1 /* 2 * bsg.c - block layer implementation of the sg v4 interface 3 * 4 * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs 5 * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com> 6 * 7 * This file is subject to the terms and conditions of the GNU General Public 8 * License version 2. See the file "COPYING" in the main directory of this 9 * archive for more details. 10 * 11 */ 12 #include <linux/module.h> 13 #include <linux/init.h> 14 #include <linux/file.h> 15 #include <linux/blkdev.h> 16 #include <linux/poll.h> 17 #include <linux/cdev.h> 18 #include <linux/percpu.h> 19 #include <linux/uio.h> 20 #include <linux/idr.h> 21 #include <linux/bsg.h> 22 #include <linux/smp_lock.h> 23 24 #include <scsi/scsi.h> 25 #include <scsi/scsi_ioctl.h> 26 #include <scsi/scsi_cmnd.h> 27 #include <scsi/scsi_device.h> 28 #include <scsi/scsi_driver.h> 29 #include <scsi/sg.h> 30 31 #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" 32 #define BSG_VERSION "0.4" 33 34 struct bsg_device { 35 struct request_queue *queue; 36 spinlock_t lock; 37 struct list_head busy_list; 38 struct list_head done_list; 39 struct hlist_node dev_list; 40 atomic_t ref_count; 41 int queued_cmds; 42 int done_cmds; 43 wait_queue_head_t wq_done; 44 wait_queue_head_t wq_free; 45 char name[BUS_ID_SIZE]; 46 int max_queue; 47 unsigned long flags; 48 }; 49 50 enum { 51 BSG_F_BLOCK = 1, 52 }; 53 54 #define BSG_DEFAULT_CMDS 64 55 #define BSG_MAX_DEVS 32768 56 57 #undef BSG_DEBUG 58 59 #ifdef BSG_DEBUG 60 #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args) 61 #else 62 #define dprintk(fmt, args...) 63 #endif 64 65 static DEFINE_MUTEX(bsg_mutex); 66 static DEFINE_IDR(bsg_minor_idr); 67 68 #define BSG_LIST_ARRAY_SIZE 8 69 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; 70 71 static struct class *bsg_class; 72 static int bsg_major; 73 74 static struct kmem_cache *bsg_cmd_cachep; 75 76 /* 77 * our internal command type 78 */ 79 struct bsg_command { 80 struct bsg_device *bd; 81 struct list_head list; 82 struct request *rq; 83 struct bio *bio; 84 struct bio *bidi_bio; 85 int err; 86 struct sg_io_v4 hdr; 87 char sense[SCSI_SENSE_BUFFERSIZE]; 88 }; 89 90 static void bsg_free_command(struct bsg_command *bc) 91 { 92 struct bsg_device *bd = bc->bd; 93 unsigned long flags; 94 95 kmem_cache_free(bsg_cmd_cachep, bc); 96 97 spin_lock_irqsave(&bd->lock, flags); 98 bd->queued_cmds--; 99 spin_unlock_irqrestore(&bd->lock, flags); 100 101 wake_up(&bd->wq_free); 102 } 103 104 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) 105 { 106 struct bsg_command *bc = ERR_PTR(-EINVAL); 107 108 spin_lock_irq(&bd->lock); 109 110 if (bd->queued_cmds >= bd->max_queue) 111 goto out; 112 113 bd->queued_cmds++; 114 spin_unlock_irq(&bd->lock); 115 116 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); 117 if (unlikely(!bc)) { 118 spin_lock_irq(&bd->lock); 119 bd->queued_cmds--; 120 bc = ERR_PTR(-ENOMEM); 121 goto out; 122 } 123 124 bc->bd = bd; 125 INIT_LIST_HEAD(&bc->list); 126 dprintk("%s: returning free cmd %p\n", bd->name, bc); 127 return bc; 128 out: 129 spin_unlock_irq(&bd->lock); 130 return bc; 131 } 132 133 static inline struct hlist_head *bsg_dev_idx_hash(int index) 134 { 135 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; 136 } 137 138 static int bsg_io_schedule(struct bsg_device *bd) 139 { 140 DEFINE_WAIT(wait); 141 int ret = 0; 142 143 spin_lock_irq(&bd->lock); 144 145 BUG_ON(bd->done_cmds > bd->queued_cmds); 146 147 /* 148 * -ENOSPC or -ENODATA? I'm going for -ENODATA, meaning "I have no 149 * work to do", even though we return -ENOSPC after this same test 150 * during bsg_write() -- there, it means our buffer can't have more 151 * bsg_commands added to it, thus has no space left. 152 */ 153 if (bd->done_cmds == bd->queued_cmds) { 154 ret = -ENODATA; 155 goto unlock; 156 } 157 158 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 159 ret = -EAGAIN; 160 goto unlock; 161 } 162 163 prepare_to_wait(&bd->wq_done, &wait, TASK_UNINTERRUPTIBLE); 164 spin_unlock_irq(&bd->lock); 165 io_schedule(); 166 finish_wait(&bd->wq_done, &wait); 167 168 return ret; 169 unlock: 170 spin_unlock_irq(&bd->lock); 171 return ret; 172 } 173 174 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, 175 struct sg_io_v4 *hdr, struct bsg_device *bd, 176 fmode_t has_write_perm) 177 { 178 if (hdr->request_len > BLK_MAX_CDB) { 179 rq->cmd = kzalloc(hdr->request_len, GFP_KERNEL); 180 if (!rq->cmd) 181 return -ENOMEM; 182 } 183 184 if (copy_from_user(rq->cmd, (void *)(unsigned long)hdr->request, 185 hdr->request_len)) 186 return -EFAULT; 187 188 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) { 189 if (blk_verify_command(&q->cmd_filter, rq->cmd, has_write_perm)) 190 return -EPERM; 191 } else if (!capable(CAP_SYS_RAWIO)) 192 return -EPERM; 193 194 /* 195 * fill in request structure 196 */ 197 rq->cmd_len = hdr->request_len; 198 rq->cmd_type = REQ_TYPE_BLOCK_PC; 199 200 rq->timeout = (hdr->timeout * HZ) / 1000; 201 if (!rq->timeout) 202 rq->timeout = q->sg_timeout; 203 if (!rq->timeout) 204 rq->timeout = BLK_DEFAULT_SG_TIMEOUT; 205 206 return 0; 207 } 208 209 /* 210 * Check if sg_io_v4 from user is allowed and valid 211 */ 212 static int 213 bsg_validate_sgv4_hdr(struct request_queue *q, struct sg_io_v4 *hdr, int *rw) 214 { 215 int ret = 0; 216 217 if (hdr->guard != 'Q') 218 return -EINVAL; 219 if (hdr->dout_xfer_len > (q->max_sectors << 9) || 220 hdr->din_xfer_len > (q->max_sectors << 9)) 221 return -EIO; 222 223 switch (hdr->protocol) { 224 case BSG_PROTOCOL_SCSI: 225 switch (hdr->subprotocol) { 226 case BSG_SUB_PROTOCOL_SCSI_CMD: 227 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT: 228 break; 229 default: 230 ret = -EINVAL; 231 } 232 break; 233 default: 234 ret = -EINVAL; 235 } 236 237 *rw = hdr->dout_xfer_len ? WRITE : READ; 238 return ret; 239 } 240 241 /* 242 * map sg_io_v4 to a request. 243 */ 244 static struct request * 245 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm) 246 { 247 struct request_queue *q = bd->queue; 248 struct request *rq, *next_rq = NULL; 249 int ret, rw; 250 unsigned int dxfer_len; 251 void *dxferp = NULL; 252 253 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, 254 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, 255 hdr->din_xfer_len); 256 257 ret = bsg_validate_sgv4_hdr(q, hdr, &rw); 258 if (ret) 259 return ERR_PTR(ret); 260 261 /* 262 * map scatter-gather elements seperately and string them to request 263 */ 264 rq = blk_get_request(q, rw, GFP_KERNEL); 265 if (!rq) 266 return ERR_PTR(-ENOMEM); 267 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); 268 if (ret) 269 