1 #ifndef _LINUX_BLKDEV_H 2 #define _LINUX_BLKDEV_H 3 4 #ifdef CONFIG_BLOCK 5 6 #include <linux/sched.h> 7 #include <linux/major.h> 8 #include <linux/genhd.h> 9 #include <linux/list.h> 10 #include <linux/timer.h> 11 #include <linux/workqueue.h> 12 #include <linux/pagemap.h> 13 #include <linux/backing-dev.h> 14 #include <linux/wait.h> 15 #include <linux/mempool.h> 16 #include <linux/bio.h> 17 #include <linux/module.h> 18 #include <linux/stringify.h> 19 #include <linux/gfp.h> 20 #include <linux/bsg.h> 21 #include <linux/smp.h> 22 23 #include <asm/scatterlist.h> 24 25 struct scsi_ioctl_command; 26 27 struct request_queue; 28 struct elevator_queue; 29 struct request_pm_state; 30 struct blk_trace; 31 struct request; 32 struct sg_io_hdr; 33 34 #define BLKDEV_MIN_RQ 4 35 #define BLKDEV_MAX_RQ 128 /* Default maximum */ 36 37 struct request; 38 typedef void (rq_end_io_fn)(struct request *, int); 39 40 struct request_list { 41 /* 42 * count[], starved[], and wait[] are indexed by 43 * BLK_RW_SYNC/BLK_RW_ASYNC 44 */ 45 int count[2]; 46 int starved[2]; 47 int elvpriv; 48 mempool_t *rq_pool; 49 wait_queue_head_t wait[2]; 50 }; 51 52 /* 53 * request command types 54 */ 55 enum rq_cmd_type_bits { 56 REQ_TYPE_FS = 1, /* fs request */ 57 REQ_TYPE_BLOCK_PC, /* scsi command */ 58 REQ_TYPE_SENSE, /* sense request */ 59 REQ_TYPE_PM_SUSPEND, /* suspend request */ 60 REQ_TYPE_PM_RESUME, /* resume request */ 61 REQ_TYPE_PM_SHUTDOWN, /* shutdown request */ 62 REQ_TYPE_SPECIAL, /* driver defined type */ 63 /* 64 * for ATA/ATAPI devices. this really doesn't belong here, ide should 65 * use REQ_TYPE_SPECIAL and use rq->cmd[0] with the range of driver 66 * private REQ_LB opcodes to differentiate what type of request this is 67 */ 68 REQ_TYPE_ATA_TASKFILE, 69 REQ_TYPE_ATA_PC, 70 }; 71 72 #define BLK_MAX_CDB 16 73 74 /* 75 * try to put the fields that are referenced together in the same cacheline. 76 * if you modify this structure, be sure to check block/blk-core.c:rq_init() 77 * as well! 78 */ 79 struct request { 80 struct list_head queuelist; 81 struct call_single_data csd; 82 83 struct request_queue *q; 84 85 unsigned int cmd_flags; 86 enum rq_cmd_type_bits cmd_type; 87 unsigned long atomic_flags; 88 89 int cpu; 90 91 /* the following two fields are internal, NEVER access directly */ 92 unsigned int __data_len; /* total data len */ 93 sector_t __sector; /* sector cursor */ 94 95 struct bio *bio; 96 struct bio *biotail; 97 98 struct hlist_node hash; /* merge hash */ 99 /* 100 * The rb_node is only used inside the io scheduler, requests 101 * are pruned when moved to the dispatch queue. So let the 102 * completion_data share space with the rb_node. 103 */ 104 union { 105 struct rb_node rb_node; /* sort/lookup */ 106 void *completion_data; 107 }; 108 109 /* 110 * Three pointers are available for the IO schedulers, if they need 111 * more they have to dynamically allocate it. 112 */ 113 void *elevator_private; 114 void *elevator_private2; 115 void *elevator_private3; 116 117 struct gendisk *rq_disk; 118 struct hd_struct *part; 119 unsigned long start_time; 120 #ifdef CONFIG_BLK_CGROUP 121 unsigned long long start_time_ns; 122 unsigned long long io_start_time_ns; /* when passed to hardware */ 123 #endif 124 /* Number of scatter-gather DMA addr+len pairs after 125 * physical address coalescing is performed. 