blob: 412a351c6cf77ba3b7f36bc45fd5fd75c96a8309 [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/*
82 * Macro to determine the size of SCSI command. This macro takes vendor
83 * unique commands into account. SCSI commands in groups 6 and 7 are
84 * vendor unique and we will depend upon the command length being
85 * supplied correctly in cmd_len.
86 */
87#define CDB_SIZE(cmd) (((((cmd)->cmnd[0] >> 5) & 7) < 6) ? \
88 COMMAND_SIZE((cmd)->cmnd[0]) : (cmd)->cmd_len)
89
90/*
91 * Note - the initial logging level can be set here to log events at boot time.
92 * After the system is up, you may enable logging via the /proc interface.
93 */
94unsigned int scsi_logging_level;
95#if defined(CONFIG_SCSI_LOGGING)
96EXPORT_SYMBOL(scsi_logging_level);
97#endif
98
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -060099/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
100 * You may not alter any existing entry (although adding new ones is
101 * encouraged once assigned by ANSI/INCITS T10
102 */
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600103static const char *const scsi_device_types[] = {
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600104 "Direct-Access ",
105 "Sequential-Access",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 "Printer ",
107 "Processor ",
108 "WORM ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600109 "CD-ROM ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 "Scanner ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600111 "Optical Device ",
112 "Medium Changer ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 "Communications ",
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600114 "ASC IT8 ",
115 "ASC IT8 ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 "RAID ",
117 "Enclosure ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600118 "Direct-Access-RBC",
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600119 "Optical card ",
120 "Bridge controller",
121 "Object storage ",
122 "Automation/Drive ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123};
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600124
Rob Landleyeb448202007-11-03 13:30:39 -0500125/**
126 * scsi_device_type - Return 17 char string indicating device type.
127 * @type: type number to look up
128 */
129
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600130const char * scsi_device_type(unsigned type)
131{
132 if (type == 0x1e)
133 return "Well-known LUN ";
134 if (type == 0x1f)
135 return "No Device ";
Eric Sesterhenn80c6e3c2006-09-26 13:22:13 +0200136 if (type >= ARRAY_SIZE(scsi_device_types))
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600137 return "Unknown ";
138 return scsi_device_types[type];
139}
140
141EXPORT_SYMBOL(scsi_device_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143struct scsi_host_cmd_pool {
Christoph Lametere18b8902006-12-06 20:33:20 -0800144 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 unsigned int users;
146 char *name;
147 unsigned int slab_flags;
Al Viroc53033f2005-10-21 03:22:08 -0400148 gfp_t gfp_mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149};
150
151static struct scsi_host_cmd_pool scsi_cmd_pool = {
152 .name = "scsi_cmd_cache",
153 .slab_flags = SLAB_HWCACHE_ALIGN,
154};
155
156static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
157 .name = "scsi_cmd_cache(DMA)",
158 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
159 .gfp_mask = __GFP_DMA,
160};
161
Arjan van de Ven0b950672006-01-11 13:16:10 +0100162static DEFINE_MUTEX(host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163
Rob Landleyeb448202007-11-03 13:30:39 -0500164/**
165 * __scsi_get_command - Allocate a struct scsi_cmnd
166 * @shost: host to transmit command
167 * @gfp_mask: allocation mask
168 *
169 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
170 * host's free_list if necessary.
171 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900172struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173{
174 struct scsi_cmnd *cmd;
175
176 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
177 gfp_mask | shost->cmd_pool->gfp_mask);
178
179 if (unlikely(!cmd)) {
180 unsigned long flags;
181
182 spin_lock_irqsave(&shost->free_list_lock, flags);
183 if (likely(!list_empty(&shost->free_list))) {
184 cmd = list_entry(shost->free_list.next,
185 struct scsi_cmnd, list);
186 list_del_init(&cmd->list);
187 }
188 spin_unlock_irqrestore(&shost->free_list_lock, flags);
189 }
190
191 return cmd;
192}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900193EXPORT_SYMBOL_GPL(__scsi_get_command);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194
Rob Landleyeb448202007-11-03 13:30:39 -0500195/**
196 * scsi_get_command - Allocate and setup a scsi command block
197 * @dev: parent scsi device
198 * @gfp_mask: allocator flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 *
200 * Returns: The allocated scsi command structure.
