blob: 4c1e3133476509e882e5e4333c74f0705ccb8d23 [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>
62#include <scsi/scsi_eh.h>
63#include <scsi/scsi_host.h>
64#include <scsi/scsi_tcq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66#include "scsi_priv.h"
67#include "scsi_logging.h"
68
Adrian Bunk52c1da32005-06-23 22:05:33 -070069static void scsi_done(struct scsi_cmnd *cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
71/*
72 * Definitions and constants.
73 */
74
75#define MIN_RESET_DELAY (2*HZ)
76
77/* Do not call reset on error if we just did a reset within 15 sec. */
78#define MIN_RESET_PERIOD (15*HZ)
79
80/*
81 * Macro to determine the size of SCSI command. This macro takes vendor
82 * unique commands into account. SCSI commands in groups 6 and 7 are
83 * vendor unique and we will depend upon the command length being
84 * supplied correctly in cmd_len.
85 */
86#define CDB_SIZE(cmd) (((((cmd)->cmnd[0] >> 5) & 7) < 6) ? \
87 COMMAND_SIZE((cmd)->cmnd[0]) : (cmd)->cmd_len)
88
89/*
90 * Note - the initial logging level can be set here to log events at boot time.
91 * After the system is up, you may enable logging via the /proc interface.
92 */
93unsigned int scsi_logging_level;
94#if defined(CONFIG_SCSI_LOGGING)
95EXPORT_SYMBOL(scsi_logging_level);
96#endif
97
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -060098/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
99 * You may not alter any existing entry (although adding new ones is
100 * encouraged once assigned by ANSI/INCITS T10
101 */
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600102static const char *const scsi_device_types[] = {
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600103 "Direct-Access ",
104 "Sequential-Access",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 "Printer ",
106 "Processor ",
107 "WORM ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600108 "CD-ROM ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 "Scanner ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600110 "Optical Device ",
111 "Medium Changer ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 "Communications ",
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600113 "ASC IT8 ",
114 "ASC IT8 ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 "RAID ",
116 "Enclosure ",
Matthew Wilcox8a1cdc92006-09-24 20:22:52 -0600117 "Direct-Access-RBC",
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600118 "Optical card ",
119 "Bridge controller",
120 "Object storage ",
121 "Automation/Drive ",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122};
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600123
124const char * scsi_device_type(unsigned type)
125{
126 if (type == 0x1e)
127 return "Well-known LUN ";
128 if (type == 0x1f)
129 return "No Device ";
Eric Sesterhenn80c6e3c2006-09-26 13:22:13 +0200130 if (type >= ARRAY_SIZE(scsi_device_types))
Matthew Wilcox4ff36712006-07-04 12:15:20 -0600131 return "Unknown ";
132 return scsi_device_types[type];
133}
134
135EXPORT_SYMBOL(scsi_device_type);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137struct scsi_host_cmd_pool {
Christoph Lametere18b8902006-12-06 20:33:20 -0800138 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 unsigned int users;
140 char *name;
141 unsigned int slab_flags;
Al Viroc53033f2005-10-21 03:22:08 -0400142 gfp_t gfp_mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143};
144
145static struct scsi_host_cmd_pool scsi_cmd_pool = {
146 .name = "scsi_cmd_cache",
147 .slab_flags = SLAB_HWCACHE_ALIGN,
148};
149
150static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
151 .name = "scsi_cmd_cache(DMA)",
152 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
153 .gfp_mask = __GFP_DMA,
154};
155
Arjan van de Ven0b950672006-01-11 13:16:10 +0100156static DEFINE_MUTEX(host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900158struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159{
160 struct scsi_cmnd *cmd;
161
162 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
163 gfp_mask | shost->cmd_pool->gfp_mask);
164
165 if (unlikely(!cmd)) {
166 unsigned long flags;
167
168 spin_lock_irqsave(&shost->free_list_lock, flags);
169 if (likely(!list_empty(&shost->free_list))) {
170 cmd = list_entry(shost->free_list.next,
171 struct scsi_cmnd, list);
172 list_del_init(&cmd->list);
173 }
174 spin_unlock_irqrestore(&shost->free_list_lock, flags);
175 }
176
177 return cmd;
178}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900179EXPORT_SYMBOL_GPL(__scsi_get_command);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180
181/*
182 * Function: scsi_get_command()
183 *
184 * Purpose: Allocate and setup a scsi command block
185 *
186 * Arguments: dev - parent scsi device
187 * gfp_mask- allocator flags
188 *
189 * Returns: The allocated scsi command structure.