126 */ 127 unsigned short nr_phys_segments; 128 #if defined(CONFIG_BLK_DEV_INTEGRITY) 129 unsigned short nr_integrity_segments; 130 #endif 131 132 unsigned short ioprio; 133 134 int ref_count; 135 136 void *special; /* opaque pointer available for LLD use */ 137 char *buffer; /* kaddr of the current segment if available */ 138 139 int tag; 140 int errors; 141 142 /* 143 * when request is used as a packet command carrier 144 */ 145 unsigned char __cmd[BLK_MAX_CDB]; 146 unsigned char *cmd; 147 unsigned short cmd_len; 148 149 unsigned int extra_len; /* length of alignment and padding */ 150 unsigned int sense_len; 151 unsigned int resid_len; /* residual count */ 152 void *sense; 153 154 unsigned long deadline; 155 struct list_head timeout_list; 156 unsigned int timeout; 157 int retries; 158 159 /* 160 * completion callback. 161 */ 162 rq_end_io_fn *end_io; 163 void *end_io_data; 164 165 /* for bidi */ 166 struct request *next_rq; 167 }; 168 169 static inline unsigned short req_get_ioprio(struct request *req) 170 { 171 return req->ioprio; 172 } 173 174 /* 175 * State information carried for REQ_TYPE_PM_SUSPEND and REQ_TYPE_PM_RESUME 176 * requests. Some step values could eventually be made generic. 177 */ 178 struct request_pm_state 179 { 180 /* PM state machine step value, currently driver specific */ 181 int pm_step; 182 /* requested PM state value (S1, S2, S3, S4, ...) */ 183 u32 pm_state; 184 void* data; /* for driver use */ 185 }; 186 187 #include <linux/elevator.h> 188 189 typedef void (request_fn_proc) (struct request_queue *q); 190 typedef int (make_request_fn) (struct request_queue *q, struct bio *bio); 191 typedef int (prep_rq_fn) (struct request_queue *, struct request *); 192 typedef void (unprep_rq_fn) (struct request_queue *, struct request *); 193 typedef void (unplug_fn) (struct request_queue *); 194 195 struct bio_vec; 196 struct bvec_merge_data { 197 struct block_device *bi_bdev; 198 sector_t bi_sector; 199 unsigned bi_size; 200 unsigned long bi_rw; 201 }; 202 typedef int (merge_bvec_fn) (struct request_queue *, struct bvec_merge_data *, 203 struct bio_vec *); 204 typedef void (softirq_done_fn)(struct request *); 205 typedef int (dma_drain_needed_fn)(struct request *); 206 typedef int (lld_busy_fn) (struct request_queue *q); 207 208 enum blk_eh_timer_return { 209 BLK_EH_NOT_HANDLED, 210 BLK_EH_HANDLED, 211 BLK_EH_RESET_TIMER, 212 }; 213 214 typedef enum blk_eh_timer_return (rq_timed_out_fn)(struct request *); 215 216 enum blk_queue_state { 217 Queue_down, 218 Queue_up, 219 }; 220 221 struct blk_queue_tag { 222 struct request **tag_index; /* map of busy tags */ 223 unsigned long *tag_map; /* bit map of free/busy tags */ 224 int busy; /* current depth */ 225 int max_depth; /* what we will send to device */ 226 int real_max_depth; /* what the array can hold */ 227 atomic_t refcnt; /* map can be shared */ 228 }; 229 230 #define BLK_SCSI_MAX_CMDS (256) 231 #define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8)) 232 233 struct queue_limits { 234 unsigned long bounce_pfn; 235 unsigned long seg_boundary_mask; 236 237 unsigned int max_hw_sectors; 238 unsigned int max_sectors; 239 unsigned int max_segment_size; 240 unsigned int physical_block_size; 241 unsigned int alignment_offset; 242 unsigned int io_min; 243 unsigned int io_opt; 244 unsigned int max_discard_sectors; 245 unsigned int discard_granularity; 246 unsigned int discard_alignment; 247 248 unsigned short logical_block_size; 249 unsigned short max_segments; 250 unsigned short max_integrity_segments; 251 252 unsigned char misaligned; 253 unsigned char discard_misaligned; 254 unsigned char no_cluster; 255 signed char discard_zeroes_data; 256 }; 257 258 struct request_queue 259 { 260 /* 261 * Together with queue_head for cacheline sharing 262 */ 263 struct list_head