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 */ 83 unsigned int scsi_logging_level; 84 #if defined(CONFIG_SCSI_LOGGING) 85 EXPORT_SYMBOL(scsi_logging_level); 86 #endif 87 88 #ifdef CONFIG_SCSI_LOGGING 89 void 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 } 114 115 void 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 */ 158 void scsi_finish_command(struct scsi_cmnd *cmd) 159 { 160 struct scsi_device *sdev = cmd->device; 161 struct scsi_target *starget = scsi_target(sdev); 162 struct Scsi_Host *shost = sdev->host; 163 struct scsi_driver *drv; 164 unsigned int good_bytes; 165 166 scsi_device_unbusy(sdev, cmd); 167 168 /* 169 * Clear the flags that say that the device/target/host is no longer 170 * capable of accepting new commands. 171 */ 172 if (atomic_read(&shost->host_blocked)) 173 atomic_set(&shost->host_blocked, 0); 174 if (atomic_read(&starget->target_blocked)) 175 atomic_set(&starget->target_blocked, 0); 176 if (atomic_read(&sdev->device_blocked)) 177 atomic_set(&sdev->device_blocked, 0); 178 179 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev, 180 "Notifying upper driver of completion " 181 "(result %x)\n", cmd->result)); 182 183 good_bytes = scsi_bufflen(cmd); 184 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) { 185 int old_good_bytes = good_bytes; 186 drv = scsi_cmd_to_driver(cmd); 187 if (drv->done) 188 good_bytes = drv->done(cmd); 189 /* 190 * USB may not give sense identifying bad sector and 191 * simply return a residue instead, so subtract off the 192 * residue if drv->done() error processing indicates no 193 * change to the completion length. 194 */ 195 if (good_bytes == old_good_bytes) 196 good_bytes -= scsi_get_resid(cmd); 197 } 198 scsi_io_completion(cmd, good_bytes); 199 } 200 201 202 /* 203 * 4096 is big enough for saturating fast SCSI LUNs. 204 */ 205 int 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 */ 217 int scsi_change_queue_depth(struct scsi_device *sdev, int depth) 218 { 219 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev)); 220 221 if (depth > 0) { 222 sdev->queue_depth = depth; 223 wmb(); 224 } 225 226 if (sdev->request_queue) 227 blk_set_queue_depth(sdev->request_queue, depth); 228 229 sbitmap_resize(&sdev->budget_map, sdev->queue_depth); 230 231 return sdev->queue_depth; 232 } 233 EXPORT_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 */ 254 int 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 } 278 EXPORT_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 */ 292 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, 293 u8 page, unsigned len) 294 { 295 int result; 296 unsigned char cmd[16]; 297 298 if (len < 4) 299 return -EINVAL; 300 301 cmd[0] = INQUIRY; 302 cmd[1] = 1; /* EVPD */ 303 cmd[2] = page; 304 cmd[3] = len >> 8; 305 cmd[4] = len & 0xff; 306 cmd[5] = 0; /* Control byte */ 307 308 /* 309 * I'm not convinced we need to try quite this hard to get VPD, but 310 * all the existing users tried this hard. 311 */ 312 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, 313 len, NULL, 30 * HZ, 3, NULL); 314 if (result) 315 return -EIO; 316 317 /* Sanity check that we got the page back that we asked for */ 318 if (buffer[1] != page) 319 return -EIO; 320 321 return get_unaligned_be16(&buffer[2]) + 4; 322 } 323 324 static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page) 325 { 326 unsigned char vpd_header[SCSI_VPD_HEADER_SIZE] __aligned(4); 327 int result; 328 329 /* 330 * Fetch the VPD page header to find out how big the page 331 * is. This is done to prevent problems on legacy devices 332 * which can not handle allocation lengths as large as 333 * potentially requested by the caller. 