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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#include <linux/async.h>
58#include <asm/unaligned.h>
59
60#include <scsi/scsi.h>
61#include <scsi/scsi_cmnd.h>
62#include <scsi/scsi_dbg.h>
63#include <scsi/scsi_device.h>
64#include <scsi/scsi_driver.h>
65#include <scsi/scsi_eh.h>
66#include <scsi/scsi_host.h>
67#include <scsi/scsi_tcq.h>
68
69#include "scsi_priv.h"
70#include "scsi_logging.h"
71
72#define CREATE_TRACE_POINTS
73#include <trace/events/scsi.h>
74
75/*
76 * Definitions and constants.
77 */
78
79/*
80 * Note - the initial logging level can be set here to log events at boot time.
81 * After the system is up, you may enable logging via the /proc interface.
82 */
83unsigned int scsi_logging_level;
84#if defined(CONFIG_SCSI_LOGGING)
85EXPORT_SYMBOL(scsi_logging_level);
86#endif
87
88/* sd, scsi core and power management need to coordinate flushing async actions */
89ASYNC_DOMAIN(scsi_sd_probe_domain);
90EXPORT_SYMBOL(scsi_sd_probe_domain);
91
92/*
93 * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of
94 * asynchronous system resume operations. It is marked 'exclusive' to avoid
95 * being included in the async_synchronize_full() that is invoked by
96 * dpm_resume()
97 */
98ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
99EXPORT_SYMBOL(scsi_sd_pm_domain);
100
101/**
102 * scsi_put_command - Free a scsi command block
103 * @cmd: command block to free
104 *
105 * Returns: Nothing.
106 *
107 * Notes: The command must not belong to any lists.
108 */
109void scsi_put_command(struct scsi_cmnd *cmd)
110{
111 scsi_del_cmd_from_list(cmd);
112 BUG_ON(delayed_work_pending(&cmd->abort_work));
113}
114
115#ifdef CONFIG_SCSI_LOGGING
116void scsi_log_send(struct scsi_cmnd *cmd)
117{
118 unsigned int level;
119
120 /*
121 * If ML QUEUE log level is greater than or equal to:
122 *
123 * 1: nothing (match completion)
124 *
125 * 2: log opcode + command of all commands + cmd address
126 *
127 * 3: same as 2
128 *
129 * 4: same as 3
130 */
131 if (unlikely(scsi_logging_level)) {
132 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
133 SCSI_LOG_MLQUEUE_BITS);
134 if (level > 1) {
135 scmd_printk(KERN_INFO, cmd,
136 "Send: scmd 0x%p\n", cmd);
137 scsi_print_command(cmd);
138 }
139 }
140}
141
142void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
143{
144 unsigned int level;
145
146 /*
147 * If ML COMPLETE log level is greater than or equal to:
148 *
149 * 1: log disposition, result, opcode + command, and conditionally
150 * sense data for failures or non SUCCESS dispositions.
151 *
152 * 2: same as 1 but for all command completions.
153 *
154 * 3: same as 2
155 *
156 * 4: same as 3 plus dump extra junk
157 */
158 if (unlikely(scsi_logging_level)) {
159 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
160 SCSI_LOG_MLCOMPLETE_BITS);
161 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
162 (level > 1)) {
163 scsi_print_result(cmd, "Done", disposition);
164 scsi_print_command(cmd);
165 if (status_byte(cmd->result) & CHECK_CONDITION)
166 scsi_print_sense(cmd);
167 if (level > 3)
168 scmd_printk(KERN_INFO, cmd,
169 "scsi host busy %d failed %d\n",
170 atomic_read(&cmd->device->host->host_busy),
171 cmd->device->host->host_failed);
172 }
173 }
174}
175#endif
176
177/**
178 * scsi_cmd_get_serial - Assign a serial number to a command
179 * @host: the scsi host
180 * @cmd: command to assign serial number to
181 *
182 * Description: a serial number identifies a request for error recovery
183 * and debugging purposes. Protected by the Host_Lock of host.
184 */
185void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
186{
187 cmd->serial_number = host->cmd_serial_number++;
188 if (cmd->serial_number == 0)
189 cmd->serial_number = host->cmd_serial_number++;
190}
191EXPORT_SYMBOL(scsi_cmd_get_serial);
192
193/**
194 * scsi_finish_command - cleanup and pass command back to upper layer
195 * @cmd: the command
196 *
197 * Description: Pass command off to upper layer for finishing of I/O
198 * request, waking processes that are waiting on results,
199 * etc.
200 */
201void scsi_finish_command(struct scsi_cmnd *cmd)
202{
203 struct scsi_device *sdev = cmd->device;
204 struct scsi_target *starget = scsi_target(sdev);
205 struct Scsi_Host *shost = sdev->host;
206 struct scsi_driver *drv;
207 unsigned int good_bytes;
208
209 scsi_device_unbusy(sdev);
210
211 /*
212 * Clear the flags that say that the device/target/host is no longer
213 * capable of accepting new commands.
214 */
215 if (atomic_read(&shost->host_blocked))
216 atomic_set(&shost->host_blocked, 0);
217 if (atomic_read(&starget->target_blocked))
218 atomic_set(&starget->target_blocked, 0);
219 if (atomic_read(&sdev->device_blocked))
220 atomic_set(&sdev->device_blocked, 0);
221
222 /*
223 * If we have valid sense information, then some kind of recovery
224 * must have taken place. Make a note of this.
225 */
226 if (SCSI_SENSE_VALID(cmd))
227 cmd->result |= (DRIVER_SENSE << 24);
228
229 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
230 "Notifying upper driver of completion "
231 "(result %x)\n", cmd->result));
232
233 good_bytes = scsi_bufflen(cmd);
234 if (!blk_rq_is_passthrough(cmd->request)) {
235 int old_good_bytes = good_bytes;
236 drv = scsi_cmd_to_driver(cmd);
237 if (drv->done)
238 good_bytes = drv->done(cmd);
239 /*
240 * USB may not give sense identifying bad sector and
241 * simply return a residue instead, so subtract off the
242 * residue if drv->done() error processing indicates no
243 * change to the completion length.