190 */
Al Viroc53033f2005-10-21 03:22:08 -0400191struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192{
193 struct scsi_cmnd *cmd;
194
195 /* Bail if we can't get a reference to the device */
196 if (!get_device(&dev->sdev_gendev))
197 return NULL;
198
199 cmd = __scsi_get_command(dev->host, gfp_mask);
200
201 if (likely(cmd != NULL)) {
202 unsigned long flags;
203
204 memset(cmd, 0, sizeof(*cmd));
205 cmd->device = dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 init_timer(&cmd->eh_timeout);
207 INIT_LIST_HEAD(&cmd->list);
208 spin_lock_irqsave(&dev->list_lock, flags);
209 list_add_tail(&cmd->list, &dev->cmd_list);
210 spin_unlock_irqrestore(&dev->list_lock, flags);
Matthew Dobson79e448b2005-11-21 21:32:29 -0800211 cmd->jiffies_at_alloc = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 } else
213 put_device(&dev->sdev_gendev);
214
215 return cmd;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900216}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217EXPORT_SYMBOL(scsi_get_command);
218
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900219void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
220 struct device *dev)
221{
222 unsigned long flags;
223
224 /* changing locks here, don't need to restore the irq state */
225 spin_lock_irqsave(&shost->free_list_lock, flags);
226 if (unlikely(list_empty(&shost->free_list))) {
227 list_add(&cmd->list, &shost->free_list);
228 cmd = NULL;
229 }
230 spin_unlock_irqrestore(&shost->free_list_lock, flags);
231
232 if (likely(cmd != NULL))
233 kmem_cache_free(shost->cmd_pool->slab, cmd);
234
235 put_device(dev);
236}
237EXPORT_SYMBOL(__scsi_put_command);
238
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239/*
240 * Function: scsi_put_command()
241 *
242 * Purpose: Free a scsi command block
243 *
244 * Arguments: cmd - command block to free
245 *
246 * Returns: Nothing.
247 *
248 * Notes: The command must not belong to any lists.
249 */
250void scsi_put_command(struct scsi_cmnd *cmd)
251{
252 struct scsi_device *sdev = cmd->device;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 unsigned long flags;
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900254
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 /* serious error if the command hasn't come from a device list */
256 spin_lock_irqsave(&cmd->device->list_lock, flags);
257 BUG_ON(list_empty(&cmd->list));
258 list_del_init(&cmd->list);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900259 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
FUJITA Tomonorib58d9152006-11-16 19:24:10 +0900261 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262}
263EXPORT_SYMBOL(scsi_put_command);
264
265/*
266 * Function: scsi_setup_command_freelist()
267 *
268 * Purpose: Setup the command freelist for a scsi host.
269 *
270 * Arguments: shost - host to allocate the freelist for.
271 *
272 * Returns: Nothing.
273 */
274int scsi_setup_command_freelist(struct Scsi_Host *shost)
275{
276 struct scsi_host_cmd_pool *pool;
277 struct scsi_cmnd *cmd;
278
279 spin_lock_init(&shost->free_list_lock);
280 INIT_LIST_HEAD(&shost->free_list);
281
282 /*
283 * Select a command slab for this host and create it if not
284 * yet existant.
285 */
Arjan van de Ven0b950672006-01-11 13:16:10 +0100286 mutex_lock(&host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 pool = (shost->unchecked_isa_dma ? &scsi_cmd_dma_pool : &scsi_cmd_pool);
288 if (!pool->users) {
289 pool->slab = kmem_cache_create(pool->name,
290 sizeof(struct scsi_cmnd), 0,
291 pool->slab_flags, NULL, NULL);
292 if (!pool->slab)
293 goto fail;
294 }
295
296 pool->users++;
297 shost->cmd_pool = pool;
Arjan van de Ven0b950672006-01-11 13:16:10 +0100298 mutex_unlock(&host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299
300 /*
301 * Get one backup command for this host.