201 */
Al Viroc53033f2005-10-21 03:22:08 -0400202struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203{
204 struct scsi_cmnd *cmd;
205
206 /* Bail if we can't get a reference to the device */
207 if (!get_device(&dev->sdev_gendev))
208 return NULL;
209
210 cmd = __scsi_get_command(dev->host, gfp_mask);
211
212 if (likely(cmd != NULL)) {
213 unsigned long flags;
214
215 memset(cmd, 0, sizeof(*cmd));
216 cmd->device = dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 init_timer(&cmd->eh_timeout);
218 INIT_LIST_HEAD(&cmd->list);
219 spin_lock_irqsave(&dev->list_lock, flags);
220 list_add_tail(&cmd->list, &dev->cmd_list);
221 spin_unlock_irqrestore(&dev->list_lock, flags);
Matthew Dobson79e448b2005-11-21 21:32:29 -0800222 cmd->jiffies_at_alloc = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 } else
224 put_device(&dev->sdev_gendev);
225
226 return cmd;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900227}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228EXPORT_SYMBOL(scsi_get_command);
229
Rob Landleyeb448202007-11-03 13:30:39 -0500230/**
231 * __scsi_put_command - Free a struct scsi_cmnd
232 * @shost: dev->host
233 * @cmd: Command to free
234 * @dev: parent scsi device
235 */
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900236void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
237 struct device *dev)
238{
239 unsigned long flags;
240
241 /* changing locks here, don't need to restore the irq state */
242 spin_lock_irqsave(&shost->free_list_lock, flags);
243 if (unlikely(list_empty(&shost->free_list))) {
244 list_add(&cmd->list, &shost->free_list);
245 cmd = NULL;
246 }
247 spin_unlock_irqrestore(&shost->free_list_lock, flags);
248
249 if (likely(cmd != NULL))
250 kmem_cache_free(shost->cmd_pool->slab, cmd);
251
252 put_device(dev);
253}
254EXPORT_SYMBOL(__scsi_put_command);
255
Rob Landleyeb448202007-11-03 13:30:39 -0500256/**
257 * scsi_put_command - Free a scsi command block
258 * @cmd: command block to free
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 *
260 * Returns: Nothing.
261 *
262 * Notes: The command must not belong to any lists.
263 */
264void scsi_put_command(struct scsi_cmnd *cmd)
265{
266 struct scsi_device *sdev = cmd->device;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267 unsigned long flags;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900268
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 /* serious error if the command hasn't come from a device list */
270 spin_lock_irqsave(&cmd->device->list_lock, flags);
271 BUG_ON(list_empty(&cmd->list));
272 list_del_init(&cmd->list);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900273 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900275 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276}
277EXPORT_SYMBOL(scsi_put_command);
278
Rob Landleyeb448202007-11-03 13:30:39 -0500279/**
280 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
281 * @shost: host to allocate the freelist for.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 *
Rob Landleyeb448202007-11-03 13:30:39 -0500283 * Description: The command freelist protects against system-wide out of memory
284 * deadlock by preallocating one SCSI command structure for each host, so the
285 * system can always write to a swap file on a device associated with that host.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 *
287 * Returns: Nothing.
288 */
289int scsi_setup_command_freelist(struct Scsi_Host *shost)
290{
291 struct scsi_host_cmd_pool *pool;
292 struct scsi_cmnd *cmd;
293
294 spin_lock_init(&shost->free_list_lock);
295 INIT_LIST_HEAD(&shost->free_list);
296
297 /*
298 * Select a command slab for this host and create it if not
Rob Landleyeb448202007-11-03 13:30:39 -0500299 * yet existent.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 */
Arjan van de Ven0b950672006-01-11 13:16:10 +0100301 mutex_lock(&host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
303 if (!pool->users) {
304 pool->slab = kmem_cache_create(pool->name,
305 sizeof(struct scsi_cmnd), 0,
Paul Mundt20c2df82007-07-20 10:11:58 +0900306 pool->slab_flags, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 if (!pool->slab)
308 goto fail;
309 }
310
311 pool->users++;
312 shost->cmd_pool = pool;
Arjan van de Ven0b950672006-01-11 13:16:10 +0100313 mutex_unlock(&host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314
315 /*
316 * Get one backup command for this host.
