1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * scsi.c Copyright (C) 1992 Drew Eckhardt 4 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale 5 * Copyright (C) 2002, 2003 Christoph Hellwig 6 * 7 * generic mid-level SCSI driver 8 * Initial versions: Drew Eckhardt 9 * Subsequent revisions: Eric Youngdale 10 * 11 * <drew@colorado.edu> 12 * 13 * Bug correction thanks go to : 14 * Rik Faith <faith@cs.unc.edu> 15 * Tommy Thorn <tthorn> 16 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de> 17 * 18 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to 19 * add scatter-gather, multiple outstanding request, and other 20 * enhancements. 21 * 22 * Native multichannel, wide scsi, /proc/scsi and hot plugging 23 * support added by Michael Neuffer <mike@i-connect.net> 24 * 25 * Added request_module("scsi_hostadapter") for kerneld: 26 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf) 27 * Bjorn Ekwall <bj0rn@blox.se> 28 * (changed to kmod) 29 * 30 * Major improvements to the timeout, abort, and reset processing, 31 * as well as performance modifications for large queue depths by 32 * Leonard N. Zubkoff <lnz@dandelion.com> 33 * 34 * Converted cli() code to spinlocks, Ingo Molnar 35 * 36 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli 37 * 38 * out_of_space hacks, D. Gilbert (dpg) 990608 39 */ 40 41 #include <linux/module.h> 42 #include <linux/moduleparam.h> 43 #include <linux/kernel.h> 44 #include <linux/timer.h> 45 #include <linux/string.h> 46 #include <linux/slab.h> 47 #include <linux/blkdev.h> 48 #include <linux/delay.h> 49 #include <linux/init.h> 50 #include <linux/completion.h> 51 #include <linux/unistd.h> 52 #include <linux/spinlock.h> 53 #include <linux/kmod.h> 54 #include <linux/interrupt.h> 55 #include <linux/notifier.h> 56 #include <linux/cpu.h> 57 #include <linux/mutex.h> 58 #include <linux/async.h> 59 #include <asm/unaligned.h> 60 61 #include <scsi/scsi.h> 62 #include <scsi/scsi_cmnd.h> 63 #include <scsi/scsi_dbg.h> 64 #include <scsi/scsi_device.h> 65 #include <scsi/scsi_driver.h> 66 #include <scsi/scsi_eh.h> 67 #include <scsi/scsi_host.h> 68 #include <scsi/scsi_tcq.h> 69 70 #include "scsi_priv.h" 71 #include "scsi_logging.h" 72 73 #define CREATE_TRACE_POINTS 74 #include <trace/events/scsi.h> 75 76 /* 77 * Definitions and constants. 78 */ 79 80 /* 81 * Note - the initial logging level can be set here to log events at boot time. 82 * After the system is up, you may enable logging via the /proc interface. 83 */ 84 unsigned int scsi_logging_level; 85 #if defined(CONFIG_SCSI_LOGGING) 86 EXPORT_SYMBOL(scsi_logging_level); 87 #endif 88 89 /* 90 * Domain for asynchronous system resume operations. It is marked 'exclusive' 91 * to avoid being included in the async_synchronize_full() that is invoked by 92 * dpm_resume(). 93 */ 94 ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain); 95 EXPORT_SYMBOL(scsi_sd_pm_domain); 96 97 #ifdef CONFIG_SCSI_LOGGING 98 void scsi_log_send(struct scsi_cmnd *cmd) 99 { 100 unsigned int level; 101 102 /* 103 * If ML QUEUE log level is greater than or equal to: 104 * 105 * 1: nothing (match completion) 106 * 107 * 2: log opcode + command of all commands + cmd address 108 * 109 * 3: same as 2 110 * 111 * 4: same as 3 112 */ 113 if (unlikely(scsi_logging_level)) { 114 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT, 115 SCSI_LOG_MLQUEUE_BITS); 116 if (level > 1) { 117 scmd_printk(KERN_INFO, cmd, 118 "Send: scmd 0x%p\n", cmd); 119 scsi_print_command(cmd); 120 } 121 } 122 } 123 124 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition) 125 { 126 unsigned int level; 127 128 /* 129 * If ML COMPLETE log level is greater than or equal to: 130 * 131 * 1: log disposition, result, opcode + command, and conditionally 132 * sense data for failures or non SUCCESS dispositions. 133 * 134 * 2: same as 1 but for all command completions. 