302 */
303 cmd = kmem_cache_alloc(shost->cmd_pool->slab,
304 GFP_KERNEL | shost->cmd_pool->gfp_mask);
305 if (!cmd)
306 goto fail2;
307 list_add(&cmd->list, &shost->free_list);
308 return 0;
309
310 fail2:
311 if (!--pool->users)
312 kmem_cache_destroy(pool->slab);
313 return -ENOMEM;
314 fail:
Arjan van de Ven0b950672006-01-11 13:16:10 +0100315 mutex_unlock(&host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 return -ENOMEM;
317
318}
319
320/*
321 * Function: scsi_destroy_command_freelist()
322 *
323 * Purpose: Release the command freelist for a scsi host.
324 *
325 * Arguments: shost - host that's freelist is going to be destroyed
326 */
327void scsi_destroy_command_freelist(struct Scsi_Host *shost)
328{
329 while (!list_empty(&shost->free_list)) {
330 struct scsi_cmnd *cmd;
331
332 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
333 list_del_init(&cmd->list);
334 kmem_cache_free(shost->cmd_pool->slab, cmd);
335 }
336
Arjan van de Ven0b950672006-01-11 13:16:10 +0100337 mutex_lock(&host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 if (!--shost->cmd_pool->users)
339 kmem_cache_destroy(shost->cmd_pool->slab);
Arjan van de Ven0b950672006-01-11 13:16:10 +0100340 mutex_unlock(&host_cmd_pool_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341}
342
343#ifdef CONFIG_SCSI_LOGGING
344void scsi_log_send(struct scsi_cmnd *cmd)
345{
346 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347
348 /*
349 * If ML QUEUE log level is greater than or equal to:
350 *
351 * 1: nothing (match completion)
352 *
353 * 2: log opcode + command of all commands
354 *
355 * 3: same as 2 plus dump cmd address
356 *
357 * 4: same as 3 plus dump extra junk
358 */
359 if (unlikely(scsi_logging_level)) {
360 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
361 SCSI_LOG_MLQUEUE_BITS);
362 if (level > 1) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500363 scmd_printk(KERN_INFO, cmd, "Send: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 if (level > 2)
365 printk("0x%p ", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500366 printk("\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 scsi_print_command(cmd);
368 if (level > 3) {
369 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
370 " done = 0x%p, queuecommand 0x%p\n",
Christoph Hellwig631c2282006-07-08 20:42:15 +0200371 cmd->request_buffer, cmd->request_bufflen,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 cmd->done,
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500373 cmd->device->host->hostt->queuecommand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374
375 }
376 }
377 }
378}
379
380void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
381{
382 unsigned int level;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383
384 /*
385 * If ML COMPLETE log level is greater than or equal to:
386 *
387 * 1: log disposition, result, opcode + command, and conditionally
388 * sense data for failures or non SUCCESS dispositions.
389 *
390 * 2: same as 1 but for all command completions.
391 *
392 * 3: same as 2 plus dump cmd address
393 *
394 * 4: same as 3 plus dump extra junk
395 */
396 if (unlikely(scsi_logging_level)) {
397 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
398 SCSI_LOG_MLCOMPLETE_BITS);
399 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
400 (level > 1)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500401 scmd_printk(KERN_INFO, cmd, "Done: ");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 if (level > 2)
403 printk("0x%p ", cmd);
404 /*
405 * Dump truncated values, so we usually fit within
406 * 80 chars.
407 */
408 switch (disposition) {
409 case SUCCESS:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500410 printk("SUCCESS\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 break;
412 case NEEDS_RETRY:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500413 printk("RETRY\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 break;
415 case ADD_TO_MLQUEUE:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500416 printk("MLQUEUE\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 break;
418 case FAILED:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500419 printk("FAILED\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 break;
421 case TIMEOUT_ERROR:
422 /*
423 * If called via scsi_times_out.
424 */
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500425 printk("TIMEOUT\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 break;
427 default:
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500428 printk("UNKNOWN\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 }
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500430 scsi_print_result(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 scsi_print_command(cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500432 if (status_byte(cmd->result) & CHECK_CONDITION)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 scsi_print_sense("", cmd);
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500434 if (level > 3)
435 scmd_printk(KERN_INFO, cmd,
436 "scsi host busy %d failed %d\n",
437 cmd->device->host->host_busy,
438 cmd->device->host->host_failed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 }
440 }
441}
442#endif
443
444/*
445 * Assign a serial number and pid to the request for error recovery
446 * and debugging purposes. Protected by the Host_Lock of host.