goto out; 270 271 if (rw == WRITE && hdr->din_xfer_len) { 272 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 273 ret = -EOPNOTSUPP; 274 goto out; 275 } 276 277 next_rq = blk_get_request(q, READ, GFP_KERNEL); 278 if (!next_rq) { 279 ret = -ENOMEM; 280 goto out; 281 } 282 rq->next_rq = next_rq; 283 next_rq->cmd_type = rq->cmd_type; 284 285 dxferp = (void*)(unsigned long)hdr->din_xferp; 286 ret = blk_rq_map_user(q, next_rq, NULL, dxferp, 287 hdr->din_xfer_len, GFP_KERNEL); 288 if (ret) 289 goto out; 290 } 291 292 if (hdr->dout_xfer_len) { 293 dxfer_len = hdr->dout_xfer_len; 294 dxferp = (void*)(unsigned long)hdr->dout_xferp; 295 } else if (hdr->din_xfer_len) { 296 dxfer_len = hdr->din_xfer_len; 297 dxferp = (void*)(unsigned long)hdr->din_xferp; 298 } else 299 dxfer_len = 0; 300 301 if (dxfer_len) { 302 ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len, 303 GFP_KERNEL); 304 if (ret) 305 goto out; 306 } 307 return rq; 308 out: 309 if (rq->cmd != rq->__cmd) 310 kfree(rq->cmd); 311 blk_put_request(rq); 312 if (next_rq) { 313 blk_rq_unmap_user(next_rq->bio); 314 blk_put_request(next_rq); 315 } 316 return ERR_PTR(ret); 317 } 318 319 /* 320 * async completion call-back from the block layer, when scsi/ide/whatever 321 * calls end_that_request_last() on a request 322 */ 323 static void bsg_rq_end_io(struct request *rq, int uptodate) 324 { 325 struct bsg_command *bc = rq->end_io_data; 326 struct bsg_device *bd = bc->bd; 327 unsigned long flags; 328 329 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", 330 bd->name, rq, bc, bc->bio, uptodate); 331 332 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); 333 334 spin_lock_irqsave(&bd->lock, flags); 335 list_move_tail(&bc->list, &bd->done_list); 336 bd->done_cmds++; 337 spin_unlock_irqrestore(&bd->lock, flags); 338 339 wake_up(&bd->wq_done); 340 } 341 342 /* 343 * do final setup of a 'bc' and submit the matching 'rq' to the block 344 * layer for io 345 */ 346 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, 347 struct bsg_command *bc, struct request *rq) 348 { 349 rq->sense = bc->sense; 350 rq->sense_len = 0; 351 352 /* 353 * add bc command to busy queue and submit rq for io 354 */ 355 bc->rq = rq; 356 bc->bio = rq->bio; 357 if (rq->next_rq) 358 bc->bidi_bio = rq->next_rq->bio; 359 bc->hdr.duration = jiffies; 360 spin_lock_irq(&bd->lock); 361 list_add_tail(&bc->list, &bd->busy_list); 362 spin_unlock_irq(&bd->lock); 363 364 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); 365 366 rq->end_io_data = bc; 367 blk_execute_rq_nowait(q, NULL, rq, 1, bsg_rq_end_io); 368 } 369 370 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) 371 { 372 struct bsg_command *bc = NULL; 373 374 spin_lock_irq(&bd->lock); 375 if (bd->done_cmds) { 376 bc = list_first_entry(&bd->done_list, struct bsg_command, list); 377 list_del(&bc->list); 378 bd->done_cmds--; 379 } 380 spin_unlock_irq(&bd->lock); 381 382 return bc; 383 } 384 385 /* 386 * Get a finished command from the done list 387 */ 388 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) 389 { 390 struct bsg_command *bc; 391 int ret; 392 393 do { 394 bc = bsg_next_done_cmd(bd); 395 if (bc) 396 break; 397 398 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 399 bc = ERR_PTR(-EAGAIN); 400 break; 401 } 402 403 