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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 <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#ifdef CONFIG_SCSI_LOGGING
89void scsi_log_send(struct scsi_cmnd *cmd)
90{
91 unsigned int level;
92
93 /*
94 * If ML QUEUE log level is greater than or equal to:
95 *
96 * 1: nothing (match completion)
97 *
98 * 2: log opcode + command of all commands + cmd address
99 *
100 * 3: same as 2
101 *
102 * 4: same as 3
103 */
104 if (unlikely(scsi_logging_level)) {
105 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
106 SCSI_LOG_MLQUEUE_BITS);
107 if (level > 1) {
108 scmd_printk(KERN_INFO, cmd,
109 "Send: scmd 0x%p\n", cmd);
110 scsi_print_command(cmd);
111 }
112 }
113}
114
115void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
116{
117 unsigned int level;
118
119 /*
120 * If ML COMPLETE log level is greater than or equal to:
121 *
122 * 1: log disposition, result, opcode + command, and conditionally
123 * sense data for failures or non SUCCESS dispositions.
124 *
125 * 2: same as 1 but for all command completions.
126 *
127 * 3: same as 2
128 *
129 * 4: same as 3 plus dump extra junk
130 */
131 if (unlikely(scsi_logging_level)) {
132 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
133 SCSI_LOG_MLCOMPLETE_BITS);
134 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
135 (level > 1)) {
136 scsi_print_result(cmd, "Done", disposition);
137 scsi_print_command(cmd);
138 if (scsi_status_is_check_condition(cmd->result))
139 scsi_print_sense(cmd);
140 if (level > 3)
141 scmd_printk(KERN_INFO, cmd,
142 "scsi host busy %d failed %d\n",
143 scsi_host_busy(cmd->device->host),
144 cmd->device->host->host_failed);
145 }
146 }
147}
148#endif
149
150/**
151 * scsi_finish_command - cleanup and pass command back to upper layer
152 * @cmd: the command
153 *
154 * Description: Pass command off to upper layer for finishing of I/O
155 * request, waking processes that are waiting on results,
156 * etc.
157 */
158void scsi_finish_command(struct scsi_cmnd *cmd)
159{
160 struct scsi_device *sdev = cmd->device;
161 struct scsi_target *starget = scsi_target(sdev);
162 struct Scsi_Host *shost = sdev->host;
163 struct scsi_driver *drv;
164 unsigned int good_bytes;
165
166 scsi_device_unbusy(sdev, cmd);
167
168 /*
169 * Clear the flags that say that the device/target/host is no longer
170 * capable of accepting new commands.
171 */
172 if (atomic_read(&shost->host_blocked))
173 atomic_set(&shost->host_blocked, 0);
174 if (atomic_read(&starget->target_blocked))
175 atomic_set(&starget->target_blocked, 0);
176 if (atomic_read(&sdev->device_blocked))
177 atomic_set(&sdev->device_blocked, 0);
178
179 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
180 "Notifying upper driver of completion "
181 "(result %x)\n", cmd->result));
182
183 good_bytes = scsi_bufflen(cmd);
184 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
185 int old_good_bytes = good_bytes;
186 drv = scsi_cmd_to_driver(cmd);
187 if (drv->done)
188 good_bytes = drv->done(cmd);
189 /*
190 * USB may not give sense identifying bad sector and
191 * simply return a residue instead, so subtract off the
192 * residue if drv->done() error processing indicates no
193 * change to the completion length.
194 */
195 if (good_bytes == old_good_bytes)
196 good_bytes -= scsi_get_resid(cmd);
197 }
198 scsi_io_completion(cmd, good_bytes);
199}
200
201
202/*
203 * 4096 is big enough for saturating fast SCSI LUNs.
204 */
205int scsi_device_max_queue_depth(struct scsi_device *sdev)
206{
207 return min_t(int, sdev->host->can_queue, 4096);
208}
209
210/**
211 * scsi_change_queue_depth - change a device's queue depth
212 * @sdev: SCSI Device in question
213 * @depth: number of commands allowed to be queued to the driver
214 *
215 * Sets the device queue depth and returns the new value.
216 */
217int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
218{
219 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev));
220
221 if (depth > 0) {
222 sdev->queue_depth = depth;
223 wmb();
224 }
225
226 if (sdev->request_queue)
227 blk_set_queue_depth(sdev->request_queue, depth);
228
229 sbitmap_resize(&sdev->budget_map, sdev->queue_depth);
230
231 return sdev->queue_depth;
232}
233EXPORT_SYMBOL(scsi_change_queue_depth);
234
235/**
236 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
237 * @sdev: SCSI Device in question
238 * @depth: Current number of outstanding SCSI commands on this device,
239 * not counting the one returned as QUEUE_FULL.
