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

source code of linux/drivers/scsi/scsi.c