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); 404 if (ret) { 405 bc = ERR_PTR(-ERESTARTSYS); 406 break; 407 } 408 } while (1); 409 410 dprintk("%s: returning done %p\n", bd->name, bc); 411 412 return bc; 413 } 414 415 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 416 struct bio *bio, struct bio *bidi_bio) 417 { 418 int ret = 0; 419 420 dprintk("rq %p bio %p %u\n", rq, bio, rq->errors); 421 /* 422 * fill in all the output members 423 */ 424 hdr->device_status = status_byte(rq->errors); 425 hdr->transport_status = host_byte(rq->errors); 426 hdr->driver_status = driver_byte(rq->errors); 427 hdr->info = 0; 428 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 429 hdr->info |= SG_INFO_CHECK; 430 hdr->response_len = 0; 431 432 if (rq->sense_len && hdr->response) { 433 int len = min_t(unsigned int, hdr->max_response_len, 434 rq->sense_len); 435 436 ret = copy_to_user((void*)(unsigned long)hdr->response, 437 rq->sense, len); 438 if (!ret) 439 hdr->response_len = len; 440 else 441 ret = -EFAULT; 442 } 443 444 if (rq->next_rq) { 445 hdr->dout_resid = rq->data_len; 446 hdr->din_resid = rq->next_rq->data_len; 447 blk_rq_unmap_user(bidi_bio); 448 blk_put_request(rq->next_rq); 449 } else if (rq_data_dir(rq) == READ) 450 hdr->din_resid = rq->data_len; 451 else 452 hdr->dout_resid = rq->data_len; 453 454 /* 455 * If the request generated a negative error number, return it 456 * (providing we aren't already returning an error); if it's 457 * just a protocol response (i.e. non negative), that gets 458 * processed above. 459 */ 460 if (!ret && rq->errors < 0) 461 ret = rq->errors; 462 463 blk_rq_unmap_user(bio); 464 if (rq->cmd != rq->__cmd) 465 kfree(rq->cmd); 466 blk_put_request(rq); 467 468 return ret; 469 } 470 471 static int bsg_complete_all_commands(struct bsg_device *bd) 472 { 473 struct bsg_command *bc; 474 int ret, tret; 475 476 dprintk("%s: entered\n", bd->name); 477 478 /* 479 * wait for all commands to complete 480 */ 481 ret = 0; 482 do { 483 ret = bsg_io_schedule(bd); 484 /* 485 * look for -ENODATA specifically -- we'll sometimes get 486 * -ERESTARTSYS when we've taken a signal, but we can't 487 * return until we're done freeing the queue, so ignore 488 * it. The signal will get handled when we're done freeing 489 * the bsg_device. 490 */ 491 } while (ret != -ENODATA); 492 493 /* 494 * discard done commands 495 */ 496 ret = 0; 497 do { 498 spin_lock_irq(&bd->lock); 499 if (!bd->queued_cmds) { 500 spin_unlock_irq(&bd->lock); 501 break; 502 } 503 spin_unlock_irq(&bd->lock); 504 505 bc = bsg_get_done_cmd(bd); 506 if (IS_ERR(bc)) 507 break; 508 509 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 510 bc->bidi_bio); 511 if (!ret) 512 ret = tret; 513 514 bsg_free_command(bc); 515 } while (1); 516 517 return ret; 518 } 519 520 static int 521 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 522 const struct iovec *iov, ssize_t *bytes_read) 523 { 524 struct bsg_command *bc; 525 int nr_commands, ret; 526 527 if (count % sizeof(struct sg_io_v4)) 528 return -EINVAL; 529 530 ret = 0; 531 nr_commands = count / sizeof(struct sg_io_v4); 532 while (nr_commands) { 533 bc = bsg_get_done_cmd(bd); 534 if (IS_ERR(bc)) { 535 ret = PTR_ERR(bc); 536 break; 537 } 538 539 /* 540 * this is the only case where we need to copy data back 541 * after completing