135 * 136 * 3: same as 2 137 * 138 * 4: same as 3 plus dump extra junk 139 */ 140 if (unlikely(scsi_logging_level)) { 141 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT, 142 SCSI_LOG_MLCOMPLETE_BITS); 143 if (((level > 0) && (cmd->result || disposition != SUCCESS)) || 144 (level > 1)) { 145 scsi_print_result(cmd, "Done", disposition); 146 scsi_print_command(cmd); 147 if (scsi_status_is_check_condition(cmd->result)) 148 scsi_print_sense(cmd); 149 if (level > 3) 150 scmd_printk(KERN_INFO, cmd, 151 "scsi host busy %d failed %d\n", 152 scsi_host_busy(cmd->device->host), 153 cmd->device->host->host_failed); 154 } 155 } 156 } 157 #endif 158 159 /** 160 * scsi_finish_command - cleanup and pass command back to upper layer 161 * @cmd: the command 162 * 163 * Description: Pass command off to upper layer for finishing of I/O 164 * request, waking processes that are waiting on results, 165 * etc. 166 */ 167 void scsi_finish_command(struct scsi_cmnd *cmd) 168 { 169 struct scsi_device *sdev = cmd->device; 170 struct scsi_target *starget = scsi_target(sdev); 171 struct Scsi_Host *shost = sdev->host; 172 struct scsi_driver *drv; 173 unsigned int good_bytes; 174 175 scsi_device_unbusy(sdev, cmd); 176 177 /* 178 * Clear the flags that say that the device/target/host is no longer 179 * capable of accepting new commands. 180 */ 181 if (atomic_read(&shost->host_blocked)) 182 atomic_set(&shost->host_blocked, 0); 183 if (atomic_read(&starget->target_blocked)) 184 atomic_set(&starget->target_blocked, 0); 185 if (atomic_read(&sdev->device_blocked)) 186 atomic_set(&sdev->device_blocked, 0); 187 188 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev, 189 "Notifying upper driver of completion " 190 "(result %x)\n", cmd->result)); 191 192 good_bytes = scsi_bufflen(cmd); 193 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) { 194 int old_good_bytes = good_bytes; 195 drv = scsi_cmd_to_driver(cmd); 196 if (drv->done) 197 good_bytes = drv->done(cmd); 198 /* 199 * USB may not give sense identifying bad sector and 200 * simply return a residue instead, so subtract off the 201 * residue if drv->done() error processing indicates no 202 * change to the completion length. 203 */ 204 if (good_bytes == old_good_bytes) 205 good_bytes -= scsi_get_resid(cmd); 206 } 207 scsi_io_completion(cmd, good_bytes); 208 } 209 210 211 /* 212 * 1024 is big enough for saturating the fast scsi LUN now 213 */ 214 int scsi_device_max_queue_depth(struct scsi_device *sdev) 215 { 216 return max_t(int, sdev->host->can_queue, 1024); 217 } 218 219 /** 220 * scsi_change_queue_depth - change a device's queue depth 221 * @sdev: SCSI Device in question 222 * @depth: number of commands allowed to be queued to the driver 223 * 224 * Sets the device queue depth and returns the new value. 225 */ 226 int scsi_change_queue_depth(struct scsi_device *sdev, int depth) 227 { 228 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev)); 229 230 if (depth > 0) { 231 sdev->queue_depth = depth; 232 wmb(); 233 } 234 235 if (sdev->request_queue) 236 blk_set_queue_depth(sdev->request_queue, depth); 237 238 sbitmap_resize(&sdev->budget_map, sdev->queue_depth); 239 240 return sdev->queue_depth; 241 } 242 EXPORT_SYMBOL(scsi_change_queue_depth); 243 244 /** 245 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth 246 * @sdev: SCSI Device in question 247 * @depth: Current number of outstanding SCSI commands on this device, 248 * not counting the one returned as QUEUE_FULL. 249 * 250 * Description: This function will track successive QUEUE_FULL events on a 251 * specific SCSI device to determine if and when there is a 252 * need to adjust the queue depth on the device. 253 * 254 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth, 255 * -1 - Drop back to untagged operation using host->cmd_per_lun 256 * as the untagged command depth 257 * 258 * Lock Status: None held on entry 259 * 260 * Notes: Low level drivers may call this at any time and we will do 261 * "The Right Thing." We are interrupt context safe. 262 */ 263 int scsi_track_queue_full(struct scsi_device *sdev, int depth) 264 { 265 266 /* 267 * Don't let QUEUE_FULLs on the same 268 * jiffies count, they could all be from 269 * same event. 