334 */ 335 result = scsi_vpd_inquiry(sdev, vpd_header, page, sizeof(vpd_header)); 336 if (result < 0) 337 return 0; 338 339 if (result < SCSI_VPD_HEADER_SIZE) { 340 dev_warn_once(&sdev->sdev_gendev, 341 "%s: short VPD page 0x%02x length: %d bytes\n", 342 __func__, page, result); 343 return 0; 344 } 345 346 return result; 347 } 348 349 /** 350 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device 351 * @sdev: The device to ask 352 * @page: Which Vital Product Data to return 353 * @buf: where to store the VPD 354 * @buf_len: number of bytes in the VPD buffer area 355 * 356 * SCSI devices may optionally supply Vital Product Data. Each 'page' 357 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC). 358 * If the device supports this VPD page, this routine fills @buf 359 * with the data from that page and return 0. If the VPD page is not 360 * supported or its content cannot be retrieved, -EINVAL is returned. 361 */ 362 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf, 363 int buf_len) 364 { 365 int result, vpd_len; 366 367 if (!scsi_device_supports_vpd(sdev)) 368 return -EINVAL; 369 370 vpd_len = scsi_get_vpd_size(sdev, page); 371 if (vpd_len <= 0) 372 return -EINVAL; 373 374 vpd_len = min(vpd_len, buf_len); 375 376 /* 377 * Fetch the actual page. Since the appropriate size was reported 378 * by the device it is now safe to ask for something bigger. 379 */ 380 memset(buf, 0, buf_len); 381 result = scsi_vpd_inquiry(sdev, buf, page, vpd_len); 382 if (result < 0) 383 return -EINVAL; 384 else if (result > vpd_len) 385 dev_warn_once(&sdev->sdev_gendev, 386 "%s: VPD page 0x%02x result %d > %d bytes\n", 387 __func__, page, result, vpd_len); 388 389 return 0; 390 } 391 EXPORT_SYMBOL_GPL(scsi_get_vpd_page); 392 393 /** 394 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device 395 * @sdev: The device to ask 396 * @page: Which Vital Product Data to return 397 * 398 * Returns %NULL upon failure. 399 */ 400 static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page) 401 { 402 struct scsi_vpd *vpd_buf; 403 int vpd_len, result; 404 405 vpd_len = scsi_get_vpd_size(sdev, page); 406 if (vpd_len <= 0) 407 return NULL; 408 409 retry_pg: 410 /* 411 * Fetch the actual page. Since the appropriate size was reported 412 * by the device it is now safe to ask for something bigger. 413 */ 414 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL); 415 if (!vpd_buf) 416 return NULL; 417 418 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len); 419 if (result < 0) { 420 kfree(vpd_buf); 421 return NULL; 422 } 423 if (result > vpd_len) { 424 dev_warn_once(&sdev->sdev_gendev, 425 "%s: VPD page 0x%02x result %d > %d bytes\n", 426 __func__, page, result, vpd_len); 427 vpd_len = result; 428 kfree(vpd_buf); 429 goto retry_pg; 430 } 431 432 vpd_buf->len = result; 433 434 return vpd_buf; 435 } 436 437 static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page, 438 struct scsi_vpd __rcu **sdev_vpd_buf) 439 { 440 struct scsi_vpd *vpd_buf; 441 442 vpd_buf = scsi_get_vpd_buf(sdev, page); 443 if (!vpd_buf) 444 return; 445 446 mutex_lock(&sdev->inquiry_mutex); 447 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf, 448 lockdep_is_held(&sdev->inquiry_mutex)); 449 mutex_unlock(&sdev->inquiry_mutex); 450 451 if (vpd_buf) 452 kfree_rcu(vpd_buf, rcu); 453 } 454 455 /** 456 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure 457 * @sdev: The device to ask 458 * 459 * Attach the 'Device Identification' VPD page (0x83) and the 460 * 'Unit Serial Number' VPD page (0x80) to a SCSI device 461 * structure. This information can be used to identify the device 462 * uniquely. 