the request. so do that here, 542 * bsg_complete_work() cannot do that for us 543 */ 544 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 545 bc->bidi_bio); 546 547 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 548 ret = -EFAULT; 549 550 bsg_free_command(bc); 551 552 if (ret) 553 break; 554 555 buf += sizeof(struct sg_io_v4); 556 *bytes_read += sizeof(struct sg_io_v4); 557 nr_commands--; 558 } 559 560 return ret; 561 } 562 563 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 564 { 565 if (file->f_flags & O_NONBLOCK) 566 clear_bit(BSG_F_BLOCK, &bd->flags); 567 else 568 set_bit(BSG_F_BLOCK, &bd->flags); 569 } 570 571 /* 572 * Check if the error is a "real" error that we should return. 573 */ 574 static inline int err_block_err(int ret) 575 { 576 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 577 return 1; 578 579 return 0; 580 } 581 582 static ssize_t 583 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 584 { 585 struct bsg_device *bd = file->private_data; 586 int ret; 587 ssize_t bytes_read; 588 589 dprintk("%s: read %Zd bytes\n", bd->name, count); 590 591 bsg_set_block(bd, file); 592 593 bytes_read = 0; 594 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 595 *ppos = bytes_read; 596 597 if (!bytes_read || (bytes_read && err_block_err(ret))) 598 bytes_read = ret; 599 600 return bytes_read; 601 } 602 603 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 604 size_t count, ssize_t *bytes_written, 605 fmode_t has_write_perm) 606 { 607 struct bsg_command *bc; 608 struct request *rq; 609 int ret, nr_commands; 610 611 if (count % sizeof(struct sg_io_v4)) 612 return -EINVAL; 613 614 nr_commands = count / sizeof(struct sg_io_v4); 615 rq = NULL; 616 bc = NULL; 617 ret = 0; 618 while (nr_commands) { 619 struct request_queue *q = bd->queue; 620 621 bc = bsg_alloc_command(bd); 622 if (IS_ERR(bc)) { 623 ret = PTR_ERR(bc); 624 bc = NULL; 625 break; 626 } 627 628 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 629 ret = -EFAULT; 630 break; 631 } 632 633 /* 634 * get a request, fill in the blanks, and add to request queue 635 */ 636 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm); 637 if (IS_ERR(rq)) { 638 ret = PTR_ERR(rq); 639 rq = NULL; 640 break; 641 } 642 643 bsg_add_command(bd, q, bc, rq); 644 bc = NULL; 645 rq = NULL; 646 nr_commands--; 647 buf += sizeof(struct sg_io_v4); 648 *bytes_written += sizeof(struct sg_io_v4); 649 } 650 651 if (bc) 652 bsg_free_command(bc); 653 654 return ret; 655 } 656 657 static ssize_t 658 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 659 { 660 struct bsg_device *bd = file->private_data; 661 ssize_t bytes_written; 662 int ret; 663 664 dprintk("%s: write %Zd bytes\n", bd->name, count); 665 666 bsg_set_block(bd, file); 667 668 bytes_written = 0; 669 ret = __bsg_write(bd, buf, count, &bytes_written, 670 file->f_mode & FMODE_WRITE); 671 672 *ppos = bytes_written; 673 674 /* 675 * return bytes written on non-fatal errors 676 */ 677 if (!bytes_written || (bytes_written && err_block_err(ret))) 678 bytes_written = ret; 679 680 dprintk("%s: returning %Zd\n", bd->name, bytes_written); 681 return bytes_written; 682 } 683 684 static struct bsg_device *bsg_alloc_device(void) 685 { 686 struct bsg_device *bd; 687 688 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 