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 (status_byte(cmd->result) == CHECK_CONDITION) 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 /* 189 * If we have valid sense information, then some kind of recovery 190 * must have taken place. Make a note of this. 191 */ 192 if (SCSI_SENSE_VALID(cmd)) 193 cmd->result |= (DRIVER_SENSE << 24); 194 195 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev, 196 "Notifying upper driver of completion " 197 "(result %x)\n", cmd->result)); 198 199 good_bytes = scsi_bufflen(cmd); 200 if (!blk_rq_is_passthrough(cmd->request)) { 201 int old_good_bytes = good_bytes; 202 drv = scsi_cmd_to_driver(cmd); 203 if (drv->done) 204 good_bytes = drv->done(cmd); 205 /* 206 * USB may not give sense identifying bad sector and 207 * simply return a residue instead, so subtract off the 208 * residue if drv->done() error processing indicates no 209 * change to the completion length. 210 */ 211 if (good_bytes == old_good_bytes) 212 good_bytes -= scsi_get_resid(cmd); 213 } 214 scsi_io_completion(cmd, good_bytes); 215 } 216 217 /** 218 * scsi_change_queue_depth - change a device's queue depth 219 * @sdev: SCSI Device in question 220 * @depth: number of commands allowed to be queued to the driver 221 * 222 * Sets the device queue depth and returns the new value. 223 */ 224 int scsi_change_queue_depth(struct scsi_device *sdev, int depth) 225 { 226 if (depth > 0) { 227 sdev->queue_depth = depth; 228 wmb(); 229 } 230 231 if (sdev->request_queue) 232 blk_set_queue_depth(sdev->request_queue, depth); 233 234 return sdev->queue_depth; 235 } 236 EXPORT_SYMBOL(scsi_change_queue_depth); 237 238 /** 239 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth 240 * @sdev: SCSI Device in question 241 * @depth: Current number of outstanding SCSI commands on this device, 242 * not counting the one returned as QUEUE_FULL. 243 * 244 * Description: This function will track successive QUEUE_FULL events on a 245 * specific SCSI device to determine if and when there is a 246 * need to adjust the queue depth on the device. 247 * 248 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth, 249 * -1 - Drop back to untagged operation using host->cmd_per_lun 250 * as the untagged command depth 251 * 252 * Lock Status: None held on entry 253 * 254 * Notes: Low level drivers may call this at any time and we will do 255 * "The Right Thing." We are interrupt context safe. 256 */ 257 int scsi_track_queue_full(struct scsi_device *sdev, int depth) 258 { 259 260 /* 261 * Don't let QUEUE_FULLs on the same 262 * jiffies count, they could all be from 263 * same event. 264 */ 265 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4)) 266 return 0; 267 268 sdev->last_queue_full_time = jiffies; 269 if (sdev->last_queue_full_depth != depth) { 270 sdev->last_queue_full_count = 1; 271 sdev->last_queue_full_depth = depth; 272 } else { 273 sdev->last_queue_full_count++; 274 } 275 276 if (sdev->last_queue_full_count <= 10) 277 return 0; 278 279 return scsi_change_queue_depth(sdev, depth); 280 } 281 EXPORT_SYMBOL(scsi_track_queue_full); 282 283 /** 284 * scsi_vpd_inquiry - Request a device provide us with a VPD page 285 * @sdev: The device to ask 286 * @buffer: Where to put the result 287 * @page: Which Vital Product Data to return 288 * @len: The length of the buffer 289 * 290 * This is an internal helper function. You probably want to use 291 * scsi_get_vpd_page instead. 292 * 293 * Returns size of the vpd page on success or a negative error number. 