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/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(v: &shost->host_blocked))
173 atomic_set(v: &shost->host_blocked, i: 0);
174 if (atomic_read(v: &starget->target_blocked))
175 atomic_set(v: &starget->target_blocked, i: 0);
176 if (atomic_read(v: &sdev->device_blocked))
177 atomic_set(v: &sdev->device_blocked, i: 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(rq: scsi_cmd_to_rq(scmd: 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(q: sdev->request_queue, depth);
228
229 sbitmap_resize(sb: &sdev->budget_map, depth: 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:
246 * * 0 - No change needed
247 * * >0 - Adjust queue depth to this new depth,
248 * * -1 - Drop back to untagged operation using host->cmd_per_lun as the
249 * untagged command depth
250 *
251 * Lock Status: None held on entry
252 *
253 * Notes: Low level drivers may call this at any time and we will do
254 * "The Right Thing." We are interrupt context safe.
255 */
256int scsi_track_queue_full(struct scsi_device *sdev, int depth)
257{
258
259 /*
260 * Don't let QUEUE_FULLs on the same
261 * jiffies count, they could all be from
262 * same event.
263 */
264 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
265 return 0;
266
267 sdev->last_queue_full_time = jiffies;
268 if (sdev->last_queue_full_depth != depth) {
269 sdev->last_queue_full_count = 1;
270 sdev->last_queue_full_depth = depth;
271 } else {
272 sdev->last_queue_full_count++;
273 }
274
275 if (sdev->last_queue_full_count <= 10)
276 return 0;
277
278 return scsi_change_queue_depth(sdev, depth);
279}
280EXPORT_SYMBOL(scsi_track_queue_full);
281
282/**
283 * scsi_vpd_inquiry - Request a device provide us with a VPD page
284 * @sdev: The device to ask
285 * @buffer: Where to put the result
286 * @page: Which Vital Product Data to return
287 * @len: The length of the buffer
288 *
289 * This is an internal helper function. You probably want to use
290 * scsi_get_vpd_page instead.
291 *
292 * Returns size of the vpd page on success or a negative error number.
293 */
294static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
295 u8 page, unsigned len)
296{
297 int result;
298 unsigned char cmd[16];
299
300 if (len < 4)
301 return -EINVAL;
302
303 cmd[0] = INQUIRY;
304 cmd[1] = 1; /* EVPD */
305 cmd[2] = page;
306 cmd[3] = len >> 8;
307 cmd[4] = len & 0xff;
308 cmd[5] = 0; /* Control byte */
309
310 /*
311 * I'm not convinced we need to try quite this hard to get VPD, but
312 * all the existing users tried this hard.
313 */
314 result = scsi_execute_cmd(sdev, cmd, opf: REQ_OP_DRV_IN, buffer, bufflen: len,
315 timeout: 30 * HZ, retries: 3, NULL);
316 if (result)
317 return -EIO;
318
319 /*
320 * Sanity check that we got the page back that we asked for and that
321 * the page size is not 0.
322 */
323 if (buffer[1] != page)
324 return -EIO;
325
326 result = get_unaligned_be16(p: &buffer[2]);
327 if (!result)
328 return -EIO;
329
330 return result + 4;
331}
332
333enum scsi_vpd_parameters {
334 SCSI_VPD_HEADER_SIZE = 4,
335 SCSI_VPD_LIST_SIZE = 36,
336};
337
338static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page)
339{
340 unsigned char vpd[SCSI_VPD_LIST_SIZE] __aligned(4);
341 int result;
342
343 if (sdev->no_vpd_size)
344 return SCSI_DEFAULT_VPD_LEN;
345
346 /*
347 * Fetch the supported pages VPD and validate that the requested page
348 * number is present.