240 *
241 * Description: This function will track successive QUEUE_FULL events on a
242 * specific SCSI device to determine if and when there is a
243 * need to adjust the queue depth on the device.
244 *
245 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
246 * -1 - Drop back to untagged operation using host->cmd_per_lun
247 * as the untagged command depth
248 *
249 * Lock Status: None held on entry
250 *
251 * Notes: Low level drivers may call this at any time and we will do
252 * "The Right Thing." We are interrupt context safe.
253 */
254int scsi_track_queue_full(struct scsi_device *sdev, int depth)
255{
256
257 /*
258 * Don't let QUEUE_FULLs on the same
259 * jiffies count, they could all be from
260 * same event.
261 */
262 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
263 return 0;
264
265 sdev->last_queue_full_time = jiffies;
266 if (sdev->last_queue_full_depth != depth) {
267 sdev->last_queue_full_count = 1;
268 sdev->last_queue_full_depth = depth;
269 } else {
270 sdev->last_queue_full_count++;
271 }
272
273 if (sdev->last_queue_full_count <= 10)
274 return 0;
275
276 return scsi_change_queue_depth(sdev, depth);
277}
278EXPORT_SYMBOL(scsi_track_queue_full);
279
280/**
281 * scsi_vpd_inquiry - Request a device provide us with a VPD page
282 * @sdev: The device to ask
283 * @buffer: Where to put the result
284 * @page: Which Vital Product Data to return
285 * @len: The length of the buffer
286 *
287 * This is an internal helper function. You probably want to use
288 * scsi_get_vpd_page instead.
289 *
290 * Returns size of the vpd page on success or a negative error number.
291 */
292static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
293 u8 page, unsigned len)
294{
295 int result;
296 unsigned char cmd[16];
297
298 if (len < 4)
299 return -EINVAL;
300
301 cmd[0] = INQUIRY;
302 cmd[1] = 1; /* EVPD */
303 cmd[2] = page;
304 cmd[3] = len >> 8;
305 cmd[4] = len & 0xff;
306 cmd[5] = 0; /* Control byte */
307
308 /*
309 * I'm not convinced we need to try quite this hard to get VPD, but
310 * all the existing users tried this hard.
311 */
312 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
313 len, NULL, 30 * HZ, 3, NULL);
314 if (result)
315 return -EIO;
316
317 /* Sanity check that we got the page back that we asked for */
318 if (buffer[1] != page)
319 return -EIO;
320
321 return get_unaligned_be16(&buffer[2]) + 4;
322}
323
324static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page)
325{
326 unsigned char vpd_header[SCSI_VPD_HEADER_SIZE] __aligned(4);
327 int result;
328
329 /*
330 * Fetch the VPD page header to find out how big the page
331 * is. This is done to prevent problems on legacy devices
332 * which can not handle allocation lengths as large as
333 * potentially requested by the caller.
334 */
335 result = scsi_vpd_inquiry(sdev, vpd_header, page, sizeof(vpd_header));
336 if (result < 0)
337 return 0;
338
339 if (result < SCSI_VPD_HEADER_SIZE) {
340 dev_warn_once(&sdev->sdev_gendev,
341 "%s: short VPD page 0x%02x length: %d bytes\n",
342 __func__, page, result);
343 return 0;
344 }
345
346 return result;
347}
348
349/**
350 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
351 * @sdev: The device to ask
352 * @page: Which Vital Product Data to return
353 * @buf: where to store the VPD
354 * @buf_len: number of bytes in the VPD buffer area
355 *
356 * SCSI devices may optionally supply Vital Product Data. Each 'page'
357 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
358 * If the device supports this VPD page, this routine fills @buf
359 * with the data from that page and return 0. If the VPD page is not
360 * supported or its content cannot be retrieved, -EINVAL is returned.
361 */
362int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
363 int buf_len)
364{
365 int result, vpd_len;
366
367 if (!scsi_device_supports_vpd(sdev))
368 return -EINVAL;
369
370 vpd_len = scsi_get_vpd_size(sdev, page);
371 if (vpd_len <= 0)
372 return -EINVAL;
373
374 vpd_len = min(vpd_len, buf_len);
375
376 /*
377 * Fetch the actual page. Since the appropriate size was reported
378 * by the device it is now safe to ask for something bigger.