689 if (unlikely(!bd)) 690 return NULL; 691 692 spin_lock_init(&bd->lock); 693 694 bd->max_queue = BSG_DEFAULT_CMDS; 695 696 INIT_LIST_HEAD(&bd->busy_list); 697 INIT_LIST_HEAD(&bd->done_list); 698 INIT_HLIST_NODE(&bd->dev_list); 699 700 init_waitqueue_head(&bd->wq_free); 701 init_waitqueue_head(&bd->wq_done); 702 return bd; 703 } 704 705 static void bsg_kref_release_function(struct kref *kref) 706 { 707 struct bsg_class_device *bcd = 708 container_of(kref, struct bsg_class_device, ref); 709 struct device *parent = bcd->parent; 710 711 if (bcd->release) 712 bcd->release(bcd->parent); 713 714 put_device(parent); 715 } 716 717 static int bsg_put_device(struct bsg_device *bd) 718 { 719 int ret = 0, do_free; 720 struct request_queue *q = bd->queue; 721 722 mutex_lock(&bsg_mutex); 723 724 do_free = atomic_dec_and_test(&bd->ref_count); 725 if (!do_free) { 726 mutex_unlock(&bsg_mutex); 727 goto out; 728 } 729 730 hlist_del(&bd->dev_list); 731 mutex_unlock(&bsg_mutex); 732 733 dprintk("%s: tearing down\n", bd->name); 734 735 /* 736 * close can always block 737 */ 738 set_bit(BSG_F_BLOCK, &bd->flags); 739 740 /* 741 * correct error detection baddies here again. it's the responsibility 742 * of the app to properly reap commands before close() if it wants 743 * fool-proof error detection 744 */ 745 ret = bsg_complete_all_commands(bd); 746 747 kfree(bd); 748 out: 749 kref_put(&q->bsg_dev.ref, bsg_kref_release_function); 750 if (do_free) 751 blk_put_queue(q); 752 return ret; 753 } 754 755 static struct bsg_device *bsg_add_device(struct inode *inode, 756 struct request_queue *rq, 757 struct file *file) 758 { 759 struct bsg_device *bd; 760 int ret; 761 #ifdef BSG_DEBUG 762 unsigned char buf[32]; 763 #endif 764 ret = blk_get_queue(rq); 765 if (ret) 766 return ERR_PTR(-ENXIO); 767 768 bd = bsg_alloc_device(); 769 if (!bd) { 770 blk_put_queue(rq); 771 return ERR_PTR(-ENOMEM); 772 } 773 774 bd->queue = rq; 775 776 bsg_set_block(bd, file); 777 778 atomic_set(&bd->ref_count, 1); 779 mutex_lock(&bsg_mutex); 780 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 781 782 strncpy(bd->name, rq->bsg_dev.class_dev->bus_id, sizeof(bd->name) - 1); 783 dprintk("bound to <%s>, max queue %d\n", 784 format_dev_t(buf, inode->i_rdev), bd->max_queue); 785 786 mutex_unlock(&bsg_mutex); 787 return bd; 788 } 789 790 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 791 { 792 struct bsg_device *bd; 793 struct hlist_node *entry; 794 795 mutex_lock(&bsg_mutex); 796 797 hlist_for_each_entry(bd, entry, bsg_dev_idx_hash(minor), dev_list) { 798 if (bd->queue == q) { 799 atomic_inc(&bd->ref_count); 800 goto found; 801 } 802 } 803 bd = NULL; 804 found: 805 mutex_unlock(&bsg_mutex); 806 return bd; 807 } 808 809 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 810 { 811 struct bsg_device *bd; 812 struct bsg_class_device *bcd; 813 814 /* 815 * find the class device 816 */ 817 mutex_lock(&bsg_mutex); 818 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 819 if (bcd) 820 kref_get(&bcd->ref); 821 mutex_unlock(&bsg_mutex); 822 823 if (!bcd) 824 return ERR_PTR(-ENODEV); 825 826 bd = __bsg_get_device(iminor(inode), bcd->queue); 827 if (bd) 828 return bd; 829 830 bd = bsg_add_device(inode, bcd->queue, file); 831 if (IS_ERR(bd)) 832 kref_put(&bcd->ref, bsg_kref_release_function); 