463 */ 464 void scsi_attach_vpd(struct scsi_device *sdev) 465 { 466 int i; 467 struct scsi_vpd *vpd_buf; 468 469 if (!scsi_device_supports_vpd(sdev)) 470 return; 471 472 /* Ask for all the pages supported by this device */ 473 vpd_buf = scsi_get_vpd_buf(sdev, 0); 474 if (!vpd_buf) 475 return; 476 477 for (i = 4; i < vpd_buf->len; i++) { 478 if (vpd_buf->data[i] == 0x0) 479 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0); 480 if (vpd_buf->data[i] == 0x80) 481 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80); 482 if (vpd_buf->data[i] == 0x83) 483 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83); 484 if (vpd_buf->data[i] == 0x89) 485 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89); 486 if (vpd_buf->data[i] == 0xb0) 487 scsi_update_vpd_page(sdev, 0xb0, &sdev->vpd_pgb0); 488 if (vpd_buf->data[i] == 0xb1) 489 scsi_update_vpd_page(sdev, 0xb1, &sdev->vpd_pgb1); 490 if (vpd_buf->data[i] == 0xb2) 491 scsi_update_vpd_page(sdev, 0xb2, &sdev->vpd_pgb2); 492 } 493 kfree(vpd_buf); 494 } 495 496 /** 497 * scsi_report_opcode - Find out if a given command opcode is supported 498 * @sdev: scsi device to query 499 * @buffer: scratch buffer (must be at least 20 bytes long) 500 * @len: length of buffer 501 * @opcode: opcode for command to look up 502 * 503 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given 504 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is 505 * unsupported and 1 if the device claims to support the command. 506 */ 507 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer, 508 unsigned int len, unsigned char opcode) 509 { 510 unsigned char cmd[16]; 511 struct scsi_sense_hdr sshdr; 512 int result, request_len; 513 514 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3) 515 return -EINVAL; 516 517 /* RSOC header + size of command we are asking about */ 518 request_len = 4 + COMMAND_SIZE(opcode); 519 if (request_len > len) { 520 dev_warn_once(&sdev->sdev_gendev, 521 "%s: len %u bytes, opcode 0x%02x needs %u\n", 522 __func__, len, opcode, request_len); 523 return -EINVAL; 524 } 525 526 memset(cmd, 0, 16); 527 cmd[0] = MAINTENANCE_IN; 528 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES; 529 cmd[2] = 1; /* One command format */ 530 cmd[3] = opcode; 531 put_unaligned_be32(request_len, &cmd[6]); 532 memset(buffer, 0, len); 533 534 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, 535 request_len, &sshdr, 30 * HZ, 3, NULL); 536 537 if (result < 0) 538 return result; 539 if (result && scsi_sense_valid(&sshdr) && 540 sshdr.sense_key == ILLEGAL_REQUEST && 541 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00) 542 return -EINVAL; 543 544 if ((buffer[1] & 3) == 3) /* Command supported */ 545 return 1; 546 547 return 0; 548 } 549 EXPORT_SYMBOL(scsi_report_opcode); 550 551 /** 552 * scsi_device_get - get an additional reference to a scsi_device 553 * @sdev: device to get a reference to 554 * 555 * Description: Gets a reference to the scsi_device and increments the use count 556 * of the underlying LLDD module. You must hold host_lock of the 557 * parent Scsi_Host or already have a reference when calling this. 558 * 559 * This will fail if a device is deleted or cancelled, or when the LLD module 560 * is in the process of being unloaded. 561 */ 562 int scsi_device_get(struct scsi_device *sdev) 563 { 564 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL) 565 goto fail; 566 if (!get_device(&sdev->sdev_gendev)) 567 goto fail; 568 if (!try_module_get(sdev->host->hostt->module)) 569 goto fail_put_device; 570 return 0; 571 572 fail_put_device: 573 put_device(&sdev->sdev_gendev); 574 fail: 575 return -ENXIO; 576 } 577 EXPORT_SYMBOL(scsi_device_get); 578 579 /** 580 * scsi_device_put - release a reference to a scsi_device 581 * @sdev: device to release a reference on. 582 * 583 * Description: Release a reference to the scsi_device and decrements the use 584 * count of the underlying LLDD module. The device is freed once the last 585 * user vanishes. 