317 */
318 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
319 GFP_KERNEL | shost->cmd_pool->gfp_mask);
320 if (!cmd)
321 goto fail2;
322 list_add(&cmd->list, &shost->free_list);
323 return 0;
324
325 fail2:
326 if (!--pool->users)
327 kmem_cache_destroy(pool->slab);
328 return -ENOMEM;
329 fail:
Arjan van de Ven0b950672006-01-11 13:16:10 +0100330 mutex_unlock(&host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 return -ENOMEM;
332
333}
334
Rob Landleyeb448202007-11-03 13:30:39 -0500335/**
336 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
337 * @shost: host whose freelist is going to be destroyed
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 */
339void scsi_destroy_command_freelist(struct Scsi_Host *shost)
340{
341 while (!list_empty(&shost->free_list)) {
342 struct scsi_cmnd *cmd;
343
344 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
345 list_del_init(&cmd->list);
346 kmem_cache_free(shost->cmd_pool->slab, cmd);
347 }
348
Arjan van de Ven0b950672006-01-11 13:16:10 +0100349 mutex_lock(&host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 if (!--shost->cmd_pool->users)
351 kmem_cache_destroy(shost->cmd_pool->slab);
Arjan van de Ven0b950672006-01-11 13:16:10 +0100352 mutex_unlock(&host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353}
354
355#ifdef CONFIG_SCSI_LOGGING
356void scsi_log_send(struct scsi_cmnd *cmd)
357{
358 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359
360 /*
361 * If ML QUEUE log level is greater than or equal to:
362 *
363 * 1: nothing (match completion)
364 *
365 * 2: log opcode + command of all commands
366 *
367 * 3: same as 2 plus dump cmd address
368 *
369 * 4: same as 3 plus dump extra junk
370 */
371 if (unlikely(scsi_logging_level)) {
372 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
373 SCSI_LOG_MLQUEUE_BITS);
374 if (level > 1) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500375 scmd_printk(KERN_INFO, cmd, "Send: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 if (level > 2)
377 printk("0x%p ", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500378 printk("\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 scsi_print_command(cmd);
380 if (level > 3) {
381 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800382 " queuecommand 0x%p\n",
Boaz Harrosha73e45b2007-07-04 21:26:01 +0300383 scsi_sglist(cmd), scsi_bufflen(cmd),
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500384 cmd->device->host->hostt->queuecommand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385
386 }
387 }
388 }
389}
390
391void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
392{
393 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394
395 /*
396 * If ML COMPLETE log level is greater than or equal to:
397 *
398 * 1: log disposition, result, opcode + command, and conditionally
399 * sense data for failures or non SUCCESS dispositions.
400 *
401 * 2: same as 1 but for all command completions.
402 *
403 * 3: same as 2 plus dump cmd address
404 *
405 * 4: same as 3 plus dump extra junk
406 */
407 if (unlikely(scsi_logging_level)) {
408 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
409 SCSI_LOG_MLCOMPLETE_BITS);
410 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
411 (level > 1)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500412 scmd_printk(KERN_INFO, cmd, "Done: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 if (level > 2)
414 printk("0x%p ", cmd);
415 /*
416 * Dump truncated values, so we usually fit within
417 * 80 chars.
418 */
419 switch (disposition) {
420 case SUCCESS:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500421 printk("SUCCESS\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 break;
423 case NEEDS_RETRY:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500424 printk("RETRY\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 break;
426 case ADD_TO_MLQUEUE:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500427 printk("MLQUEUE\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 break;
429 case FAILED:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500430 printk("FAILED\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 break;
432 case TIMEOUT_ERROR:
433 /*
434 * If called via scsi_times_out.
435 */
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500436 printk("TIMEOUT\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 break;
438 default:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500439 printk("UNKNOWN\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 }
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500441 scsi_print_result(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 scsi_print_command(cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500443 if (status_byte(cmd->result) & CHECK_CONDITION)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 scsi_print_sense("", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500445 if (level > 3)
446 scmd_printk(KERN_INFO, cmd,
447 "scsi host busy %d failed %d\n",
448 cmd->device->host->host_busy,
449 cmd->device->host->host_failed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 }
451 }
452}
453#endif
454
Rob Landleyeb448202007-11-03 13:30:39 -0500455/**
456 * scsi_cmd_get_serial - Assign a serial number to a command
457 * @host: the scsi host
458 * @cmd: command to assign serial number to
459 *
460 * Description: a serial number identifies a request for error recovery
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 * and debugging purposes. Protected by the Host_Lock of host.
462 */
463static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
464{
465 cmd->serial_number = host->cmd_serial_number++;
466 if (cmd->serial_number == 0)
467 cmd->serial_number = host->cmd_serial_number++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468}
469
Rob Landleyeb448202007-11-03 13:30:39 -0500470/**
471 * scsi_dispatch_command - Dispatch a command to the low-level driver.