833 834 return bd; 835 } 836 837 static int bsg_open(struct inode *inode, struct file *file) 838 { 839 struct bsg_device *bd; 840 841 lock_kernel(); 842 bd = bsg_get_device(inode, file); 843 unlock_kernel(); 844 845 if (IS_ERR(bd)) 846 return PTR_ERR(bd); 847 848 file->private_data = bd; 849 return 0; 850 } 851 852 static int bsg_release(struct inode *inode, struct file *file) 853 { 854 struct bsg_device *bd = file->private_data; 855 856 file->private_data = NULL; 857 return bsg_put_device(bd); 858 } 859 860 static unsigned int bsg_poll(struct file *file, poll_table *wait) 861 { 862 struct bsg_device *bd = file->private_data; 863 unsigned int mask = 0; 864 865 poll_wait(file, &bd->wq_done, wait); 866 poll_wait(file, &bd->wq_free, wait); 867 868 spin_lock_irq(&bd->lock); 869 if (!list_empty(&bd->done_list)) 870 mask |= POLLIN | POLLRDNORM; 871 if (bd->queued_cmds >= bd->max_queue) 872 mask |= POLLOUT; 873 spin_unlock_irq(&bd->lock); 874 875 return mask; 876 } 877 878 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 879 { 880 struct bsg_device *bd = file->private_data; 881 int __user *uarg = (int __user *) arg; 882 int ret; 883 884 switch (cmd) { 885 /* 886 * our own ioctls 887 */ 888 case SG_GET_COMMAND_Q: 889 return put_user(bd->max_queue, uarg); 890 case SG_SET_COMMAND_Q: { 891 int queue; 892 893 if (get_user(queue, uarg)) 894 return -EFAULT; 895 if (queue < 1) 896 return -EINVAL; 897 898 spin_lock_irq(&bd->lock); 899 bd->max_queue = queue; 900 spin_unlock_irq(&bd->lock); 901 return 0; 902 } 903 904 /* 905 * SCSI/sg ioctls 906 */ 907 case SG_GET_VERSION_NUM: 908 case SCSI_IOCTL_GET_IDLUN: 909 case SCSI_IOCTL_GET_BUS_NUMBER: 910 case SG_SET_TIMEOUT: 911 case SG_GET_TIMEOUT: 912 case SG_GET_RESERVED_SIZE: 913 case SG_SET_RESERVED_SIZE: 914 case SG_EMULATED_HOST: 915 case SCSI_IOCTL_SEND_COMMAND: { 916 void __user *uarg = (void __user *) arg; 917 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); 918 } 919 case SG_IO: { 920 struct request *rq; 921 struct bio *bio, *bidi_bio = NULL; 922 struct sg_io_v4 hdr; 923 924 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 925 return -EFAULT; 926 927 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE); 928 if (IS_ERR(rq)) 929 return PTR_ERR(rq); 930 931 bio = rq->bio; 932 if (rq->next_rq) 933 bidi_bio = rq->next_rq->bio; 934 blk_execute_rq(bd->queue, NULL, rq, 0); 935 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 936 937 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 938 return -EFAULT; 939 940 return ret; 941 } 942 /* 943 * block device ioctls 944 */ 945 default: 946 #if 0 947 return ioctl_by_bdev(bd->bdev, cmd, arg); 948 #else 949 return -ENOTTY; 950 #endif 951 } 952 } 953 954 static const struct file_operations bsg_fops = { 955 .read = bsg_read, 956 .write = bsg_write, 957 .poll = bsg_poll, 958 .open = bsg_open, 959 .release = bsg_release, 960 .unlocked_ioctl = bsg_ioctl, 961 .owner = THIS_MODULE, 962 }; 963 964 void bsg_unregister_queue(struct request_queue *q) 965 { 966 struct bsg_class_device *bcd = &q->bsg_dev; 967 968 if (!bcd->class_dev) 969 return; 970 971 mutex_lock(&bsg_mutex); 972 idr_remove(&bsg_minor_idr, bcd->minor); 973 sysfs_remove_link(&q->kobj, "bsg"); 974 device_unregister(bcd->class_dev); 975 bcd->class_dev = NULL; 976 