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 */
84 unsigned int scsi_logging_level;
85 #if defined(CONFIG_SCSI_LOGGING)
86 EXPORT_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 */
94 ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
95 EXPORT_SYMBOL(scsi_sd_pm_domain);
96
97 #ifdef CONFIG_SCSI_LOGGING
scsi_log_send(struct scsi_cmnd * cmd)98 void 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
scsi_log_completion(struct scsi_cmnd * cmd,int disposition)124 void 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 */
scsi_finish_command(struct scsi_cmnd * cmd)167 void 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 /*
219 * 1024 is big enough for saturating the fast scsi LUN now
220 */
scsi_device_max_queue_depth(struct scsi_device * sdev)221 int scsi_device_max_queue_depth(struct scsi_device *sdev)
222 {
223 return max_t(int, sdev->host->can_queue, 1024);
224 }
225
226 /**
227 * scsi_change_queue_depth - change a device's queue depth
228 * @sdev: SCSI Device in question
229 * @depth: number of commands allowed to be queued to the driver
230 *
231 * Sets the device queue depth and returns the new value.
232 */
scsi_change_queue_depth(struct scsi_device * sdev,int depth)233 int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
234 {
235 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev));
236
237 if (depth > 0) {
238 sdev->queue_depth = depth;
239 wmb();
240 }
241
242 if (sdev->request_queue)
243 blk_set_queue_depth(sdev->request_queue, depth);
244
245 sbitmap_resize(&sdev->budget_map, sdev->queue_depth);
246
247 return sdev->queue_depth;
248 }
249 EXPORT_SYMBOL(scsi_change_queue_depth);
250
251 /**
252 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
253 * @sdev: SCSI Device in question
254 * @depth: Current number of outstanding SCSI commands on this device,
255 * not counting the one returned as QUEUE_FULL.
256 *
257 * Description: This function will track successive QUEUE_FULL events on a
258 * specific SCSI device to determine if and when there is a
259 * need to adjust the queue depth on the device.
260 *
261 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
262 * -1 - Drop back to untagged operation using host->cmd_per_lun
263 * as the untagged command depth
264 *
265 * Lock Status: None held on entry
266 *
267 * Notes: Low level drivers may call this at any time and we will do
268 * "The Right Thing." We are interrupt context safe.
269 */
scsi_track_queue_full(struct scsi_device * sdev,int depth)270 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
271 {
272
273 /*
274 * Don't let QUEUE_FULLs on the same
275 * jiffies count, they could all be from
276 * same event.
277 */
278 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
279 return 0;
280
281 sdev->last_queue_full_time = jiffies;
282 if (sdev->last_queue_full_depth != depth) {
283 sdev->last_queue_full_count = 1;
284 sdev->last_queue_full_depth = depth;
285 } else {
286 sdev->last_queue_full_count++;
287 }
288
289 if (sdev->last_queue_full_count <= 10)
290 return 0;
291
292 return scsi_change_queue_depth(sdev, depth);
293 }
294 EXPORT_SYMBOL(scsi_track_queue_full);
295
296 /**
297 * scsi_vpd_inquiry - Request a device provide us with a VPD page
298 * @sdev: The device to ask
299 * @buffer: Where to put the result
300 * @page: Which Vital Product Data to return
301 * @len: The length of the buffer
302 *
303 * This is an internal helper function. You probably want to use
304 * scsi_get_vpd_page instead.
305 *
306 * Returns size of the vpd page on success or a negative error number.
307 */
scsi_vpd_inquiry(struct scsi_device * sdev,unsigned char * buffer,u8 page,unsigned len)308 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
309 u8 page, unsigned len)
310 {
311 int result;
312 unsigned char cmd[16];
313
314 if (len < 4)
315 return -EINVAL;
316
317 cmd[0] = INQUIRY;
318 cmd[1] = 1; /* EVPD */
319 cmd[2] = page;
320 cmd[3] = len >> 8;
321 cmd[4] = len & 0xff;
322 cmd[5] = 0; /* Control byte */
323
324 /*
325 * I'm not convinced we need to try quite this hard to get VPD, but
326 * all the existing users tried this hard.