447 */
448static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
449{
450 cmd->serial_number = host->cmd_serial_number++;
451 if (cmd->serial_number == 0)
452 cmd->serial_number = host->cmd_serial_number++;
453
454 cmd->pid = host->cmd_pid++;
455 if (cmd->pid == 0)
456 cmd->pid = host->cmd_pid++;
457}
458
459/*
460 * Function: scsi_dispatch_command
461 *
462 * Purpose: Dispatch a command to the low-level driver.
463 *
464 * Arguments: cmd - command block we are dispatching.
465 *
466 * Notes:
467 */
468int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
469{
470 struct Scsi_Host *host = cmd->device->host;
471 unsigned long flags = 0;
472 unsigned long timeout;
473 int rtn = 0;
474
475 /* check if the device is still usable */
476 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
477 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
478 * returns an immediate error upwards, and signals
479 * that the device is no longer present */
480 cmd->result = DID_NO_CONNECT << 16;
481 atomic_inc(&cmd->device->iorequest_cnt);
Mike Christie69b52892005-05-01 14:47:15 -0500482 __scsi_done(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 /* return 0 (because the command has been processed) */
484 goto out;
485 }
486
487 /* Check to see if the scsi lld put this device into state SDEV_BLOCK. */
488 if (unlikely(cmd->device->sdev_state == SDEV_BLOCK)) {
489 /*
490 * in SDEV_BLOCK, the command is just put back on the device
491 * queue. The suspend state has already blocked the queue so
492 * future requests should not occur until the device
493 * transitions out of the suspend state.
494 */
495 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
496
497 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
498
499 /*
500 * NOTE: rtn is still zero here because we don't need the
501 * queue to be plugged on return (it's already stopped)
502 */
503 goto out;
504 }
505
506 /*
507 * If SCSI-2 or lower, store the LUN value in cmnd.
508 */
James Bottomley4d7db042006-03-31 20:07:45 -0600509 if (cmd->device->scsi_level <= SCSI_2 &&
510 cmd->device->scsi_level != SCSI_UNKNOWN) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
512 (cmd->device->lun << 5 & 0xe0);
513 }
514
515 /*
516 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
517 * we can avoid the drive not being ready.
518 */
519 timeout = host->last_reset + MIN_RESET_DELAY;
520
521 if (host->resetting && time_before(jiffies, timeout)) {
522 int ticks_remaining = timeout - jiffies;
523 /*
524 * NOTE: This may be executed from within an interrupt
525 * handler! This is bad, but for now, it'll do. The irq
526 * level of the interrupt handler has been masked out by the
527 * platform dependent interrupt handling code already, so the
528 * sti() here will not cause another call to the SCSI host's
529 * interrupt handler (assuming there is one irq-level per
530 * host).
531 */
532 while (--ticks_remaining >= 0)
533 mdelay(1 + 999 / HZ);
534 host->resetting = 0;
535 }
536
537 /*
538 * AK: unlikely race here: for some reason the timer could
539 * expire before the serial number is set up below.
540 */
541 scsi_add_timer(cmd, cmd->timeout_per_command, scsi_times_out);
542
543 scsi_log_send(cmd);
544
545 /*
546 * We will use a queued command if possible, otherwise we will
547 * emulate the queuing and calling of completion function ourselves.
548 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 atomic_inc(&cmd->device->iorequest_cnt);
550
551 /*
552 * Before we queue this command, check if the command
553 * length exceeds what the host adapter can handle.
554 */
555 if (CDB_SIZE(cmd) > cmd->device->host->max_cmd_len) {
556 SCSI_LOG_MLQUEUE(3,
557 printk("queuecommand : command too long.\n"));
558 cmd->result = (DID_ABORT << 16);
559
560 scsi_done(cmd);
561 goto out;
562 }
563
564 spin_lock_irqsave(host->host_lock, flags);
565 scsi_cmd_get_serial(host, cmd);
566
Mike Andersond2c9d9e2005-06-16 11:13:42 -0700567 if (unlikely(host->shost_state == SHOST_DEL)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 cmd->result = (DID_NO_CONNECT << 16);
569 scsi_done(cmd);
570 } else {
571 rtn = host->hostt->queuecommand(cmd, scsi_done);
572 }
573 spin_unlock_irqrestore(host->host_lock, flags);
574 if (rtn) {
Tejun Heo d8c37e72005-05-14 00:46:08 +0900575 if (scsi_delete_timer(cmd)) {
576 atomic_inc(&cmd->device->iodone_cnt);
577 scsi_queue_insert(cmd,
578 (rtn == SCSI_MLQUEUE_DEVICE_BUSY) ?
