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1/*
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>
43#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>
50#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>
56#include <linux/mutex.h>
57
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_driver.h>
63#include <scsi/scsi_eh.h>
64#include <scsi/scsi_host.h>
65#include <scsi/scsi_tcq.h>
66
67#include "scsi_priv.h"
68#include "scsi_logging.h"
69
70#define CREATE_TRACE_POINTS
71#include <trace/events/scsi.h>
72
73static void scsi_done(struct scsi_cmnd *cmd);
74
75/*
76 * Definitions and constants.
77 */
78
79#define MIN_RESET_DELAY (2*HZ)
80
81/* Do not call reset on error if we just did a reset within 15 sec. */
82#define MIN_RESET_PERIOD (15*HZ)
83
84/*
85 * Note - the initial logging level can be set here to log events at boot time.
86 * After the system is up, you may enable logging via the /proc interface.
87 */
88unsigned int scsi_logging_level;
89#if defined(CONFIG_SCSI_LOGGING)
90EXPORT_SYMBOL(scsi_logging_level);
91#endif
92
93/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
94 * You may not alter any existing entry (although adding new ones is
95 * encouraged once assigned by ANSI/INCITS T10
96 */
97static const char *const scsi_device_types[] = {
98 "Direct-Access ",
99 "Sequential-Access",
100 "Printer ",
101 "Processor ",
102 "WORM ",
103 "CD-ROM ",
104 "Scanner ",
105 "Optical Device ",
106 "Medium Changer ",
107 "Communications ",
108 "ASC IT8 ",
109 "ASC IT8 ",
110 "RAID ",
111 "Enclosure ",
112 "Direct-Access-RBC",
113 "Optical card ",
114 "Bridge controller",
115 "Object storage ",
116 "Automation/Drive ",
117};
118
119/**
120 * scsi_device_type - Return 17 char string indicating device type.
121 * @type: type number to look up
122 */
123
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 ";
130 if (type >= ARRAY_SIZE(scsi_device_types))
131 return "Unknown ";
132 return scsi_device_types[type];
133}
134
135EXPORT_SYMBOL(scsi_device_type);
136
137struct scsi_host_cmd_pool {
138 struct kmem_cache *cmd_slab;
139 struct kmem_cache *sense_slab;
140 unsigned int users;
141 char *cmd_name;
142 char *sense_name;
143 unsigned int slab_flags;
144 gfp_t gfp_mask;
145};
146
147static struct scsi_host_cmd_pool scsi_cmd_pool = {
148 .cmd_name = "scsi_cmd_cache",
149 .sense_name = "scsi_sense_cache",
150 .slab_flags = SLAB_HWCACHE_ALIGN,
151};
152
153static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
154 .cmd_name = "scsi_cmd_cache(DMA)",
155 .sense_name = "scsi_sense_cache(DMA)",
156 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
157 .gfp_mask = __GFP_DMA,
158};
159
160static DEFINE_MUTEX(host_cmd_pool_mutex);
161
162/**
163 * scsi_pool_alloc_command - internal function to get a fully allocated command
164 * @pool: slab pool to allocate the command from
165 * @gfp_mask: mask for the allocation
166 *
167 * Returns a fully allocated command (with the allied sense buffer) or
168 * NULL on failure
169 */
170static struct scsi_cmnd *
171scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
172{
173 struct scsi_cmnd *cmd;
174
175 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
176 if (!cmd)
177 return NULL;
178
179 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
180 gfp_mask | pool->gfp_mask);
181 if (!cmd->sense_buffer) {
182 kmem_cache_free(pool->cmd_slab, cmd);
183 return NULL;
184 }
185
186 return cmd;
187}
188
189/**
190 * scsi_pool_free_command - internal function to release a command
191 * @pool: slab pool to allocate the command from
192 * @cmd: command to release
193 *
194 * the command must previously have been allocated by
195 * scsi_pool_alloc_command.
196 */
197static void
198scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
199 struct scsi_cmnd *cmd)
200{
201 if (cmd->prot_sdb)
202 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
203
204 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
205 kmem_cache_free(pool->cmd_slab, cmd);
206}
207
208/**
209 * scsi_host_alloc_command - internal function to allocate command
210 * @shost: SCSI host whose pool to allocate from
211 * @gfp_mask: mask for the allocation
212 *
213 * Returns a fully allocated command with sense buffer and protection
214 * data buffer (where applicable) or NULL on failure
215 */
216static struct scsi_cmnd *
217scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
218{
219 struct scsi_cmnd *cmd;
220
221 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
222 if (!cmd)
223 return NULL;
224
225 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
226 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
227
228 if (!cmd->prot_sdb) {
229 scsi_pool_free_command(shost->cmd_pool, cmd);
230 return NULL;
231 }
232 }
233
234 return cmd;
235}
236
237/**
238 * __scsi_get_command - Allocate a struct scsi_cmnd
239 * @shost: host to transmit command
240 * @gfp_mask: allocation mask
241 *
242 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
243 * host's free_list if necessary.
244 */
245struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
246{
247 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
248
249 if (unlikely(!cmd)) {
250 unsigned long flags;
251
252 spin_lock_irqsave(&shost->free_list_lock, flags);
253 if (likely(!list_empty(&shost->free_list))) {
254 cmd = list_entry(shost->free_list.next,
255 struct scsi_cmnd, list);
256 list_del_init(&cmd->list);
257 }
258 spin_unlock_irqrestore(&shost->free_list_lock, flags);
259
260 if (cmd) {
261 void *buf, *prot;
262
263 buf = cmd->sense_buffer;
264 prot = cmd->prot_sdb;
265
266 memset(cmd, 0, sizeof(*cmd));
267
268 cmd->sense_buffer = buf;
269 cmd->prot_sdb = prot;
270 }
271 }
272
273 return cmd;
274}
275EXPORT_SYMBOL_GPL(__scsi_get_command);
276
277/**
278 * scsi_get_command - Allocate and setup a scsi command block
279 * @dev: parent scsi device
280 * @gfp_mask: allocator flags
281 *
282 * Returns: The allocated scsi command structure.
283 */
284struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
285{
286 struct scsi_cmnd *cmd;
287
288 /* Bail if we can't get a reference to the device */
289 if (!get_device(&dev->sdev_gendev))
290 return NULL;
291
292 cmd = __scsi_get_command(dev->host, gfp_mask);
293
294 if (likely(cmd != NULL)) {
295 unsigned long flags;
296
297 cmd->device = dev;
298 INIT_LIST_HEAD(&cmd->list);
299 spin_lock_irqsave(&dev->list_lock, flags);
300 list_add_tail(&cmd->list, &dev->cmd_list);
301 spin_unlock_irqrestore(&dev->list_lock, flags);
302 cmd->jiffies_at_alloc = jiffies;
303 } else
304 put_device(&dev->sdev_gendev);
305
306 return cmd;
307}
308EXPORT_SYMBOL(scsi_get_command);
309
310/**
311 * __scsi_put_command - Free a struct scsi_cmnd
312 * @shost: dev->host
313 * @cmd: Command to free
314 * @dev: parent scsi device
315 */
316void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
317 struct device *dev)
318{
319 unsigned long flags;
320
321 /* changing locks here, don't need to restore the irq state */
322 spin_lock_irqsave(&shost->free_list_lock, flags);
323 if (unlikely(list_empty(&shost->free_list))) {
324 list_add(&cmd->list, &shost->free_list);
325 cmd = NULL;
326 }
327 spin_unlock_irqrestore(&shost->free_list_lock, flags);
328
329 if (likely(cmd != NULL))
330 scsi_pool_free_command(shost->cmd_pool, cmd);
331
332 put_device(dev);
333}
334EXPORT_SYMBOL(__scsi_put_command);
335
336/**
337 * scsi_put_command - Free a scsi command block
338 * @cmd: command block to free
339 *
340 * Returns: Nothing.
341 *
342 * Notes: The command must not belong to any lists.
343 */
344void scsi_put_command(struct scsi_cmnd *cmd)
345{
346 struct scsi_device *sdev = cmd->device;
347 unsigned long flags;
348
349 /* serious error if the command hasn't come from a device list */
350 spin_lock_irqsave(&cmd->device->list_lock, flags);
351 BUG_ON(list_empty(&cmd->list));
352 list_del_init(&cmd->list);
353 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
354
355 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
356}
357EXPORT_SYMBOL(scsi_put_command);
358
359static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
360{
361 struct scsi_host_cmd_pool *retval = NULL, *pool;
362 /*
363 * Select a command slab for this host and create it if not
364 * yet existent.
365 */
366 mutex_lock(&host_cmd_pool_mutex);
367 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
368 &scsi_cmd_pool;
369 if (!pool->users) {
370 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
371 sizeof(struct scsi_cmnd), 0,
372 pool->slab_flags, NULL);
373 if (!pool->cmd_slab)
374 goto fail;
375
376 pool->sense_slab = kmem_cache_create(pool->sense_name,
377 SCSI_SENSE_BUFFERSIZE, 0,
378 pool->slab_flags, NULL);
379 if (!pool->sense_slab) {
380 kmem_cache_destroy(pool->cmd_slab);
381 goto fail;
382 }
383 }
384
385 pool->users++;
386 retval = pool;
387 fail:
388 mutex_unlock(&host_cmd_pool_mutex);
389 return retval;
390}
391
392static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
393{
394 struct scsi_host_cmd_pool *pool;
395
396 mutex_lock(&host_cmd_pool_mutex);
397 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
398 &scsi_cmd_pool;
399 /*
400 * This may happen if a driver has a mismatched get and put
401 * of the command pool; the driver should be implicated in
402 * the stack trace
403 */
404 BUG_ON(pool->users == 0);
405
406 if (!--pool->users) {
407 kmem_cache_destroy(pool->cmd_slab);
408 kmem_cache_destroy(pool->sense_slab);
409 }
410 mutex_unlock(&host_cmd_pool_mutex);
411}
412
413/**
414 * scsi_allocate_command - get a fully allocated SCSI command
415 * @gfp_mask: allocation mask
416 *
417 * This function is for use outside of the normal host based pools.