270 */ 271 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4)) 272 return 0; 273 274 sdev->last_queue_full_time = jiffies; 275 if (sdev->last_queue_full_depth != depth) { 276 sdev->last_queue_full_count = 1; 277 sdev->last_queue_full_depth = depth; 278 } else { 279 sdev->last_queue_full_count++; 280 } 281 282 if (sdev->last_queue_full_count <= 10) 283 return 0; 284 285 return scsi_change_queue_depth(sdev, depth); 286 } 287 EXPORT_SYMBOL(scsi_track_queue_full); 288 289 /** 290 * scsi_vpd_inquiry - Request a device provide us with a VPD page 291 * @sdev: The device to ask 292 * @buffer: Where to put the result 293 * @page: Which Vital Product Data to return 294 * @len: The length of the buffer 295 * 296 * This is an internal helper function. You probably want to use 297 * scsi_get_vpd_page instead. 298 * 299 * Returns size of the vpd page on success or a negative error number. 300 */ 301 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, 302 u8 page, unsigned len) 303 { 304 int result; 305 unsigned char cmd[16]; 306 307 if (len < 4) 308 return -EINVAL; 309 310 cmd[0] = INQUIRY; 311 cmd[1] = 1; /* EVPD */ 312 cmd[2] = page; 313 cmd[3] = len >> 8; 314 cmd[4] = len & 0xff; 315 cmd[5] = 0; /* Control byte */ 316 317 /* 318 * I'm not convinced we need to try quite this hard to get VPD, but 319 * all the existing users tried this hard. 320 */ 321 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, 322 len, NULL, 30 * HZ, 3, NULL); 323 if (result) 324 return -EIO; 325 326 /* Sanity check that we got the page back that we asked for */ 327 if (buffer[1] != page) 328 return -EIO; 329 330 return get_unaligned_be16(&buffer[2]) + 4; 331 } 332 333 /** 334 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device 335 * @sdev: The device to ask 336 * @page: Which Vital Product Data to return 337 * @buf: where to store the VPD 338 * @buf_len: number of bytes in the VPD buffer area 339 * 340 * SCSI devices may optionally supply Vital Product Data. Each 'page' 341 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC). 342 * If the device supports this VPD page, this routine returns a pointer 343 * to a buffer containing the data from that page. The caller is 344 * responsible for calling kfree() on this pointer when it is no longer 345 * needed. If we cannot retrieve the VPD page this routine returns %NULL. 346 */ 347 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf, 348 int buf_len) 349 { 350 int i, result; 351 352 if (sdev->skip_vpd_pages) 353 goto fail; 354 355 /* Ask for all the pages supported by this device */ 356 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len); 357 if (result < 4) 358 goto fail; 359 360 /* If the user actually wanted this page, we can skip the rest */ 361 if (page == 0) 362 return 0; 363 364 for (i = 4; i < min(result, buf_len); i++) 365 if (buf[i] == page) 366 goto found; 367 368 if (i < result && i >= buf_len) 369 /* ran off the end of the buffer, give us benefit of doubt */ 370 goto found; 371 /* The device claims it doesn't support the requested page */ 372 goto fail; 373 374 found: 375 result = scsi_vpd_inquiry(sdev, buf, page, buf_len); 376 if (result < 0) 377 goto fail; 378 379 return 0; 380 381 fail: 382 return -EINVAL; 383 } 384 EXPORT_SYMBOL_GPL(scsi_get_vpd_page); 385 386 /** 387 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device 388 * @sdev: The device to ask 389 * @page: Which Vital Product Data to return 390 * 391 * Returns %NULL upon failure. 392 */ 393 static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page) 394 { 395 struct scsi_vpd *vpd_buf; 396 int vpd_len = SCSI_VPD_PG_LEN, result; 397 398 retry_pg: 399 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL); 400 if (!vpd_buf) 401 return NULL; 402 403 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len); 404 if (result < 0) { 405 kfree(vpd_buf); 406 return NULL; 407 } 408 if (result > vpd_len) { 409 vpd_len = result; 410 kfree(vpd_buf); 411 goto retry_pg; 412 } 413 414 vpd_buf->len = result; 415 416 return vpd_buf; 417 } 418 419 static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page, 420 struct scsi_vpd __rcu **sdev_vpd_buf) 421 { 422 struct