244 */
245 if (good_bytes == old_good_bytes)
246 good_bytes -= scsi_get_resid(cmd);
247 }
248 scsi_io_completion(cmd, good_bytes);
249}
250
251/**
252 * scsi_change_queue_depth - change a device's queue depth
253 * @sdev: SCSI Device in question
254 * @depth: number of commands allowed to be queued to the driver
255 *
256 * Sets the device queue depth and returns the new value.
257 */
258int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
259{
260 if (depth > 0) {
261 sdev->queue_depth = depth;
262 wmb();
263 }
264
265 if (sdev->request_queue)
266 blk_set_queue_depth(sdev->request_queue, depth);
267
268 return sdev->queue_depth;
269}
270EXPORT_SYMBOL(scsi_change_queue_depth);
271
272/**
273 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
274 * @sdev: SCSI Device in question
275 * @depth: Current number of outstanding SCSI commands on this device,
276 * not counting the one returned as QUEUE_FULL.
277 *
278 * Description: This function will track successive QUEUE_FULL events on a
279 * specific SCSI device to determine if and when there is a
280 * need to adjust the queue depth on the device.
281 *
282 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
283 * -1 - Drop back to untagged operation using host->cmd_per_lun
284 * as the untagged command depth
285 *
286 * Lock Status: None held on entry
287 *
288 * Notes: Low level drivers may call this at any time and we will do
289 * "The Right Thing." We are interrupt context safe.
290 */
291int scsi_track_queue_full(struct scsi_device *sdev, int depth)
292{
293
294 /*
295 * Don't let QUEUE_FULLs on the same
296 * jiffies count, they could all be from
297 * same event.
298 */
299 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
300 return 0;
301
302 sdev->last_queue_full_time = jiffies;
303 if (sdev->last_queue_full_depth != depth) {
304 sdev->last_queue_full_count = 1;
305 sdev->last_queue_full_depth = depth;
306 } else {
307 sdev->last_queue_full_count++;
308 }
309
310 if (sdev->last_queue_full_count <= 10)
311 return 0;
312
313 return scsi_change_queue_depth(sdev, depth);
314}
315EXPORT_SYMBOL(scsi_track_queue_full);
316
317/**
318 * scsi_vpd_inquiry - Request a device provide us with a VPD page
319 * @sdev: The device to ask
320 * @buffer: Where to put the result
321 * @page: Which Vital Product Data to return
322 * @len: The length of the buffer
323 *
324 * This is an internal helper function. You probably want to use
325 * scsi_get_vpd_page instead.
326 *
327 * Returns size of the vpd page on success or a negative error number.
328 */
329static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
330 u8 page, unsigned len)
331{
332 int result;
333 unsigned char cmd[16];
334
335 if (len < 4)
336 return -EINVAL;
337
338 cmd[0] = INQUIRY;
339 cmd[1] = 1; /* EVPD */
340 cmd[2] = page;
341 cmd[3] = len >> 8;
342 cmd[4] = len & 0xff;
343 cmd[5] = 0; /* Control byte */
344
345 /*
346 * I'm not convinced we need to try quite this hard to get VPD, but
347 * all the existing users tried this hard.
348 */
349 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
350 len, NULL, 30 * HZ, 3, NULL);
351 if (result)
352 return -EIO;
353
354 /* Sanity check that we got the page back that we asked for */
355 if (buffer[1] != page)
356 return -EIO;
357
358 return get_unaligned_be16(&buffer[2]) + 4;
359}
360
361/**
362 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
363 * @sdev: The device to ask
364 * @page: Which Vital Product Data to return
365 * @buf: where to store the VPD
366 * @buf_len: number of bytes in the VPD buffer area
367 *
368 * SCSI devices may optionally supply Vital Product Data. Each 'page'
369 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
370 * If the device supports this VPD page, this routine returns a pointer
371 * to a buffer containing the data from that page. The caller is
372 * responsible for calling kfree() on this pointer when it is no longer
373 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
374 */
375int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
376 int buf_len)
377{
378 int i, result;
379
380 if (sdev->skip_vpd_pages)
381 goto fail;
382
383 /* Ask for all the pages supported by this device */
384 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
385 if (result < 4)
386 goto fail;
387
388 /* If the user actually wanted this page, we can skip the rest */
389 if (page == 0)
390 return 0;
391
392 for (i = 4; i < min(result, buf_len); i++)
393 if (buf[i] == page)
394 goto found;
395
396 if (i < result && i >= buf_len)
397 /* ran off the end of the buffer, give us benefit of doubt */
398 goto found;
399 /* The device claims it doesn't support the requested page */
400 goto fail;
401
402 found:
403 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
404 if (result < 0)
405 goto fail;
406
407 return 0;
408
409 fail:
410 return -EINVAL;
411}
412EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
413
414/**
415 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
416 * @sdev: The device to ask
417 * @page: Which Vital Product Data to return
418 *
419 * Returns %NULL upon failure.
420 */
421static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
422{
423 struct scsi_vpd *vpd_buf;
424 int vpd_len = SCSI_VPD_PG_LEN, result;
425
426retry_pg:
427 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
428 if (!vpd_buf)
429 return NULL;
430
431 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
432 if (result < 0) {
433 kfree(vpd_buf);
434 return NULL;
435 }
436 if (result > vpd_len) {
437 vpd_len = result;
438 kfree(vpd_buf);
439 goto retry_pg;
440 }
441
442 vpd_buf->len = result;
443
444 return vpd_buf;
445}
446
447static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
448 struct scsi_vpd __rcu **sdev_vpd_buf)
449{
450 struct scsi_vpd *vpd_buf;
451
452 vpd_buf = scsi_get_vpd_buf(sdev, page);
453 if (!vpd_buf)
454 return;
455
456 mutex_lock(&sdev->inquiry_mutex);
457 rcu_swap_protected(*sdev_vpd_buf, vpd_buf,
458 lockdep_is_held(&sdev->inquiry_mutex));
459 mutex_unlock(&sdev->inquiry_mutex);
460
461 if (vpd_buf)
462 kfree_rcu(vpd_buf, rcu);
463}
464
465/**
466 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
467 * @sdev: The device to ask
468 *
469 * Attach the 'Device Identification' VPD page (0x83) and the
470 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
471 * structure. This information can be used to identify the device
472 * uniquely.