327 */
328 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
329 len, NULL, 30 * HZ, 3, NULL);
330 if (result)
331 return -EIO;
332
333 /* Sanity check that we got the page back that we asked for */
334 if (buffer[1] != page)
335 return -EIO;
336
337 return get_unaligned_be16(&buffer[2]) + 4;
338 }
339
340 /**
341 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
342 * @sdev: The device to ask
343 * @page: Which Vital Product Data to return
344 * @buf: where to store the VPD
345 * @buf_len: number of bytes in the VPD buffer area
346 *
347 * SCSI devices may optionally supply Vital Product Data. Each 'page'
348 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
349 * If the device supports this VPD page, this routine returns a pointer
350 * to a buffer containing the data from that page. The caller is
351 * responsible for calling kfree() on this pointer when it is no longer
352 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
353 */
scsi_get_vpd_page(struct scsi_device * sdev,u8 page,unsigned char * buf,int buf_len)354 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
355 int buf_len)
356 {
357 int i, result;
358
359 if (sdev->skip_vpd_pages)
360 goto fail;
361
362 /* Ask for all the pages supported by this device */
363 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
364 if (result < 4)
365 goto fail;
366
367 /* If the user actually wanted this page, we can skip the rest */
368 if (page == 0)
369 return 0;
370
371 for (i = 4; i < min(result, buf_len); i++)
372 if (buf[i] == page)
373 goto found;
374
375 if (i < result && i >= buf_len)
376 /* ran off the end of the buffer, give us benefit of doubt */
377 goto found;
378 /* The device claims it doesn't support the requested page */
379 goto fail;
380
381 found:
382 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
383 if (result < 0)
384 goto fail;
385
386 return 0;
387
388 fail:
389 return -EINVAL;
390 }
391 EXPORT_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 */
scsi_get_vpd_buf(struct scsi_device * sdev,u8 page)400 static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
401 {
402 struct scsi_vpd *vpd_buf;
403 int vpd_len = SCSI_VPD_PG_LEN, result;
404
405 retry_pg:
406 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
407 if (!vpd_buf)
408 return NULL;
409
410 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
411 if (result < 0) {
412 kfree(vpd_buf);
413 return NULL;
414 }
415 if (result > vpd_len) {
416 vpd_len = result;
417 kfree(vpd_buf);
418 goto retry_pg;
419 }
420
421 vpd_buf->len = result;
422
423 return vpd_buf;
424 }
425
scsi_update_vpd_page(struct scsi_device * sdev,u8 page,struct scsi_vpd __rcu ** sdev_vpd_buf)426 static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
427 struct scsi_vpd __rcu **sdev_vpd_buf)
428 {
429 struct scsi_vpd *vpd_buf;
430
431 vpd_buf = scsi_get_vpd_buf(sdev, page);
432 if (!vpd_buf)
433 return;
434
435 mutex_lock(&sdev->inquiry_mutex);
436 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
437 lockdep_is_held(&sdev->inquiry_mutex));
438 mutex_unlock(&sdev->inquiry_mutex);
439
440 if (vpd_buf)
441 kfree_rcu(vpd_buf, rcu);
442 }
443
444 /**
445 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
446 * @sdev: The device to ask
447 *
448 * Attach the 'Device Identification' VPD page (0x83) and the
449 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
450 * structure. This information can be used to identify the device
451 * uniquely.
