0500978 * Description: Gets a reference to the scsi_device and increments the use count
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979 * of the underlying LLDD module. You must hold host_lock of the
980 * parent Scsi_Host or already have a reference when calling this.
981 */
982int scsi_device_get(struct scsi_device *sdev)
983{
James Bottomley85b6c722006-08-31 18:15:22 -0400984 if (sdev->sdev_state == SDEV_DEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985 return -ENXIO;
986 if (!get_device(&sdev->sdev_gendev))
987 return -ENXIO;
James Bottomley85b6c722006-08-31 18:15:22 -0400988 /* We can fail this if we're doing SCSI operations
989 * from module exit (like cache flush) */
990 try_module_get(sdev->host->hostt->module);
991
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 return 0;
993}
994EXPORT_SYMBOL(scsi_device_get);
995
996/**
997 * scsi_device_put - release a reference to a scsi_device
998 * @sdev: device to release a reference on.
999 *
Rob Landleyeb448202007-11-03 13:30:39 -05001000 * Description: Release a reference to the scsi_device and decrements the use
1001 * count of the underlying LLDD module. The device is freed once the last
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 * user vanishes.
1003 */
1004void scsi_device_put(struct scsi_device *sdev)
1005{
Ingo Molnar504fb372006-11-09 10:09:35 +01001006#ifdef CONFIG_MODULE_UNLOAD
James Bottomleyf479ab82006-09-06 09:00:29 -05001007 struct module *module = sdev->host->hostt->module;
1008
James Bottomley85b6c722006-08-31 18:15:22 -04001009 /* The module refcount will be zero if scsi_device_get()
1010 * was called from a module removal routine */
James Bottomleyf479ab82006-09-06 09:00:29 -05001011 if (module && module_refcount(module) != 0)
1012 module_put(module);
Daniel Walkera506b442006-09-09 09:31:03 -07001013#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 put_device(&sdev->sdev_gendev);
1015}
1016EXPORT_SYMBOL(scsi_device_put);
1017
Rob Landleyeb448202007-11-03 13:30:39 -05001018/* helper for shost_for_each_device, see that for documentation */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1020 struct scsi_device *prev)
1021{
1022 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1023 struct scsi_device *next = NULL;
1024 unsigned long flags;
1025
1026 spin_lock_irqsave(shost->host_lock, flags);
1027 while (list->next != &shost->__devices) {
1028 next = list_entry(list->next, struct scsi_device, siblings);
1029 /* skip devices that we can't get a reference to */
1030 if (!scsi_device_get(next))
1031 break;
1032 next = NULL;
1033 list = list->next;
1034 }
1035 spin_unlock_irqrestore(shost->host_lock, flags);
1036
1037 if (prev)
1038 scsi_device_put(prev);
1039 return next;
1040}
1041EXPORT_SYMBOL(__scsi_iterate_devices);
1042
1043/**
1044 * starget_for_each_device - helper to walk all devices of a target
1045 * @starget: target whose devices we want to iterate over.
Rob Landleyeb448202007-11-03 13:30:39 -05001046 * @data: Opaque passed to each function call.
1047 * @fn: Function to call on each device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048 *
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001049 * This traverses over each device of @starget. The devices have
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050 * a reference that must be released by scsi_host_put when breaking
1051 * out of the loop.
1052 */
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001053void starget_for_each_device(struct scsi_target *starget, void *data,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054 void (*fn)(struct scsi_device *, void *))
1055{
1056 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1057 struct scsi_device *sdev;
1058
1059 shost_for_each_device(sdev, shost) {
1060 if ((sdev->channel == starget->channel) &&
1061 (sdev->id == starget->id))
1062 fn(sdev, data);
1063 }
1064}
1065EXPORT_SYMBOL(starget_for_each_device);
1066
1067/**
Randy Dunlap14f501a2008-02-03 15:06:36 -08001068 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001069 * @starget: target whose devices we want to iterate over.
Randy Dunlap14f501a2008-02-03 15:06:36 -08001070 * @data: parameter for callback @fn()
1071 * @fn: callback function that is invoked for each device
Maciej W. Rozycki522939d2007-12-10 15:49:31 -08001072 *
1073 * This traverses over each device of @starget. It does _not_
1074 * take a reference on the scsi_device, so the whole loop must be
1075 * protected by shost->host_lock.
1076 *
1077 * Note: The only reason why drivers would want to use this is because
1078 * they need to access the device list in irq context. Otherwise you
1079 * really want to use starget_for_each_device instead.
1080 **/
1081void __starget_for_each_device(struct scsi_target *starget, void *data,
1082 void (*fn)(struct scsi_device *, void *))
1083{
1084 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1085 struct scsi_device *sdev;
1086
1087 __shost_for_each_device(sdev, shost) {
1088 if ((sdev->channel == starget->channel) &&
1089 (sdev->id == starget->id))
1090 fn(sdev, data);
1091 }
1092}
1093EXPORT_SYMBOL(__starget_for_each_device);
1094
1095/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1097 * @starget: SCSI target pointer
1098 * @lun: SCSI Logical Unit Number
1099 *
Rob Landleyeb448202007-11-03 13:30:39 -05001100 * Description: Looks up the scsi_device with the specified @lun for a given
1101 * @starget. The returned scsi_device does not have an additional
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 * reference. You must hold the host's host_lock over this call and
1103 * any access to the returned scsi_device.