473 */
474void scsi_attach_vpd(struct scsi_device *sdev)
475{
476 int i;
477 struct scsi_vpd *vpd_buf;
478
479 if (!scsi_device_supports_vpd(sdev))
480 return;
481
482 /* Ask for all the pages supported by this device */
483 vpd_buf = scsi_get_vpd_buf(sdev, 0);
484 if (!vpd_buf)
485 return;
486
487 for (i = 4; i < vpd_buf->len; i++) {
488 if (vpd_buf->data[i] == 0x80)
489 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
490 if (vpd_buf->data[i] == 0x83)
491 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
492 }
493 kfree(vpd_buf);
494}
495
496/**
497 * scsi_report_opcode - Find out if a given command opcode is supported
498 * @sdev: scsi device to query
499 * @buffer: scratch buffer (must be at least 20 bytes long)
500 * @len: length of buffer
501 * @opcode: opcode for command to look up
502 *
503 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
504 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
505 * unsupported and 1 if the device claims to support the command.
506 */
507int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
508 unsigned int len, unsigned char opcode)
509{
510 unsigned char cmd[16];
511 struct scsi_sense_hdr sshdr;
512 int result;
513
514 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
515 return -EINVAL;
516
517 memset(cmd, 0, 16);
518 cmd[0] = MAINTENANCE_IN;
519 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
520 cmd[2] = 1; /* One command format */
521 cmd[3] = opcode;
522 put_unaligned_be32(len, &cmd[6]);
523 memset(buffer, 0, len);
524
525 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
526 &sshdr, 30 * HZ, 3, NULL);
527
528 if (result && scsi_sense_valid(&sshdr) &&
529 sshdr.sense_key == ILLEGAL_REQUEST &&
530 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
531 return -EINVAL;
532
533 if ((buffer[1] & 3) == 3) /* Command supported */
534 return 1;
535
536 return 0;
537}
538EXPORT_SYMBOL(scsi_report_opcode);
539
540/**
541 * scsi_device_get - get an additional reference to a scsi_device
542 * @sdev: device to get a reference to
543 *
544 * Description: Gets a reference to the scsi_device and increments the use count
545 * of the underlying LLDD module. You must hold host_lock of the
546 * parent Scsi_Host or already have a reference when calling this.
547 *
548 * This will fail if a device is deleted or cancelled, or when the LLD module
549 * is in the process of being unloaded.
550 */
551int scsi_device_get(struct scsi_device *sdev)
552{
553 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
554 goto fail;
555 if (!get_device(&sdev->sdev_gendev))
556 goto fail;
557 if (!try_module_get(sdev->host->hostt->module))
558 goto fail_put_device;
559 return 0;
560
561fail_put_device:
562 put_device(&sdev->sdev_gendev);
563fail:
564 return -ENXIO;
565}
566EXPORT_SYMBOL(scsi_device_get);
567
568/**
569 * scsi_device_put - release a reference to a scsi_device
570 * @sdev: device to release a reference on.
571 *
572 * Description: Release a reference to the scsi_device and decrements the use
573 * count of the underlying LLDD module. The device is freed once the last
574 * user vanishes.
575 */
576void scsi_device_put(struct scsi_device *sdev)
577{
578 module_put(sdev->host->hostt->module);
579 put_device(&sdev->sdev_gendev);
580}
581EXPORT_SYMBOL(scsi_device_put);
582
583/* helper for shost_for_each_device, see that for documentation */
584struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
585 struct scsi_device *prev)
586{
587 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
588 struct scsi_device *next = NULL;
589 unsigned long flags;
590
591 spin_lock_irqsave(shost->host_lock, flags);
592 while (list->next != &shost->__devices) {
593 next = list_entry(list->next, struct scsi_device, siblings);
594 /* skip devices that we can't get a reference to */
595 if (!scsi_device_get(next))
596 break;
597 next = NULL;
598 list = list->next;
599 }
600 spin_unlock_irqrestore(shost->host_lock, flags);
601
602 if (prev)
603 scsi_device_put(prev);
604 return next;
605}
606EXPORT_SYMBOL(__scsi_iterate_devices);
607
608/**
609 * starget_for_each_device - helper to walk all devices of a target
610 * @starget: target whose devices we want to iterate over.
611 * @data: Opaque passed to each function call.
612 * @fn: Function to call on each device
613 *
614 * This traverses over each device of @starget. The devices have
615 * a reference that must be released by scsi_host_put when breaking
616 * out of the loop.
617 */
618void starget_for_each_device(struct scsi_target *starget, void *data,
619 void (*fn)(struct scsi_device *, void *))
620{
621 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
622 struct scsi_device *sdev;
623
624 shost_for_each_device(sdev, shost) {
625 if ((sdev->channel == starget->channel) &&
626 (sdev->id == starget->id))
627 fn(sdev, data);
628 }
629}
630EXPORT_SYMBOL(starget_for_each_device);
631
632/**
633 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
634 * @starget: target whose devices we want to iterate over.
635 * @data: parameter for callback @fn()
636 * @fn: callback function that is invoked for each device
637 *
638 * This traverses over each device of @starget. It does _not_
639 * take a reference on the scsi_device, so the whole loop must be
640 * protected by shost->host_lock.
641 *
642 * Note: The only reason why drivers would want to use this is because
643 * they need to access the device list in irq context. Otherwise you
644 * really want to use starget_for_each_device instead.