452 */
scsi_attach_vpd(struct scsi_device * sdev)453 void scsi_attach_vpd(struct scsi_device *sdev)
454 {
455 int i;
456 struct scsi_vpd *vpd_buf;
457
458 if (!scsi_device_supports_vpd(sdev))
459 return;
460
461 /* Ask for all the pages supported by this device */
462 vpd_buf = scsi_get_vpd_buf(sdev, 0);
463 if (!vpd_buf)
464 return;
465
466 for (i = 4; i < vpd_buf->len; i++) {
467 if (vpd_buf->data[i] == 0x0)
468 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0);
469 if (vpd_buf->data[i] == 0x80)
470 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
471 if (vpd_buf->data[i] == 0x83)
472 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
473 if (vpd_buf->data[i] == 0x89)
474 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89);
475 }
476 kfree(vpd_buf);
477 }
478
479 /**
480 * scsi_report_opcode - Find out if a given command opcode is supported
481 * @sdev: scsi device to query
482 * @buffer: scratch buffer (must be at least 20 bytes long)
483 * @len: length of buffer
484 * @opcode: opcode for command to look up
485 *
486 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
487 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
488 * unsupported and 1 if the device claims to support the command.
489 */
scsi_report_opcode(struct scsi_device * sdev,unsigned char * buffer,unsigned int len,unsigned char opcode)490 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
491 unsigned int len, unsigned char opcode)
492 {
493 unsigned char cmd[16];
494 struct scsi_sense_hdr sshdr;
495 int result;
496
497 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
498 return -EINVAL;
499
500 memset(cmd, 0, 16);
501 cmd[0] = MAINTENANCE_IN;
502 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
503 cmd[2] = 1; /* One command format */
504 cmd[3] = opcode;
505 put_unaligned_be32(len, &cmd[6]);
506 memset(buffer, 0, len);
507
508 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
509 &sshdr, 30 * HZ, 3, NULL);
510
511 if (result && scsi_sense_valid(&sshdr) &&
512 sshdr.sense_key == ILLEGAL_REQUEST &&
513 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
514 return -EINVAL;
515
516 if ((buffer[1] & 3) == 3) /* Command supported */
517 return 1;
518
519 return 0;
520 }
521 EXPORT_SYMBOL(scsi_report_opcode);
522
523 /**
524 * scsi_device_get - get an additional reference to a scsi_device
525 * @sdev: device to get a reference to
526 *
527 * Description: Gets a reference to the scsi_device and increments the use count
528 * of the underlying LLDD module. You must hold host_lock of the
529 * parent Scsi_Host or already have a reference when calling this.
530 *
531 * This will fail if a device is deleted or cancelled, or when the LLD module
532 * is in the process of being unloaded.
533 */
scsi_device_get(struct scsi_device * sdev)534 int scsi_device_get(struct scsi_device *sdev)
535 {
536 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
537 goto fail;
538 if (!get_device(&sdev->sdev_gendev))
539 goto fail;
540 if (!try_module_get(sdev->host->hostt->module))
541 goto fail_put_device;
542 return 0;
543
544 fail_put_device:
545 put_device(&sdev->sdev_gendev);
546 fail:
547 return -ENXIO;
548 }
549 EXPORT_SYMBOL(scsi_device_get);
550
551 /**
552 * scsi_device_put - release a reference to a scsi_device
553 * @sdev: device to release a reference on.
554 *
555 * Description: Release a reference to the scsi_device and decrements the use
556 * count of the underlying LLDD module. The device is freed once the last
557 * user vanishes.
558 */
scsi_device_put(struct scsi_device * sdev)559 void scsi_device_put(struct scsi_device *sdev)
560 {
561 module_put(sdev->host->hostt->module);
562 put_device(&sdev->sdev_gendev);
563 }
564 EXPORT_SYMBOL(scsi_device_put);
565
566 /* helper for shost_for_each_device, see that for documentation */
__scsi_iterate_devices(struct Scsi_Host * shost,struct scsi_device * prev)567 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
568 struct scsi_device *prev)
569 {
570 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
571 struct scsi_device *next = NULL;
572 unsigned long flags;
573
574 spin_lock_irqsave(shost->host_lock, flags);
575 while (list->next != &shost->__devices) {
576 next = list_entry(list->next, struct scsi_device, siblings);
577 /* skip devices that we can't get a reference to */
578 if (!scsi_device_get(next))
579 break;
580 next = NULL;
581 list = list->next;
582 }
583 spin_unlock_irqrestore(shost->host_lock, flags);
584
585 if (prev)
586 scsi_device_put(prev);
587 return next;
588 }
589 EXPORT_SYMBOL(__scsi_iterate_devices);
590
591 /**
592 * starget_for_each_device - helper to walk all devices of a target
593 * @starget: target whose devices we want to iterate over.