379 */
380 memset(buf, 0, buf_len);
381 result = scsi_vpd_inquiry(sdev, buf, page, vpd_len);
382 if (result < 0)
383 return -EINVAL;
384 else if (result > vpd_len)
385 dev_warn_once(&sdev->sdev_gendev,
386 "%s: VPD page 0x%02x result %d > %d bytes\n",
387 __func__, page, result, vpd_len);
388
389 return 0;
390}
391EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
392
393/**
394 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
395 * @sdev: The device to ask
396 * @page: Which Vital Product Data to return
397 *
398 * Returns %NULL upon failure.
399 */
400static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
401{
402 struct scsi_vpd *vpd_buf;
403 int vpd_len, result;
404
405 vpd_len = scsi_get_vpd_size(sdev, page);
406 if (vpd_len <= 0)
407 return NULL;
408
409retry_pg:
410 /*
411 * Fetch the actual page. Since the appropriate size was reported
412 * by the device it is now safe to ask for something bigger.
413 */
414 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
415 if (!vpd_buf)
416 return NULL;
417
418 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
419 if (result < 0) {
420 kfree(vpd_buf);
421 return NULL;
422 }
423 if (result > vpd_len) {
424 dev_warn_once(&sdev->sdev_gendev,
425 "%s: VPD page 0x%02x result %d > %d bytes\n",
426 __func__, page, result, vpd_len);
427 vpd_len = result;
428 kfree(vpd_buf);
429 goto retry_pg;
430 }
431
432 vpd_buf->len = result;
433
434 return vpd_buf;
435}
436
437static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
438 struct scsi_vpd __rcu **sdev_vpd_buf)
439{
440 struct scsi_vpd *vpd_buf;
441
442 vpd_buf = scsi_get_vpd_buf(sdev, page);
443 if (!vpd_buf)
444 return;
445
446 mutex_lock(&sdev->inquiry_mutex);
447 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
448 lockdep_is_held(&sdev->inquiry_mutex));
449 mutex_unlock(&sdev->inquiry_mutex);
450
451 if (vpd_buf)
452 kfree_rcu(vpd_buf, rcu);
453}
454
455/**
456 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
457 * @sdev: The device to ask
458 *
459 * Attach the 'Device Identification' VPD page (0x83) and the
460 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
461 * structure. This information can be used to identify the device
462 * uniquely.
463 */
464void scsi_attach_vpd(struct scsi_device *sdev)
465{
466 int i;
467 struct scsi_vpd *vpd_buf;
468
469 if (!scsi_device_supports_vpd(sdev))
470 return;
471
472 /* Ask for all the pages supported by this device */
473 vpd_buf = scsi_get_vpd_buf(sdev, 0);
474 if (!vpd_buf)
475 return;
476
477 for (i = 4; i < vpd_buf->len; i++) {
478 if (vpd_buf->data[i] == 0x0)
479 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0);
480 if (vpd_buf->data[i] == 0x80)
481 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
482 if (vpd_buf->data[i] == 0x83)
483 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
484 if (vpd_buf->data[i] == 0x89)
485 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89);
486 if (vpd_buf->data[i] == 0xb0)
487 scsi_update_vpd_page(sdev, 0xb0, &sdev->vpd_pgb0);
488 if (vpd_buf->data[i] == 0xb1)
489 scsi_update_vpd_page(sdev, 0xb1, &sdev->vpd_pgb1);
490 if (vpd_buf->data[i] == 0xb2)
491 scsi_update_vpd_page(sdev, 0xb2, &sdev->vpd_pgb2);
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, request_len;
513
514 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
515 return -EINVAL;
516
517 /* RSOC header + size of command we are asking about */
518 request_len = 4 + COMMAND_SIZE(opcode);
519 if (request_len > len) {
520 dev_warn_once(&sdev->sdev_gendev,
521 "%s: len %u bytes, opcode 0x%02x needs %u\n",
522 __func__, len, opcode, request_len);
523 return -EINVAL;
524 }
525
526 memset(cmd, 0, 16);
527 cmd[0] = MAINTENANCE_IN;
528 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
529 cmd[2] = 1; /* One command format */
530 cmd[3] = opcode;
531 put_unaligned_be32(request_len, &cmd[6]);
532 memset(buffer, 0, len);
533
534 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
535 request_len, &sshdr, 30 * HZ, 3, NULL);
536
537 if (result < 0)
538 return result;
539 if (result && scsi_sense_valid(&sshdr) &&
540 sshdr.sense_key == ILLEGAL_REQUEST &&
541 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
542 return -EINVAL;
543
544 if ((buffer[1] & 3) == 3) /* Command supported */
545 return 1;
546
547 return 0;
548}
549EXPORT_SYMBOL(scsi_report_opcode);
550
551/**
552 * scsi_device_get - get an additional reference to a scsi_device
553 * @sdev: device to get a reference to
554 *
555 * Description: Gets a reference to the scsi_device and increments the use count
556 * of the underlying LLDD module. You must hold host_lock of the
557 * parent Scsi_Host or already have a reference when calling this.