294 */ 295 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, 296 u8 page, unsigned len) 297 { 298 int result; 299 unsigned char cmd[16]; 300 301 if (len < 4) 302 return -EINVAL; 303 304 cmd[0] = INQUIRY; 305 cmd[1] = 1; /* EVPD */ 306 cmd[2] = page; 307 cmd[3] = len >> 8; 308 cmd[4] = len & 0xff; 309 cmd[5] = 0; /* Control byte */ 310 311 /* 312 * I'm not convinced we need to try quite this hard to get VPD, but 313 * all the existing users tried this hard. 314 */ 315 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, 316 len, NULL, 30 * HZ, 3, NULL); 317 if (result) 318 return -EIO; 319 320 /* Sanity check that we got the page back that we asked for */ 321 if (buffer[1] != page) 322 return -EIO; 323 324 return get_unaligned_be16(&buffer[2]) + 4; 325 } 326 327 /** 328 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device 329 * @sdev: The device to ask 330 * @page: Which Vital Product Data to return 331 * @buf: where to store the VPD 332 * @buf_len: number of bytes in the VPD buffer area 333 * 334 * SCSI devices may optionally supply Vital Product Data. Each 'page' 335 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC). 336 * If the device supports this VPD page, this routine returns a pointer 337 * to a buffer containing the data from that page. The caller is 338 * responsible for calling kfree() on this pointer when it is no longer 339 * needed. If we cannot retrieve the VPD page this routine returns %NULL. 340 */ 341 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf, 342 int buf_len) 343 { 344 int i, result; 345 346 if (sdev->skip_vpd_pages) 347 goto fail; 348 349 /* Ask for all the pages supported by this device */ 350 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len); 351 if (result < 4) 352 goto fail; 353 354 /* If the user actually wanted this page, we can skip the rest */ 355 if (page == 0) 356 return 0; 357 358 for (i = 4; i < min(result, buf_len); i++) 359 if (buf[i] == page) 360 goto found; 361 362 if (i < result && i >= buf_len) 363 /* ran off the end of the buffer, give us benefit of doubt */ 364 goto found; 365 /* The device claims it doesn't support the requested page */ 366 goto fail; 367 368 found: 369 result = scsi_vpd_inquiry(sdev, buf, page, buf_len); 370 if (result < 0) 371 goto fail; 372 373 return 0; 374 375 fail: 376 return -EINVAL; 377 } 378 EXPORT_SYMBOL_GPL(scsi_get_vpd_page); 379 380 /** 381 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device 382 * @sdev: The device to ask 383 * @page: Which Vital Product Data to return 384 * 385 * Returns %NULL upon failure. 386 */ 387 static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page) 388 { 389 struct scsi_vpd *vpd_buf; 390 int vpd_len = SCSI_VPD_PG_LEN, result; 391 392 retry_pg: 393 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL); 394 if (!vpd_buf) 395 return NULL; 396 397 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len); 398 if (result < 0) { 399 kfree(vpd_buf); 400 return NULL; 401 } 402 if (result > vpd_len) { 403 vpd_len = result; 404 kfree(vpd_buf); 405 goto retry_pg; 406 } 407 408 vpd_buf->len = result; 409 410 return vpd_buf; 411 } 412 413 static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page, 414 struct scsi_vpd __rcu **sdev_vpd_buf) 415 { 416 struct scsi_vpd *vpd_buf; 417 418 vpd_buf = scsi_get_vpd_buf(sdev, page); 419 if (!vpd_buf) 420 return; 421 422 mutex_lock(&sdev->inquiry_mutex); 423 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf, 424 lockdep_is_held(&sdev->inquiry_mutex)); 425 mutex_unlock(&sdev->inquiry_mutex); 426 427 if (vpd_buf) 428 kfree_rcu(vpd_buf, rcu); 429 } 430 431 /** 432 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure 433 * @sdev: The device to ask 434 * 435 * Attach the 'Device Identification' VPD page (0x83) and the 436 * 'Unit Serial Number' VPD page (0x80) to a SCSI device 437 * structure. This information can be used to identify the device 438 * uniquely. 