418 * It allocates the relevant command and takes an additional reference
419 * on the pool it used. This function *must* be paired with
420 * scsi_free_command which also has the identical mask, otherwise the
421 * free pool counts will eventually go wrong and you'll trigger a bug.
422 *
423 * This function should *only* be used by drivers that need a static
424 * command allocation at start of day for internal functions.
425 */
426struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
427{
428 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
429
430 if (!pool)
431 return NULL;
432
433 return scsi_pool_alloc_command(pool, gfp_mask);
434}
435EXPORT_SYMBOL(scsi_allocate_command);
436
437/**
438 * scsi_free_command - free a command allocated by scsi_allocate_command
439 * @gfp_mask: mask used in the original allocation
440 * @cmd: command to free
441 *
442 * Note: using the original allocation mask is vital because that's
443 * what determines which command pool we use to free the command. Any
444 * mismatch will cause the system to BUG eventually.
445 */
446void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
447{
448 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
449
450 /*
451 * this could trigger if the mask to scsi_allocate_command
452 * doesn't match this mask. Otherwise we're guaranteed that this
453 * succeeds because scsi_allocate_command must have taken a reference
454 * on the pool
455 */
456 BUG_ON(!pool);
457
458 scsi_pool_free_command(pool, cmd);
459 /*
460 * scsi_put_host_cmd_pool is called twice; once to release the
461 * reference we took above, and once to release the reference
462 * originally taken by scsi_allocate_command
463 */
464 scsi_put_host_cmd_pool(gfp_mask);
465 scsi_put_host_cmd_pool(gfp_mask);
466}
467EXPORT_SYMBOL(scsi_free_command);
468
469/**
470 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
471 * @shost: host to allocate the freelist for.
472 *
473 * Description: The command freelist protects against system-wide out of memory
474 * deadlock by preallocating one SCSI command structure for each host, so the
475 * system can always write to a swap file on a device associated with that host.
476 *
477 * Returns: Nothing.
478 */
479int scsi_setup_command_freelist(struct Scsi_Host *shost)
480{
481 struct scsi_cmnd *cmd;
482 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
483
484 spin_lock_init(&shost->free_list_lock);
485 INIT_LIST_HEAD(&shost->free_list);
486
487 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
488
489 if (!shost->cmd_pool)
490 return -ENOMEM;
491
492 /*
493 * Get one backup command for this host.
494 */
495 cmd = scsi_host_alloc_command(shost, gfp_mask);
496 if (!cmd) {
497 scsi_put_host_cmd_pool(gfp_mask);
498 shost->cmd_pool = NULL;
499 return -ENOMEM;
500 }
501 list_add(&cmd->list, &shost->free_list);
502 return 0;
503}
504
505/**
506 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
507 * @shost: host whose freelist is going to be destroyed
508 */
509void scsi_destroy_command_freelist(struct Scsi_Host *shost)
510{
511 /*
512 * If cmd_pool is NULL the free list was not initialized, so
513 * do not attempt to release resources.
514 */
515 if (!shost->cmd_pool)
516 return;
517
518 while (!list_empty(&shost->free_list)) {
519 struct scsi_cmnd *cmd;
520
521 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
522 list_del_init(&cmd->list);
523 scsi_pool_free_command(shost->cmd_pool, cmd);
524 }
525 shost->cmd_pool = NULL;
526 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
527}
528
529#ifdef CONFIG_SCSI_LOGGING
530void scsi_log_send(struct scsi_cmnd *cmd)
531{
532 unsigned int level;
533
534 /*
535 * If ML QUEUE log level is greater than or equal to:
536 *
537 * 1: nothing (match completion)
538 *
539 * 2: log opcode + command of all commands
540 *
541 * 3: same as 2 plus dump cmd address
542 *
543 * 4: same as 3 plus dump extra junk
544 */
545 if (unlikely(scsi_logging_level)) {
546 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
547 SCSI_LOG_MLQUEUE_BITS);
548 if (level > 1) {
549 scmd_printk(KERN_INFO, cmd, "Send: ");
550 if (level > 2)
551 printk("0x%p ", cmd);
552 printk("\n");
553 scsi_print_command(cmd);
554 if (level > 3) {
555 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
556 " queuecommand 0x%p\n",
557 scsi_sglist(cmd), scsi_bufflen(cmd),
558 cmd->device->host->hostt->queuecommand);
559
560 }
561 }
562 }
563}
564
565void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
566{
567 unsigned int level;
568
569 /*
570 * If ML COMPLETE log level is greater than or equal to:
571 *
572 * 1: log disposition, result, opcode + command, and conditionally
573 * sense data for failures or non SUCCESS dispositions.
574 *
575 * 2: same as 1 but for all command completions.
576 *
577 * 3: same as 2 plus dump cmd address
578 *
579 * 4: same as 3 plus dump extra junk
580 */
581 if (unlikely(scsi_logging_level)) {
582 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
583 SCSI_LOG_MLCOMPLETE_BITS);
584 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
585 (level > 1)) {
586 scmd_printk(KERN_INFO, cmd, "Done: ");
587 if (level > 2)
588 printk("0x%p ", cmd);
589 /*
590 * Dump truncated values, so we usually fit within
591 * 80 chars.
592 */
593 switch (disposition) {
594 case SUCCESS:
595 printk("SUCCESS\n");
596 break;
597 case NEEDS_RETRY:
598 printk("RETRY\n");
599 break;
600 case ADD_TO_MLQUEUE:
601 printk("MLQUEUE\n");
602 break;
603 case FAILED:
604 printk("FAILED\n");
605 break;
606 case TIMEOUT_ERROR:
607 /*
608 * If called via scsi_times_out.
609 */
610 printk("TIMEOUT\n");
611 break;
612 default:
613 printk("UNKNOWN\n");
614 }
615 scsi_print_result(cmd);
616 scsi_print_command(cmd);
617 if (status_byte(cmd->result) & CHECK_CONDITION)
618 scsi_print_sense("", cmd);
619 if (level > 3)
620 scmd_printk(KERN_INFO, cmd,
621 "scsi host busy %d failed %d\n",
622 cmd->device->host->host_busy,
623 cmd->device->host->host_failed);
624 }
625 }
626}
627#endif
628
629/**
630 * scsi_cmd_get_serial - Assign a serial number to a command
631 * @host: the scsi host
632 * @cmd: command to assign serial number to
633 *
634 * Description: a serial number identifies a request for error recovery
635 * and debugging purposes. Protected by the Host_Lock of host.
636 */
637void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
638{
639 cmd->serial_number = host->cmd_serial_number++;
640 if (cmd->serial_number == 0)
641 cmd->serial_number = host->cmd_serial_number++;
642}
643EXPORT_SYMBOL(scsi_cmd_get_serial);
644
645/**
646 * scsi_dispatch_command - Dispatch a command to the low-level driver.
647 * @cmd: command block we are dispatching.
648 *
649 * Return: nonzero return request was rejected and device's queue needs to be
650 * plugged.
651 */
652int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
653{
654 struct Scsi_Host *host = cmd->device->host;
655 unsigned long timeout;
656 int rtn = 0;
657
658 atomic_inc(&cmd->device->iorequest_cnt);
659
660 /* check if the device is still usable */
661 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
662 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
663 * returns an immediate error upwards, and signals
664 * that the device is no longer present */
665 cmd->result = DID_NO_CONNECT << 16;
666 scsi_done(cmd);
667 /* return 0 (because the command has been processed) */
668 goto out;
669 }
670
671 /* Check to see if the scsi lld made this device blocked. */
672 if (unlikely(scsi_device_blocked(cmd->device))) {
673 /*
674 * in blocked state, the command is just put back on
675 * the device queue. The suspend state has already
676 * blocked the queue so future requests should not
677 * occur until the device transitions out of the
678 * suspend state.
679 */
680
681 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
682
683 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
684
685 /*
686 * NOTE: rtn is still zero here because we don't need the
687 * queue to be plugged on return (it's already stopped)
688 */
689 goto out;
690 }
691
692 /*
693 * If SCSI-2 or lower, store the LUN value in cmnd.
694 */
695 if (cmd->device->scsi_level <= SCSI_2 &&
696 cmd->device->scsi_level != SCSI_UNKNOWN) {
697 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
698 (cmd->device->lun << 5 & 0xe0);
699 }
700
701 /*
702 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
703 * we can avoid the drive not being ready.
704 */
705 timeout = host->last_reset + MIN_RESET_DELAY;
706
707 if (host->resetting && time_before(jiffies, timeout)) {
708 int ticks_remaining = timeout - jiffies;
709 /*
710 * NOTE: This may be executed from within an interrupt
711 * handler! This is bad, but for now, it'll do. The irq
712 * level of the interrupt handler has been masked out by the
713 * platform dependent interrupt handling code already, so the
714 * sti() here will not cause another call to the SCSI host's
715 * interrupt handler (assuming there is one irq-level per
716 * host).
717 */
718 while (--ticks_remaining >= 0)
719 mdelay(1 + 999 / HZ);
720 host->resetting = 0;
721 }
722
723 scsi_log_send(cmd);
724
725 /*
726 * Before we queue this command, check if the command
727 * length exceeds what the host adapter can handle.