472 * @cmd: command block we are dispatching.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 *
Rob Landleyeb448202007-11-03 13:30:39 -0500474 * Return: nonzero return request was rejected and device's queue needs to be
475 * plugged.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 */
477int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
478{
479 struct Scsi_Host *host = cmd->device->host;
480 unsigned long flags = 0;
481 unsigned long timeout;
482 int rtn = 0;
483
484 /* check if the device is still usable */
485 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
486 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
487 * returns an immediate error upwards, and signals
488 * that the device is no longer present */
489 cmd->result = DID_NO_CONNECT << 16;
490 atomic_inc(&cmd->device->iorequest_cnt);
Mike Christie69b52892005-05-01 14:47:15 -0500491 __scsi_done(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 /* return 0 (because the command has been processed) */
493 goto out;
494 }
495
496 /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
497 if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) {
498 /*
499 * in SDEV_BLOCK, the command is just put back on the device
500 * queue. The suspend state has already blocked the queue so
501 * future requests should not occur until the device
502 * transitions out of the suspend state.
503 */
504 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
505
506 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
507
508 /*
509 * NOTE: rtn is still zero here because we don't need the
510 * queue to be plugged on return (it's already stopped)
511 */
512 goto out;
513 }
514
515 /*
516 * If SCSI-2 or lower, store the LUN value in cmnd.
517 */
James Bottomley4d7db042006-03-31 20:07:45 -0600518 if (cmd->device->scsi_level <= SCSI_2 &&
519 cmd->device->scsi_level != SCSI_UNKNOWN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
521 (cmd->device->lun << 5 & 0xe0);
522 }
523
524 /*
525 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
526 * we can avoid the drive not being ready.
527 */
528 timeout = host->last_reset + MIN_RESET_DELAY;
529
530 if (host->resetting && time_before(jiffies, timeout)) {
531 int ticks_remaining = timeout - jiffies;
532 /*
533 * NOTE: This may be executed from within an interrupt
534 * handler! This is bad, but for now, it'll do. The irq
535 * level of the interrupt handler has been masked out by the
536 * platform dependent interrupt handling code already, so the
537 * sti() here will not cause another call to the SCSI host's
538 * interrupt handler (assuming there is one irq-level per
539 * host).
540 */
541 while (--ticks_remaining >= 0)
542 mdelay(1 + 999 / HZ);
543 host->resetting = 0;
544 }
545
546 /*
547 * AK: unlikely race here: for some reason the timer could
548 * expire before the serial number is set up below.
549 */
550 scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
551
552 scsi_log_send(cmd);
553
554 /*
555 * We will use a queued command if possible, otherwise we will
556 * emulate the queuing and calling of completion function ourselves.
557 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 atomic_inc(&cmd->device->iorequest_cnt);
559
560 /*
561 * Before we queue this command, check if the command
562 * length exceeds what the host adapter can handle.
563 */
564 if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) {
565 SCSI_LOG_MLQUEUE(3,
566 printk("queuecommand : command too long.\n"));
567 cmd->result = (DID_ABORT << 16);
568
569 scsi_done(cmd);
570 goto out;
571 }
572
573 spin_lock_irqsave(host->host_lock, flags);
574 scsi_cmd_get_serial(host, cmd);
575
Mike Andersond2c9d9e2005-06-16 11:13:42 -0700576 if (unlikely(host->shost_state == SHOST_DEL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 cmd->result = (DID_NO_CONNECT << 16);
578 scsi_done(cmd);
579 } else {
580 rtn = host->hostt->queuecommand(cmd, scsi_done);
581 }
582 spin_unlock_irqrestore(host->host_lock, flags);
583 if (rtn) {
Tejun Heo d8c37e72005-05-14 00:46:08 +0900584 if (scsi_delete_timer(cmd)) {
585 atomic_inc(&cmd->device->iodone_cnt);
586 scsi_queue_insert(cmd,
587 (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
588 rtn : SCSI_MLQUEUE_HOST_BUSY);
589 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 SCSI_LOG_MLQUEUE(3,
591 printk("queuecommand : request rejected\n"));
592 }
593
594 out:
595 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
596 return rtn;
597}
598
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599/**
Luben Tuikov89f48c42006-05-15 20:57:18 +0900600 * scsi_req_abort_cmd -- Request command recovery for the specified command
Rob Landleyeb448202007-11-03 13:30:39 -0500601 * @cmd: pointer to the SCSI command of interest
Luben Tuikov89f48c42006-05-15 20:57:18 +0900602 *
603 * This function requests that SCSI Core start recovery for the
604 * command by deleting the timer and adding the command to the eh
605 * queue. It can be called by either LLDDs or SCSI Core. LLDDs who
606 * implement their own error recovery MAY ignore the timeout event if
607 * they generated scsi_req_abort_cmd.
608 */
609void scsi_req_abort_cmd(struct scsi_cmnd *cmd)
610{
611 if (!scsi_delete_timer(cmd))
612 return;
613 scsi_times_out(cmd);
614}
615EXPORT_SYMBOL(scsi_req_abort_cmd);
616
617/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 * scsi_done - Enqueue the finished SCSI command into the done queue.