558 *
559 * This will fail if a device is deleted or cancelled, or when the LLD module
560 * is in the process of being unloaded.
561 */
562int scsi_device_get(struct scsi_device *sdev)
563{
564 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
565 goto fail;
566 if (!try_module_get(sdev->host->hostt->module))
567 goto fail;
568 if (!get_device(&sdev->sdev_gendev))
569 goto fail_put_module;
570 return 0;
571
572fail_put_module:
573 module_put(sdev->host->hostt->module);
574fail:
575 return -ENXIO;
576}
577EXPORT_SYMBOL(scsi_device_get);
578
579/**
580 * scsi_device_put - release a reference to a scsi_device
581 * @sdev: device to release a reference on.
582 *
583 * Description: Release a reference to the scsi_device and decrements the use
584 * count of the underlying LLDD module. The device is freed once the last
585 * user vanishes.
586 */
587void scsi_device_put(struct scsi_device *sdev)
588{
589 struct module *mod = sdev->host->hostt->module;
590
591 put_device(&sdev->sdev_gendev);
592 module_put(mod);
593}
594EXPORT_SYMBOL(scsi_device_put);
595
596/* helper for shost_for_each_device, see that for documentation */
597struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
598 struct scsi_device *prev)
599{
600 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
601 struct scsi_device *next = NULL;
602 unsigned long flags;
603
604 spin_lock_irqsave(shost->host_lock, flags);
605 while (list->next != &shost->__devices) {
606 next = list_entry(list->next, struct scsi_device, siblings);
607 /* skip devices that we can't get a reference to */
608 if (!scsi_device_get(next))
609 break;
610 next = NULL;
611 list = list->next;
612 }
613 spin_unlock_irqrestore(shost->host_lock, flags);
614
615 if (prev)
616 scsi_device_put(prev);
617 return next;
618}
619EXPORT_SYMBOL(__scsi_iterate_devices);
620
621/**
622 * starget_for_each_device - helper to walk all devices of a target
623 * @starget: target whose devices we want to iterate over.
624 * @data: Opaque passed to each function call.
625 * @fn: Function to call on each device
626 *
627 * This traverses over each device of @starget. The devices have
628 * a reference that must be released by scsi_host_put when breaking
629 * out of the loop.
630 */
631void starget_for_each_device(struct scsi_target *starget, void *data,
632 void (*fn)(struct scsi_device *, void *))
633{
634 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
635 struct scsi_device *sdev;
636
637 shost_for_each_device(sdev, shost) {
638 if ((sdev->channel == starget->channel) &&
639 (sdev->id == starget->id))
640 fn(sdev, data);
641 }
642}
643EXPORT_SYMBOL(starget_for_each_device);
644
645/**
646 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
647 * @starget: target whose devices we want to iterate over.
648 * @data: parameter for callback @fn()
649 * @fn: callback function that is invoked for each device
650 *
651 * This traverses over each device of @starget. It does _not_
652 * take a reference on the scsi_device, so the whole loop must be
653 * protected by shost->host_lock.
654 *
655 * Note: The only reason why drivers would want to use this is because
656 * they need to access the device list in irq context. Otherwise you
657 * really want to use starget_for_each_device instead.
658 **/
659void __starget_for_each_device(struct scsi_target *starget, void *data,
660 void (*fn)(struct scsi_device *, void *))
661{
662 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
663 struct scsi_device *sdev;
664
665 __shost_for_each_device(sdev, shost) {
666 if ((sdev->channel == starget->channel) &&
667 (sdev->id == starget->id))
668 fn(sdev, data);
669 }
670}
671EXPORT_SYMBOL(__starget_for_each_device);
672
673/**
674 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
675 * @starget: SCSI target pointer
676 * @lun: SCSI Logical Unit Number
677 *
678 * Description: Looks up the scsi_device with the specified @lun for a given
679 * @starget. The returned scsi_device does not have an additional
680 * reference. You must hold the host's host_lock over this call and
681 * any access to the returned scsi_device. A scsi_device in state
682 * SDEV_DEL is skipped.
683 *
684 * Note: The only reason why drivers should use this is because
685 * they need to access the device list in irq context. Otherwise you
686 * really want to use scsi_device_lookup_by_target instead.