645 **/
646void __starget_for_each_device(struct scsi_target *starget, void *data,
647 void (*fn)(struct scsi_device *, void *))
648{
649 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
650 struct scsi_device *sdev;
651
652 __shost_for_each_device(sdev, shost) {
653 if ((sdev->channel == starget->channel) &&
654 (sdev->id == starget->id))
655 fn(sdev, data);
656 }
657}
658EXPORT_SYMBOL(__starget_for_each_device);
659
660/**
661 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
662 * @starget: SCSI target pointer
663 * @lun: SCSI Logical Unit Number
664 *
665 * Description: Looks up the scsi_device with the specified @lun for a given
666 * @starget. The returned scsi_device does not have an additional
667 * reference. You must hold the host's host_lock over this call and
668 * any access to the returned scsi_device. A scsi_device in state
669 * SDEV_DEL is skipped.
670 *
671 * Note: The only reason why drivers should use this is because
672 * they need to access the device list in irq context. Otherwise you
673 * really want to use scsi_device_lookup_by_target instead.
674 **/
675struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
676 u64 lun)
677{
678 struct scsi_device *sdev;
679
680 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
681 if (sdev->sdev_state == SDEV_DEL)
682 continue;
683 if (sdev->lun ==lun)
684 return sdev;
685 }
686
687 return NULL;
688}
689EXPORT_SYMBOL(__scsi_device_lookup_by_target);
690
691/**
692 * scsi_device_lookup_by_target - find a device given the target
693 * @starget: SCSI target pointer
694 * @lun: SCSI Logical Unit Number
695 *
696 * Description: Looks up the scsi_device with the specified @lun for a given
697 * @starget. The returned scsi_device has an additional reference that
698 * needs to be released with scsi_device_put once you're done with it.
699 **/
700struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
701 u64 lun)
702{
703 struct scsi_device *sdev;
704 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
705 unsigned long flags;
706
707 spin_lock_irqsave(shost->host_lock, flags);
708 sdev = __scsi_device_lookup_by_target(starget, lun);
709 if (sdev && scsi_device_get(sdev))
710 sdev = NULL;
711 spin_unlock_irqrestore(shost->host_lock, flags);
712
713 return sdev;
714}
715EXPORT_SYMBOL(scsi_device_lookup_by_target);
716
717/**
718 * __scsi_device_lookup - find a device given the host (UNLOCKED)
719 * @shost: SCSI host pointer
720 * @channel: SCSI channel (zero if only one channel)
721 * @id: SCSI target number (physical unit number)
722 * @lun: SCSI Logical Unit Number
723 *
724 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
725 * for a given host. The returned scsi_device does not have an additional
726 * reference. You must hold the host's host_lock over this call and any access
727 * to the returned scsi_device.
728 *
729 * Note: The only reason why drivers would want to use this is because
730 * they need to access the device list in irq context. Otherwise you
731 * really want to use scsi_device_lookup instead.
732 **/
733struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
734 uint channel, uint id, u64 lun)
735{
736 struct scsi_device *sdev;
737
738 list_for_each_entry(sdev, &shost->__devices, siblings) {
739 if (sdev->sdev_state == SDEV_DEL)
740 continue;
741 if (sdev->channel == channel && sdev->id == id &&
742 sdev->lun ==lun)
743 return sdev;
744 }
745
746 return NULL;
747}
748EXPORT_SYMBOL(__scsi_device_lookup);
749
750/**
751 * scsi_device_lookup - find a device given the host
752 * @shost: SCSI host pointer
753 * @channel: SCSI channel (zero if only one channel)
754 * @id: SCSI target number (physical unit number)
755 * @lun: SCSI Logical Unit Number
756 *
757 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
758 * for a given host. The returned scsi_device has an additional reference that
759 * needs to be released with scsi_device_put once you're done with it.
760 **/
761struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
762 uint channel, uint id, u64 lun)
763{
764 struct scsi_device *sdev;
765 unsigned long flags;
766
767 spin_lock_irqsave(shost->host_lock, flags);
768 sdev = __scsi_device_lookup(shost, channel, id, lun);
769 if (sdev && scsi_device_get(sdev))
770 sdev = NULL;
771 spin_unlock_irqrestore(shost->host_lock, flags);
772
773 return sdev;
774}
775EXPORT_SYMBOL(scsi_device_lookup);
776
777MODULE_DESCRIPTION("SCSI core");
778MODULE_LICENSE("GPL");
779
780module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
781MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
782
783#ifdef CONFIG_SCSI_MQ_DEFAULT
784bool scsi_use_blk_mq = true;
785#else
786bool scsi_use_blk_mq = false;
787#endif
788module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
789
790static int __init init_scsi(void)
791{
792 int error;
793
794 error = scsi_init_queue();
795 if (error)
796 return error;
797 error = scsi_init_procfs();
798 if (error)
799 goto cleanup_queue;
800 error = scsi_init_devinfo();
801 if (error)
802 goto cleanup_procfs;
803 error = scsi_init_hosts();
804 if (error)
805 goto cleanup_devlist;
806 error = scsi_init_sysctl();
807 if (error)
808 goto cleanup_hosts;
809 error = scsi_sysfs_register();
810 if (error)
811 goto cleanup_sysctl;
812
813 scsi_netlink_init();
814
815 printk(KERN_NOTICE "SCSI subsystem initialized\n");
816 return 0;
817
818cleanup_sysctl:
819 scsi_exit_sysctl();
820cleanup_hosts:
821 scsi_exit_hosts();
822cleanup_devlist:
823 scsi_exit_devinfo();
824cleanup_procfs:
825 scsi_exit_procfs();
826cleanup_queue:
827 scsi_exit_queue();
828 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
829 -error);
830 return error;
831}
832
833static void __exit exit_scsi(void)
834{
835 scsi_netlink_exit();
836 scsi_sysfs_unregister();
837 scsi_exit_sysctl();
838 scsi_exit_hosts();
839 scsi_exit_devinfo();
840 scsi_exit_procfs();
841 scsi_exit_queue();
842 async_unregister_domain(&scsi_sd_probe_domain);
843}
844
845subsys_initcall(init_scsi);
846module_exit(exit_scsi);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * scsi.c Copyright (C) 1992 Drew Eckhardt
4 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
5 * Copyright (C) 2002, 2003 Christoph Hellwig
6 *
7 * generic mid-level SCSI driver
8 * Initial versions: Drew Eckhardt
9 * Subsequent revisions: Eric Youngdale
10 *
11 * <drew@colorado.edu>
12 *
13 * Bug correction thanks go to :
14 * Rik Faith <faith@cs.unc.edu>
15 * Tommy Thorn <tthorn>
16 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
17 *
18 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
19 * add scatter-gather, multiple outstanding request, and other
20 * enhancements.