queue_head; 264 struct request *last_merge; 265 struct elevator_queue *elevator; 266 267 /* 268 * the queue request freelist, one for reads and one for writes 269 */ 270 struct request_list rq; 271 272 request_fn_proc *request_fn; 273 make_request_fn *make_request_fn; 274 prep_rq_fn *prep_rq_fn; 275 unprep_rq_fn *unprep_rq_fn; 276 unplug_fn *unplug_fn; 277 merge_bvec_fn *merge_bvec_fn; 278 softirq_done_fn *softirq_done_fn; 279 rq_timed_out_fn *rq_timed_out_fn; 280 dma_drain_needed_fn *dma_drain_needed; 281 lld_busy_fn *lld_busy_fn; 282 283 /* 284 * Dispatch queue sorting 285 */ 286 sector_t end_sector; 287 struct request *boundary_rq; 288 289 /* 290 * Auto-unplugging state 291 */ 292 struct timer_list unplug_timer; 293 int unplug_thresh; /* After this many requests */ 294 unsigned long unplug_delay; /* After this many jiffies */ 295 struct work_struct unplug_work; 296 297 struct backing_dev_info backing_dev_info; 298 299 /* 300 * The queue owner gets to use this for whatever they like. 301 * ll_rw_blk doesn't touch it. 302 */ 303 void *queuedata; 304 305 /* 306 * queue needs bounce pages for pages above this limit 307 */ 308 gfp_t bounce_gfp; 309 310 /* 311 * various queue flags, see QUEUE_* below 312 */ 313 unsigned long queue_flags; 314 315 /* 316 * protects queue structures from reentrancy. ->__queue_lock should 317 * _never_ be used directly, it is queue private. always use 318 * ->queue_lock. 319 */ 320 spinlock_t __queue_lock; 321 spinlock_t *queue_lock; 322 323 /* 324 * queue kobject 325 */ 326 struct kobject kobj; 327 328 /* 329 * queue settings 330 */ 331 unsigned long nr_requests; /* Max # of requests */ 332 unsigned int nr_congestion_on; 333 unsigned int nr_congestion_off; 334 unsigned int nr_batching; 335 336 void *dma_drain_buffer; 337 unsigned int dma_drain_size; 338 unsigned int dma_pad_mask; 339 unsigned int dma_alignment; 340 341 struct blk_queue_tag *queue_tags; 342 struct list_head tag_busy_list; 343 344 unsigned int nr_sorted; 345 unsigned int in_flight[2]; 346 347 unsigned int rq_timeout; 348 struct timer_list timeout; 349 struct list_head timeout_list; 350 351 struct queue_limits limits; 352 353 /* 354 * sg stuff 355 */ 356 unsigned int sg_timeout; 357 unsigned int sg_reserved_size; 358 int node; 359 #ifdef CONFIG_BLK_DEV_IO_TRACE 360 struct blk_trace *blk_trace; 361 #endif 362 /* 363 * for flush operations 364 */ 365 unsigned int flush_flags; 366 unsigned int flush_seq; 367 int flush_err; 368 struct request flush_rq; 369 struct request *orig_flush_rq; 370 struct list_head pending_flushes; 371 372 struct mutex sysfs_lock; 373 374 #if defined(CONFIG_BLK_DEV_BSG) 375 struct bsg_class_device bsg_dev; 376 #endif 377 378 #ifdef CONFIG_BLK_DEV_THROTTLING 379 /* Throttle data */ 380 struct throtl_data *td; 381 #endif 382 }; 383 384 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */ 385 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */ 386 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */ 387 #define QUEUE_FLAG_SYNCFULL 3 /* read queue has been filled */ 388 #define QUEUE_FLAG_ASYNCFULL 4 /* write queue has been filled */ 389 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */ 390 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */ 391 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */ 392 #define QUEUE_FLAG_ELVSWITCH 8 /* don't use elevator, just do FIFO */ 393 #define QUEUE_FLAG_BIDI 9 /* queue supports bidi requests */ 394 #define QUEUE_FLAG_NOMERGES 10 /* disable merge attempts */ 395 #define QUEUE_FLAG_SAME_COMP 11 /* force complete on same CPU */ 396 #define