349 */
350 if (page != 0) {
351 result = scsi_vpd_inquiry(sdev, buffer: vpd, page: 0, len: sizeof(vpd));
352 if (result < SCSI_VPD_HEADER_SIZE)
353 return 0;
354
355 if (result > sizeof(vpd)) {
356 dev_warn_once(&sdev->sdev_gendev,
357 "%s: long VPD page 0 length: %d bytes\n",
358 __func__, result);
359 result = sizeof(vpd);
360 }
361
362 result -= SCSI_VPD_HEADER_SIZE;
363 if (!memchr(&vpd[SCSI_VPD_HEADER_SIZE], page, result))
364 return 0;
365 }
366 /*
367 * Fetch the VPD page header to find out how big the page
368 * is. This is done to prevent problems on legacy devices
369 * which can not handle allocation lengths as large as
370 * potentially requested by the caller.
371 */
372 result = scsi_vpd_inquiry(sdev, buffer: vpd, page, len: SCSI_VPD_HEADER_SIZE);
373 if (result < 0)
374 return 0;
375
376 if (result < SCSI_VPD_HEADER_SIZE) {
377 dev_warn_once(&sdev->sdev_gendev,
378 "%s: short VPD page 0x%02x length: %d bytes\n",
379 __func__, page, result);
380 return 0;
381 }
382
383 return result;
384}
385
386/**
387 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
388 * @sdev: The device to ask
389 * @page: Which Vital Product Data to return
390 * @buf: where to store the VPD
391 * @buf_len: number of bytes in the VPD buffer area
392 *
393 * SCSI devices may optionally supply Vital Product Data. Each 'page'
394 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
395 * If the device supports this VPD page, this routine fills @buf
396 * with the data from that page and return 0. If the VPD page is not
397 * supported or its content cannot be retrieved, -EINVAL is returned.
398 */
399int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
400 int buf_len)
401{
402 int result, vpd_len;
403
404 if (!scsi_device_supports_vpd(sdev))
405 return -EINVAL;
406
407 vpd_len = scsi_get_vpd_size(sdev, page);
408 if (vpd_len <= 0)
409 return -EINVAL;
410
411 vpd_len = min(vpd_len, buf_len);
412
413 /*
414 * Fetch the actual page. Since the appropriate size was reported
415 * by the device it is now safe to ask for something bigger.
416 */
417 memset(s: buf, c: 0, n: buf_len);
418 result = scsi_vpd_inquiry(sdev, buffer: buf, page, len: vpd_len);
419 if (result < 0)
420 return -EINVAL;
421 else if (result > vpd_len)
422 dev_warn_once(&sdev->sdev_gendev,
423 "%s: VPD page 0x%02x result %d > %d bytes\n",
424 __func__, page, result, vpd_len);
425
426 return 0;
427}
428EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
429
430/**
431 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
432 * @sdev: The device to ask
433 * @page: Which Vital Product Data to return
434 *
435 * Returns %NULL upon failure.
436 */
437static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
438{
439 struct scsi_vpd *vpd_buf;
440 int vpd_len, result;
441
442 vpd_len = scsi_get_vpd_size(sdev, page);
443 if (vpd_len <= 0)
444 return NULL;
445
446retry_pg:
447 /*
448 * Fetch the actual page. Since the appropriate size was reported
449 * by the device it is now safe to ask for something bigger.
450 */
451 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
452 if (!vpd_buf)
453 return NULL;
454
455 result = scsi_vpd_inquiry(sdev, buffer: vpd_buf->data, page, len: vpd_len);
456 if (result < 0) {
457 kfree(objp: vpd_buf);
458 return NULL;
459 }
460 if (result > vpd_len) {
461 dev_warn_once(&sdev->sdev_gendev,
462 "%s: VPD page 0x%02x result %d > %d bytes\n",
463 __func__, page, result, vpd_len);
464 vpd_len = result;
465 kfree(objp: vpd_buf);
466 goto retry_pg;
467 }
468
469 vpd_buf->len = result;
470
471 return vpd_buf;
472}
473
474static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
475 struct scsi_vpd __rcu **sdev_vpd_buf)
476{
477 struct scsi_vpd *vpd_buf;
478
479 vpd_buf = scsi_get_vpd_buf(sdev, page);
480 if (!vpd_buf)
481 return;
482
483 mutex_lock(lock: &sdev->inquiry_mutex);
484 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
485 lockdep_is_held(&sdev->inquiry_mutex));
486 mutex_unlock(lock: &sdev->inquiry_mutex);
487
488 if (vpd_buf)
489 kfree_rcu(vpd_buf, rcu);
490}
491
492/**
493 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
494 * @sdev: The device to ask
495 *
496 * Attach the 'Device Identification' VPD page (0x83) and the
497 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
498 * structure. This information can be used to identify the device
499 * uniquely.