728 */
729 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
730 SCSI_LOG_MLQUEUE(3,
731 printk("queuecommand : command too long. "
732 "cdb_size=%d host->max_cmd_len=%d\n",
733 cmd->cmd_len, cmd->device->host->max_cmd_len));
734 cmd->result = (DID_ABORT << 16);
735
736 scsi_done(cmd);
737 goto out;
738 }
739
740 if (unlikely(host->shost_state == SHOST_DEL)) {
741 cmd->result = (DID_NO_CONNECT << 16);
742 scsi_done(cmd);
743 } else {
744 trace_scsi_dispatch_cmd_start(cmd);
745 cmd->scsi_done = scsi_done;
746 rtn = host->hostt->queuecommand(host, cmd);
747 }
748
749 if (rtn) {
750 trace_scsi_dispatch_cmd_error(cmd, rtn);
751 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
752 rtn != SCSI_MLQUEUE_TARGET_BUSY)
753 rtn = SCSI_MLQUEUE_HOST_BUSY;
754
755 scsi_queue_insert(cmd, rtn);
756
757 SCSI_LOG_MLQUEUE(3,
758 printk("queuecommand : request rejected\n"));
759 }
760
761 out:
762 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
763 return rtn;
764}
765
766/**
767 * scsi_done - Enqueue the finished SCSI command into the done queue.
768 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
769 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
770 *
771 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
772 * which regains ownership of the SCSI command (de facto) from a LLDD, and
773 * enqueues the command to the done queue for further processing.
774 *
775 * This is the producer of the done queue who enqueues at the tail.
776 *
777 * This function is interrupt context safe.
778 */
779static void scsi_done(struct scsi_cmnd *cmd)
780{
781 trace_scsi_dispatch_cmd_done(cmd);
782 blk_complete_request(cmd->request);
783}
784
785/* Move this to a header if it becomes more generally useful */
786static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
787{
788 return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
789}
790
791/**
792 * scsi_finish_command - cleanup and pass command back to upper layer
793 * @cmd: the command
794 *
795 * Description: Pass command off to upper layer for finishing of I/O
796 * request, waking processes that are waiting on results,
797 * etc.
798 */
799void scsi_finish_command(struct scsi_cmnd *cmd)
800{
801 struct scsi_device *sdev = cmd->device;
802 struct scsi_target *starget = scsi_target(sdev);
803 struct Scsi_Host *shost = sdev->host;
804 struct scsi_driver *drv;
805 unsigned int good_bytes;
806
807 scsi_device_unbusy(sdev);
808
809 /*
810 * Clear the flags which say that the device/host is no longer
811 * capable of accepting new commands. These are set in scsi_queue.c
812 * for both the queue full condition on a device, and for a
813 * host full condition on the host.
814 *
815 * XXX(hch): What about locking?
816 */
817 shost->host_blocked = 0;
818 starget->target_blocked = 0;
819 sdev->device_blocked = 0;
820
821 /*
822 * If we have valid sense information, then some kind of recovery
823 * must have taken place. Make a note of this.
824 */
825 if (SCSI_SENSE_VALID(cmd))
826 cmd->result |= (DRIVER_SENSE << 24);
827
828 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
829 "Notifying upper driver of completion "
830 "(result %x)\n", cmd->result));
831
832 good_bytes = scsi_bufflen(cmd);
833 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
834 int old_good_bytes = good_bytes;
835 drv = scsi_cmd_to_driver(cmd);
836 if (drv->done)
837 good_bytes = drv->done(cmd);
838 /*
839 * USB may not give sense identifying bad sector and
840 * simply return a residue instead, so subtract off the
841 * residue if drv->done() error processing indicates no
842 * change to the completion length.
843 */
844 if (good_bytes == old_good_bytes)
845 good_bytes -= scsi_get_resid(cmd);
846 }
847 scsi_io_completion(cmd, good_bytes);
848}
849EXPORT_SYMBOL(scsi_finish_command);
850
851/**
852 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
853 * @sdev: SCSI Device in question
854 * @tagged: Do we use tagged queueing (non-0) or do we treat
855 * this device as an untagged device (0)
856 * @tags: Number of tags allowed if tagged queueing enabled,
857 * or number of commands the low level driver can
858 * queue up in non-tagged mode (as per cmd_per_lun).
859 *
860 * Returns: Nothing
861 *
862 * Lock Status: None held on entry
863 *
864 * Notes: Low level drivers may call this at any time and we will do
865 * the right thing depending on whether or not the device is
866 * currently active and whether or not it even has the
867 * command blocks built yet.
868 */
869void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
870{
871 unsigned long flags;
872
873 /*
874 * refuse to set tagged depth to an unworkable size
875 */
876 if (tags <= 0)
877 return;
878
879 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
880
881 /*
882 * Check to see if the queue is managed by the block layer.
883 * If it is, and we fail to adjust the depth, exit.
884 *
885 * Do not resize the tag map if it is a host wide share bqt,
886 * because the size should be the hosts's can_queue. If there
887 * is more IO than the LLD's can_queue (so there are not enuogh
888 * tags) request_fn's host queue ready check will handle it.
889 */
890 if (!sdev->host->bqt) {
891 if (blk_queue_tagged(sdev->request_queue) &&
892 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
893 goto out;
894 }
895
896 sdev->queue_depth = tags;
897 switch (tagged) {
898 case MSG_ORDERED_TAG:
899 sdev->ordered_tags = 1;
900 sdev->simple_tags = 1;
901 break;
902 case MSG_SIMPLE_TAG:
903 sdev->ordered_tags = 0;
904 sdev->simple_tags = 1;
905 break;
906 default:
907 sdev_printk(KERN_WARNING, sdev,
908 "scsi_adjust_queue_depth, bad queue type, "
909 "disabled\n");
910 case 0:
911 sdev->ordered_tags = sdev->simple_tags = 0;
912 sdev->queue_depth = tags;
913 break;
914 }
915 out:
916 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
917}
918EXPORT_SYMBOL(scsi_adjust_queue_depth);
919
920/**
921 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
922 * @sdev: SCSI Device in question
923 * @depth: Current number of outstanding SCSI commands on this device,
924 * not counting the one returned as QUEUE_FULL.
925 *
926 * Description: This function will track successive QUEUE_FULL events on a
927 * specific SCSI device to determine if and when there is a
928 * need to adjust the queue depth on the device.
929 *
930 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
931 * -1 - Drop back to untagged operation using host->cmd_per_lun
932 * as the untagged command depth
933 *
934 * Lock Status: None held on entry
935 *
936 * Notes: Low level drivers may call this at any time and we will do
937 * "The Right Thing." We are interrupt context safe.
938 */
939int scsi_track_queue_full(struct scsi_device *sdev, int depth)
940{
941
942 /*
943 * Don't let QUEUE_FULLs on the same
944 * jiffies count, they could all be from
945 * same event.
946 */
947 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
948 return 0;
949
950 sdev->last_queue_full_time = jiffies;
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/**
975 * scsi_vpd_inquiry - Request a device provide us with a VPD page
976 * @sdev: The device to ask
977 * @buffer: Where to put the result
978 * @page: Which Vital Product Data to return
979 * @len: The length of the buffer
980 *
981 * This is an internal helper function. You probably want to use
982 * scsi_get_vpd_page instead.
983 *
984 * Returns 0 on success or a negative error number.
985 */
986static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
987 u8 page, unsigned len)
988{
989 int result;
990 unsigned char cmd[16];
991
992 cmd[0] = INQUIRY;
993 cmd[1] = 1; /* EVPD */
994 cmd[2] = page;
995 cmd[3] = len >> 8;
996 cmd[4] = len & 0xff;
997 cmd[5] = 0; /* Control byte */
998
999 /*
1000 * I'm not convinced we need to try quite this hard to get VPD, but
1001 * all the existing users tried this hard.
1002 */
1003 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
1004 len, NULL, 30 * HZ, 3, NULL);
1005 if (result)
1006 return result;
1007
1008 /* Sanity check that we got the page back that we asked for */
1009 if (buffer[1] != page)
1010 return -EIO;
1011
1012 return 0;
1013}
1014
1015/**
1016 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1017 * @sdev: The device to ask
1018 * @page: Which Vital Product Data to return
1019 * @buf: where to store the VPD
1020 * @buf_len: number of bytes in the VPD buffer area
1021 *
1022 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1023 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1024 * If the device supports this VPD page, this routine returns a pointer
1025 * to a buffer containing the data from that page. The caller is
1026 * responsible for calling kfree() on this pointer when it is no longer
1027 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1028 */
1029int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1030 int buf_len)
1031{
1032 int i, result;
1033
1034 /* Ask for all the pages supported by this device */
1035 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
1036 if (result)
1037 goto fail;
1038
1039 /* If the user actually wanted this page, we can skip the rest */
1040 if (page == 0)
1041 return 0;
1042
1043 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
1044 if (buf[i + 4] == page)
1045 goto found;
1046
1047 if (i < buf[3] && i >= buf_len - 4)
1048 /* ran off the end of the buffer, give us benefit of doubt */
1049 goto found;
1050 /* The device claims it doesn't support the requested page */
1051 goto fail;
1052
1053 found:
1054 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1055 if (result)
1056 goto fail;
1057
1058 return 0;
1059
1060 fail:
1061 return -EINVAL;
1062}
1063EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1064
1065/**
1066 * scsi_device_get - get an additional reference to a scsi_device
1067 * @sdev: device to get a reference to
1068 *
1069 * Description: Gets a reference to the scsi_device and increments the use count
1070 * of the underlying LLDD module. You must hold host_lock of the
1071 * parent Scsi_Host or already have a reference when calling this.
1072 */
1073int scsi_device_get(struct scsi_device *sdev)
1074{
1075 if (sdev->sdev_state == SDEV_DEL)
1076 return -ENXIO;
1077 if (!get_device(&sdev->sdev_gendev))
1078 return -ENXIO;
1079 /* We can fail this if we're doing SCSI operations
1080 * from module exit (like cache flush) */
1081 try_module_get(sdev->host->hostt->module);
1082
1083 return 0;
1084}
1085EXPORT_SYMBOL(scsi_device_get);
1086
1087/**
1088 * scsi_device_put - release a reference to a scsi_device
1089 * @sdev: device to release a reference on.