QUEUE_FLAG_FAIL_IO 12 /* fake timeout */ 397 #define QUEUE_FLAG_STACKABLE 13 /* supports request stacking */ 398 #define QUEUE_FLAG_NONROT 14 /* non-rotational device (SSD) */ 399 #define QUEUE_FLAG_VIRT QUEUE_FLAG_NONROT /* paravirt device */ 400 #define QUEUE_FLAG_IO_STAT 15 /* do IO stats */ 401 #define QUEUE_FLAG_DISCARD 16 /* supports DISCARD */ 402 #define QUEUE_FLAG_NOXMERGES 17 /* No extended merges */ 403 #define QUEUE_FLAG_ADD_RANDOM 18 /* Contributes to random pool */ 404 #define QUEUE_FLAG_SECDISCARD 19 /* supports SECDISCARD */ 405 406 #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ 407 (1 << QUEUE_FLAG_CLUSTER) | \ 408 (1 << QUEUE_FLAG_STACKABLE) | \ 409 (1 << QUEUE_FLAG_SAME_COMP) | \ 410 (1 << QUEUE_FLAG_ADD_RANDOM)) 411 412 static inline int queue_is_locked(struct request_queue *q) 413 { 414 #ifdef CONFIG_SMP 415 spinlock_t *lock = q->queue_lock; 416 return lock && spin_is_locked(lock); 417 #else 418 return 1; 419 #endif 420 } 421 422 static inline void queue_flag_set_unlocked(unsigned int flag, 423 struct request_queue *q) 424 { 425 __set_bit(flag, &q->queue_flags); 426 } 427 428 static inline int queue_flag_test_and_clear(unsigned int flag, 429 struct request_queue *q) 430 { 431 WARN_ON_ONCE(!queue_is_locked(q)); 432 433 if (test_bit(flag, &q->queue_flags)) { 434 __clear_bit(flag, &q->queue_flags); 435 return 1; 436 } 437 438 return 0; 439 } 440 441 static inline int queue_flag_test_and_set(unsigned int flag, 442 struct request_queue *q) 443 { 444 WARN_ON_ONCE(!queue_is_locked(q)); 445 446 if (!test_bit(flag, &q->queue_flags)) { 447 __set_bit(flag, &q->queue_flags); 448 return 0; 449 } 450 451 return 1; 452 } 453 454 static inline void queue_flag_set(unsigned int flag, struct request_queue *q) 455 { 456 WARN_ON_ONCE(!queue_is_locked(q)); 457 __set_bit(flag, &q->queue_flags); 458 } 459 460 static inline void queue_flag_clear_unlocked(unsigned int flag, 461 struct request_queue *q) 462 { 463 __clear_bit(flag, &q->queue_flags); 464 } 465 466 static inline int queue_in_flight(struct request_queue *q) 467 { 468 return q->in_flight[0] + q->in_flight[1]; 469 } 470 471 static inline void queue_flag_clear(unsigned int flag, struct request_queue *q) 472 { 473 WARN_ON_ONCE(!queue_is_locked(q)); 474 __clear_bit(flag, &q->queue_flags); 475 } 476 477 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags) 478 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags) 479 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags) 480 #define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags) 481 #define blk_queue_noxmerges(q) \ 482 test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags) 483 #define blk_queue_nonrot(q) test_bit(QUEUE_FLAG_NONROT, &(q)->queue_flags) 484 #define blk_queue_io_stat(q) test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags) 485 #define blk_queue_add_random(q) test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags) 486 #define blk_queue_stackable(q) \ 487 test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags) 488 #define blk_queue_discard(q) test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags) 489 #define blk_queue_secdiscard(q) (blk_queue_discard(q) && \ 490 test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags)) 491 492 #define blk_noretry_request(rq) \ 493 ((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \ 494 REQ_FAILFAST_DRIVER)) 495 496 #define blk_account_rq(rq) \ 497 (((rq)->cmd_flags & REQ_STARTED) && \ 498 ((rq)->cmd_type == REQ_TYPE_FS || \ 499 ((rq)->cmd_flags & REQ_DISCARD))) 500 501 #define blk_pm_request(rq) \ 