439 */ 440 void scsi_attach_vpd(struct scsi_device *sdev) 441 { 442 int i; 443 struct scsi_vpd *vpd_buf; 444 445 if (!scsi_device_supports_vpd(sdev)) 446 return; 447 448 /* Ask for all the pages supported by this device */ 449 vpd_buf = scsi_get_vpd_buf(sdev, 0); 450 if (!vpd_buf) 451 return; 452 453 for (i = 4; i < vpd_buf->len; i++) { 454 if (vpd_buf->data[i] == 0x0) 455 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0); 456 if (vpd_buf->data[i] == 0x80) 457 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80); 458 if (vpd_buf->data[i] == 0x83) 459 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83); 460 if (vpd_buf->data[i] == 0x89) 461 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89); 462 } 463 kfree(vpd_buf); 464 } 465 466 /** 467 * scsi_report_opcode - Find out if a given command opcode is supported 468 * @sdev: scsi device to query 469 * @buffer: scratch buffer (must be at least 20 bytes long) 470 * @len: length of buffer 471 * @opcode: opcode for command to look up 472 * 473 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given 474 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is 475 * unsupported and 1 if the device claims to support the command. 476 */ 477 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer, 478 unsigned int len, unsigned char opcode) 479 { 480 unsigned char cmd[16]; 481 struct scsi_sense_hdr sshdr; 482 int result; 483 484 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3) 485 return -EINVAL; 486 487 memset(cmd, 0, 16); 488 cmd[0] = MAINTENANCE_IN; 489 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES; 490 cmd[2] = 1; /* One command format */ 491 cmd[3] = opcode; 492 put_unaligned_be32(len, &cmd[6]); 493 memset(buffer, 0, len); 494 495 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, 496 &sshdr, 30 * HZ, 3, NULL); 497 498 if (result && scsi_sense_valid(&sshdr) && 499 sshdr.sense_key == ILLEGAL_REQUEST && 500 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00) 501 return -EINVAL; 502 503 if ((buffer[1] & 3) == 3) /* Command supported */ 504 return 1; 505 506 return 0; 507 } 508 EXPORT_SYMBOL(scsi_report_opcode); 509 510 /** 511 * scsi_device_get - get an additional reference to a scsi_device 512 * @sdev: device to get a reference to 513 * 514 * Description: Gets a reference to the scsi_device and increments the use count 515 * of the underlying LLDD module. You must hold host_lock of the 516 * parent Scsi_Host or already have a reference when calling this. 517 * 518 * This will fail if a device is deleted or cancelled, or when the LLD module 519 * is in the process of being unloaded. 520 */ 521 int scsi_device_get(struct scsi_device *sdev) 522 { 523 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL) 524 goto fail; 525 if (!get_device(&sdev->sdev_gendev)) 526 goto fail; 527 if (!try_module_get(sdev->host->hostt->module)) 528 goto fail_put_device; 529 return 0; 530 531 fail_put_device: 532 put_device(&sdev->sdev_gendev); 533 fail: 534 return -ENXIO; 535 } 536 EXPORT_SYMBOL(scsi_device_get); 537 538 /** 539 * scsi_device_put - release a reference to a scsi_device 540 * @sdev: device to release a reference on. 541 * 542 * Description: Release a reference to the scsi_device and decrements the use 543 * count of the underlying LLDD module. The device is freed once the last 544 * user vanishes. 545 */ 546 void scsi_device_put(struct scsi_device *sdev) 547 { 548 module_put(sdev->host->hostt->module); 549 put_device(&sdev->sdev_gendev); 550 } 551 EXPORT_SYMBOL(scsi_device_put); 552 553 /* helper for shost_for_each_device, see that for documentation */ 554 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost, 555 struct scsi_device *prev) 556 { 557 struct list_head *list = (prev ? &prev->siblings : &shost->__devices); 558 struct scsi_device *next = NULL; 559 unsigned long flags; 560 561 spin_lock_irqsave(shost->host_lock, flags); 562 while (list->next != &shost->__devices) { 563 next = list_entry(list->next, struct scsi_device, siblings); 564 /* skip devices that we can't get a reference to */ 565 if (!scsi_device_get(next)) 566 break; 567 next = NULL; 568 list = list->next; 569 } 570 spin_unlock_irqrestore(shost->host_lock, flags); 571 572 if (prev) 573 scsi_device_put(prev); 574 return next; 575 } 576 EXPORT_SYMBOL(__scsi_iterate_devices); 577 578 /** 579 * starget_for_each_device - helper to walk all devices of a target 580 * @starget: target whose devices we want to iterate over. 581 * @data: Opaque passed to each function call. 582 * @fn: Function to call on each device 583 * 584 * This traverses over each device of @starget. The devices have 585 * a reference that must be released by scsi_host_put when breaking 586 * out of the loop. 587 */ 588 void starget_for_each_device(struct scsi_target *starget, void *data, 589 void (*fn)(struct scsi_device *, void *)) 590 { 591 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 592 struct scsi_device *sdev; 593 594 shost_for_each_device(sdev, shost) { 595 if ((sdev->channel == starget->channel) && 596 (sdev->id == starget->id)) 597 fn(sdev, data); 598 } 599 } 600 EXPORT_SYMBOL(starget_for_each_device); 601 602 /** 603 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED) 604 * @starget: target whose devices we want to iterate over. 605 * @data: parameter for callback @fn() 606 * @fn: callback function that is invoked for each device 607 * 608 * This traverses over each device of @starget. It does _not_ 609 * take a reference on the scsi_device, so the whole loop must be 610 * protected by shost->host_lock. 611 * 612 * Note: The only reason why drivers would want to use this is because 613 * they need to access the device list in irq context. Otherwise you 614 * really want to use starget_for_each_device instead. 615 **/ 616 void __starget_for_each_device(struct scsi_target *starget, void *data, 617 void (*fn)(struct scsi_device *, void *)) 618 { 619 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 620 struct scsi_device *sdev; 621 622 __shost_for_each_device(sdev, shost) { 623 if ((sdev->channel == starget->channel) && 624 (sdev->id == starget->id)) 625 fn(sdev, data); 626 } 627 } 628 EXPORT_SYMBOL(__starget_for_each_device); 629 630 /** 631 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED) 632 * @starget: SCSI target pointer 633 * @lun: SCSI Logical Unit Number 634 * 635 * Description: Looks up the scsi_device with the specified @lun for a given 636 * @starget. The returned scsi_device does not have an additional 637 * reference. You must hold the host's host_lock over this call and 638 * any access to the returned scsi_device. A scsi_device in state 639 * SDEV_DEL is skipped. 640 * 641 * Note: The only reason why drivers should use this is because 642 * they need to access the device list in irq context. Otherwise you 643 * really want to use scsi_device_lookup_by_target instead. 644 **/ 645 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget, 646 u64 lun) 647 { 648 struct scsi_device *sdev; 649 650 list_for_each_entry(sdev, &starget->devices, same_target_siblings) { 651 if (sdev->sdev_state == SDEV_DEL) 652 continue; 653 if (sdev->lun ==lun) 654 return sdev; 655 } 656 657 return NULL; 658 } 659 EXPORT_SYMBOL(__scsi_device_lookup_by_target); 660 661 /** 662 * scsi_device_lookup_by_target - find a device given the target 663 * @starget: SCSI target pointer 664 * @lun: SCSI Logical Unit Number 665 * 666 * Description: Looks up the scsi_device with the specified @lun for a given 667 * @starget. The returned scsi_device has an additional reference that 668 * needs to be released with scsi_device_put once you're done with it. 669 **/ 670 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget, 671 u64 lun) 672 { 673 struct scsi_device *sdev; 674 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 675 unsigned long flags; 676 677 spin_lock_irqsave(shost->host_lock, flags); 678 sdev = __scsi_device_lookup_by_target(starget, lun); 679 if (sdev && scsi_device_get(sdev)) 680 sdev = NULL; 681 spin_unlock_irqrestore(shost->host_lock, flags); 682 683 return sdev; 684 } 685 EXPORT_SYMBOL(scsi_device_lookup_by_target); 686 687 /** 688 * __scsi_device_lookup - find a device given the host (UNLOCKED) 689 * @shost: SCSI host pointer 690 * @channel: SCSI channel (zero if only one channel) 691 * @id: SCSI target number (physical unit number) 692 * @lun: SCSI Logical Unit Number 693 * 694 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 695 * for a given host. The returned scsi_device does not have an additional 696 * reference. You must hold the host's host_lock over this call and any access 697 * to the returned scsi_device. 698 * 699 * Note: The only reason why drivers would want to use this is because 700 * they need to access the device list in irq context. Otherwise you 701 * really want to use scsi_device_lookup instead. 702 **/ 703 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost, 704 uint channel, uint id, u64 lun) 705 { 706 struct scsi_device *sdev; 707 708 list_for_each_entry(sdev, &shost->__devices, siblings) { 709 if (sdev->sdev_state == SDEV_DEL) 710 continue; 711 if (sdev->channel == channel && sdev->id == id && 712 sdev->lun ==lun) 713 return sdev; 714 } 715 716 return NULL; 717 } 718 EXPORT_SYMBOL(__scsi_device_lookup); 719 720 /** 721 * scsi_device_lookup - find a device given the host 722 * @shost: SCSI host pointer 723 * @channel: SCSI channel (zero if only one channel) 724 * @id: SCSI target number (physical unit number) 725 * @lun: SCSI Logical Unit Number 726 * 727 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 728 * for a given host. The returned scsi_device has an additional reference that 729 * needs to be released with scsi_device_put once you're done with it. 730 **/ 731 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost, 732 uint channel, uint id, u64 lun) 733 { 734 struct scsi_device *sdev; 735 unsigned long flags; 736 737 spin_lock_irqsave(shost->host_lock, flags); 738 sdev = __scsi_device_lookup(shost, channel, id, lun); 739 if (sdev && scsi_device_get(sdev)) 740 sdev = NULL; 741 spin_unlock_irqrestore(shost->host_lock, flags); 742 743 return sdev; 744 } 745 EXPORT_SYMBOL(scsi_device_lookup); 746 747 MODULE_DESCRIPTION("SCSI core"); 748 MODULE_LICENSE("GPL"); 749 750 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR); 751 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels"); 752 753 static int __init init_scsi(void) 754 { 755 int error; 756 757 error = scsi_init_procfs(); 758 if (error) 759 goto cleanup_queue; 760 error = scsi_init_devinfo(); 761 if (error) 762 goto cleanup_procfs; 763 error = scsi_init_hosts(); 764 if (error) 765 goto cleanup_devlist; 766 error = scsi_init_sysctl(); 767 if (error) 768 goto cleanup_hosts; 769 error = scsi_sysfs_register(); 770 if (error) 771 goto cleanup_sysctl; 772 773 scsi_netlink_init(); 774 775 printk(KERN_NOTICE "SCSI subsystem initialized\n"); 776 return 0; 777 778 cleanup_sysctl: 779 scsi_exit_sysctl(); 780 cleanup_hosts: 781 scsi_exit_hosts(); 782 cleanup_devlist: 783 scsi_exit_devinfo(); 784 cleanup_procfs: 785 scsi_exit_procfs(); 786 cleanup_queue: 787 scsi_exit_queue(); 788 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n", 789 -error); 790 return error; 791 } 792 793 static void __exit exit_scsi(void) 794 { 795 scsi_netlink_exit(); 796 scsi_sysfs_unregister(); 797 scsi_exit_sysctl(); 798 scsi_exit_hosts(); 799 scsi_exit_devinfo(); 800 scsi_exit_procfs(); 801 scsi_exit_queue(); 802 } 803 804 subsys_initcall(init_scsi); 805 module_exit(exit_scsi); 806