500 */
501void scsi_attach_vpd(struct scsi_device *sdev)
502{
503 int i;
504 struct scsi_vpd *vpd_buf;
505
506 if (!scsi_device_supports_vpd(sdev))
507 return;
508
509 /* Ask for all the pages supported by this device */
510 vpd_buf = scsi_get_vpd_buf(sdev, page: 0);
511 if (!vpd_buf)
512 return;
513
514 for (i = 4; i < vpd_buf->len; i++) {
515 switch (vpd_buf->data[i]) {
516 case 0x0:
517 scsi_update_vpd_page(sdev, page: 0x0, sdev_vpd_buf: &sdev->vpd_pg0);
518 break;
519 case 0x80:
520 scsi_update_vpd_page(sdev, page: 0x80, sdev_vpd_buf: &sdev->vpd_pg80);
521 break;
522 case 0x83:
523 scsi_update_vpd_page(sdev, page: 0x83, sdev_vpd_buf: &sdev->vpd_pg83);
524 break;
525 case 0x89:
526 scsi_update_vpd_page(sdev, page: 0x89, sdev_vpd_buf: &sdev->vpd_pg89);
527 break;
528 case 0xb0:
529 scsi_update_vpd_page(sdev, page: 0xb0, sdev_vpd_buf: &sdev->vpd_pgb0);
530 break;
531 case 0xb1:
532 scsi_update_vpd_page(sdev, page: 0xb1, sdev_vpd_buf: &sdev->vpd_pgb1);
533 break;
534 case 0xb2:
535 scsi_update_vpd_page(sdev, page: 0xb2, sdev_vpd_buf: &sdev->vpd_pgb2);
536 break;
537 case 0xb7:
538 scsi_update_vpd_page(sdev, page: 0xb7, sdev_vpd_buf: &sdev->vpd_pgb7);
539 break;
540 default:
541 break;
542 }
543 }
544 kfree(objp: vpd_buf);
545}
546
547/**
548 * scsi_report_opcode - Find out if a given command is supported
549 * @sdev: scsi device to query
550 * @buffer: scratch buffer (must be at least 20 bytes long)
551 * @len: length of buffer
552 * @opcode: opcode for the command to look up
553 * @sa: service action for the command to look up
554 *
555 * Uses the REPORT SUPPORTED OPERATION CODES to check support for the
556 * command identified with @opcode and @sa. If the command does not
557 * have a service action, @sa must be 0. Returns -EINVAL if RSOC fails,
558 * 0 if the command is not supported and 1 if the device claims to
559 * support the command.