1090 *
1091 * Description: Release a reference to the scsi_device and decrements the use
1092 * count of the underlying LLDD module. The device is freed once the last
1093 * user vanishes.
1094 */
1095void scsi_device_put(struct scsi_device *sdev)
1096{
1097#ifdef CONFIG_MODULE_UNLOAD
1098 struct module *module = sdev->host->hostt->module;
1099
1100 /* The module refcount will be zero if scsi_device_get()
1101 * was called from a module removal routine */
1102 if (module && module_refcount(module) != 0)
1103 module_put(module);
1104#endif
1105 put_device(&sdev->sdev_gendev);
1106}
1107EXPORT_SYMBOL(scsi_device_put);
1108
1109/* helper for shost_for_each_device, see that for documentation */
1110struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1111 struct scsi_device *prev)
1112{
1113 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1114 struct scsi_device *next = NULL;
1115 unsigned long flags;
1116
1117 spin_lock_irqsave(shost->host_lock, flags);
1118 while (list->next != &shost->__devices) {
1119 next = list_entry(list->next, struct scsi_device, siblings);
1120 /* skip devices that we can't get a reference to */
1121 if (!scsi_device_get(next))
1122 break;
1123 next = NULL;
1124 list = list->next;
1125 }
1126 spin_unlock_irqrestore(shost->host_lock, flags);
1127
1128 if (prev)
1129 scsi_device_put(prev);
1130 return next;
1131}
1132EXPORT_SYMBOL(__scsi_iterate_devices);
1133
1134/**
1135 * starget_for_each_device - helper to walk all devices of a target
1136 * @starget: target whose devices we want to iterate over.
1137 * @data: Opaque passed to each function call.
1138 * @fn: Function to call on each device
1139 *
1140 * This traverses over each device of @starget. The devices have
1141 * a reference that must be released by scsi_host_put when breaking
1142 * out of the loop.
1143 */
1144void starget_for_each_device(struct scsi_target *starget, void *data,
1145 void (*fn)(struct scsi_device *, void *))
1146{
1147 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1148 struct scsi_device *sdev;
1149
1150 shost_for_each_device(sdev, shost) {
1151 if ((sdev->channel == starget->channel) &&
1152 (sdev->id == starget->id))
1153 fn(sdev, data);
1154 }
1155}
1156EXPORT_SYMBOL(starget_for_each_device);
1157
1158/**
1159 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1160 * @starget: target whose devices we want to iterate over.
1161 * @data: parameter for callback @fn()
1162 * @fn: callback function that is invoked for each device
1163 *
1164 * This traverses over each device of @starget. It does _not_
1165 * take a reference on the scsi_device, so the whole loop must be
1166 * protected by shost->host_lock.
1167 *
1168 * Note: The only reason why drivers would want to use this is because
1169 * they need to access the device list in irq context. Otherwise you
1170 * really want to use starget_for_each_device instead.
1171 **/
1172void __starget_for_each_device(struct scsi_target *starget, void *data,
1173 void (*fn)(struct scsi_device *, void *))
1174{
1175 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1176 struct scsi_device *sdev;
1177
1178 __shost_for_each_device(sdev, shost) {
1179 if ((sdev->channel == starget->channel) &&
1180 (sdev->id == starget->id))
1181 fn(sdev, data);
1182 }
1183}
1184EXPORT_SYMBOL(__starget_for_each_device);
1185
1186/**
1187 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1188 * @starget: SCSI target pointer
1189 * @lun: SCSI Logical Unit Number
1190 *
1191 * Description: Looks up the scsi_device with the specified @lun for a given
1192 * @starget. The returned scsi_device does not have an additional
1193 * reference. You must hold the host's host_lock over this call and
1194 * any access to the returned scsi_device. A scsi_device in state
1195 * SDEV_DEL is skipped.
1196 *
1197 * Note: The only reason why drivers should use this is because
1198 * they need to access the device list in irq context. Otherwise you
1199 * really want to use scsi_device_lookup_by_target instead.
1200 **/
1201struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1202 uint lun)
1203{
1204 struct scsi_device *sdev;
1205
1206 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1207 if (sdev->sdev_state == SDEV_DEL)
1208 continue;
1209 if (sdev->lun ==lun)
1210 return sdev;
1211 }
1212
1213 return NULL;
1214}
1215EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1216
1217/**
1218 * scsi_device_lookup_by_target - find a device given the target
1219 * @starget: SCSI target pointer
1220 * @lun: SCSI Logical Unit Number
1221 *
1222 * Description: Looks up the scsi_device with the specified @lun for a given
1223 * @starget. The returned scsi_device has an additional reference that
1224 * needs to be released with scsi_device_put once you're done with it.
1225 **/
1226struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1227 uint lun)
1228{
1229 struct scsi_device *sdev;
1230 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1231 unsigned long flags;
1232
1233 spin_lock_irqsave(shost->host_lock, flags);
1234 sdev = __scsi_device_lookup_by_target(starget, lun);
1235 if (sdev && scsi_device_get(sdev))
1236 sdev = NULL;
1237 spin_unlock_irqrestore(shost->host_lock, flags);
1238
1239 return sdev;
1240}
1241EXPORT_SYMBOL(scsi_device_lookup_by_target);
1242
1243/**
1244 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1245 * @shost: SCSI host pointer
1246 * @channel: SCSI channel (zero if only one channel)
1247 * @id: SCSI target number (physical unit number)
1248 * @lun: SCSI Logical Unit Number
1249 *
1250 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1251 * for a given host. The returned scsi_device does not have an additional
1252 * reference. You must hold the host's host_lock over this call and any access
1253 * to the returned scsi_device.
1254 *
1255 * Note: The only reason why drivers would want to use this is because
1256 * they need to access the device list in irq context. Otherwise you
1257 * really want to use scsi_device_lookup instead.
1258 **/
1259struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1260 uint channel, uint id, uint lun)
1261{
1262 struct scsi_device *sdev;
1263
1264 list_for_each_entry(sdev, &shost->__devices, siblings) {
1265 if (sdev->channel == channel && sdev->id == id &&
1266 sdev->lun ==lun)
1267 return sdev;
1268 }
1269
1270 return NULL;
1271}
1272EXPORT_SYMBOL(__scsi_device_lookup);
1273
1274/**
1275 * scsi_device_lookup - find a device given the host
1276 * @shost: SCSI host pointer
1277 * @channel: SCSI channel (zero if only one channel)
1278 * @id: SCSI target number (physical unit number)
1279 * @lun: SCSI Logical Unit Number
1280 *
1281 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1282 * for a given host. The returned scsi_device has an additional reference that
1283 * needs to be released with scsi_device_put once you're done with it.
1284 **/
1285struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1286 uint channel, uint id, uint lun)
1287{
1288 struct scsi_device *sdev;
1289 unsigned long flags;
1290
1291 spin_lock_irqsave(shost->host_lock, flags);
1292 sdev = __scsi_device_lookup(shost, channel, id, lun);
1293 if (sdev && scsi_device_get(sdev))
1294 sdev = NULL;
1295 spin_unlock_irqrestore(shost->host_lock, flags);
1296
1297 return sdev;
1298}
1299EXPORT_SYMBOL(scsi_device_lookup);
1300
1301MODULE_DESCRIPTION("SCSI core");
1302MODULE_LICENSE("GPL");
1303
1304module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1305MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1306
1307static int __init init_scsi(void)
1308{
1309 int error;
1310
1311 error = scsi_init_queue();
1312 if (error)
1313 return error;
1314 error = scsi_init_procfs();
1315 if (error)
1316 goto cleanup_queue;
1317 error = scsi_init_devinfo();
1318 if (error)
1319 goto cleanup_procfs;
1320 error = scsi_init_hosts();
1321 if (error)
1322 goto cleanup_devlist;
1323 error = scsi_init_sysctl();
1324 if (error)
1325 goto cleanup_hosts;
1326 error = scsi_sysfs_register();
1327 if (error)
1328 goto cleanup_sysctl;
1329
1330 scsi_netlink_init();
1331
1332 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1333 return 0;
1334
1335cleanup_sysctl:
1336 scsi_exit_sysctl();
1337cleanup_hosts:
1338 scsi_exit_hosts();
1339cleanup_devlist:
1340 scsi_exit_devinfo();
1341cleanup_procfs:
1342 scsi_exit_procfs();
1343cleanup_queue:
1344 scsi_exit_queue();
1345 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1346 -error);
1347 return error;
1348}
1349
1350static void __exit exit_scsi(void)
1351{
1352 scsi_netlink_exit();
1353 scsi_sysfs_unregister();
1354 scsi_exit_sysctl();
1355 scsi_exit_hosts();
1356 scsi_exit_devinfo();
1357 scsi_exit_procfs();
1358 scsi_exit_queue();
1359}
1360
1361subsys_initcall(init_scsi);
1362module_exit(exit_scsi);
1/*
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>
43#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>
50#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>
56#include <linux/mutex.h>
57
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_driver.h>
63#include <scsi/scsi_eh.h>
64#include <scsi/scsi_host.h>
65#include <scsi/scsi_tcq.h>
66
67#include "scsi_priv.h"
68#include "scsi_logging.h"
69
70#define CREATE_TRACE_POINTS
71#include <trace/events/scsi.h>
72
73static void scsi_done(struct scsi_cmnd *cmd);
74
75/*
76 * Definitions and constants.
77 */
78
79#define MIN_RESET_DELAY (2*HZ)
80
81/* Do not call reset on error if we just did a reset within 15 sec. */
82#define MIN_RESET_PERIOD (15*HZ)
83
84/*
85 * Note - the initial logging level can be set here to log events at boot time.