scsi_vpd *vpd_buf; 423 424 vpd_buf = scsi_get_vpd_buf(sdev, page); 425 if (!vpd_buf) 426 return; 427 428 mutex_lock(&sdev->inquiry_mutex); 429 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf, 430 lockdep_is_held(&sdev->inquiry_mutex)); 431 mutex_unlock(&sdev->inquiry_mutex); 432 433 if (vpd_buf) 434 kfree_rcu(vpd_buf, rcu); 435 } 436 437 /** 438 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure 439 * @sdev: The device to ask 440 * 441 * Attach the 'Device Identification' VPD page (0x83) and the 442 * 'Unit Serial Number' VPD page (0x80) to a SCSI device 443 * structure. This information can be used to identify the device 444 * uniquely. 445 */ 446 void scsi_attach_vpd(struct scsi_device *sdev) 447 { 448 int i; 449 struct scsi_vpd *vpd_buf; 450 451 if (!scsi_device_supports_vpd(sdev)) 452 return; 453 454 /* Ask for all the pages supported by this device */ 455 vpd_buf = scsi_get_vpd_buf(sdev, 0); 456 if (!vpd_buf) 457 return; 458 459 for (i = 4; i < vpd_buf->len; i++) { 460 if (vpd_buf->data[i] == 0x0) 461 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0); 462 if (vpd_buf->data[i] == 0x80) 463 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80); 464 if (vpd_buf->data[i] == 0x83) 465 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83); 466 if (vpd_buf->data[i] == 0x89) 467 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89); 468 } 469 kfree(vpd_buf); 470 } 471 472 /** 473 * scsi_report_opcode - Find out if a given command opcode is supported 474 * @sdev: scsi device to query 475 * @buffer: scratch buffer (must be at least 20 bytes long) 476 * @len: length of buffer 477 * @opcode: opcode for command to look up 478 * 479 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given 480 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is 481 * unsupported and 1 if the device claims to support the command. 482 */ 483 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer, 484 unsigned int len, unsigned char opcode) 485 { 486 unsigned char cmd[16]; 487 struct scsi_sense_hdr sshdr; 488 int result; 489 490 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3) 491 return -EINVAL; 492 493 memset(cmd, 0, 16); 494 cmd[0] = MAINTENANCE_IN; 495 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES; 496 cmd[2] = 1; /* One command format */ 497 cmd[3] = opcode; 498 put_unaligned_be32(len, &cmd[6]); 499 memset(buffer, 0, len); 500 501 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, 502 &sshdr, 30 * HZ, 3, NULL); 503 504 if (result < 0) 505 return result; 506 if (result && scsi_sense_valid(&sshdr) && 507 sshdr.sense_key == ILLEGAL_REQUEST && 508 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00) 509 return -EINVAL; 510 511 if ((buffer[1] & 3) == 3) /* Command supported */ 512 return 1; 513 514 return 0; 515 } 516 EXPORT_SYMBOL(scsi_report_opcode); 517 518 /** 519 * scsi_device_get - get an additional reference to a scsi_device 520 * @sdev: device to get a reference to 521 * 522 * Description: Gets a reference to the scsi_device and increments the use count 523 * of the underlying LLDD module. You must hold host_lock of the 524 * parent Scsi_Host or already have a reference when calling this. 525 * 526 * This will fail if a device is deleted or cancelled, or when the LLD module 527 * is in the process of being unloaded. 528 */ 529 int scsi_device_get(struct scsi_device *sdev) 530 { 531 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL) 532 goto fail; 533 if (!get_device(&sdev->sdev_gendev)) 534 goto fail; 535 if (!try_module_get(sdev->host->hostt->module)) 536 goto fail_put_device; 537 return 0; 538 539 fail_put_device: 540 put_device(&sdev->sdev_gendev); 541 fail: 542 return -ENXIO; 543 } 544 EXPORT_SYMBOL(scsi_device_get); 545 546 /** 547 * scsi_device_put - release a reference to a scsi_device 548 * @sdev: device to release a reference on. 549 * 550 * Description: Release a reference to the scsi_device and decrements the use 551 * count of the underlying LLDD module. The device is freed once the last 552 * user vanishes. 