560 */
561int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
562 unsigned int len, unsigned char opcode,
563 unsigned short sa)
564{
565 unsigned char cmd[16];
566 struct scsi_sense_hdr sshdr;
567 int result, request_len;
568 const struct scsi_exec_args exec_args = {
569 .sshdr = &sshdr,
570 };
571
572 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
573 return -EINVAL;
574
575 /* RSOC header + size of command we are asking about */
576 request_len = 4 + COMMAND_SIZE(opcode);
577 if (request_len > len) {
578 dev_warn_once(&sdev->sdev_gendev,
579 "%s: len %u bytes, opcode 0x%02x needs %u\n",
580 __func__, len, opcode, request_len);
581 return -EINVAL;
582 }
583
584 memset(s: cmd, c: 0, n: 16);
585 cmd[0] = MAINTENANCE_IN;
586 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
587 if (!sa) {
588 cmd[2] = 1; /* One command format */
589 cmd[3] = opcode;
590 } else {
591 cmd[2] = 3; /* One command format with service action */
592 cmd[3] = opcode;
593 put_unaligned_be16(val: sa, p: &cmd[4]);
594 }
595 put_unaligned_be32(val: request_len, p: &cmd[6]);
596 memset(s: buffer, c: 0, n: len);
597
598 result = scsi_execute_cmd(sdev, cmd, opf: REQ_OP_DRV_IN, buffer,
599 bufflen: request_len, timeout: 30 * HZ, retries: 3, args: &exec_args);
600 if (result < 0)
601 return result;
602 if (result && scsi_sense_valid(sshdr: &sshdr) &&
603 sshdr.sense_key == ILLEGAL_REQUEST &&
604 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
605 return -EINVAL;
606
607 if ((buffer[1] & 3) == 3) /* Command supported */
608 return 1;
609
610 return 0;
611}
612EXPORT_SYMBOL(scsi_report_opcode);
613
614#define SCSI_CDL_CHECK_BUF_LEN 64
615
616static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa,
617 unsigned char *buf)
618{
619 int ret;
620 u8 cdlp;
621
622 /* Check operation code */
623 ret = scsi_report_opcode(sdev, buf, SCSI_CDL_CHECK_BUF_LEN, opcode, sa);
624 if (ret <= 0)
625 return false;
626
627 if ((buf[1] & 0x03) != 0x03)
628 return false;
629
630 /*
631 * See SPC-6, One_command parameter data format for
632 * REPORT SUPPORTED OPERATION CODES. We have the following cases
633 * depending on rwcdlp (buf[0] & 0x01) value:
634 * - rwcdlp == 0: then cdlp indicates support for the A mode page when
635 * it is equal to 1 and for the B mode page when it is
636 * equal to 2.
637 * - rwcdlp == 1: then cdlp indicates support for the T2A mode page
638 * when it is equal to 1 and for the T2B mode page when
639 * it is equal to 2.
640 * Overall, to detect support for command duration limits, we only need
641 * to check that cdlp is 1 or 2.
642 */
643 cdlp = (buf[1] & 0x18) >> 3;
644
645 return cdlp == 0x01 || cdlp == 0x02;
646}
647
648/**
649 * scsi_cdl_check - Check if a SCSI device supports Command Duration Limits
650 * @sdev: The device to check
651 */
652void scsi_cdl_check(struct scsi_device *sdev)
653{
654 bool cdl_supported;
655 unsigned char *buf;
656
657 /*
658 * Support for CDL was defined in SPC-5. Ignore devices reporting an
659 * lower SPC version. This also avoids problems with old drives choking
660 * on MAINTENANCE_IN / MI_REPORT_SUPPORTED_OPERATION_CODES with a
661 * service action specified, as done in scsi_cdl_check_cmd().
662 */
663 if (sdev->scsi_level < SCSI_SPC_5) {
664 sdev->cdl_supported = 0;
665 return;
666 }
667
668 buf = kmalloc(SCSI_CDL_CHECK_BUF_LEN, GFP_KERNEL);
669 if (!buf) {
670 sdev->cdl_supported = 0;
671 return;
672 }
673
674 /* Check support for READ_16, WRITE_16, READ_32 and WRITE_32 commands */
675 cdl_supported =
676 scsi_cdl_check_cmd(sdev, READ_16, sa: 0, buf) ||
677 scsi_cdl_check_cmd(sdev, WRITE_16, sa: 0, buf) ||
678 scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, READ_32, buf) ||
679 scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, WRITE_32, buf);
680 if (cdl_supported) {
681 /*
682 * We have CDL support: force the use of READ16/WRITE16.
683 * READ32 and WRITE32 will be used for devices that support
684 * the T10_PI_TYPE2_PROTECTION protection type.
685 */
686 sdev->use_16_for_rw = 1;
687 sdev->use_10_for_rw = 0;
688
689 sdev->cdl_supported = 1;
690
691 /*
692 * If the device supports CDL, make sure that the current drive
693 * feature status is consistent with the user controlled
694 * cdl_enable state.