1104 *
Randy Dunlapdc8875e2007-11-15 15:42:30 -08001105 * Note: The only reason why drivers should use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001106 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107 * really want to use scsi_device_lookup_by_target instead.
1108 **/
1109struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1110 uint lun)
1111{
1112 struct scsi_device *sdev;
1113
1114 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1115 if (sdev->lun ==lun)
1116 return sdev;
1117 }
1118
1119 return NULL;
1120}
1121EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1122
1123/**
1124 * scsi_device_lookup_by_target - find a device given the target
1125 * @starget: SCSI target pointer
1126 * @lun: SCSI Logical Unit Number
1127 *
Rob Landleyeb448202007-11-03 13:30:39 -05001128 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1129 * for a given host. The returned scsi_device has an additional reference that
1130 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001131 **/
1132struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1133 uint lun)
1134{
1135 struct scsi_device *sdev;
1136 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1137 unsigned long flags;
1138
1139 spin_lock_irqsave(shost->host_lock, flags);
1140 sdev = __scsi_device_lookup_by_target(starget, lun);
1141 if (sdev && scsi_device_get(sdev))
1142 sdev = NULL;
1143 spin_unlock_irqrestore(shost->host_lock, flags);
1144
1145 return sdev;
1146}
1147EXPORT_SYMBOL(scsi_device_lookup_by_target);
1148
1149/**
Rob Landleyeb448202007-11-03 13:30:39 -05001150 * __scsi_device_lookup - find a device given the host (UNLOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 * @shost: SCSI host pointer
1152 * @channel: SCSI channel (zero if only one channel)
Rob Landleyeb448202007-11-03 13:30:39 -05001153 * @id: SCSI target number (physical unit number)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154 * @lun: SCSI Logical Unit Number
1155 *
Rob Landleyeb448202007-11-03 13:30:39 -05001156 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1157 * for a given host. The returned scsi_device does not have an additional
1158 * reference. You must hold the host's host_lock over this call and any access
1159 * to the returned scsi_device.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160 *
1161 * Note: The only reason why drivers would want to use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001162 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 * really want to use scsi_device_lookup instead.
1164 **/
1165struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1166 uint channel, uint id, uint lun)
1167{
1168 struct scsi_device *sdev;
1169
1170 list_for_each_entry(sdev, &shost->__devices, siblings) {
1171 if (sdev->channel == channel && sdev->id == id &&
1172 sdev->lun ==lun)
1173 return sdev;
1174 }
1175
1176 return NULL;
1177}
1178EXPORT_SYMBOL(__scsi_device_lookup);
1179
1180/**
1181 * scsi_device_lookup - find a device given the host
1182 * @shost: SCSI host pointer
1183 * @channel: SCSI channel (zero if only one channel)
1184 * @id: SCSI target number (physical unit number)
1185 * @lun: SCSI Logical Unit Number
1186 *
Rob Landleyeb448202007-11-03 13:30:39 -05001187 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1188 * for a given host. The returned scsi_device has an additional reference that
1189 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 **/
1191struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1192 uint channel, uint id, uint lun)
1193{
1194 struct scsi_device *sdev;
1195 unsigned long flags;
1196
1197 spin_lock_irqsave(shost->host_lock, flags);
1198 sdev = __scsi_device_lookup(shost, channel, id, lun);
1199 if (sdev && scsi_device_get(sdev))
1200 sdev = NULL;
1201 spin_unlock_irqrestore(shost->host_lock, flags);
1202
1203 return sdev;
1204}
1205EXPORT_SYMBOL(scsi_device_lookup);
1206
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207MODULE_DESCRIPTION("SCSI core");
1208MODULE_LICENSE("GPL");
1209
1210module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1211MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1212
1213static int __init init_scsi(void)
1214{
Jens Axboe9bf09c232006-09-30 20:31:11 +02001215 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001216
1217 error = scsi_init_queue();
1218 if (error)
1219 return error;
1220 error = scsi_init_procfs();
1221 if (error)
1222 goto cleanup_queue;
1223 error = scsi_init_devinfo();
1224 if (error)
1225 goto cleanup_procfs;
1226 error = scsi_init_hosts();
1227 if (error)
1228 goto cleanup_devlist;
1229 error = scsi_init_sysctl();
1230 if (error)
1231 goto cleanup_hosts;
1232 error = scsi_sysfs_register();
1233 if (error)
1234 goto cleanup_sysctl;
1235
James Smart84314fd2006-08-18 17:30:09 -04001236 scsi_netlink_init();
1237
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1239 return 0;
1240
1241cleanup_sysctl:
1242 scsi_exit_sysctl();
1243cleanup_hosts:
1244 scsi_exit_hosts();
1245cleanup_devlist:
1246 scsi_exit_devinfo();
1247cleanup_procfs:
1248 scsi_exit_procfs();
1249cleanup_queue:
1250 scsi_exit_queue();
1251 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1252 -error);
1253 return error;
1254}
1255
1256static void __exit exit_scsi(void)
1257{
James Smart84314fd2006-08-18 17:30:09 -04001258 scsi_netlink_exit();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 scsi_sysfs_unregister();
1260 scsi_exit_sysctl();
1261 scsi_exit_hosts();
1262 scsi_exit_devinfo();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 scsi_exit_procfs();
1264 scsi_exit_queue();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265}
1266
1267subsys_initcall(init_scsi);
1268module_exit(exit_scsi);