594 * @data: Opaque passed to each function call.
595 * @fn: Function to call on each device
596 *
597 * This traverses over each device of @starget. The devices have
598 * a reference that must be released by scsi_host_put when breaking
599 * out of the loop.
600 */
starget_for_each_device(struct scsi_target * starget,void * data,void (* fn)(struct scsi_device *,void *))601 void starget_for_each_device(struct scsi_target *starget, void *data,
602 void (*fn)(struct scsi_device *, void *))
603 {
604 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
605 struct scsi_device *sdev;
606
607 shost_for_each_device(sdev, shost) {
608 if ((sdev->channel == starget->channel) &&
609 (sdev->id == starget->id))
610 fn(sdev, data);
611 }
612 }
613 EXPORT_SYMBOL(starget_for_each_device);
614
615 /**
616 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
617 * @starget: target whose devices we want to iterate over.
618 * @data: parameter for callback @fn()
619 * @fn: callback function that is invoked for each device
620 *
621 * This traverses over each device of @starget. It does _not_
622 * take a reference on the scsi_device, so the whole loop must be
623 * protected by shost->host_lock.
624 *
625 * Note: The only reason why drivers would want to use this is because
626 * they need to access the device list in irq context. Otherwise you
627 * really want to use starget_for_each_device instead.
628 **/
__starget_for_each_device(struct scsi_target * starget,void * data,void (* fn)(struct scsi_device *,void *))629 void __starget_for_each_device(struct scsi_target *starget, void *data,
630 void (*fn)(struct scsi_device *, void *))
631 {
632 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
633 struct scsi_device *sdev;
634
635 __shost_for_each_device(sdev, shost) {
636 if ((sdev->channel == starget->channel) &&
637 (sdev->id == starget->id))
638 fn(sdev, data);
639 }
640 }
641 EXPORT_SYMBOL(__starget_for_each_device);
642
643 /**
644 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
645 * @starget: SCSI target pointer
646 * @lun: SCSI Logical Unit Number
647 *
648 * Description: Looks up the scsi_device with the specified @lun for a given
649 * @starget. The returned scsi_device does not have an additional
650 * reference. You must hold the host's host_lock over this call and
651 * any access to the returned scsi_device. A scsi_device in state
652 * SDEV_DEL is skipped.
653 *
654 * Note: The only reason why drivers should use this is because
655 * they need to access the device list in irq context. Otherwise you
656 * really want to use scsi_device_lookup_by_target instead.
657 **/
__scsi_device_lookup_by_target(struct scsi_target * starget,u64 lun)658 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
659 u64 lun)
660 {
661 struct scsi_device *sdev;
662
663 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
664 if (sdev->sdev_state == SDEV_DEL)
665 continue;
666 if (sdev->lun ==lun)
667 return sdev;
668 }
669
670 return NULL;
671 }
672 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
673
674 /**
675 * scsi_device_lookup_by_target - find a device given the target
676 * @starget: SCSI target pointer
677 * @lun: SCSI Logical Unit Number
678 *
679 * Description: Looks up the scsi_device with the specified @lun for a given
680 * @starget. The returned scsi_device has an additional reference that
681 * needs to be released with scsi_device_put once you're done with it.