695 */
696 scsi_cdl_enable(sdev, enable: sdev->cdl_enable);
697 } else {
698 sdev->cdl_supported = 0;
699 }
700
701 kfree(objp: buf);
702}
703
704/**
705 * scsi_cdl_enable - Enable or disable a SCSI device supports for Command
706 * Duration Limits
707 * @sdev: The target device
708 * @enable: the target state
709 */
710int scsi_cdl_enable(struct scsi_device *sdev, bool enable)
711{
712 char buf[64];
713 int ret;
714
715 if (!sdev->cdl_supported)
716 return -EOPNOTSUPP;
717
718 /*
719 * For ATA devices, CDL needs to be enabled with a SET FEATURES command.
720 */
721 if (sdev->is_ata) {
722 struct scsi_mode_data data;
723 struct scsi_sense_hdr sshdr;
724 char *buf_data;
725 int len;
726
727 ret = scsi_mode_sense(sdev, dbd: 0x08, modepage: 0x0a, subpage: 0xf2, buffer: buf, len: sizeof(buf),
728 timeout: 5 * HZ, retries: 3, data: &data, NULL);
729 if (ret)
730 return -EINVAL;
731
732 /* Enable or disable CDL using the ATA feature page */
733 len = min_t(size_t, sizeof(buf),
734 data.length - data.header_length -
735 data.block_descriptor_length);
736 buf_data = buf + data.header_length +
737 data.block_descriptor_length;
738
739 /*
740 * If we want to enable CDL and CDL is already enabled on the
741 * device, do nothing. This avoids needlessly resetting the CDL
742 * statistics on the device as that is implied by the CDL enable
743 * action. Similar to this, there is no need to do anything if
744 * we want to disable CDL and CDL is already disabled.
745 */
746 if (enable) {
747 if ((buf_data[4] & 0x03) == 0x02)
748 goto out;
749 buf_data[4] &= ~0x03;
750 buf_data[4] |= 0x02;
751 } else {
752 if ((buf_data[4] & 0x03) == 0x00)
753 goto out;
754 buf_data[4] &= ~0x03;
755 }
756
757 ret = scsi_mode_select(sdev, pf: 1, sp: 0, buffer: buf_data, len, timeout: 5 * HZ, retries: 3,
758 data: &data, &sshdr);
759 if (ret) {
760 if (ret > 0 && scsi_sense_valid(sshdr: &sshdr))
761 scsi_print_sense_hdr(sdev,
762 dev_name(dev: &sdev->sdev_gendev), &sshdr);
763 return ret;
764 }
765 }
766
767out:
768 sdev->cdl_enable = enable;
769
770 return 0;
771}
772
773/**
774 * scsi_device_get - get an additional reference to a scsi_device
775 * @sdev: device to get a reference to
776 *
777 * Description: Gets a reference to the scsi_device and increments the use count
778 * of the underlying LLDD module. You must hold host_lock of the
779 * parent Scsi_Host or already have a reference when calling this.
780 *
781 * This will fail if a device is deleted or cancelled, or when the LLD module
782 * is in the process of being unloaded.
783 */
784int scsi_device_get(struct scsi_device *sdev)
785{
786 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
787 goto fail;
788 if (!try_module_get(module: sdev->host->hostt->module))
789 goto fail;
790 if (!get_device(dev: &sdev->sdev_gendev))
791 goto fail_put_module;
792 return 0;
793
794fail_put_module:
795 module_put(module: sdev->host->hostt->module);
796fail:
797 return -ENXIO;
798}
799EXPORT_SYMBOL(scsi_device_get);
800
801/**
802 * scsi_device_put - release a reference to a scsi_device
803 * @sdev: device to release a reference on.
804 *
805 * Description: Release a reference to the scsi_device and decrements the use
806 * count of the underlying LLDD module. The device is freed once the last
807 * user vanishes.