579 rtn : SCSI_MLQUEUE_HOST_BUSY);
580 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 SCSI_LOG_MLQUEUE(3,
582 printk("queuecommand : request rejected\n"));
583 }
584
585 out:
586 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
587 return rtn;
588}
589
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590/**
Luben Tuikov89f48c42006-05-15 20:57:18 +0900591 * scsi_req_abort_cmd -- Request command recovery for the specified command
592 * cmd: pointer to the SCSI command of interest
593 *
594 * This function requests that SCSI Core start recovery for the
595 * command by deleting the timer and adding the command to the eh
596 * queue. It can be called by either LLDDs or SCSI Core. LLDDs who
597 * implement their own error recovery MAY ignore the timeout event if
598 * they generated scsi_req_abort_cmd.
599 */
600void scsi_req_abort_cmd(struct scsi_cmnd *cmd)
601{
602 if (!scsi_delete_timer(cmd))
603 return;
604 scsi_times_out(cmd);
605}
606EXPORT_SYMBOL(scsi_req_abort_cmd);
607
608/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 * scsi_done - Enqueue the finished SCSI command into the done queue.
610 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
611 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
612 *
613 * This function is the mid-level's (SCSI Core) interrupt routine, which
614 * regains ownership of the SCSI command (de facto) from a LLDD, and enqueues
615 * the command to the done queue for further processing.
616 *
617 * This is the producer of the done queue who enqueues at the tail.
618 *
619 * This function is interrupt context safe.
620 */
Adrian Bunk52c1da32005-06-23 22:05:33 -0700621static void scsi_done(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622{
623 /*
624 * We don't have to worry about this one timing out any more.
625 * If we are unable to remove the timer, then the command
626 * has already timed out. In which case, we have no choice but to
627 * let the timeout function run, as we have no idea where in fact
628 * that function could really be. It might be on another processor,
629 * etc, etc.
630 */
631 if (!scsi_delete_timer(cmd))
632 return;
633 __scsi_done(cmd);
634}
635
636/* Private entry to scsi_done() to complete a command when the timer
637 * isn't running --- used by scsi_times_out */
638void __scsi_done(struct scsi_cmnd *cmd)
639{
Jens Axboe1aea6432006-01-09 16:03:03 +0100640 struct request *rq = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641
642 /*
643 * Set the serial numbers back to zero
644 */
645 cmd->serial_number = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646
647 atomic_inc(&cmd->device->iodone_cnt);
648 if (cmd->result)
649 atomic_inc(&cmd->device->ioerr_cnt);
650
Jens Axboe1aea6432006-01-09 16:03:03 +0100651 BUG_ON(!rq);
652
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653 /*
Jens Axboe1aea6432006-01-09 16:03:03 +0100654 * The uptodate/nbytes values don't matter, as we allow partial
655 * completes and thus will check this in the softirq callback
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 */
Jens Axboe1aea6432006-01-09 16:03:03 +0100657 rq->completion_data = cmd;
658 blk_complete_request(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659}
660
661/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 * Function: scsi_finish_command
663 *
664 * Purpose: Pass command off to upper layer for finishing of I/O
665 * request, waking processes that are waiting on results,
666 * etc.
667 */
668void scsi_finish_command(struct scsi_cmnd *cmd)
669{
670 struct scsi_device *sdev = cmd->device;
671 struct Scsi_Host *shost = sdev->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672
673 scsi_device_unbusy(sdev);
674
675 /*
676 * Clear the flags which say that the device/host is no longer
677 * capable of accepting new commands. These are set in scsi_queue.c
678 * for both the queue full condition on a device, and for a
679 * host full condition on the host.
680 *
681 * XXX(hch): What about locking?
682 */
683 shost->host_blocked = 0;
684 sdev->device_blocked = 0;
685
686 /*
687 * If we have valid sense information, then some kind of recovery
688 * must have taken place. Make a note of this.