586 */ 587 void scsi_device_put(struct scsi_device *sdev) 588 { 589 struct module *mod = sdev->host->hostt->module; 590 591 put_device(&sdev->sdev_gendev); 592 module_put(mod); 593 } 594 EXPORT_SYMBOL(scsi_device_put); 595 596 /* helper for shost_for_each_device, see that for documentation */ 597 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost, 598 struct scsi_device *prev) 599 { 600 struct list_head *list = (prev ? &prev->siblings : &shost->__devices); 601 struct scsi_device *next = NULL; 602 unsigned long flags; 603 604 spin_lock_irqsave(shost->host_lock, flags); 605 while (list->next != &shost->__devices) { 606 next = list_entry(list->next, struct scsi_device, siblings); 607 /* skip devices that we can't get a reference to */ 608 if (!scsi_device_get(next)) 609 break; 610 next = NULL; 611 list = list->next; 612 } 613 spin_unlock_irqrestore(shost->host_lock, flags); 614 615 if (prev) 616 scsi_device_put(prev); 617 return next; 618 } 619 EXPORT_SYMBOL(__scsi_iterate_devices); 620 621 /** 622 * starget_for_each_device - helper to walk all devices of a target 623 * @starget: target whose devices we want to iterate over. 624 * @data: Opaque passed to each function call. 625 * @fn: Function to call on each device 626 * 627 * This traverses over each device of @starget. The devices have 628 * a reference that must be released by scsi_host_put when breaking 629 * out of the loop. 630 */ 631 void starget_for_each_device(struct scsi_target *starget, void *data, 632 void (*fn)(struct scsi_device *, void *)) 633 { 634 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 635 struct scsi_device *sdev; 636 637 shost_for_each_device(sdev, shost) { 638 if ((sdev->channel == starget->channel) && 639 (sdev->id == starget->id)) 640 fn(sdev, data); 641 } 642 } 643 EXPORT_SYMBOL(starget_for_each_device); 644 645 /** 646 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED) 647 * @starget: target whose devices we want to iterate over. 648 * @data: parameter for callback @fn() 649 * @fn: callback function that is invoked for each device 650 * 651 * This traverses over each device of @starget. It does _not_ 652 * take a reference on the scsi_device, so the whole loop must be 653 * protected by shost->host_lock. 654 * 655 * Note: The only reason why drivers would want to use this is because 656 * they need to access the device list in irq context. Otherwise you 657 * really want to use starget_for_each_device instead. 658 **/ 659 void __starget_for_each_device(struct scsi_target *starget, void *data, 660 void (*fn)(struct scsi_device *, void *)) 661 { 662 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 663 struct scsi_device *sdev; 664 665 __shost_for_each_device(sdev, shost) { 666 if ((sdev->channel == starget->channel) && 667 (sdev->id == starget->id)) 668 fn(sdev, data); 669 } 670 } 671 EXPORT_SYMBOL(__starget_for_each_device); 672 673 /** 674 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED) 675 * @starget: SCSI target pointer 676 * @lun: SCSI Logical Unit Number 677 * 678 * Description: Looks up the scsi_device with the specified @lun for a given 679 * @starget. The returned scsi_device does not have an additional 680 * reference. You must hold the host's host_lock over this call and 681 * any access to the returned scsi_device. A scsi_device in state 682 * SDEV_DEL is skipped. 683 * 684 * Note: The only reason why drivers should use this is because 685 * they need to access the device list in irq context. Otherwise you 686 * really want to use scsi_device_lookup_by_target instead. 687 **/ 688 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget, 689 u64 lun) 690 { 691 struct scsi_device *sdev; 692 693 list_for_each_entry(sdev, &starget->devices, same_target_siblings) { 694 if (sdev->sdev_state == SDEV_DEL) 695 continue; 696 if (sdev->lun ==lun) 697 return sdev; 698 } 699 700 return NULL; 701 } 702 EXPORT_SYMBOL(__scsi_device_lookup_by_target); 703 704 /** 705 * scsi_device_lookup_by_target - find a device given the target 706 * @starget: SCSI target pointer 707 * @lun: SCSI Logical Unit Number 708 * 709 * Description: Looks up the scsi_device with the specified @lun for a given 710 * @starget. The returned scsi_device has an additional reference that 711 * needs to be released with scsi_device_put once you're done with it. 712 **/ 