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

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