86 * After the system is up, you may enable logging via the /proc interface.
87 */
88unsigned int scsi_logging_level;
89#if defined(CONFIG_SCSI_LOGGING)
90EXPORT_SYMBOL(scsi_logging_level);
91#endif
92
93/* sd, scsi core and power management need to coordinate flushing async actions */
94LIST_HEAD(scsi_sd_probe_domain);
95EXPORT_SYMBOL(scsi_sd_probe_domain);
96
97/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
98 * You may not alter any existing entry (although adding new ones is
99 * encouraged once assigned by ANSI/INCITS T10
100 */
101static const char *const scsi_device_types[] = {
102 "Direct-Access ",
103 "Sequential-Access",
104 "Printer ",
105 "Processor ",
106 "WORM ",
107 "CD-ROM ",
108 "Scanner ",
109 "Optical Device ",
110 "Medium Changer ",
111 "Communications ",
112 "ASC IT8 ",
113 "ASC IT8 ",
114 "RAID ",
115 "Enclosure ",
116 "Direct-Access-RBC",
117 "Optical card ",
118 "Bridge controller",
119 "Object storage ",
120 "Automation/Drive ",
121};
122
123/**
124 * scsi_device_type - Return 17 char string indicating device type.
125 * @type: type number to look up
126 */
127
128const char * scsi_device_type(unsigned type)
129{
130 if (type == 0x1e)
131 return "Well-known LUN ";
132 if (type == 0x1f)
133 return "No Device ";
134 if (type >= ARRAY_SIZE(scsi_device_types))
135 return "Unknown ";
136 return scsi_device_types[type];
137}
138
139EXPORT_SYMBOL(scsi_device_type);
140
141struct scsi_host_cmd_pool {
142 struct kmem_cache *cmd_slab;
143 struct kmem_cache *sense_slab;
144 unsigned int users;
145 char *cmd_name;
146 char *sense_name;
147 unsigned int slab_flags;
148 gfp_t gfp_mask;
149};
150
151static struct scsi_host_cmd_pool scsi_cmd_pool = {
152 .cmd_name = "scsi_cmd_cache",
153 .sense_name = "scsi_sense_cache",
154 .slab_flags = SLAB_HWCACHE_ALIGN,
155};
156
157static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
158 .cmd_name = "scsi_cmd_cache(DMA)",
159 .sense_name = "scsi_sense_cache(DMA)",
160 .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
161 .gfp_mask = __GFP_DMA,
162};
163
164static DEFINE_MUTEX(host_cmd_pool_mutex);
165
166/**
167 * scsi_pool_alloc_command - internal function to get a fully allocated command
168 * @pool: slab pool to allocate the command from
169 * @gfp_mask: mask for the allocation
170 *
171 * Returns a fully allocated command (with the allied sense buffer) or
172 * NULL on failure
173 */
174static struct scsi_cmnd *
175scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
176{
177 struct scsi_cmnd *cmd;
178
179 cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
180 if (!cmd)
181 return NULL;
182
183 cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
184 gfp_mask | pool->gfp_mask);
185 if (!cmd->sense_buffer) {
186 kmem_cache_free(pool->cmd_slab, cmd);
187 return NULL;
188 }
189
190 return cmd;
191}
192
193/**
194 * scsi_pool_free_command - internal function to release a command
195 * @pool: slab pool to allocate the command from
196 * @cmd: command to release
197 *
198 * the command must previously have been allocated by
199 * scsi_pool_alloc_command.
200 */
201static void
202scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
203 struct scsi_cmnd *cmd)
204{
205 if (cmd->prot_sdb)
206 kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
207
208 kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
209 kmem_cache_free(pool->cmd_slab, cmd);
210}
211
212/**
213 * scsi_host_alloc_command - internal function to allocate command
214 * @shost: SCSI host whose pool to allocate from
215 * @gfp_mask: mask for the allocation
216 *
217 * Returns a fully allocated command with sense buffer and protection
218 * data buffer (where applicable) or NULL on failure
219 */
220static struct scsi_cmnd *
221scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
222{
223 struct scsi_cmnd *cmd;
224
225 cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
226 if (!cmd)
227 return NULL;
228
229 if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
230 cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
231
232 if (!cmd->prot_sdb) {
233 scsi_pool_free_command(shost->cmd_pool, cmd);
234 return NULL;
235 }
236 }
237
238 return cmd;
239}
240
241/**
242 * __scsi_get_command - Allocate a struct scsi_cmnd
243 * @shost: host to transmit command
244 * @gfp_mask: allocation mask
245 *
246 * Description: allocate a struct scsi_cmd from host's slab, recycling from the
247 * host's free_list if necessary.
248 */
249struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
250{
251 struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
252
253 if (unlikely(!cmd)) {
254 unsigned long flags;
255
256 spin_lock_irqsave(&shost->free_list_lock, flags);
257 if (likely(!list_empty(&shost->free_list))) {
258 cmd = list_entry(shost->free_list.next,
259 struct scsi_cmnd, list);
260 list_del_init(&cmd->list);
261 }
262 spin_unlock_irqrestore(&shost->free_list_lock, flags);
263
264 if (cmd) {
265 void *buf, *prot;
266
267 buf = cmd->sense_buffer;
268 prot = cmd->prot_sdb;
269
270 memset(cmd, 0, sizeof(*cmd));
271
272 cmd->sense_buffer = buf;
273 cmd->prot_sdb = prot;
274 }
275 }
276
277 return cmd;
278}
279EXPORT_SYMBOL_GPL(__scsi_get_command);
280
281/**
282 * scsi_get_command - Allocate and setup a scsi command block
283 * @dev: parent scsi device
284 * @gfp_mask: allocator flags
285 *
286 * Returns: The allocated scsi command structure.
287 */
288struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
289{
290 struct scsi_cmnd *cmd;
291
292 /* Bail if we can't get a reference to the device */
293 if (!get_device(&dev->sdev_gendev))
294 return NULL;
295
296 cmd = __scsi_get_command(dev->host, gfp_mask);
297
298 if (likely(cmd != NULL)) {
299 unsigned long flags;
300
301 cmd->device = dev;
302 INIT_LIST_HEAD(&cmd->list);
303 spin_lock_irqsave(&dev->list_lock, flags);
304 list_add_tail(&cmd->list, &dev->cmd_list);
305 spin_unlock_irqrestore(&dev->list_lock, flags);
306 cmd->jiffies_at_alloc = jiffies;
307 } else
308 put_device(&dev->sdev_gendev);
309
310 return cmd;
311}
312EXPORT_SYMBOL(scsi_get_command);
313
314/**
315 * __scsi_put_command - Free a struct scsi_cmnd
316 * @shost: dev->host
317 * @cmd: Command to free
318 * @dev: parent scsi device
319 */
320void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
321 struct device *dev)
322{
323 unsigned long flags;
324
325 /* changing locks here, don't need to restore the irq state */
326 spin_lock_irqsave(&shost->free_list_lock, flags);
327 if (unlikely(list_empty(&shost->free_list))) {
328 list_add(&cmd->list, &shost->free_list);
329 cmd = NULL;
330 }
331 spin_unlock_irqrestore(&shost->free_list_lock, flags);
332
333 if (likely(cmd != NULL))
334 scsi_pool_free_command(shost->cmd_pool, cmd);
335
336 put_device(dev);
337}
338EXPORT_SYMBOL(__scsi_put_command);
339
340/**
341 * scsi_put_command - Free a scsi command block
342 * @cmd: command block to free
343 *
344 * Returns: Nothing.
345 *
346 * Notes: The command must not belong to any lists.
347 */
348void scsi_put_command(struct scsi_cmnd *cmd)
349{
350 struct scsi_device *sdev = cmd->device;
351 unsigned long flags;
352
353 /* serious error if the command hasn't come from a device list */
354 spin_lock_irqsave(&cmd->device->list_lock, flags);
355 BUG_ON(list_empty(&cmd->list));
356 list_del_init(&cmd->list);
357 spin_unlock_irqrestore(&cmd->device->list_lock, flags);
358
359 __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
360}
361EXPORT_SYMBOL(scsi_put_command);
362
363static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
364{
365 struct scsi_host_cmd_pool *retval = NULL, *pool;
366 /*
367 * Select a command slab for this host and create it if not
368 * yet existent.
369 */
370 mutex_lock(&host_cmd_pool_mutex);
371 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
372 &scsi_cmd_pool;
373 if (!pool->users) {
374 pool->cmd_slab = kmem_cache_create(pool->cmd_name,
375 sizeof(struct scsi_cmnd), 0,
376 pool->slab_flags, NULL);
377 if (!pool->cmd_slab)
378 goto fail;
379
380 pool->sense_slab = kmem_cache_create(pool->sense_name,
381 SCSI_SENSE_BUFFERSIZE, 0,
382 pool->slab_flags, NULL);
383 if (!pool->sense_slab) {
384 kmem_cache_destroy(pool->cmd_slab);
385 goto fail;
386 }
387 }
388
389 pool->users++;
390 retval = pool;
391 fail:
392 mutex_unlock(&host_cmd_pool_mutex);
393 return retval;
394}
395
396static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
397{
398 struct scsi_host_cmd_pool *pool;
399
400 mutex_lock(&host_cmd_pool_mutex);
401 pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
402 &scsi_cmd_pool;
403 /*
404 * This may happen if a driver has a mismatched get and put
405 * of the command pool; the driver should be implicated in
406 * the stack trace
407 */
408 BUG_ON(pool->users == 0);
409
410 if (!--pool->users) {
411 kmem_cache_destroy(pool->cmd_slab);
412 kmem_cache_destroy(pool->sense_slab);
413 }
414 mutex_unlock(&host_cmd_pool_mutex);
415}
416
417/**
418 * scsi_allocate_command - get a fully allocated SCSI command
419 * @gfp_mask: allocation mask
420 *
421 * This function is for use outside of the normal host based pools.