808 */
809void scsi_device_put(struct scsi_device *sdev)
810{
811 struct module *mod = sdev->host->hostt->module;
812
813 put_device(dev: &sdev->sdev_gendev);
814 module_put(module: mod);
815}
816EXPORT_SYMBOL(scsi_device_put);
817
818/* helper for shost_for_each_device, see that for documentation */
819struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
820 struct scsi_device *prev)
821{
822 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
823 struct scsi_device *next = NULL;
824 unsigned long flags;
825
826 spin_lock_irqsave(shost->host_lock, flags);
827 while (list->next != &shost->__devices) {
828 next = list_entry(list->next, struct scsi_device, siblings);
829 /* skip devices that we can't get a reference to */
830 if (!scsi_device_get(next))
831 break;
832 next = NULL;
833 list = list->next;
834 }
835 spin_unlock_irqrestore(lock: shost->host_lock, flags);
836
837 if (prev)
838 scsi_device_put(prev);
839 return next;
840}
841EXPORT_SYMBOL(__scsi_iterate_devices);
842
843/**
844 * starget_for_each_device - helper to walk all devices of a target
845 * @starget: target whose devices we want to iterate over.
846 * @data: Opaque passed to each function call.
847 * @fn: Function to call on each device
848 *
849 * This traverses over each device of @starget. The devices have
850 * a reference that must be released by scsi_host_put when breaking
851 * out of the loop.
852 */
853void starget_for_each_device(struct scsi_target *starget, void *data,
854 void (*fn)(struct scsi_device *, void *))
855{
856 struct Scsi_Host *shost = dev_to_shost(dev: starget->dev.parent);
857 struct scsi_device *sdev;
858
859 shost_for_each_device(sdev, shost) {
860 if ((sdev->channel == starget->channel) &&
861 (sdev->id == starget->id))
862 fn(sdev, data);
863 }
864}
865EXPORT_SYMBOL(starget_for_each_device);
866
867/**
868 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
869 * @starget: target whose devices we want to iterate over.
870 * @data: parameter for callback @fn()
871 * @fn: callback function that is invoked for each device
872 *
873 * This traverses over each device of @starget. It does _not_
874 * take a reference on the scsi_device, so the whole loop must be
875 * protected by shost->host_lock.
876 *
877 * Note: The only reason why drivers would want to use this is because
878 * they need to access the device list in irq context. Otherwise you
879 * really want to use starget_for_each_device instead.
880 **/
881void __starget_for_each_device(struct scsi_target *starget, void *data,
882 void (*fn)(struct scsi_device *, void *))
883{
884 struct Scsi_Host *shost = dev_to_shost(dev: starget->dev.parent);
885 struct scsi_device *sdev;
886
887 __shost_for_each_device(sdev, shost) {
888 if ((sdev->channel == starget->channel) &&
889 (sdev->id == starget->id))
890 fn(sdev, data);
891 }
892}
893EXPORT_SYMBOL(__starget_for_each_device);
894
895/**
896 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
897 * @starget: SCSI target pointer
898 * @lun: SCSI Logical Unit Number
899 *
900 * Description: Looks up the scsi_device with the specified @lun for a given
901 * @starget. The returned scsi_device does not have an additional
902 * reference. You must hold the host's host_lock over this call and
903 * any access to the returned scsi_device. A scsi_device in state
904 * SDEV_DEL is skipped.
905 *
906 * Note: The only reason why drivers should use this is because
907 * they need to access the device list in irq context. Otherwise you
908 * really want to use scsi_device_lookup_by_target instead.
909 **/
910struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
911 u64 lun)
912{
913 struct scsi_device *sdev;
914
915 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
916 if (sdev->sdev_state == SDEV_DEL)
917 continue;
918 if (sdev->lun ==lun)
919 return sdev;
920 }
921
922 return NULL;
923}
924EXPORT_SYMBOL(__scsi_device_lookup_by_target);
925
926/**
927 * scsi_device_lookup_by_target - find a device given the target
928 * @starget: SCSI target pointer
929 * @lun: SCSI Logical Unit Number
930 *
931 * Description: Looks up the scsi_device with the specified @lun for a given
932 * @starget. The returned scsi_device has an additional reference that
933 * needs to be released with scsi_device_put once you're done with it.