689 */
690 if (SCSI_SENSE_VALID(cmd))
691 cmd->result |= (DRIVER_SENSE << 24);
692
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400693 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
694 "Notifying upper driver of completion "
695 "(result %x)\n", cmd->result));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 cmd->done(cmd);
698}
699EXPORT_SYMBOL(scsi_finish_command);
700
701/*
702 * Function: scsi_adjust_queue_depth()
703 *
704 * Purpose: Allow low level drivers to tell us to change the queue depth
705 * on a specific SCSI device
706 *
707 * Arguments: sdev - SCSI Device in question
708 * tagged - Do we use tagged queueing (non-0) or do we treat
709 * this device as an untagged device (0)
710 * tags - Number of tags allowed if tagged queueing enabled,
711 * or number of commands the low level driver can
712 * queue up in non-tagged mode (as per cmd_per_lun).
713 *
714 * Returns: Nothing
715 *
716 * Lock Status: None held on entry
717 *
718 * Notes: Low level drivers may call this at any time and we will do
719 * the right thing depending on whether or not the device is
720 * currently active and whether or not it even has the
721 * command blocks built yet.
722 */
723void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
724{
725 unsigned long flags;
726
727 /*
728 * refuse to set tagged depth to an unworkable size
729 */
730 if (tags <= 0)
731 return;
732
733 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
734
735 /* Check to see if the queue is managed by the block layer
736 * if it is, and we fail to adjust the depth, exit */
737 if (blk_queue_tagged(sdev->request_queue) &&
738 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
739 goto out;
740
741 sdev->queue_depth = tags;
742 switch (tagged) {
743 case MSG_ORDERED_TAG:
744 sdev->ordered_tags = 1;
745 sdev->simple_tags = 1;
746 break;
747 case MSG_SIMPLE_TAG:
748 sdev->ordered_tags = 0;
749 sdev->simple_tags = 1;
750 break;
751 default:
James Bottomley9ccfc752005-10-02 11:45:08 -0500752 sdev_printk(KERN_WARNING, sdev,
753 "scsi_adjust_queue_depth, bad queue type, "
754 "disabled\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755 case 0:
756 sdev->ordered_tags = sdev->simple_tags = 0;
757 sdev->queue_depth = tags;
758 break;
759 }
760 out:
761 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
762}
763EXPORT_SYMBOL(scsi_adjust_queue_depth);
764
765/*
766 * Function: scsi_track_queue_full()
767 *
768 * Purpose: This function will track successive QUEUE_FULL events on a
769 * specific SCSI device to determine if and when there is a
770 * need to adjust the queue depth on the device.
771 *
772 * Arguments: sdev - SCSI Device in question
773 * depth - Current number of outstanding SCSI commands on
774 * this device, not counting the one returned as
775 * QUEUE_FULL.
776 *
777 * Returns: 0 - No change needed
778 * >0 - Adjust queue depth to this new depth
779 * -1 - Drop back to untagged operation using host->cmd_per_lun
780 * as the untagged command depth
781 *
782 * Lock Status: None held on entry
783 *
784 * Notes: Low level drivers may call this at any time and we will do
785 * "The Right Thing." We are interrupt context safe.
786 */
787int scsi_track_queue_full(struct scsi_device *sdev, int depth)
788{
789 if ((jiffies >> 4) == sdev->last_queue_full_time)
790 return 0;
791
792 sdev->last_queue_full_time = (jiffies >> 4);
793 if (sdev->last_queue_full_depth != depth) {
794 sdev->last_queue_full_count = 1;
795 sdev->last_queue_full_depth = depth;
796 } else {
797 sdev->last_queue_full_count++;
798 }
799
800 if (sdev->last_queue_full_count <= 10)
801 return 0;
802 if (sdev->last_queue_full_depth < 8) {
803 /* Drop back to untagged */
804 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
805 return -1;
806 }
807
808 if (sdev->ordered_tags)
809 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
810 else
811 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
812 return depth;
813}
814EXPORT_SYMBOL(scsi_track_queue_full);
815
816/**
817 * scsi_device_get - get an addition reference to a scsi_device
818 * @sdev: device to get a reference to
819 *
820 * Gets a reference to the scsi_device and increments the use count
821 * of the underlying LLDD module. You must hold host_lock of the
822 * parent Scsi_Host or already have a reference when calling this.