422 * It allocates the relevant command and takes an additional reference
423 * on the pool it used. This function *must* be paired with
424 * scsi_free_command which also has the identical mask, otherwise the
425 * free pool counts will eventually go wrong and you'll trigger a bug.
426 *
427 * This function should *only* be used by drivers that need a static
428 * command allocation at start of day for internal functions.
429 */
430struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
431{
432 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
433
434 if (!pool)
435 return NULL;
436
437 return scsi_pool_alloc_command(pool, gfp_mask);
438}
439EXPORT_SYMBOL(scsi_allocate_command);
440
441/**
442 * scsi_free_command - free a command allocated by scsi_allocate_command
443 * @gfp_mask: mask used in the original allocation
444 * @cmd: command to free
445 *
446 * Note: using the original allocation mask is vital because that's
447 * what determines which command pool we use to free the command. Any
448 * mismatch will cause the system to BUG eventually.
449 */
450void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
451{
452 struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
453
454 /*
455 * this could trigger if the mask to scsi_allocate_command
456 * doesn't match this mask. Otherwise we're guaranteed that this
457 * succeeds because scsi_allocate_command must have taken a reference
458 * on the pool
459 */
460 BUG_ON(!pool);
461
462 scsi_pool_free_command(pool, cmd);
463 /*
464 * scsi_put_host_cmd_pool is called twice; once to release the
465 * reference we took above, and once to release the reference
466 * originally taken by scsi_allocate_command
467 */
468 scsi_put_host_cmd_pool(gfp_mask);
469 scsi_put_host_cmd_pool(gfp_mask);
470}
471EXPORT_SYMBOL(scsi_free_command);
472
473/**
474 * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
475 * @shost: host to allocate the freelist for.
476 *
477 * Description: The command freelist protects against system-wide out of memory
478 * deadlock by preallocating one SCSI command structure for each host, so the
479 * system can always write to a swap file on a device associated with that host.
480 *
481 * Returns: Nothing.
482 */
483int scsi_setup_command_freelist(struct Scsi_Host *shost)
484{
485 struct scsi_cmnd *cmd;
486 const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
487
488 spin_lock_init(&shost->free_list_lock);
489 INIT_LIST_HEAD(&shost->free_list);
490
491 shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
492
493 if (!shost->cmd_pool)
494 return -ENOMEM;
495
496 /*
497 * Get one backup command for this host.
498 */
499 cmd = scsi_host_alloc_command(shost, gfp_mask);
500 if (!cmd) {
501 scsi_put_host_cmd_pool(gfp_mask);
502 shost->cmd_pool = NULL;
503 return -ENOMEM;
504 }
505 list_add(&cmd->list, &shost->free_list);
506 return 0;
507}
508
509/**
510 * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
511 * @shost: host whose freelist is going to be destroyed
512 */
513void scsi_destroy_command_freelist(struct Scsi_Host *shost)
514{
515 /*
516 * If cmd_pool is NULL the free list was not initialized, so
517 * do not attempt to release resources.
518 */
519 if (!shost->cmd_pool)
520 return;
521
522 while (!list_empty(&shost->free_list)) {
523 struct scsi_cmnd *cmd;
524
525 cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
526 list_del_init(&cmd->list);
527 scsi_pool_free_command(shost->cmd_pool, cmd);
528 }
529 shost->cmd_pool = NULL;
530 scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
531}
532
533#ifdef CONFIG_SCSI_LOGGING
534void scsi_log_send(struct scsi_cmnd *cmd)
535{
536 unsigned int level;
537
538 /*
539 * If ML QUEUE log level is greater than or equal to:
540 *
541 * 1: nothing (match completion)
542 *
543 * 2: log opcode + command of all commands
544 *
545 * 3: same as 2 plus dump cmd address
546 *
547 * 4: same as 3 plus dump extra junk
548 */
549 if (unlikely(scsi_logging_level)) {
550 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
551 SCSI_LOG_MLQUEUE_BITS);
552 if (level > 1) {
553 scmd_printk(KERN_INFO, cmd, "Send: ");
554 if (level > 2)
555 printk("0x%p ", cmd);
556 printk("\n");
557 scsi_print_command(cmd);
558 if (level > 3) {
559 printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
560 " queuecommand 0x%p\n",
561 scsi_sglist(cmd), scsi_bufflen(cmd),
562 cmd->device->host->hostt->queuecommand);
563
564 }
565 }
566 }
567}
568
569void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
570{
571 unsigned int level;
572
573 /*
574 * If ML COMPLETE log level is greater than or equal to:
575 *
576 * 1: log disposition, result, opcode + command, and conditionally
577 * sense data for failures or non SUCCESS dispositions.
578 *
579 * 2: same as 1 but for all command completions.
580 *
581 * 3: same as 2 plus dump cmd address
582 *
583 * 4: same as 3 plus dump extra junk
584 */
585 if (unlikely(scsi_logging_level)) {
586 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
587 SCSI_LOG_MLCOMPLETE_BITS);
588 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
589 (level > 1)) {
590 scmd_printk(KERN_INFO, cmd, "Done: ");
591 if (level > 2)
592 printk("0x%p ", cmd);
593 /*
594 * Dump truncated values, so we usually fit within
595 * 80 chars.
596 */
597 switch (disposition) {
598 case SUCCESS:
599 printk("SUCCESS\n");
600 break;
601 case NEEDS_RETRY:
602 printk("RETRY\n");
603 break;
604 case ADD_TO_MLQUEUE:
605 printk("MLQUEUE\n");
606 break;
607 case FAILED:
608 printk("FAILED\n");
609 break;
610 case TIMEOUT_ERROR:
611 /*
612 * If called via scsi_times_out.
613 */
614 printk("TIMEOUT\n");
615 break;
616 default:
617 printk("UNKNOWN\n");
618 }
619 scsi_print_result(cmd);
620 scsi_print_command(cmd);
621 if (status_byte(cmd->result) & CHECK_CONDITION)
622 scsi_print_sense("", cmd);
623 if (level > 3)
624 scmd_printk(KERN_INFO, cmd,
625 "scsi host busy %d failed %d\n",
626 cmd->device->host->host_busy,
627 cmd->device->host->host_failed);
628 }
629 }
630}
631#endif
632
633/**
634 * scsi_cmd_get_serial - Assign a serial number to a command
635 * @host: the scsi host
636 * @cmd: command to assign serial number to
637 *
638 * Description: a serial number identifies a request for error recovery
639 * and debugging purposes. Protected by the Host_Lock of host.
640 */
641void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
642{
643 cmd->serial_number = host->cmd_serial_number++;
644 if (cmd->serial_number == 0)
645 cmd->serial_number = host->cmd_serial_number++;
646}
647EXPORT_SYMBOL(scsi_cmd_get_serial);
648
649/**
650 * scsi_dispatch_command - Dispatch a command to the low-level driver.
651 * @cmd: command block we are dispatching.
652 *
653 * Return: nonzero return request was rejected and device's queue needs to be
654 * plugged.
655 */
656int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
657{
658 struct Scsi_Host *host = cmd->device->host;
659 unsigned long timeout;
660 int rtn = 0;
661
662 atomic_inc(&cmd->device->iorequest_cnt);
663
664 /* check if the device is still usable */
665 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
666 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
667 * returns an immediate error upwards, and signals
668 * that the device is no longer present */
669 cmd->result = DID_NO_CONNECT << 16;
670 scsi_done(cmd);
671 /* return 0 (because the command has been processed) */
672 goto out;
673 }
674
675 /* Check to see if the scsi lld made this device blocked. */
676 if (unlikely(scsi_device_blocked(cmd->device))) {
677 /*
678 * in blocked state, the command is just put back on
679 * the device queue. The suspend state has already
680 * blocked the queue so future requests should not
681 * occur until the device transitions out of the
682 * suspend state.
683 */
684
685 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
686
687 SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
688
689 /*
690 * NOTE: rtn is still zero here because we don't need the
691 * queue to be plugged on return (it's already stopped)
692 */
693 goto out;
694 }
695
696 /*
697 * If SCSI-2 or lower, store the LUN value in cmnd.
698 */
699 if (cmd->device->scsi_level <= SCSI_2 &&
700 cmd->device->scsi_level != SCSI_UNKNOWN) {
701 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
702 (cmd->device->lun << 5 & 0xe0);
703 }
704
705 /*
706 * We will wait MIN_RESET_DELAY clock ticks after the last reset so
707 * we can avoid the drive not being ready.
708 */
709 timeout = host->last_reset + MIN_RESET_DELAY;
710
711 if (host->resetting && time_before(jiffies, timeout)) {
712 int ticks_remaining = timeout - jiffies;
713 /*
714 * NOTE: This may be executed from within an interrupt
715 * handler! This is bad, but for now, it'll do. The irq
716 * level of the interrupt handler has been masked out by the
717 * platform dependent interrupt handling code already, so the
718 * sti() here will not cause another call to the SCSI host's
719 * interrupt handler (assuming there is one irq-level per
720 * host).
721 */
722 while (--ticks_remaining >= 0)
723 mdelay(1 + 999 / HZ);
724 host->resetting = 0;
725 }
726
727 scsi_log_send(cmd);
728
729 /*
730 * Before we queue this command, check if the command
731 * length exceeds what the host adapter can handle.