kref_put(&bcd->ref, bsg_kref_release_function); 977 mutex_unlock(&bsg_mutex); 978 } 979 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 980 981 int bsg_register_queue(struct request_queue *q, struct device *parent, 982 const char *name, void (*release)(struct device *)) 983 { 984 struct bsg_class_device *bcd; 985 dev_t dev; 986 int ret, minor; 987 struct device *class_dev = NULL; 988 const char *devname; 989 990 if (name) 991 devname = name; 992 else 993 devname = parent->bus_id; 994 995 /* 996 * we need a proper transport to send commands, not a stacked device 997 */ 998 if (!q->request_fn) 999 return 0; 1000 1001 bcd = &q->bsg_dev; 1002 memset(bcd, 0, sizeof(*bcd)); 1003 1004 mutex_lock(&bsg_mutex); 1005 1006 ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL); 1007 if (!ret) { 1008 ret = -ENOMEM; 1009 goto unlock; 1010 } 1011 1012 ret = idr_get_new(&bsg_minor_idr, bcd, &minor); 1013 if (ret < 0) 1014 goto unlock; 1015 1016 if (minor >= BSG_MAX_DEVS) { 1017 printk(KERN_ERR "bsg: too many bsg devices\n"); 1018 ret = -EINVAL; 1019 goto remove_idr; 1020 } 1021 1022 bcd->minor = minor; 1023 bcd->queue = q; 1024 bcd->parent = get_device(parent); 1025 bcd->release = release; 1026 kref_init(&bcd->ref); 1027 dev = MKDEV(bsg_major, bcd->minor); 1028 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); 1029 if (IS_ERR(class_dev)) { 1030 ret = PTR_ERR(class_dev); 1031 goto put_dev; 1032 } 1033 bcd->class_dev = class_dev; 1034 1035 if (q->kobj.sd) { 1036 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 1037 if (ret) 1038 goto unregister_class_dev; 1039 } 1040 1041 mutex_unlock(&bsg_mutex); 1042 return 0; 1043 1044 unregister_class_dev: 1045 device_unregister(class_dev); 1046 put_dev: 1047 put_device(parent); 1048 remove_idr: 1049 idr_remove(&bsg_minor_idr, minor); 1050 unlock: 1051 mutex_unlock(&bsg_mutex); 1052 return ret; 1053 } 1054 EXPORT_SYMBOL_GPL(bsg_register_queue); 1055 1056 static struct cdev bsg_cdev; 1057 1058 static int __init bsg_init(void) 1059 { 1060 int ret, i; 1061 dev_t devid; 1062 1063 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1064 sizeof(struct bsg_command), 0, 0, NULL); 1065 if (!bsg_cmd_cachep) { 1066 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1067 return -ENOMEM; 1068 } 1069 1070 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1071 INIT_HLIST_HEAD(&bsg_device_list[i]); 1072 1073 bsg_class = class_create(THIS_MODULE, "bsg"); 1074 if (IS_ERR(bsg_class)) { 1075 ret = PTR_ERR(bsg_class); 1076 goto destroy_kmemcache; 1077 } 1078 1079 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1080 if (ret) 1081 goto destroy_bsg_class; 1082 1083 bsg_major = MAJOR(devid); 1084 1085 cdev_init(&bsg_cdev, &bsg_fops); 1086 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1087 if (ret) 1088 goto unregister_chrdev; 1089 1090 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1091 " loaded (major %d)\n", bsg_major); 1092 return 0; 1093 unregister_chrdev: 1094 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1095 destroy_bsg_class: 1096 class_destroy(bsg_class); 1097 destroy_kmemcache: 1098 kmem_cache_destroy(bsg_cmd_cachep); 1099 return ret; 1100 } 1101 1102 MODULE_AUTHOR("Jens Axboe"); 1103 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1104 MODULE_LICENSE("GPL"); 1105 1106 device_initcall(bsg_init); 1107