619 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
620 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
621 *
Rob Landleyeb448202007-11-03 13:30:39 -0500622 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
623 * which regains ownership of the SCSI command (de facto) from a LLDD, and
624 * enqueues the command to the done queue for further processing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 *
626 * This is the producer of the done queue who enqueues at the tail.
627 *
628 * This function is interrupt context safe.
629 */
Adrian Bunk52c1da32005-06-23 22:05:33 -0700630static void scsi_done(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631{
632 /*
Rob Landleyeb448202007-11-03 13:30:39 -0500633 * We don't have to worry about this one timing out anymore.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 * If we are unable to remove the timer, then the command
635 * has already timed out. In which case, we have no choice but to
636 * let the timeout function run, as we have no idea where in fact
637 * that function could really be. It might be on another processor,
638 * etc, etc.
639 */
640 if (!scsi_delete_timer(cmd))
641 return;
642 __scsi_done(cmd);
643}
644
645/* Private entry to scsi_done() to complete a command when the timer
646 * isn't running --- used by scsi_times_out */
647void __scsi_done(struct scsi_cmnd *cmd)
648{
Jens Axboe1aea6432006-01-09 16:03:03 +0100649 struct request *rq = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650
651 /*
652 * Set the serial numbers back to zero
653 */
654 cmd->serial_number = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655
656 atomic_inc(&cmd->device->iodone_cnt);
657 if (cmd->result)
658 atomic_inc(&cmd->device->ioerr_cnt);
659
Jens Axboe1aea6432006-01-09 16:03:03 +0100660 BUG_ON(!rq);
661
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 /*
Jens Axboe1aea6432006-01-09 16:03:03 +0100663 * The uptodate/nbytes values don't matter, as we allow partial
664 * completes and thus will check this in the softirq callback
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 */
Jens Axboe1aea6432006-01-09 16:03:03 +0100666 rq->completion_data = cmd;
667 blk_complete_request(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668}
669
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800670/* Move this to a header if it becomes more generally useful */
671static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
672{
673 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
674}
675
Rob Landleyeb448202007-11-03 13:30:39 -0500676/**
677 * scsi_finish_command - cleanup and pass command back to upper layer
678 * @cmd: the command
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 *
Rob Landleyeb448202007-11-03 13:30:39 -0500680 * Description: Pass command off to upper layer for finishing of I/O
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 * request, waking processes that are waiting on results,
682 * etc.
683 */
684void scsi_finish_command(struct scsi_cmnd *cmd)
685{
686 struct scsi_device *sdev = cmd->device;
687 struct Scsi_Host *shost = sdev->host;
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800688 struct scsi_driver *drv;
689 unsigned int good_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690
691 scsi_device_unbusy(sdev);
692
693 /*
694 * Clear the flags which say that the device/host is no longer
695 * capable of accepting new commands. These are set in scsi_queue.c
696 * for both the queue full condition on a device, and for a
697 * host full condition on the host.
698 *
699 * XXX(hch): What about locking?
700 */
701 shost->host_blocked = 0;
702 sdev->device_blocked = 0;
703
704 /*
705 * If we have valid sense information, then some kind of recovery
706 * must have taken place. Make a note of this.
707 */
708 if (SCSI_SENSE_VALID(cmd))
709 cmd->result |= (DRIVER_SENSE << 24);
710
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400711 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
712 "Notifying upper driver of completion "
713 "(result %x)\n", cmd->result));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714
Linus Torvalds7b3d9542008-01-06 10:17:12 -0800715 good_bytes = cmd->request_bufflen;
716 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
717 drv = scsi_cmd_to_driver(cmd);
718 if (drv->done)
719 good_bytes = drv->done(cmd);
720 }
721 scsi_io_completion(cmd, good_bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722}
723EXPORT_SYMBOL(scsi_finish_command);
724
Rob Landleyeb448202007-11-03 13:30:39 -0500725/**
726 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
727 * @sdev: SCSI Device in question
728 * @tagged: Do we use tagged queueing (non-0) or do we treat
729 * this device as an untagged device (0)
730 * @tags: Number of tags allowed if tagged queueing enabled,
731 * or number of commands the low level driver can
732 * queue up in non-tagged mode (as per cmd_per_lun).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 *
734 * Returns: Nothing
735 *
736 * Lock Status: None held on entry
737 *
738 * Notes: Low level drivers may call this at any time and we will do
739 * the right thing depending on whether or not the device is
740 * currently active and whether or not it even has the
741 * command blocks built yet.