502 ((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \ 503 (rq)->cmd_type == REQ_TYPE_PM_RESUME) 504 505 #define blk_rq_cpu_valid(rq) ((rq)->cpu != -1) 506 #define blk_bidi_rq(rq) ((rq)->next_rq != NULL) 507 /* rq->queuelist of dequeued request must be list_empty() */ 508 #define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist)) 509 510 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist) 511 512 #define rq_data_dir(rq) ((rq)->cmd_flags & 1) 513 514 /* 515 * We regard a request as sync, if either a read or a sync write 516 */ 517 static inline bool rw_is_sync(unsigned int rw_flags) 518 { 519 return !(rw_flags & REQ_WRITE) || (rw_flags & REQ_SYNC); 520 } 521 522 static inline bool rq_is_sync(struct request *rq) 523 { 524 return rw_is_sync(rq->cmd_flags); 525 } 526 527 static inline int blk_queue_full(struct request_queue *q, int sync) 528 { 529 if (sync) 530 return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags); 531 return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags); 532 } 533 534 static inline void blk_set_queue_full(struct request_queue *q, int sync) 535 { 536 if (sync) 537 queue_flag_set(QUEUE_FLAG_SYNCFULL, q); 538 else 539 queue_flag_set(QUEUE_FLAG_ASYNCFULL, q); 540 } 541 542 static inline void blk_clear_queue_full(struct request_queue *q, int sync) 543 { 544 if (sync) 545 queue_flag_clear(QUEUE_FLAG_SYNCFULL, q); 546 else 547 queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q); 548 } 549 550 551 /* 552 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may 553 * it already be started by driver. 554 */ 555 #define RQ_NOMERGE_FLAGS \ 556 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER | \ 557 REQ_FLUSH | REQ_FUA) 558 #define rq_mergeable(rq) \ 559 (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \ 560 (((rq)->cmd_flags & REQ_DISCARD) || \ 561 (rq)->cmd_type == REQ_TYPE_FS)) 562 563 /* 564 * q->prep_rq_fn return values 565 */ 566 #define BLKPREP_OK 0 /* serve it */ 567 #define BLKPREP_KILL 1 /* fatal error, kill */ 568 #define BLKPREP_DEFER 2 /* leave on queue */ 569 570 extern unsigned long blk_max_low_pfn, blk_max_pfn; 571 572 /* 573 * standard bounce addresses: 574 * 575 * BLK_BOUNCE_HIGH : bounce all highmem pages 576 * BLK_BOUNCE_ANY : don't bounce anything 577 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary 578 */ 579 580 #if BITS_PER_LONG == 32 581 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT) 582 #else 583 #define BLK_BOUNCE_HIGH -1ULL 584 #endif 585 #define BLK_BOUNCE_ANY (-1ULL) 586 #define BLK_BOUNCE_ISA (DMA_BIT_MASK(24)) 587 588 /* 589 * default timeout for SG_IO if none specified 590 */ 591 #define BLK_DEFAULT_SG_TIMEOUT (60 * HZ) 592 #define BLK_MIN_SG_TIMEOUT (7 * HZ) 593 594 #ifdef CONFIG_BOUNCE 595 extern int init_emergency_isa_pool(void); 596 extern void blk_queue_bounce(struct request_queue *q, struct bio **bio); 597 #else 598 static inline int init_emergency_isa_pool(void) 599 { 600 return 0; 601 } 602 static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio) 603 { 604 } 605 #endif /* CONFIG_MMU */ 606 607 struct rq_map_data { 608 struct page **pages; 609 int page_order; 610 int nr_entries; 611 unsigned long offset; 612 int null_mapped; 613 int from_user; 614 }; 615 616 struct req_iterator { 617 int i; 618 struct bio *bio; 619 }; 620 621 /* This should not be used directly - use rq_for_each_segment */ 622 #define for_each_bio(_bio) \ 623 for (; _bio; _bio = _bio->bi_next) 624 #define __rq_for_each_bio(_bio, rq) \ 625 if ((rq->bio)) \ 626 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next) 