682 **/
scsi_device_lookup_by_target(struct scsi_target * starget,u64 lun)683 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
684 u64 lun)
685 {
686 struct scsi_device *sdev;
687 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
688 unsigned long flags;
689
690 spin_lock_irqsave(shost->host_lock, flags);
691 sdev = __scsi_device_lookup_by_target(starget, lun);
692 if (sdev && scsi_device_get(sdev))
693 sdev = NULL;
694 spin_unlock_irqrestore(shost->host_lock, flags);
695
696 return sdev;
697 }
698 EXPORT_SYMBOL(scsi_device_lookup_by_target);
699
700 /**
701 * __scsi_device_lookup - find a device given the host (UNLOCKED)
702 * @shost: SCSI host pointer
703 * @channel: SCSI channel (zero if only one channel)
704 * @id: SCSI target number (physical unit number)
705 * @lun: SCSI Logical Unit Number
706 *
707 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
708 * for a given host. The returned scsi_device does not have an additional
709 * reference. You must hold the host's host_lock over this call and any access
710 * to the returned scsi_device.
711 *
712 * Note: The only reason why drivers would want to use this is because
713 * they need to access the device list in irq context. Otherwise you
714 * really want to use scsi_device_lookup instead.
715 **/
__scsi_device_lookup(struct Scsi_Host * shost,uint channel,uint id,u64 lun)716 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
717 uint channel, uint id, u64 lun)
718 {
719 struct scsi_device *sdev;
720
721 list_for_each_entry(sdev, &shost->__devices, siblings) {
722 if (sdev->sdev_state == SDEV_DEL)
723 continue;
724 if (sdev->channel == channel && sdev->id == id &&
725 sdev->lun ==lun)
726 return sdev;
727 }
728
729 return NULL;
730 }
731 EXPORT_SYMBOL(__scsi_device_lookup);
732
733 /**
734 * scsi_device_lookup - find a device given the host
735 * @shost: SCSI host pointer
736 * @channel: SCSI channel (zero if only one channel)
737 * @id: SCSI target number (physical unit number)
738 * @lun: SCSI Logical Unit Number
739 *
740 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
741 * for a given host. The returned scsi_device has an additional reference that
742 * needs to be released with scsi_device_put once you're done with it.
743 **/
scsi_device_lookup(struct Scsi_Host * shost,uint channel,uint id,u64 lun)744 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
745 uint channel, uint id, u64 lun)
746 {
747 struct scsi_device *sdev;
748 unsigned long flags;
749
750 spin_lock_irqsave(shost->host_lock, flags);
751 sdev = __scsi_device_lookup(shost, channel, id, lun);
752 if (sdev && scsi_device_get(sdev))
753 sdev = NULL;
754 spin_unlock_irqrestore(shost->host_lock, flags);
755
756 return sdev;
757 }
758 EXPORT_SYMBOL(scsi_device_lookup);
759
760 MODULE_DESCRIPTION("SCSI core");
761 MODULE_LICENSE("GPL");
762
763 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
764 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
765
init_scsi(void)766 static int __init init_scsi(void)
767 {
768 int error;
769
770 error = scsi_init_procfs();
771 if (error)
772 goto cleanup_queue;
773 error = scsi_init_devinfo();
774 if (error)
775 goto cleanup_procfs;
776 error = scsi_init_hosts();
777 if (error)
778 goto cleanup_devlist;
779 error = scsi_init_sysctl();
780 if (error)
781 goto cleanup_hosts;
782 error = scsi_sysfs_register();
783 if (error)
784 goto cleanup_sysctl;
785
786 scsi_netlink_init();
787
788 printk(KERN_NOTICE "SCSI subsystem initialized\n");
789 return 0;
790
791 cleanup_sysctl:
792 scsi_exit_sysctl();
793 cleanup_hosts:
794 scsi_exit_hosts();
795 cleanup_devlist:
796 scsi_exit_devinfo();
797 cleanup_procfs:
798 scsi_exit_procfs();
799 cleanup_queue:
800 scsi_exit_queue();
801 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
802 -error);
803 return error;
804 }
805
exit_scsi(void)806 static void __exit exit_scsi(void)
807 {
808 scsi_netlink_exit();
809 scsi_sysfs_unregister();
810 scsi_exit_sysctl();
811 scsi_exit_hosts();
812 scsi_exit_devinfo();
813 scsi_exit_procfs();
814 scsi_exit_queue();
815 }
816
817 subsys_initcall(init_scsi);
818 module_exit(exit_scsi);
819