21 *
22 * Native multichannel, wide scsi, /proc/scsi and hot plugging
23 * support added by Michael Neuffer <mike@i-connect.net>
24 *
25 * Added request_module("scsi_hostadapter") for kerneld:
26 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
27 * Bjorn Ekwall <bj0rn@blox.se>
28 * (changed to kmod)
29 *
30 * Major improvements to the timeout, abort, and reset processing,
31 * as well as performance modifications for large queue depths by
32 * Leonard N. Zubkoff <lnz@dandelion.com>
33 *
34 * Converted cli() code to spinlocks, Ingo Molnar
35 *
36 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
37 *
38 * out_of_space hacks, D. Gilbert (dpg) 990608
39 */
40
41#include <linux/module.h>
42#include <linux/moduleparam.h>
43#include <linux/kernel.h>
44#include <linux/timer.h>
45#include <linux/string.h>
46#include <linux/slab.h>
47#include <linux/blkdev.h>
48#include <linux/delay.h>
49#include <linux/init.h>
50#include <linux/completion.h>
51#include <linux/unistd.h>
52#include <linux/spinlock.h>
53#include <linux/kmod.h>
54#include <linux/interrupt.h>
55#include <linux/notifier.h>
56#include <linux/cpu.h>
57#include <linux/mutex.h>
58#include <linux/async.h>
59#include <asm/unaligned.h>
60
61#include <scsi/scsi.h>
62#include <scsi/scsi_cmnd.h>
63#include <scsi/scsi_dbg.h>
64#include <scsi/scsi_device.h>
65#include <scsi/scsi_driver.h>
66#include <scsi/scsi_eh.h>
67#include <scsi/scsi_host.h>
68#include <scsi/scsi_tcq.h>
69
70#include "scsi_priv.h"
71#include "scsi_logging.h"
72
73#define CREATE_TRACE_POINTS
74#include <trace/events/scsi.h>
75
76/*
77 * Definitions and constants.
78 */
79
80/*
81 * Note - the initial logging level can be set here to log events at boot time.
82 * After the system is up, you may enable logging via the /proc interface.
83 */
84unsigned int scsi_logging_level;
85#if defined(CONFIG_SCSI_LOGGING)
86EXPORT_SYMBOL(scsi_logging_level);
87#endif
88
89/*
90 * Domain for asynchronous system resume operations. It is marked 'exclusive'
91 * to avoid being included in the async_synchronize_full() that is invoked by
92 * dpm_resume().
93 */
94ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
95EXPORT_SYMBOL(scsi_sd_pm_domain);
96
97#ifdef CONFIG_SCSI_LOGGING
98void scsi_log_send(struct scsi_cmnd *cmd)
99{
100 unsigned int level;
101
102 /*
103 * If ML QUEUE log level is greater than or equal to:
104 *
105 * 1: nothing (match completion)
106 *
107 * 2: log opcode + command of all commands + cmd address
108 *
109 * 3: same as 2
110 *
111 * 4: same as 3
112 */
113 if (unlikely(scsi_logging_level)) {
114 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
115 SCSI_LOG_MLQUEUE_BITS);
116 if (level > 1) {
117 scmd_printk(KERN_INFO, cmd,
118 "Send: scmd 0x%p\n", cmd);
119 scsi_print_command(cmd);
120 }
121 }
122}
123
124void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
125{
126 unsigned int level;
127
128 /*
129 * If ML COMPLETE log level is greater than or equal to:
130 *
131 * 1: log disposition, result, opcode + command, and conditionally
132 * sense data for failures or non SUCCESS dispositions.
133 *
134 * 2: same as 1 but for all command completions.
135 *
136 * 3: same as 2
137 *
138 * 4: same as 3 plus dump extra junk
139 */
140 if (unlikely(scsi_logging_level)) {
141 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
142 SCSI_LOG_MLCOMPLETE_BITS);
143 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
144 (level > 1)) {
145 scsi_print_result(cmd, "Done", disposition);
146 scsi_print_command(cmd);
147 if (status_byte(cmd->result) == CHECK_CONDITION)
148 scsi_print_sense(cmd);
149 if (level > 3)
150 scmd_printk(KERN_INFO, cmd,
151 "scsi host busy %d failed %d\n",
152 scsi_host_busy(cmd->device->host),
153 cmd->device->host->host_failed);
154 }
155 }
156}
157#endif
158
159/**
160 * scsi_finish_command - cleanup and pass command back to upper layer
161 * @cmd: the command
162 *
163 * Description: Pass command off to upper layer for finishing of I/O
164 * request, waking processes that are waiting on results,
165 * etc.
166 */
167void scsi_finish_command(struct scsi_cmnd *cmd)
168{
169 struct scsi_device *sdev = cmd->device;
170 struct scsi_target *starget = scsi_target(sdev);
171 struct Scsi_Host *shost = sdev->host;
172 struct scsi_driver *drv;
173 unsigned int good_bytes;
174
175 scsi_device_unbusy(sdev, cmd);
176
177 /*
178 * Clear the flags that say that the device/target/host is no longer
179 * capable of accepting new commands.
180 */
181 if (atomic_read(&shost->host_blocked))
182 atomic_set(&shost->host_blocked, 0);
183 if (atomic_read(&starget->target_blocked))
184 atomic_set(&starget->target_blocked, 0);
185 if (atomic_read(&sdev->device_blocked))
186 atomic_set(&sdev->device_blocked, 0);
187
188 /*
189 * If we have valid sense information, then some kind of recovery
190 * must have taken place. Make a note of this.