742 */
743void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
744{
745 unsigned long flags;
746
747 /*
748 * refuse to set tagged depth to an unworkable size
749 */
750 if (tags <= 0)
751 return;
752
753 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
754
Rob Landleyeb448202007-11-03 13:30:39 -0500755 /* Check to see if the queue is managed by the block layer.
756 * If it is, and we fail to adjust the depth, exit. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 if (blk_queue_tagged(sdev->request_queue) &&
758 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
759 goto out;
760
761 sdev->queue_depth = tags;
762 switch (tagged) {
763 case MSG_ORDERED_TAG:
764 sdev->ordered_tags = 1;
765 sdev->simple_tags = 1;
766 break;
767 case MSG_SIMPLE_TAG:
768 sdev->ordered_tags = 0;
769 sdev->simple_tags = 1;
770 break;
771 default:
James Bottomley9ccfc752005-10-02 11:45:08 -0500772 sdev_printk(KERN_WARNING, sdev,
773 "scsi_adjust_queue_depth, bad queue type, "
774 "disabled\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 case 0:
776 sdev->ordered_tags = sdev->simple_tags = 0;
777 sdev->queue_depth = tags;
778 break;
779 }
780 out:
781 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
782}
783EXPORT_SYMBOL(scsi_adjust_queue_depth);
784
Rob Landleyeb448202007-11-03 13:30:39 -0500785/**
786 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
787 * @sdev: SCSI Device in question
788 * @depth: Current number of outstanding SCSI commands on this device,
789 * not counting the one returned as QUEUE_FULL.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 *
Rob Landleyeb448202007-11-03 13:30:39 -0500791 * Description: This function will track successive QUEUE_FULL events on a
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 * specific SCSI device to determine if and when there is a
793 * need to adjust the queue depth on the device.
794 *
Rob Landleyeb448202007-11-03 13:30:39 -0500795 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 * -1 - Drop back to untagged operation using host->cmd_per_lun
797 * as the untagged command depth
798 *
799 * Lock Status: None held on entry
800 *
801 * Notes: Low level drivers may call this at any time and we will do
802 * "The Right Thing." We are interrupt context safe.
803 */
804int scsi_track_queue_full(struct scsi_device *sdev, int depth)
805{
806 if ((jiffies >> 4) == sdev->last_queue_full_time)
807 return 0;
808
809 sdev->last_queue_full_time = (jiffies >> 4);
810 if (sdev->last_queue_full_depth != depth) {
811 sdev->last_queue_full_count = 1;
812 sdev->last_queue_full_depth = depth;
813 } else {
814 sdev->last_queue_full_count++;
815 }
816
817 if (sdev->last_queue_full_count <= 10)
818 return 0;
819 if (sdev->last_queue_full_depth < 8) {
820 /* Drop back to untagged */
821 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
822 return -1;
823 }
824
825 if (sdev->ordered_tags)
826 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
827 else
828 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
829 return depth;
830}
831EXPORT_SYMBOL(scsi_track_queue_full);
832
833/**
Rob Landleyeb448202007-11-03 13:30:39 -0500834 * scsi_device_get - get an additional reference to a scsi_device
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835 * @sdev: device to get a reference to
836 *
Rob Landleyeb448202007-11-03 13:30:39 -0500837 * Description: Gets a reference to the scsi_device and increments the use count
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 * of the underlying LLDD module. You must hold host_lock of the
839 * parent Scsi_Host or already have a reference when calling this.
840 */
841int scsi_device_get(struct scsi_device *sdev)
842{
James Bottomley85b6c722006-08-31 18:15:22 -0400843 if (sdev->sdev_state == SDEV_DEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 return -ENXIO;
845 if (!get_device(&sdev->sdev_gendev))
846 return -ENXIO;
James Bottomley85b6c722006-08-31 18:15:22 -0400847 /* We can fail this if we're doing SCSI operations
848 * from module exit (like cache flush) */
849 try_module_get(sdev->host->hostt->module);
850
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 return 0;
852}
853EXPORT_SYMBOL(scsi_device_get);
854
855/**
856 * scsi_device_put - release a reference to a scsi_device
857 * @sdev: device to release a reference on.
858 *
Rob Landleyeb448202007-11-03 13:30:39 -0500859 * Description: Release a reference to the scsi_device and decrements the use
860 * count of the underlying LLDD module. The device is freed once the last
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 * user vanishes.