553 */ 554 void scsi_device_put(struct scsi_device *sdev) 555 { 556 module_put(sdev->host->hostt->module); 557 put_device(&sdev->sdev_gendev); 558 } 559 EXPORT_SYMBOL(scsi_device_put); 560 561 /* helper for shost_for_each_device, see that for documentation */ 562 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost, 563 struct scsi_device *prev) 564 { 565 struct list_head *list = (prev ? &prev->siblings : &shost->__devices); 566 struct scsi_device *next = NULL; 567 unsigned long flags; 568 569 spin_lock_irqsave(shost->host_lock, flags); 570 while (list->next != &shost->__devices) { 571 next = list_entry(list->next, struct scsi_device, siblings); 572 /* skip devices that we can't get a reference to */ 573 if (!scsi_device_get(next)) 574 break; 575 next = NULL; 576 list = list->next; 577 } 578 spin_unlock_irqrestore(shost->host_lock, flags); 579 580 if (prev) 581 scsi_device_put(prev); 582 return next; 583 } 584 EXPORT_SYMBOL(__scsi_iterate_devices); 585 586 /** 587 * starget_for_each_device - helper to walk all devices of a target 588 * @starget: target whose devices we want to iterate over. 589 * @data: Opaque passed to each function call. 590 * @fn: Function to call on each device 591 * 592 * This traverses over each device of @starget. The devices have 593 * a reference that must be released by scsi_host_put when breaking 594 * out of the loop. 595 */ 596 void starget_for_each_device(struct scsi_target *starget, void *data, 597 void (*fn)(struct scsi_device *, void *)) 598 { 599 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 600 struct scsi_device *sdev; 601 602 shost_for_each_device(sdev, shost) { 603 if ((sdev->channel == starget->channel) && 604 (sdev->id == starget->id)) 605 fn(sdev, data); 606 } 607 } 608 EXPORT_SYMBOL(starget_for_each_device); 609 610 /** 611 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED) 612 * @starget: target whose devices we want to iterate over. 613 * @data: parameter for callback @fn() 614 * @fn: callback function that is invoked for each device 615 * 616 * This traverses over each device of @starget. It does _not_ 617 * take a reference on the scsi_device, so the whole loop must be 618 * protected by shost->host_lock. 619 * 620 * Note: The only reason why drivers would want to use this is because 621 * they need to access the device list in irq context. Otherwise you 622 * really want to use starget_for_each_device instead. 623 **/ 624 void __starget_for_each_device(struct scsi_target *starget, void *data, 625 void (*fn)(struct scsi_device *, void *)) 626 { 627 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 628 struct scsi_device *sdev; 629 630 __shost_for_each_device(sdev, shost) { 631 if ((sdev->channel == starget->channel) && 632 (sdev->id == starget->id)) 633 fn(sdev, data); 634 } 635 } 636 EXPORT_SYMBOL(__starget_for_each_device); 637 638 /** 639 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED) 640 * @starget: SCSI target pointer 641 * @lun: SCSI Logical Unit Number 642 * 643 * Description: Looks up the scsi_device with the specified @lun for a given 644 * @starget. The returned scsi_device does not have an additional 645 * reference. You must hold the host's host_lock over this call and 646 * any access to the returned scsi_device. A scsi_device in state 647 * SDEV_DEL is skipped. 648 * 649 * Note: The only reason why drivers should use this is because 650 * they need to access the device list in irq context. Otherwise you 651 * really want to use scsi_device_lookup_by_target instead. 