191 */
192 if (SCSI_SENSE_VALID(cmd))
193 cmd->result |= (DRIVER_SENSE << 24);
194
195 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
196 "Notifying upper driver of completion "
197 "(result %x)\n", cmd->result));
198
199 good_bytes = scsi_bufflen(cmd);
200 if (!blk_rq_is_passthrough(cmd->request)) {
201 int old_good_bytes = good_bytes;
202 drv = scsi_cmd_to_driver(cmd);
203 if (drv->done)
204 good_bytes = drv->done(cmd);
205 /*
206 * USB may not give sense identifying bad sector and
207 * simply return a residue instead, so subtract off the
208 * residue if drv->done() error processing indicates no
209 * change to the completion length.
210 */
211 if (good_bytes == old_good_bytes)
212 good_bytes -= scsi_get_resid(cmd);
213 }
214 scsi_io_completion(cmd, good_bytes);
215}
216
217/**
218 * scsi_change_queue_depth - change a device's queue depth
219 * @sdev: SCSI Device in question
220 * @depth: number of commands allowed to be queued to the driver
221 *
222 * Sets the device queue depth and returns the new value.
223 */
224int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
225{
226 if (depth > 0) {
227 sdev->queue_depth = depth;
228 wmb();
229 }
230
231 if (sdev->request_queue)
232 blk_set_queue_depth(sdev->request_queue, depth);
233
234 return sdev->queue_depth;
235}
236EXPORT_SYMBOL(scsi_change_queue_depth);
237
238/**
239 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
240 * @sdev: SCSI Device in question
241 * @depth: Current number of outstanding SCSI commands on this device,
242 * not counting the one returned as QUEUE_FULL.
243 *
244 * Description: This function will track successive QUEUE_FULL events on a
245 * specific SCSI device to determine if and when there is a
246 * need to adjust the queue depth on the device.
247 *
248 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
249 * -1 - Drop back to untagged operation using host->cmd_per_lun
250 * as the untagged command depth
251 *
252 * Lock Status: None held on entry
253 *
254 * Notes: Low level drivers may call this at any time and we will do
255 * "The Right Thing." We are interrupt context safe.
256 */
257int scsi_track_queue_full(struct scsi_device *sdev, int depth)
258{
259
260 /*
261 * Don't let QUEUE_FULLs on the same
262 * jiffies count, they could all be from
263 * same event.
264 */
265 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
266 return 0;
267
268 sdev->last_queue_full_time = jiffies;
269 if (sdev->last_queue_full_depth != depth) {
270 sdev->last_queue_full_count = 1;
271 sdev->last_queue_full_depth = depth;
272 } else {
273 sdev->last_queue_full_count++;
274 }
275
276 if (sdev->last_queue_full_count <= 10)
277 return 0;
278
279 return scsi_change_queue_depth(sdev, depth);
280}
281EXPORT_SYMBOL(scsi_track_queue_full);
282
283/**
284 * scsi_vpd_inquiry - Request a device provide us with a VPD page
285 * @sdev: The device to ask
286 * @buffer: Where to put the result
287 * @page: Which Vital Product Data to return
288 * @len: The length of the buffer
289 *
290 * This is an internal helper function. You probably want to use
291 * scsi_get_vpd_page instead.
292 *
293 * Returns size of the vpd page on success or a negative error number.
294 */
295static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
296 u8 page, unsigned len)
297{
298 int result;
299 unsigned char cmd[16];
300
301 if (len < 4)
302 return -EINVAL;
303
304 cmd[0] = INQUIRY;
305 cmd[1] = 1; /* EVPD */
306 cmd[2] = page;
307 cmd[3] = len >> 8;
308 cmd[4] = len & 0xff;
309 cmd[5] = 0; /* Control byte */
310
311 /*
312 * I'm not convinced we need to try quite this hard to get VPD, but
313 * all the existing users tried this hard.
314 */
315 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
316 len, NULL, 30 * HZ, 3, NULL);
317 if (result)
318 return -EIO;
319
320 /* Sanity check that we got the page back that we asked for */
321 if (buffer[1] != page)
322 return -EIO;
323
324 return get_unaligned_be16(&buffer[2]) + 4;
325}
326
327/**
328 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
329 * @sdev: The device to ask
330 * @page: Which Vital Product Data to return
331 * @buf: where to store the VPD
332 * @buf_len: number of bytes in the VPD buffer area
333 *
334 * SCSI devices may optionally supply Vital Product Data. Each 'page'
335 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
336 * If the device supports this VPD page, this routine returns a pointer
337 * to a buffer containing the data from that page. The caller is
338 * responsible for calling kfree() on this pointer when it is no longer
339 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
340 */
341int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
342 int buf_len)
343{
344 int i, result;
345
346 if (sdev->skip_vpd_pages)
347 goto fail;
348
349 /* Ask for all the pages supported by this device */
350 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
351 if (result < 4)
352 goto fail;
353
354 /* If the user actually wanted this page, we can skip the rest */
355 if (page == 0)
356 return 0;
357
358 for (i = 4; i < min(result, buf_len); i++)
359 if (buf[i] == page)
360 goto found;
361
362 if (i < result && i >= buf_len)
363 /* ran off the end of the buffer, give us benefit of doubt */
364 goto found;
365 /* The device claims it doesn't support the requested page */
366 goto fail;
367
368 found:
369 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
370 if (result < 0)
371 goto fail;
372
373 return 0;
374
375 fail:
376 return -EINVAL;
377}
378EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
379
380/**
381 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
382 * @sdev: The device to ask
383 * @page: Which Vital Product Data to return
384 *
385 * Returns %NULL upon failure.