862 */
863void scsi_device_put(struct scsi_device *sdev)
864{
Ingo Molnar504fb372006-11-09 10:09:35 +0100865#ifdef CONFIG_MODULE_UNLOAD
James Bottomleyf479ab82006-09-06 09:00:29 -0500866 struct module *module = sdev->host->hostt->module;
867
James Bottomley85b6c722006-08-31 18:15:22 -0400868 /* The module refcount will be zero if scsi_device_get()
869 * was called from a module removal routine */
James Bottomleyf479ab82006-09-06 09:00:29 -0500870 if (module && module_refcount(module) != 0)
871 module_put(module);
Daniel Walkera506b442006-09-09 09:31:03 -0700872#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 put_device(&sdev->sdev_gendev);
874}
875EXPORT_SYMBOL(scsi_device_put);
876
Rob Landleyeb448202007-11-03 13:30:39 -0500877/* helper for shost_for_each_device, see that for documentation */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
879 struct scsi_device *prev)
880{
881 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
882 struct scsi_device *next = NULL;
883 unsigned long flags;
884
885 spin_lock_irqsave(shost->host_lock, flags);
886 while (list->next != &shost->__devices) {
887 next = list_entry(list->next, struct scsi_device, siblings);
888 /* skip devices that we can't get a reference to */
889 if (!scsi_device_get(next))
890 break;
891 next = NULL;
892 list = list->next;
893 }
894 spin_unlock_irqrestore(shost->host_lock, flags);
895
896 if (prev)
897 scsi_device_put(prev);
898 return next;
899}
900EXPORT_SYMBOL(__scsi_iterate_devices);
901
902/**
903 * starget_for_each_device - helper to walk all devices of a target
904 * @starget: target whose devices we want to iterate over.
Rob Landleyeb448202007-11-03 13:30:39 -0500905 * @data: Opaque passed to each function call.
906 * @fn: Function to call on each device
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 *
Maciej W. Rozycki522939d2007-12-10 15:49:31 -0800908 * This traverses over each device of @starget. The devices have
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909 * a reference that must be released by scsi_host_put when breaking
910 * out of the loop.
911 */
Maciej W. Rozycki522939d2007-12-10 15:49:31 -0800912void starget_for_each_device(struct scsi_target *starget, void *data,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 void (*fn)(struct scsi_device *, void *))
914{
915 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
916 struct scsi_device *sdev;
917
918 shost_for_each_device(sdev, shost) {
919 if ((sdev->channel == starget->channel) &&
920 (sdev->id == starget->id))
921 fn(sdev, data);
922 }
923}
924EXPORT_SYMBOL(starget_for_each_device);
925
926/**
Maciej W. Rozycki522939d2007-12-10 15:49:31 -0800927 * __starget_for_each_device - helper to walk all devices of a target
928 * (UNLOCKED)
929 * @starget: target whose devices we want to iterate over.
930 *
931 * This traverses over each device of @starget. It does _not_
932 * take a reference on the scsi_device, so the whole loop must be
933 * protected by shost->host_lock.
934 *
935 * Note: The only reason why drivers would want to use this is because
936 * they need to access the device list in irq context. Otherwise you
937 * really want to use starget_for_each_device instead.
938 **/
939void __starget_for_each_device(struct scsi_target *starget, void *data,
940 void (*fn)(struct scsi_device *, void *))
941{
942 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
943 struct scsi_device *sdev;
944
945 __shost_for_each_device(sdev, shost) {
946 if ((sdev->channel == starget->channel) &&
947 (sdev->id == starget->id))
948 fn(sdev, data);
949 }
950}
951EXPORT_SYMBOL(__starget_for_each_device);
952
953/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
955 * @starget: SCSI target pointer
956 * @lun: SCSI Logical Unit Number
957 *
Rob Landleyeb448202007-11-03 13:30:39 -0500958 * Description: Looks up the scsi_device with the specified @lun for a given
959 * @starget. The returned scsi_device does not have an additional
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 * reference. You must hold the host's host_lock over this call and
961 * any access to the returned scsi_device.
962 *
963 * Note: The only reason why drivers would want to use this is because
Rob Landleyeb448202007-11-03 13:30:39 -0500964 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 * really want to use scsi_device_lookup_by_target instead.