732 */
733 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
734 SCSI_LOG_MLQUEUE(3,
735 printk("queuecommand : command too long. "
736 "cdb_size=%d host->max_cmd_len=%d\n",
737 cmd->cmd_len, cmd->device->host->max_cmd_len));
738 cmd->result = (DID_ABORT << 16);
739
740 scsi_done(cmd);
741 goto out;
742 }
743
744 if (unlikely(host->shost_state == SHOST_DEL)) {
745 cmd->result = (DID_NO_CONNECT << 16);
746 scsi_done(cmd);
747 } else {
748 trace_scsi_dispatch_cmd_start(cmd);
749 cmd->scsi_done = scsi_done;
750 rtn = host->hostt->queuecommand(host, cmd);
751 }
752
753 if (rtn) {
754 trace_scsi_dispatch_cmd_error(cmd, rtn);
755 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
756 rtn != SCSI_MLQUEUE_TARGET_BUSY)
757 rtn = SCSI_MLQUEUE_HOST_BUSY;
758
759 scsi_queue_insert(cmd, rtn);
760
761 SCSI_LOG_MLQUEUE(3,
762 printk("queuecommand : request rejected\n"));
763 }
764
765 out:
766 SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
767 return rtn;
768}
769
770/**
771 * scsi_done - Enqueue the finished SCSI command into the done queue.
772 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
773 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
774 *
775 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
776 * which regains ownership of the SCSI command (de facto) from a LLDD, and
777 * enqueues the command to the done queue for further processing.
778 *
779 * This is the producer of the done queue who enqueues at the tail.
780 *
781 * This function is interrupt context safe.
782 */
783static void scsi_done(struct scsi_cmnd *cmd)
784{
785 trace_scsi_dispatch_cmd_done(cmd);
786 blk_complete_request(cmd->request);
787}
788
789/**
790 * scsi_finish_command - cleanup and pass command back to upper layer
791 * @cmd: the command
792 *
793 * Description: Pass command off to upper layer for finishing of I/O
794 * request, waking processes that are waiting on results,
795 * etc.
796 */
797void scsi_finish_command(struct scsi_cmnd *cmd)
798{
799 struct scsi_device *sdev = cmd->device;
800 struct scsi_target *starget = scsi_target(sdev);
801 struct Scsi_Host *shost = sdev->host;
802 struct scsi_driver *drv;
803 unsigned int good_bytes;
804
805 scsi_device_unbusy(sdev);
806
807 /*
808 * Clear the flags which say that the device/host is no longer
809 * capable of accepting new commands. These are set in scsi_queue.c
810 * for both the queue full condition on a device, and for a
811 * host full condition on the host.
812 *
813 * XXX(hch): What about locking?
814 */
815 shost->host_blocked = 0;
816 starget->target_blocked = 0;
817 sdev->device_blocked = 0;
818
819 /*
820 * If we have valid sense information, then some kind of recovery
821 * must have taken place. Make a note of this.
822 */
823 if (SCSI_SENSE_VALID(cmd))
824 cmd->result |= (DRIVER_SENSE << 24);
825
826 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
827 "Notifying upper driver of completion "
828 "(result %x)\n", cmd->result));
829
830 good_bytes = scsi_bufflen(cmd);
831 if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
832 int old_good_bytes = good_bytes;
833 drv = scsi_cmd_to_driver(cmd);
834 if (drv->done)
835 good_bytes = drv->done(cmd);
836 /*
837 * USB may not give sense identifying bad sector and
838 * simply return a residue instead, so subtract off the
839 * residue if drv->done() error processing indicates no
840 * change to the completion length.
841 */
842 if (good_bytes == old_good_bytes)
843 good_bytes -= scsi_get_resid(cmd);
844 }
845 scsi_io_completion(cmd, good_bytes);
846}
847EXPORT_SYMBOL(scsi_finish_command);
848
849/**
850 * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
851 * @sdev: SCSI Device in question
852 * @tagged: Do we use tagged queueing (non-0) or do we treat
853 * this device as an untagged device (0)
854 * @tags: Number of tags allowed if tagged queueing enabled,
855 * or number of commands the low level driver can
856 * queue up in non-tagged mode (as per cmd_per_lun).
857 *
858 * Returns: Nothing
859 *
860 * Lock Status: None held on entry
861 *
862 * Notes: Low level drivers may call this at any time and we will do
863 * the right thing depending on whether or not the device is
864 * currently active and whether or not it even has the
865 * command blocks built yet.
866 */
867void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
868{
869 unsigned long flags;
870
871 /*
872 * refuse to set tagged depth to an unworkable size
873 */
874 if (tags <= 0)
875 return;
876
877 spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
878
879 /*
880 * Check to see if the queue is managed by the block layer.
881 * If it is, and we fail to adjust the depth, exit.
882 *
883 * Do not resize the tag map if it is a host wide share bqt,
884 * because the size should be the hosts's can_queue. If there
885 * is more IO than the LLD's can_queue (so there are not enuogh
886 * tags) request_fn's host queue ready check will handle it.
887 */
888 if (!sdev->host->bqt) {
889 if (blk_queue_tagged(sdev->request_queue) &&
890 blk_queue_resize_tags(sdev->request_queue, tags) != 0)
891 goto out;
892 }
893
894 sdev->queue_depth = tags;
895 switch (tagged) {
896 case MSG_ORDERED_TAG:
897 sdev->ordered_tags = 1;
898 sdev->simple_tags = 1;
899 break;
900 case MSG_SIMPLE_TAG:
901 sdev->ordered_tags = 0;
902 sdev->simple_tags = 1;
903 break;
904 default:
905 sdev_printk(KERN_WARNING, sdev,
906 "scsi_adjust_queue_depth, bad queue type, "
907 "disabled\n");
908 case 0:
909 sdev->ordered_tags = sdev->simple_tags = 0;
910 sdev->queue_depth = tags;
911 break;
912 }
913 out:
914 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
915}
916EXPORT_SYMBOL(scsi_adjust_queue_depth);
917
918/**
919 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
920 * @sdev: SCSI Device in question
921 * @depth: Current number of outstanding SCSI commands on this device,
922 * not counting the one returned as QUEUE_FULL.
923 *
924 * Description: This function will track successive QUEUE_FULL events on a
925 * specific SCSI device to determine if and when there is a
926 * need to adjust the queue depth on the device.
927 *
928 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
929 * -1 - Drop back to untagged operation using host->cmd_per_lun
930 * as the untagged command depth
931 *
932 * Lock Status: None held on entry
933 *
934 * Notes: Low level drivers may call this at any time and we will do
935 * "The Right Thing." We are interrupt context safe.
936 */
937int scsi_track_queue_full(struct scsi_device *sdev, int depth)
938{
939
940 /*
941 * Don't let QUEUE_FULLs on the same
942 * jiffies count, they could all be from
943 * same event.
944 */
945 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
946 return 0;
947
948 sdev->last_queue_full_time = jiffies;
949 if (sdev->last_queue_full_depth != depth) {
950 sdev->last_queue_full_count = 1;
951 sdev->last_queue_full_depth = depth;
952 } else {
953 sdev->last_queue_full_count++;
954 }
955
956 if (sdev->last_queue_full_count <= 10)
957 return 0;
958 if (sdev->last_queue_full_depth < 8) {
959 /* Drop back to untagged */
960 scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
961 return -1;
962 }
963
964 if (sdev->ordered_tags)
965 scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
966 else
967 scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
968 return depth;
969}
970EXPORT_SYMBOL(scsi_track_queue_full);
971
972/**
973 * scsi_vpd_inquiry - Request a device provide us with a VPD page
974 * @sdev: The device to ask
975 * @buffer: Where to put the result
976 * @page: Which Vital Product Data to return
977 * @len: The length of the buffer
978 *
979 * This is an internal helper function. You probably want to use
980 * scsi_get_vpd_page instead.
981 *
982 * Returns 0 on success or a negative error number.
983 */
984static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
985 u8 page, unsigned len)
986{
987 int result;
988 unsigned char cmd[16];
989
990 cmd[0] = INQUIRY;
991 cmd[1] = 1; /* EVPD */
992 cmd[2] = page;
993 cmd[3] = len >> 8;
994 cmd[4] = len & 0xff;
995 cmd[5] = 0; /* Control byte */
996
997 /*
998 * I'm not convinced we need to try quite this hard to get VPD, but
999 * all the existing users tried this hard.
1000 */
1001 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
1002 len, NULL, 30 * HZ, 3, NULL);
1003 if (result)
1004 return result;
1005
1006 /* Sanity check that we got the page back that we asked for */
1007 if (buffer[1] != page)
1008 return -EIO;
1009
1010 return 0;
1011}
1012
1013/**
1014 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1015 * @sdev: The device to ask
1016 * @page: Which Vital Product Data to return
1017 * @buf: where to store the VPD
1018 * @buf_len: number of bytes in the VPD buffer area
1019 *
1020 * SCSI devices may optionally supply Vital Product Data. Each 'page'
1021 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1022 * If the device supports this VPD page, this routine returns a pointer
1023 * to a buffer containing the data from that page. The caller is
1024 * responsible for calling kfree() on this pointer when it is no longer
1025 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1026 */
1027int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
1028 int buf_len)
1029{
1030 int i, result;
1031
1032 /* Ask for all the pages supported by this device */
1033 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
1034 if (result)
1035 goto fail;
1036
1037 /* If the user actually wanted this page, we can skip the rest */
1038 if (page == 0)
1039 return 0;
1040
1041 for (i = 0; i < min((int)buf[3], buf_len - 4); i++)
1042 if (buf[i + 4] == page)
1043 goto found;
1044
1045 if (i < buf[3] && i >= buf_len - 4)
1046 /* ran off the end of the buffer, give us benefit of doubt */
1047 goto found;
1048 /* The device claims it doesn't support the requested page */
1049 goto fail;
1050
1051 found:
1052 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
1053 if (result)
1054 goto fail;
1055
1056 return 0;
1057
1058 fail:
1059 return -EINVAL;
1060}
1061EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1062
1063/**
1064 * scsi_device_get - get an additional reference to a scsi_device
1065 * @sdev: device to get a reference to
1066 *
1067 * Description: Gets a reference to the scsi_device and increments the use count
1068 * of the underlying LLDD module. You must hold host_lock of the
1069 * parent Scsi_Host or already have a reference when calling this.