713 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget, 714 u64 lun) 715 { 716 struct scsi_device *sdev; 717 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 718 unsigned long flags; 719 720 spin_lock_irqsave(shost->host_lock, flags); 721 sdev = __scsi_device_lookup_by_target(starget, lun); 722 if (sdev && scsi_device_get(sdev)) 723 sdev = NULL; 724 spin_unlock_irqrestore(shost->host_lock, flags); 725 726 return sdev; 727 } 728 EXPORT_SYMBOL(scsi_device_lookup_by_target); 729 730 /** 731 * __scsi_device_lookup - find a device given the host (UNLOCKED) 732 * @shost: SCSI host pointer 733 * @channel: SCSI channel (zero if only one channel) 734 * @id: SCSI target number (physical unit number) 735 * @lun: SCSI Logical Unit Number 736 * 737 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 738 * for a given host. The returned scsi_device does not have an additional 739 * reference. You must hold the host's host_lock over this call and any access 740 * to the returned scsi_device. 741 * 742 * Note: The only reason why drivers would want to use this is because 743 * they need to access the device list in irq context. Otherwise you 744 * really want to use scsi_device_lookup instead. 745 **/ 746 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost, 747 uint channel, uint id, u64 lun) 748 { 749 struct scsi_device *sdev; 750 751 list_for_each_entry(sdev, &shost->__devices, siblings) { 752 if (sdev->sdev_state == SDEV_DEL) 753 continue; 754 if (sdev->channel == channel && sdev->id == id && 755 sdev->lun ==lun) 756 return sdev; 757 } 758 759 return NULL; 760 } 761 EXPORT_SYMBOL(__scsi_device_lookup); 762 763 /** 764 * scsi_device_lookup - find a device given the host 765 * @shost: SCSI host pointer 766 * @channel: SCSI channel (zero if only one channel) 767 * @id: SCSI target number (physical unit number) 768 * @lun: SCSI Logical Unit Number 769 * 770 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 771 * for a given host. The returned scsi_device has an additional reference that 772 * needs to be released with scsi_device_put once you're done with it. 773 **/ 774 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost, 775 uint channel, uint id, u64 lun) 776 { 777 struct scsi_device *sdev; 778 unsigned long flags; 779 780 spin_lock_irqsave(shost->host_lock, flags); 781 sdev = __scsi_device_lookup(shost, channel, id, lun); 782 if (sdev && scsi_device_get(sdev)) 783 sdev = NULL; 784 spin_unlock_irqrestore(shost->host_lock, flags); 785 786 return sdev; 787 } 788 EXPORT_SYMBOL(scsi_device_lookup); 789 790 MODULE_DESCRIPTION("SCSI core"); 791 MODULE_LICENSE("GPL"); 792 793 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR); 794 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels"); 795 796 static int __init init_scsi(void) 797 { 798 int error; 799 800 error = scsi_init_procfs(); 801 if (error) 802 goto cleanup_queue; 803 error = scsi_init_devinfo(); 804 if (error) 805 goto cleanup_procfs; 806 error = scsi_init_hosts(); 807 if (error) 808 goto cleanup_devlist; 809 error = scsi_init_sysctl(); 810 if (error) 811 goto cleanup_hosts; 812 error = scsi_sysfs_register(); 813 if (error) 814 goto cleanup_sysctl; 815 816 scsi_netlink_init(); 817 818 printk(KERN_NOTICE "SCSI subsystem initialized\n"); 819 return 0; 820 821 cleanup_sysctl: 822 scsi_exit_sysctl(); 823 cleanup_hosts: 824 scsi_exit_hosts(); 825 cleanup_devlist: 826 scsi_exit_devinfo(); 827 cleanup_procfs: 828 scsi_exit_procfs(); 829 cleanup_queue: 830 scsi_exit_queue(); 831 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n", 832 -error); 833 return error; 834 } 835 836 static void __exit exit_scsi(void) 837 { 838 scsi_netlink_exit(); 839 scsi_sysfs_unregister(); 840 scsi_exit_sysctl(); 841 scsi_exit_hosts(); 842 scsi_exit_devinfo(); 843 scsi_exit_procfs(); 844 scsi_exit_queue(); 845 } 846 847 subsys_initcall(init_scsi); 848 module_exit(exit_scsi); 849