652 **/ 653 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget, 654 u64 lun) 655 { 656 struct scsi_device *sdev; 657 658 list_for_each_entry(sdev, &starget->devices, same_target_siblings) { 659 if (sdev->sdev_state == SDEV_DEL) 660 continue; 661 if (sdev->lun ==lun) 662 return sdev; 663 } 664 665 return NULL; 666 } 667 EXPORT_SYMBOL(__scsi_device_lookup_by_target); 668 669 /** 670 * scsi_device_lookup_by_target - find a device given the target 671 * @starget: SCSI target pointer 672 * @lun: SCSI Logical Unit Number 673 * 674 * Description: Looks up the scsi_device with the specified @lun for a given 675 * @starget. The returned scsi_device has an additional reference that 676 * needs to be released with scsi_device_put once you're done with it. 677 **/ 678 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget, 679 u64 lun) 680 { 681 struct scsi_device *sdev; 682 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 683 unsigned long flags; 684 685 spin_lock_irqsave(shost->host_lock, flags); 686 sdev = __scsi_device_lookup_by_target(starget, lun); 687 if (sdev && scsi_device_get(sdev)) 688 sdev = NULL; 689 spin_unlock_irqrestore(shost->host_lock, flags); 690 691 return sdev; 692 } 693 EXPORT_SYMBOL(scsi_device_lookup_by_target); 694 695 /** 696 * __scsi_device_lookup - find a device given the host (UNLOCKED) 697 * @shost: SCSI host pointer 698 * @channel: SCSI channel (zero if only one channel) 699 * @id: SCSI target number (physical unit number) 700 * @lun: SCSI Logical Unit Number 701 * 702 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 703 * for a given host. The returned scsi_device does not have an additional 704 * reference. You must hold the host's host_lock over this call and any access 705 * to the returned scsi_device. 706 * 707 * Note: The only reason why drivers would want to use this is because 708 * they need to access the device list in irq context. Otherwise you 709 * really want to use scsi_device_lookup instead. 710 **/ 711 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost, 712 uint channel, uint id, u64 lun) 713 { 714 struct scsi_device *sdev; 715 716 list_for_each_entry(sdev, &shost->__devices, siblings) { 717 if (sdev->sdev_state == SDEV_DEL) 718 continue; 719 if (sdev->channel == channel && sdev->id == id && 720 sdev->lun ==lun) 721 return sdev; 722 } 723 724 return NULL; 725 } 726 EXPORT_SYMBOL(__scsi_device_lookup); 727 728 /** 729 * scsi_device_lookup - find a device given the host 730 * @shost: SCSI host pointer 731 * @channel: SCSI channel (zero if only one channel) 732 * @id: SCSI target number (physical unit number) 733 * @lun: SCSI Logical Unit Number 734 * 735 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 736 * for a given host. The returned scsi_device has an additional reference that 737 * needs to be released with scsi_device_put once you're done with it. 738 **/ 739 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost, 740 uint channel, uint id, u64 lun) 741 { 742 struct scsi_device *sdev; 743 unsigned long flags; 744 745 spin_lock_irqsave(shost->host_lock, flags); 746 sdev = __scsi_device_lookup(shost, channel, id, lun); 747 if (sdev && scsi_device_get(sdev)) 748 sdev = NULL; 749 spin_unlock_irqrestore(shost->host_lock, flags); 750 751 return sdev; 752 } 753 EXPORT_SYMBOL(scsi_device_lookup); 754 755 MODULE_DESCRIPTION("SCSI core"); 756 MODULE_LICENSE("GPL"); 757 758 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR); 759 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels"); 760 761 static int __init init_scsi(void) 762 { 763 int error; 764 765 error = scsi_init_procfs(); 766 if (error) 767 goto cleanup_queue; 768 error = scsi_init_devinfo(); 769 if (error) 770 goto cleanup_procfs; 771 error = scsi_init_hosts(); 772 if (error) 773 goto cleanup_devlist; 774 error = scsi_init_sysctl(); 775 if (error) 776 goto cleanup_hosts; 777 error = scsi_sysfs_register(); 778 if (error) 779 goto cleanup_sysctl; 780 781 scsi_netlink_init(); 782 783 printk(KERN_NOTICE "SCSI subsystem initialized\n"); 784 return 0; 785 786 cleanup_sysctl: 787 scsi_exit_sysctl(); 788 cleanup_hosts: 789 scsi_exit_hosts(); 790 cleanup_devlist: 791 scsi_exit_devinfo(); 792 cleanup_procfs: 793 scsi_exit_procfs(); 794 cleanup_queue: 795 scsi_exit_queue(); 796 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n", 797 -error); 798 return error; 799 } 800 801 static void __exit exit_scsi(void) 802 { 803 scsi_netlink_exit(); 804 scsi_sysfs_unregister(); 805 scsi_exit_sysctl(); 806 scsi_exit_hosts(); 807 scsi_exit_devinfo(); 808 scsi_exit_procfs(); 809 scsi_exit_queue(); 810 } 811 812 subsys_initcall(init_scsi); 813 module_exit(exit_scsi); 814