687 **/
688struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
689 u64 lun)
690{
691 struct scsi_device *sdev;
692
693 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
694 if (sdev->sdev_state == SDEV_DEL)
695 continue;
696 if (sdev->lun ==lun)
697 return sdev;
698 }
699
700 return NULL;
701}
702EXPORT_SYMBOL(__scsi_device_lookup_by_target);
703
704/**
705 * scsi_device_lookup_by_target - find a device given the target
706 * @starget: SCSI target pointer
707 * @lun: SCSI Logical Unit Number
708 *
709 * Description: Looks up the scsi_device with the specified @lun for a given
710 * @starget. The returned scsi_device has an additional reference that
711 * needs to be released with scsi_device_put once you're done with it.
712 **/
713struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
714 u64 lun)
715{
716 struct scsi_device *sdev;
717 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
718 unsigned long flags;
719
720 spin_lock_irqsave(shost->host_lock, flags);
721 sdev = __scsi_device_lookup_by_target(starget, lun);
722 if (sdev && scsi_device_get(sdev))
723 sdev = NULL;
724 spin_unlock_irqrestore(shost->host_lock, flags);
725
726 return sdev;
727}
728EXPORT_SYMBOL(scsi_device_lookup_by_target);
729
730/**
731 * __scsi_device_lookup - find a device given the host (UNLOCKED)
732 * @shost: SCSI host pointer
733 * @channel: SCSI channel (zero if only one channel)
734 * @id: SCSI target number (physical unit number)
735 * @lun: SCSI Logical Unit Number
736 *
737 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
738 * for a given host. The returned scsi_device does not have an additional
739 * reference. You must hold the host's host_lock over this call and any access
740 * to the returned scsi_device.
741 *
742 * Note: The only reason why drivers would want to use this is because
743 * they need to access the device list in irq context. Otherwise you
744 * really want to use scsi_device_lookup instead.
745 **/
746struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
747 uint channel, uint id, u64 lun)
748{
749 struct scsi_device *sdev;
750
751 list_for_each_entry(sdev, &shost->__devices, siblings) {
752 if (sdev->sdev_state == SDEV_DEL)
753 continue;
754 if (sdev->channel == channel && sdev->id == id &&
755 sdev->lun ==lun)
756 return sdev;
757 }
758
759 return NULL;
760}
761EXPORT_SYMBOL(__scsi_device_lookup);
762
763/**
764 * scsi_device_lookup - find a device given the host
765 * @shost: SCSI host pointer
766 * @channel: SCSI channel (zero if only one channel)
767 * @id: SCSI target number (physical unit number)
768 * @lun: SCSI Logical Unit Number
769 *
770 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
771 * for a given host. The returned scsi_device has an additional reference that
772 * needs to be released with scsi_device_put once you're done with it.
773 **/
774struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
775 uint channel, uint id, u64 lun)
776{
777 struct scsi_device *sdev;
778 unsigned long flags;
779
780 spin_lock_irqsave(shost->host_lock, flags);
781 sdev = __scsi_device_lookup(shost, channel, id, lun);
782 if (sdev && scsi_device_get(sdev))
783 sdev = NULL;
784 spin_unlock_irqrestore(shost->host_lock, flags);
785
786 return sdev;
787}
788EXPORT_SYMBOL(scsi_device_lookup);
789
790MODULE_DESCRIPTION("SCSI core");
791MODULE_LICENSE("GPL");
792
793module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
794MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
795
796static int __init init_scsi(void)
797{
798 int error;
799
800 error = scsi_init_procfs();
801 if (error)
802 goto cleanup_queue;
803 error = scsi_init_devinfo();
804 if (error)
805 goto cleanup_procfs;
806 error = scsi_init_hosts();
807 if (error)
808 goto cleanup_devlist;
809 error = scsi_init_sysctl();
810 if (error)
811 goto cleanup_hosts;
812 error = scsi_sysfs_register();
813 if (error)
814 goto cleanup_sysctl;
815
816 scsi_netlink_init();
817
818 printk(KERN_NOTICE "SCSI subsystem initialized\n");
819 return 0;
820
821cleanup_sysctl:
822 scsi_exit_sysctl();
823cleanup_hosts:
824 scsi_exit_hosts();
825cleanup_devlist:
826 scsi_exit_devinfo();
827cleanup_procfs:
828 scsi_exit_procfs();
829cleanup_queue:
830 scsi_exit_queue();
831 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
832 -error);
833 return error;
834}
835
836static void __exit exit_scsi(void)
837{
838 scsi_netlink_exit();
839 scsi_sysfs_unregister();
840 scsi_exit_sysctl();
841 scsi_exit_hosts();
842 scsi_exit_devinfo();
843 scsi_exit_procfs();
844 scsi_exit_queue();
845}
846
847subsys_initcall(init_scsi);
848module_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#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);