386 */
387static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
388{
389 struct scsi_vpd *vpd_buf;
390 int vpd_len = SCSI_VPD_PG_LEN, result;
391
392retry_pg:
393 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
394 if (!vpd_buf)
395 return NULL;
396
397 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
398 if (result < 0) {
399 kfree(vpd_buf);
400 return NULL;
401 }
402 if (result > vpd_len) {
403 vpd_len = result;
404 kfree(vpd_buf);
405 goto retry_pg;
406 }
407
408 vpd_buf->len = result;
409
410 return vpd_buf;
411}
412
413static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
414 struct scsi_vpd __rcu **sdev_vpd_buf)
415{
416 struct scsi_vpd *vpd_buf;
417
418 vpd_buf = scsi_get_vpd_buf(sdev, page);
419 if (!vpd_buf)
420 return;
421
422 mutex_lock(&sdev->inquiry_mutex);
423 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
424 lockdep_is_held(&sdev->inquiry_mutex));
425 mutex_unlock(&sdev->inquiry_mutex);
426
427 if (vpd_buf)
428 kfree_rcu(vpd_buf, rcu);
429}
430
431/**
432 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
433 * @sdev: The device to ask
434 *
435 * Attach the 'Device Identification' VPD page (0x83) and the
436 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
437 * structure. This information can be used to identify the device
438 * uniquely.
439 */
440void scsi_attach_vpd(struct scsi_device *sdev)
441{
442 int i;
443 struct scsi_vpd *vpd_buf;
444
445 if (!scsi_device_supports_vpd(sdev))
446 return;
447
448 /* Ask for all the pages supported by this device */
449 vpd_buf = scsi_get_vpd_buf(sdev, 0);
450 if (!vpd_buf)
451 return;
452
453 for (i = 4; i < vpd_buf->len; i++) {
454 if (vpd_buf->data[i] == 0x0)
455 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0);
456 if (vpd_buf->data[i] == 0x80)
457 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
458 if (vpd_buf->data[i] == 0x83)
459 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
460 if (vpd_buf->data[i] == 0x89)
461 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89);
462 }
463 kfree(vpd_buf);
464}
465
466/**
467 * scsi_report_opcode - Find out if a given command opcode is supported
468 * @sdev: scsi device to query
469 * @buffer: scratch buffer (must be at least 20 bytes long)
470 * @len: length of buffer
471 * @opcode: opcode for command to look up
472 *
473 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
474 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
475 * unsupported and 1 if the device claims to support the command.
476 */
477int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
478 unsigned int len, unsigned char opcode)
479{
480 unsigned char cmd[16];
481 struct scsi_sense_hdr sshdr;
482 int result;
483
484 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
485 return -EINVAL;
486
487 memset(cmd, 0, 16);
488 cmd[0] = MAINTENANCE_IN;
489 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
490 cmd[2] = 1; /* One command format */
491 cmd[3] = opcode;
492 put_unaligned_be32(len, &cmd[6]);
493 memset(buffer, 0, len);
494
495 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
496 &sshdr, 30 * HZ, 3, NULL);
497
498 if (result && scsi_sense_valid(&sshdr) &&
499 sshdr.sense_key == ILLEGAL_REQUEST &&
500 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
501 return -EINVAL;
502
503 if ((buffer[1] & 3) == 3) /* Command supported */
504 return 1;
505
506 return 0;
507}
508EXPORT_SYMBOL(scsi_report_opcode);
509
510/**
511 * scsi_device_get - get an additional reference to a scsi_device
512 * @sdev: device to get a reference to
513 *
514 * Description: Gets a reference to the scsi_device and increments the use count
515 * of the underlying LLDD module. You must hold host_lock of the
516 * parent Scsi_Host or already have a reference when calling this.
517 *
518 * This will fail if a device is deleted or cancelled, or when the LLD module
519 * is in the process of being unloaded.
520 */
521int scsi_device_get(struct scsi_device *sdev)
522{
523 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
524 goto fail;
525 if (!get_device(&sdev->sdev_gendev))
526 goto fail;
527 if (!try_module_get(sdev->host->hostt->module))
528 goto fail_put_device;
529 return 0;
530
531fail_put_device:
532 put_device(&sdev->sdev_gendev);
533fail:
534 return -ENXIO;
535}
536EXPORT_SYMBOL(scsi_device_get);
537
538/**
539 * scsi_device_put - release a reference to a scsi_device
540 * @sdev: device to release a reference on.
541 *
542 * Description: Release a reference to the scsi_device and decrements the use
543 * count of the underlying LLDD module. The device is freed once the last
544 * user vanishes.
545 */
546void scsi_device_put(struct scsi_device *sdev)
547{
548 module_put(sdev->host->hostt->module);
549 put_device(&sdev->sdev_gendev);
550}
551EXPORT_SYMBOL(scsi_device_put);
552
553/* helper for shost_for_each_device, see that for documentation */
554struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
555 struct scsi_device *prev)
556{
557 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
558 struct scsi_device *next = NULL;
559 unsigned long flags;
560
561 spin_lock_irqsave(shost->host_lock, flags);
562 while (list->next != &shost->__devices) {
563 next = list_entry(list->next, struct scsi_device, siblings);
564 /* skip devices that we can't get a reference to */
565 if (!scsi_device_get(next))
566 break;
567 next = NULL;
568 list = list->next;
569 }
570 spin_unlock_irqrestore(shost->host_lock, flags);
571
572 if (prev)
573 scsi_device_put(prev);
574 return next;
575}
576EXPORT_SYMBOL(__scsi_iterate_devices);
577
578/**
579 * starget_for_each_device - helper to walk all devices of a target
580 * @starget: target whose devices we want to iterate over.
581 * @data: Opaque passed to each function call.
582 * @fn: Function to call on each device
583 *
584 * This traverses over each device of @starget. The devices have
585 * a reference that must be released by scsi_host_put when breaking
586 * out of the loop.
587 */
588void starget_for_each_device(struct scsi_target *starget, void *data,
589 void (*fn)(struct scsi_device *, void *))
590{
591 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
592 struct scsi_device *sdev;
593
594 shost_for_each_device(sdev, shost) {
595 if ((sdev->channel == starget->channel) &&
596 (sdev->id == starget->id))
597 fn(sdev, data);
598 }
599}
600EXPORT_SYMBOL(starget_for_each_device);
601
602/**
603 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
604 * @starget: target whose devices we want to iterate over.
605 * @data: parameter for callback @fn()
606 * @fn: callback function that is invoked for each device
607 *
608 * This traverses over each device of @starget. It does _not_
609 * take a reference on the scsi_device, so the whole loop must be
610 * protected by shost->host_lock.