823 */
824int scsi_device_get(struct scsi_device *sdev)
825{
James Bottomley85b6c722006-08-31 18:15:22 -0400826 if (sdev->sdev_state == SDEV_DEL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 return -ENXIO;
828 if (!get_device(&sdev->sdev_gendev))
829 return -ENXIO;
James Bottomley85b6c722006-08-31 18:15:22 -0400830 /* We can fail this if we're doing SCSI operations
831 * from module exit (like cache flush) */
832 try_module_get(sdev->host->hostt->module);
833
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 return 0;
835}
836EXPORT_SYMBOL(scsi_device_get);
837
838/**
839 * scsi_device_put - release a reference to a scsi_device
840 * @sdev: device to release a reference on.
841 *
842 * Release a reference to the scsi_device and decrements the use count
843 * of the underlying LLDD module. The device is freed once the last
844 * user vanishes.
845 */
846void scsi_device_put(struct scsi_device *sdev)
847{
Ingo Molnar504fb372006-11-09 10:09:35 +0100848#ifdef CONFIG_MODULE_UNLOAD
James Bottomleyf479ab82006-09-06 09:00:29 -0500849 struct module *module = sdev->host->hostt->module;
850
James Bottomley85b6c722006-08-31 18:15:22 -0400851 /* The module refcount will be zero if scsi_device_get()
852 * was called from a module removal routine */
James Bottomleyf479ab82006-09-06 09:00:29 -0500853 if (module && module_refcount(module) != 0)
854 module_put(module);
Daniel Walkera506b442006-09-09 09:31:03 -0700855#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 put_device(&sdev->sdev_gendev);
857}
858EXPORT_SYMBOL(scsi_device_put);
859
860/* helper for shost_for_each_device, thus not documented */
861struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
862 struct scsi_device *prev)
863{
864 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
865 struct scsi_device *next = NULL;
866 unsigned long flags;
867
868 spin_lock_irqsave(shost->host_lock, flags);
869 while (list->next != &shost->__devices) {
870 next = list_entry(list->next, struct scsi_device, siblings);
871 /* skip devices that we can't get a reference to */
872 if (!scsi_device_get(next))
873 break;
874 next = NULL;
875 list = list->next;
876 }
877 spin_unlock_irqrestore(shost->host_lock, flags);
878
879 if (prev)
880 scsi_device_put(prev);
881 return next;
882}
883EXPORT_SYMBOL(__scsi_iterate_devices);
884
885/**
886 * starget_for_each_device - helper to walk all devices of a target
887 * @starget: target whose devices we want to iterate over.
888 *
889 * This traverses over each devices of @shost. The devices have
890 * a reference that must be released by scsi_host_put when breaking
891 * out of the loop.
892 */
893void starget_for_each_device(struct scsi_target *starget, void * data,
894 void (*fn)(struct scsi_device *, void *))
895{
896 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
897 struct scsi_device *sdev;
898
899 shost_for_each_device(sdev, shost) {
900 if ((sdev->channel == starget->channel) &&
901 (sdev->id == starget->id))
902 fn(sdev, data);
903 }
904}
905EXPORT_SYMBOL(starget_for_each_device);
906
907/**
908 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
909 * @starget: SCSI target pointer
910 * @lun: SCSI Logical Unit Number
911 *
912 * Looks up the scsi_device with the specified @lun for a give
913 * @starget. The returned scsi_device does not have an additional
914 * reference. You must hold the host's host_lock over this call and
915 * any access to the returned scsi_device.
916 *
917 * Note: The only reason why drivers would want to use this is because
918 * they're need to access the device list in irq context. Otherwise you
919 * really want to use scsi_device_lookup_by_target instead.
920 **/
921struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
922 uint lun)
923{
924 struct scsi_device *sdev;
925
926 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
927 if (sdev->lun ==lun)
928 return sdev;
929 }
930
931 return NULL;
932}
933EXPORT_SYMBOL(__scsi_device_lookup_by_target);
934
935/**
936 * scsi_device_lookup_by_target - find a device given the target
937 * @starget: SCSI target pointer
938 * @lun: SCSI Logical Unit Number
939 *
940 * Looks up the scsi_device with the specified @channel, @id, @lun for a
941 * give host. The returned scsi_device has an additional reference that
942 * needs to be release with scsi_host_put once you're done with it.