1070 */
1071int scsi_device_get(struct scsi_device *sdev)
1072{
1073 if (sdev->sdev_state == SDEV_DEL)
1074 return -ENXIO;
1075 if (!get_device(&sdev->sdev_gendev))
1076 return -ENXIO;
1077 /* We can fail this if we're doing SCSI operations
1078 * from module exit (like cache flush) */
1079 try_module_get(sdev->host->hostt->module);
1080
1081 return 0;
1082}
1083EXPORT_SYMBOL(scsi_device_get);
1084
1085/**
1086 * scsi_device_put - release a reference to a scsi_device
1087 * @sdev: device to release a reference on.
1088 *
1089 * Description: Release a reference to the scsi_device and decrements the use
1090 * count of the underlying LLDD module. The device is freed once the last
1091 * user vanishes.
1092 */
1093void scsi_device_put(struct scsi_device *sdev)
1094{
1095#ifdef CONFIG_MODULE_UNLOAD
1096 struct module *module = sdev->host->hostt->module;
1097
1098 /* The module refcount will be zero if scsi_device_get()
1099 * was called from a module removal routine */
1100 if (module && module_refcount(module) != 0)
1101 module_put(module);
1102#endif
1103 put_device(&sdev->sdev_gendev);
1104}
1105EXPORT_SYMBOL(scsi_device_put);
1106
1107/* helper for shost_for_each_device, see that for documentation */
1108struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1109 struct scsi_device *prev)
1110{
1111 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1112 struct scsi_device *next = NULL;
1113 unsigned long flags;
1114
1115 spin_lock_irqsave(shost->host_lock, flags);
1116 while (list->next != &shost->__devices) {
1117 next = list_entry(list->next, struct scsi_device, siblings);
1118 /* skip devices that we can't get a reference to */
1119 if (!scsi_device_get(next))
1120 break;
1121 next = NULL;
1122 list = list->next;
1123 }
1124 spin_unlock_irqrestore(shost->host_lock, flags);
1125
1126 if (prev)
1127 scsi_device_put(prev);
1128 return next;
1129}
1130EXPORT_SYMBOL(__scsi_iterate_devices);
1131
1132/**
1133 * starget_for_each_device - helper to walk all devices of a target
1134 * @starget: target whose devices we want to iterate over.
1135 * @data: Opaque passed to each function call.
1136 * @fn: Function to call on each device
1137 *
1138 * This traverses over each device of @starget. The devices have
1139 * a reference that must be released by scsi_host_put when breaking
1140 * out of the loop.
1141 */
1142void starget_for_each_device(struct scsi_target *starget, void *data,
1143 void (*fn)(struct scsi_device *, void *))
1144{
1145 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1146 struct scsi_device *sdev;
1147
1148 shost_for_each_device(sdev, shost) {
1149 if ((sdev->channel == starget->channel) &&
1150 (sdev->id == starget->id))
1151 fn(sdev, data);
1152 }
1153}
1154EXPORT_SYMBOL(starget_for_each_device);
1155
1156/**
1157 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1158 * @starget: target whose devices we want to iterate over.
1159 * @data: parameter for callback @fn()
1160 * @fn: callback function that is invoked for each device
1161 *
1162 * This traverses over each device of @starget. It does _not_
1163 * take a reference on the scsi_device, so the whole loop must be
1164 * protected by shost->host_lock.
1165 *
1166 * Note: The only reason why drivers would want to use this is because
1167 * they need to access the device list in irq context. Otherwise you
1168 * really want to use starget_for_each_device instead.
1169 **/
1170void __starget_for_each_device(struct scsi_target *starget, void *data,
1171 void (*fn)(struct scsi_device *, void *))
1172{
1173 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1174 struct scsi_device *sdev;
1175
1176 __shost_for_each_device(sdev, shost) {
1177 if ((sdev->channel == starget->channel) &&
1178 (sdev->id == starget->id))
1179 fn(sdev, data);
1180 }
1181}
1182EXPORT_SYMBOL(__starget_for_each_device);
1183
1184/**
1185 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1186 * @starget: SCSI target pointer
1187 * @lun: SCSI Logical Unit Number
1188 *
1189 * Description: Looks up the scsi_device with the specified @lun for a given
1190 * @starget. The returned scsi_device does not have an additional
1191 * reference. You must hold the host's host_lock over this call and
1192 * any access to the returned scsi_device. A scsi_device in state
1193 * SDEV_DEL is skipped.
1194 *
1195 * Note: The only reason why drivers should use this is because
1196 * they need to access the device list in irq context. Otherwise you
1197 * really want to use scsi_device_lookup_by_target instead.
1198 **/
1199struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1200 uint lun)
1201{
1202 struct scsi_device *sdev;
1203
1204 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1205 if (sdev->sdev_state == SDEV_DEL)
1206 continue;
1207 if (sdev->lun ==lun)
1208 return sdev;
1209 }
1210
1211 return NULL;
1212}
1213EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1214
1215/**
1216 * scsi_device_lookup_by_target - find a device given the target
1217 * @starget: SCSI target pointer
1218 * @lun: SCSI Logical Unit Number
1219 *
1220 * Description: Looks up the scsi_device with the specified @lun for a given
1221 * @starget. The returned scsi_device has an additional reference that
1222 * needs to be released with scsi_device_put once you're done with it.
1223 **/
1224struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1225 uint lun)
1226{
1227 struct scsi_device *sdev;
1228 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1229 unsigned long flags;
1230
1231 spin_lock_irqsave(shost->host_lock, flags);
1232 sdev = __scsi_device_lookup_by_target(starget, lun);
1233 if (sdev && scsi_device_get(sdev))
1234 sdev = NULL;
1235 spin_unlock_irqrestore(shost->host_lock, flags);
1236
1237 return sdev;
1238}
1239EXPORT_SYMBOL(scsi_device_lookup_by_target);
1240
1241/**
1242 * __scsi_device_lookup - find a device given the host (UNLOCKED)
1243 * @shost: SCSI host pointer
1244 * @channel: SCSI channel (zero if only one channel)
1245 * @id: SCSI target number (physical unit number)
1246 * @lun: SCSI Logical Unit Number
1247 *
1248 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1249 * for a given host. The returned scsi_device does not have an additional
1250 * reference. You must hold the host's host_lock over this call and any access
1251 * to the returned scsi_device.
1252 *
1253 * Note: The only reason why drivers would want to use this is because
1254 * they need to access the device list in irq context. Otherwise you
1255 * really want to use scsi_device_lookup instead.
1256 **/
1257struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1258 uint channel, uint id, uint lun)
1259{
1260 struct scsi_device *sdev;
1261
1262 list_for_each_entry(sdev, &shost->__devices, siblings) {
1263 if (sdev->channel == channel && sdev->id == id &&
1264 sdev->lun ==lun)
1265 return sdev;
1266 }
1267
1268 return NULL;
1269}
1270EXPORT_SYMBOL(__scsi_device_lookup);
1271
1272/**
1273 * scsi_device_lookup - find a device given the host
1274 * @shost: SCSI host pointer
1275 * @channel: SCSI channel (zero if only one channel)
1276 * @id: SCSI target number (physical unit number)
1277 * @lun: SCSI Logical Unit Number
1278 *
1279 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1280 * for a given host. The returned scsi_device has an additional reference that
1281 * needs to be released with scsi_device_put once you're done with it.
1282 **/
1283struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1284 uint channel, uint id, uint lun)
1285{
1286 struct scsi_device *sdev;
1287 unsigned long flags;
1288
1289 spin_lock_irqsave(shost->host_lock, flags);
1290 sdev = __scsi_device_lookup(shost, channel, id, lun);
1291 if (sdev && scsi_device_get(sdev))
1292 sdev = NULL;
1293 spin_unlock_irqrestore(shost->host_lock, flags);
1294
1295 return sdev;
1296}
1297EXPORT_SYMBOL(scsi_device_lookup);
1298
1299MODULE_DESCRIPTION("SCSI core");
1300MODULE_LICENSE("GPL");
1301
1302module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1303MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1304
1305static int __init init_scsi(void)
1306{
1307 int error;
1308
1309 error = scsi_init_queue();
1310 if (error)
1311 return error;
1312 error = scsi_init_procfs();
1313 if (error)
1314 goto cleanup_queue;
1315 error = scsi_init_devinfo();
1316 if (error)
1317 goto cleanup_procfs;
1318 error = scsi_init_hosts();
1319 if (error)
1320 goto cleanup_devlist;
1321 error = scsi_init_sysctl();
1322 if (error)
1323 goto cleanup_hosts;
1324 error = scsi_sysfs_register();
1325 if (error)
1326 goto cleanup_sysctl;
1327
1328 scsi_netlink_init();
1329
1330 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1331 return 0;
1332
1333cleanup_sysctl:
1334 scsi_exit_sysctl();
1335cleanup_hosts:
1336 scsi_exit_hosts();
1337cleanup_devlist:
1338 scsi_exit_devinfo();
1339cleanup_procfs:
1340 scsi_exit_procfs();
1341cleanup_queue:
1342 scsi_exit_queue();
1343 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1344 -error);
1345 return error;
1346}
1347
1348static void __exit exit_scsi(void)
1349{
1350 scsi_netlink_exit();
1351 scsi_sysfs_unregister();
1352 scsi_exit_sysctl();
1353 scsi_exit_hosts();
1354 scsi_exit_devinfo();
1355 scsi_exit_procfs();
1356 scsi_exit_queue();
1357}
1358
1359subsys_initcall(init_scsi);
1360module_exit(exit_scsi);