934 **/
935struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
936 u64 lun)
937{
938 struct scsi_device *sdev;
939 struct Scsi_Host *shost = dev_to_shost(dev: starget->dev.parent);
940 unsigned long flags;
941
942 spin_lock_irqsave(shost->host_lock, flags);
943 sdev = __scsi_device_lookup_by_target(starget, lun);
944 if (sdev && scsi_device_get(sdev))
945 sdev = NULL;
946 spin_unlock_irqrestore(lock: shost->host_lock, flags);
947
948 return sdev;
949}
950EXPORT_SYMBOL(scsi_device_lookup_by_target);
951
952/**
953 * __scsi_device_lookup - find a device given the host (UNLOCKED)
954 * @shost: SCSI host pointer
955 * @channel: SCSI channel (zero if only one channel)
956 * @id: SCSI target number (physical unit number)
957 * @lun: SCSI Logical Unit Number
958 *
959 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
960 * for a given host. The returned scsi_device does not have an additional
961 * reference. You must hold the host's host_lock over this call and any access
962 * to the returned scsi_device.
963 *
964 * Note: The only reason why drivers would want to use this is because
965 * they need to access the device list in irq context. Otherwise you
966 * really want to use scsi_device_lookup instead.
967 **/
968struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
969 uint channel, uint id, u64 lun)
970{
971 struct scsi_device *sdev;
972
973 list_for_each_entry(sdev, &shost->__devices, siblings) {
974 if (sdev->sdev_state == SDEV_DEL)
975 continue;
976 if (sdev->channel == channel && sdev->id == id &&
977 sdev->lun ==lun)
978 return sdev;
979 }
980
981 return NULL;
982}
983EXPORT_SYMBOL(__scsi_device_lookup);
984
985/**
986 * scsi_device_lookup - find a device given the host
987 * @shost: SCSI host pointer
988 * @channel: SCSI channel (zero if only one channel)
989 * @id: SCSI target number (physical unit number)
990 * @lun: SCSI Logical Unit Number
991 *
992 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
993 * for a given host. The returned scsi_device has an additional reference that
994 * needs to be released with scsi_device_put once you're done with it.
995 **/
996struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
997 uint channel, uint id, u64 lun)
998{
999 struct scsi_device *sdev;
1000 unsigned long flags;
1001
1002 spin_lock_irqsave(shost->host_lock, flags);
1003 sdev = __scsi_device_lookup(shost, channel, id, lun);
1004 if (sdev && scsi_device_get(sdev))
1005 sdev = NULL;
1006 spin_unlock_irqrestore(lock: shost->host_lock, flags);
1007
1008 return sdev;
1009}
1010EXPORT_SYMBOL(scsi_device_lookup);
1011
1012MODULE_DESCRIPTION("SCSI core");
1013MODULE_LICENSE("GPL");
1014
1015module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1016MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1017
1018static int __init init_scsi(void)
1019{
1020 int error;
1021
1022 error = scsi_init_procfs();
1023 if (error)
1024 goto cleanup_queue;
1025 error = scsi_init_devinfo();
1026 if (error)
1027 goto cleanup_procfs;
1028 error = scsi_init_hosts();
1029 if (error)
1030 goto cleanup_devlist;
1031 error = scsi_init_sysctl();
1032 if (error)
1033 goto cleanup_hosts;
1034 error = scsi_sysfs_register();
1035 if (error)
1036 goto cleanup_sysctl;
1037
1038 scsi_netlink_init();
1039
1040 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1041 return 0;
1042
1043cleanup_sysctl:
1044 scsi_exit_sysctl();
1045cleanup_hosts:
1046 scsi_exit_hosts();
1047cleanup_devlist:
1048 scsi_exit_devinfo();
1049cleanup_procfs:
1050 scsi_exit_procfs();
1051cleanup_queue:
1052 scsi_exit_queue();
1053 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1054 -error);
1055 return error;
1056}
1057
1058static void __exit exit_scsi(void)
1059{
1060 scsi_netlink_exit();
1061 scsi_sysfs_unregister();
1062 scsi_exit_sysctl();
1063 scsi_exit_hosts();
1064 scsi_exit_devinfo();
1065 scsi_exit_procfs();
1066 scsi_exit_queue();
1067}
1068
1069subsys_initcall(init_scsi);
1070module_exit(exit_scsi);
1071