943 **/
944struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
945 uint lun)
946{
947 struct scsi_device *sdev;
948 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
949 unsigned long flags;
950
951 spin_lock_irqsave(shost->host_lock, flags);
952 sdev = __scsi_device_lookup_by_target(starget, lun);
953 if (sdev && scsi_device_get(sdev))
954 sdev = NULL;
955 spin_unlock_irqrestore(shost->host_lock, flags);
956
957 return sdev;
958}
959EXPORT_SYMBOL(scsi_device_lookup_by_target);
960
961/**
962 * scsi_device_lookup - find a device given the host (UNLOCKED)
963 * @shost: SCSI host pointer
964 * @channel: SCSI channel (zero if only one channel)
965 * @pun: SCSI target number (physical unit number)
966 * @lun: SCSI Logical Unit Number
967 *
968 * Looks up the scsi_device with the specified @channel, @id, @lun for a
969 * give host. The returned scsi_device does not have an additional reference.
970 * You must hold the host's host_lock over this call and any access to the
971 * returned scsi_device.
972 *
973 * Note: The only reason why drivers would want to use this is because
974 * they're need to access the device list in irq context. Otherwise you
975 * really want to use scsi_device_lookup instead.
976 **/
977struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
978 uint channel, uint id, uint lun)
979{
980 struct scsi_device *sdev;
981
982 list_for_each_entry(sdev, &shost->__devices, siblings) {
983 if (sdev->channel == channel && sdev->id == id &&
984 sdev->lun ==lun)
985 return sdev;
986 }
987
988 return NULL;
989}
990EXPORT_SYMBOL(__scsi_device_lookup);
991
992/**
993 * scsi_device_lookup - find a device given the host
994 * @shost: SCSI host pointer
995 * @channel: SCSI channel (zero if only one channel)
996 * @id: SCSI target number (physical unit number)
997 * @lun: SCSI Logical Unit Number
998 *
999 * Looks up the scsi_device with the specified @channel, @id, @lun for a
1000 * give host. The returned scsi_device has an additional reference that
1001 * needs to be release with scsi_host_put once you're done with it.
1002 **/
1003struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1004 uint channel, uint id, uint lun)
1005{
1006 struct scsi_device *sdev;
1007 unsigned long flags;
1008
1009 spin_lock_irqsave(shost->host_lock, flags);
1010 sdev = __scsi_device_lookup(shost, channel, id, lun);
1011 if (sdev && scsi_device_get(sdev))
1012 sdev = NULL;
1013 spin_unlock_irqrestore(shost->host_lock, flags);
1014
1015 return sdev;
1016}
1017EXPORT_SYMBOL(scsi_device_lookup);
1018
1019/**
1020 * scsi_device_cancel - cancel outstanding IO to this device
1021 * @sdev: Pointer to struct scsi_device
1022 * @recovery: Boolean instructing function to recover device or not.
1023 *
1024 **/
1025int scsi_device_cancel(struct scsi_device *sdev, int recovery)
1026{
1027 struct scsi_cmnd *scmd;
1028 LIST_HEAD(active_list);
1029 struct list_head *lh, *lh_sf;
1030 unsigned long flags;
1031
1032 scsi_device_set_state(sdev, SDEV_CANCEL);
1033
1034 spin_lock_irqsave(&sdev->list_lock, flags);
1035 list_for_each_entry(scmd, &sdev->cmd_list, list) {
Jens Axboecdd60262006-07-28 09:32:07 +02001036 if (scmd->request) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037 /*
1038 * If we are unable to remove the timer, it means
1039 * that the command has already timed out or
1040 * finished.
1041 */
1042 if (!scsi_delete_timer(scmd))
1043 continue;
1044 list_add_tail(&scmd->eh_entry, &active_list);
1045 }
1046 }
1047 spin_unlock_irqrestore(&sdev->list_lock, flags);
1048
1049 if (!list_empty(&active_list)) {
1050 list_for_each_safe(lh, lh_sf, &active_list) {
1051 scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
1052 list_del_init(lh);
James Bottomley939647e2005-09-18 15:05:20 -05001053 if (recovery &&
1054 !scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055 scmd->result = (DID_ABORT << 16);
1056 scsi_finish_command(scmd);
1057 }
1058 }
1059 }
1060
1061 return 0;
1062}
1063EXPORT_SYMBOL(scsi_device_cancel);
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 Axboe9bf09c22006-09-30 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);