966 **/
967struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
968 uint lun)
969{
970 struct scsi_device *sdev;
971
972 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
973 if (sdev->lun ==lun)
974 return sdev;
975 }
976
977 return NULL;
978}
979EXPORT_SYMBOL(__scsi_device_lookup_by_target);
980
981/**
982 * scsi_device_lookup_by_target - find a device given the target
983 * @starget: SCSI target pointer
984 * @lun: SCSI Logical Unit Number
985 *
Rob Landleyeb448202007-11-03 13:30:39 -0500986 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
987 * for a given host. The returned scsi_device has an additional reference that
988 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989 **/
990struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
991 uint lun)
992{
993 struct scsi_device *sdev;
994 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
995 unsigned long flags;
996
997 spin_lock_irqsave(shost->host_lock, flags);
998 sdev = __scsi_device_lookup_by_target(starget, lun);
999 if (sdev && scsi_device_get(sdev))
1000 sdev = NULL;
1001 spin_unlock_irqrestore(shost->host_lock, flags);
1002
1003 return sdev;
1004}
1005EXPORT_SYMBOL(scsi_device_lookup_by_target);
1006
1007/**
Rob Landleyeb448202007-11-03 13:30:39 -05001008 * __scsi_device_lookup - find a device given the host (UNLOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009 * @shost: SCSI host pointer
1010 * @channel: SCSI channel (zero if only one channel)
Rob Landleyeb448202007-11-03 13:30:39 -05001011 * @id: SCSI target number (physical unit number)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 * @lun: SCSI Logical Unit Number
1013 *
Rob Landleyeb448202007-11-03 13:30:39 -05001014 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1015 * for a given host. The returned scsi_device does not have an additional
1016 * reference. You must hold the host's host_lock over this call and any access
1017 * to the returned scsi_device.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 *
1019 * Note: The only reason why drivers would want to use this is because
Rob Landleyeb448202007-11-03 13:30:39 -05001020 * they need to access the device list in irq context. Otherwise you
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 * really want to use scsi_device_lookup instead.
1022 **/
1023struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1024 uint channel, uint id, uint lun)
1025{
1026 struct scsi_device *sdev;
1027
1028 list_for_each_entry(sdev, &shost->__devices, siblings) {
1029 if (sdev->channel == channel && sdev->id == id &&
1030 sdev->lun ==lun)
1031 return sdev;
1032 }
1033
1034 return NULL;
1035}
1036EXPORT_SYMBOL(__scsi_device_lookup);
1037
1038/**
1039 * scsi_device_lookup - find a device given the host
1040 * @shost: SCSI host pointer
1041 * @channel: SCSI channel (zero if only one channel)
1042 * @id: SCSI target number (physical unit number)
1043 * @lun: SCSI Logical Unit Number
1044 *
Rob Landleyeb448202007-11-03 13:30:39 -05001045 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1046 * for a given host. The returned scsi_device has an additional reference that
1047 * needs to be released with scsi_device_put once you're done with it.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048 **/
1049struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1050 uint channel, uint id, uint lun)
1051{
1052 struct scsi_device *sdev;
1053 unsigned long flags;
1054
1055 spin_lock_irqsave(shost->host_lock, flags);
1056 sdev = __scsi_device_lookup(shost, channel, id, lun);
1057 if (sdev && scsi_device_get(sdev))
1058 sdev = NULL;
1059 spin_unlock_irqrestore(shost->host_lock, flags);
1060
1061 return sdev;
1062}
1063EXPORT_SYMBOL(scsi_device_lookup);
1064
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065MODULE_DESCRIPTION("SCSI core");
1066MODULE_LICENSE("GPL");
1067
1068module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1069MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1070
1071static int __init init_scsi(void)
1072{
Jens Axboe9bf09c232006-09-30 20:31:11 +02001073 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074
1075 error = scsi_init_queue();
1076 if (error)
1077 return error;
1078 error = scsi_init_procfs();
1079 if (error)
1080 goto cleanup_queue;
1081 error = scsi_init_devinfo();
1082 if (error)
1083 goto cleanup_procfs;
1084 error = scsi_init_hosts();
1085 if (error)
1086 goto cleanup_devlist;
1087 error = scsi_init_sysctl();
1088 if (error)
1089 goto cleanup_hosts;
1090 error = scsi_sysfs_register();
1091 if (error)
1092 goto cleanup_sysctl;
1093
James Smart84314fd2006-08-18 17:30:09 -04001094 scsi_netlink_init();
1095
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1097 return 0;
1098
1099cleanup_sysctl:
1100 scsi_exit_sysctl();
1101cleanup_hosts:
1102 scsi_exit_hosts();
1103cleanup_devlist:
1104 scsi_exit_devinfo();
1105cleanup_procfs:
1106 scsi_exit_procfs();
1107cleanup_queue:
1108 scsi_exit_queue();
1109 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1110 -error);
1111 return error;
1112}
1113
1114static void __exit exit_scsi(void)
1115{
James Smart84314fd2006-08-18 17:30:09 -04001116 scsi_netlink_exit();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117 scsi_sysfs_unregister();
1118 scsi_exit_sysctl();
1119 scsi_exit_hosts();
1120 scsi_exit_devinfo();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121 scsi_exit_procfs();
1122 scsi_exit_queue();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123}
1124
1125subsys_initcall(init_scsi);
1126module_exit(exit_scsi);