611 *
612 * Note: The only reason why drivers would want to use this is because
613 * they need to access the device list in irq context. Otherwise you
614 * really want to use starget_for_each_device instead.
615 **/
616void __starget_for_each_device(struct scsi_target *starget, void *data,
617 void (*fn)(struct scsi_device *, void *))
618{
619 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
620 struct scsi_device *sdev;
621
622 __shost_for_each_device(sdev, shost) {
623 if ((sdev->channel == starget->channel) &&
624 (sdev->id == starget->id))
625 fn(sdev, data);
626 }
627}
628EXPORT_SYMBOL(__starget_for_each_device);
629
630/**
631 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
632 * @starget: SCSI target pointer
633 * @lun: SCSI Logical Unit Number
634 *
635 * Description: Looks up the scsi_device with the specified @lun for a given
636 * @starget. The returned scsi_device does not have an additional
637 * reference. You must hold the host's host_lock over this call and
638 * any access to the returned scsi_device. A scsi_device in state
639 * SDEV_DEL is skipped.
640 *
641 * Note: The only reason why drivers should use this is because
642 * they need to access the device list in irq context. Otherwise you
643 * really want to use scsi_device_lookup_by_target instead.
644 **/
645struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
646 u64 lun)
647{
648 struct scsi_device *sdev;
649
650 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
651 if (sdev->sdev_state == SDEV_DEL)
652 continue;
653 if (sdev->lun ==lun)
654 return sdev;
655 }
656
657 return NULL;
658}
659EXPORT_SYMBOL(__scsi_device_lookup_by_target);
660
661/**
662 * scsi_device_lookup_by_target - find a device given the target
663 * @starget: SCSI target pointer
664 * @lun: SCSI Logical Unit Number
665 *
666 * Description: Looks up the scsi_device with the specified @lun for a given
667 * @starget. The returned scsi_device has an additional reference that
668 * needs to be released with scsi_device_put once you're done with it.
669 **/
670struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
671 u64 lun)
672{
673 struct scsi_device *sdev;
674 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
675 unsigned long flags;
676
677 spin_lock_irqsave(shost->host_lock, flags);
678 sdev = __scsi_device_lookup_by_target(starget, lun);
679 if (sdev && scsi_device_get(sdev))
680 sdev = NULL;
681 spin_unlock_irqrestore(shost->host_lock, flags);
682
683 return sdev;
684}
685EXPORT_SYMBOL(scsi_device_lookup_by_target);
686
687/**
688 * __scsi_device_lookup - find a device given the host (UNLOCKED)
689 * @shost: SCSI host pointer
690 * @channel: SCSI channel (zero if only one channel)
691 * @id: SCSI target number (physical unit number)
692 * @lun: SCSI Logical Unit Number
693 *
694 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
695 * for a given host. The returned scsi_device does not have an additional
696 * reference. You must hold the host's host_lock over this call and any access
697 * to the returned scsi_device.
698 *
699 * Note: The only reason why drivers would want to use this is because
700 * they need to access the device list in irq context. Otherwise you
701 * really want to use scsi_device_lookup instead.
702 **/
703struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
704 uint channel, uint id, u64 lun)
705{
706 struct scsi_device *sdev;
707
708 list_for_each_entry(sdev, &shost->__devices, siblings) {
709 if (sdev->sdev_state == SDEV_DEL)
710 continue;
711 if (sdev->channel == channel && sdev->id == id &&
712 sdev->lun ==lun)
713 return sdev;
714 }
715
716 return NULL;
717}
718EXPORT_SYMBOL(__scsi_device_lookup);
719
720/**
721 * scsi_device_lookup - find a device given the host
722 * @shost: SCSI host pointer
723 * @channel: SCSI channel (zero if only one channel)
724 * @id: SCSI target number (physical unit number)
725 * @lun: SCSI Logical Unit Number
726 *
727 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
728 * for a given host. The returned scsi_device has an additional reference that
729 * needs to be released with scsi_device_put once you're done with it.
730 **/
731struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
732 uint channel, uint id, u64 lun)
733{
734 struct scsi_device *sdev;
735 unsigned long flags;
736
737 spin_lock_irqsave(shost->host_lock, flags);
738 sdev = __scsi_device_lookup(shost, channel, id, lun);
739 if (sdev && scsi_device_get(sdev))
740 sdev = NULL;
741 spin_unlock_irqrestore(shost->host_lock, flags);
742
743 return sdev;
744}
745EXPORT_SYMBOL(scsi_device_lookup);
746
747MODULE_DESCRIPTION("SCSI core");
748MODULE_LICENSE("GPL");
749
750module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
751MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
752
753static int __init init_scsi(void)
754{
755 int error;
756
757 error = scsi_init_procfs();
758 if (error)
759 goto cleanup_queue;
760 error = scsi_init_devinfo();
761 if (error)
762 goto cleanup_procfs;
763 error = scsi_init_hosts();
764 if (error)
765 goto cleanup_devlist;
766 error = scsi_init_sysctl();
767 if (error)
768 goto cleanup_hosts;
769 error = scsi_sysfs_register();
770 if (error)
771 goto cleanup_sysctl;
772
773 scsi_netlink_init();
774
775 printk(KERN_NOTICE "SCSI subsystem initialized\n");
776 return 0;
777
778cleanup_sysctl:
779 scsi_exit_sysctl();
780cleanup_hosts:
781 scsi_exit_hosts();
782cleanup_devlist:
783 scsi_exit_devinfo();
784cleanup_procfs:
785 scsi_exit_procfs();
786cleanup_queue:
787 scsi_exit_queue();
788 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
789 -error);
790 return error;
791}
792
793static void __exit exit_scsi(void)
794{
795 scsi_netlink_exit();
796 scsi_sysfs_unregister();
797 scsi_exit_sysctl();
798 scsi_exit_hosts();
799 scsi_exit_devinfo();
800 scsi_exit_procfs();
801 scsi_exit_queue();
802}
803
804subsys_initcall(init_scsi);
805module_exit(exit_scsi);