627 628 #define rq_for_each_segment(bvl, _rq, _iter) \ 629 __rq_for_each_bio(_iter.bio, _rq) \ 630 bio_for_each_segment(bvl, _iter.bio, _iter.i) 631 632 #define rq_iter_last(rq, _iter) \ 633 (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1) 634 635 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 636 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform" 637 #endif 638 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 639 extern void rq_flush_dcache_pages(struct request *rq); 640 #else 641 static inline void rq_flush_dcache_pages(struct request *rq) 642 { 643 } 644 #endif 645 646 extern int blk_register_queue(struct gendisk *disk); 647 extern void blk_unregister_queue(struct gendisk *disk); 648 extern void register_disk(struct gendisk *dev); 649 extern void generic_make_request(struct bio *bio); 650 extern void blk_rq_init(struct request_queue *q, struct request *rq); 651 extern void blk_put_request(struct request *); 652 extern void __blk_put_request(struct request_queue *, struct request *); 653 extern struct request *blk_get_request(struct request_queue *, int, gfp_t); 654 extern struct request *blk_make_request(struct request_queue *, struct bio *, 655 gfp_t); 656 extern void blk_insert_request(struct request_queue *, struct request *, int, void *); 657 extern void blk_requeue_request(struct request_queue *, struct request *); 658 extern void blk_add_request_payload(struct request *rq, struct page *page, 659 unsigned int len); 660 extern int blk_rq_check_limits(struct request_queue *q, struct request *rq); 661 extern int blk_lld_busy(struct request_queue *q); 662 extern int blk_rq_prep_clone(struct request *rq, struct request *rq_src, 663 struct bio_set *bs, gfp_t gfp_mask, 664 int (*bio_ctr)(struct bio *, struct bio *, void *), 665 void *data); 666 extern void blk_rq_unprep_clone(struct request *rq); 667 extern int blk_insert_cloned_request(struct request_queue *q, 668 struct request *rq); 669 extern void blk_plug_device(struct request_queue *); 670 extern void blk_plug_device_unlocked(struct request_queue *); 671 extern int blk_remove_plug(struct request_queue *); 672 extern void blk_recount_segments(struct request_queue *, struct bio *); 673 extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t, 674 unsigned int, void __user *); 675 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t, 676 struct scsi_ioctl_command __user *); 677 678 /* 679 * A queue has just exitted congestion. Note this in the global counter of 680 * congested queues, and wake up anyone who was waiting for requests to be 681 * put back. 682 */ 683 static inline void blk_clear_queue_congested(struct request_queue *q, int sync) 684 { 685 clear_bdi_congested(&q->backing_dev_info, sync); 686 } 687 688 /* 689 * A queue has just entered congestion. Flag that in the queue's VM-visible 690 * state flags and increment the global gounter of congested queues. 691 */ 692 static inline void blk_set_queue_congested(struct request_queue *q, int sync) 693 { 694 set_bdi_congested(&q->backing_dev_info, sync); 695 } 696 697 extern void blk_start_queue(struct request_queue *q); 698 extern void blk_stop_queue(struct request_queue *q); 699 extern void blk_sync_queue(struct request_queue *q); 700 extern void __blk_stop_queue(struct request_queue *q); 701 extern void __blk_run_queue(struct request_queue *); 702 extern void blk_run_queue(struct request_queue *); 703 extern int blk_rq_map_user(struct request_queue *, struct request *, 704 struct rq_map_data *, void __user *, unsigned long, 705 gfp_t); 706 extern int blk_rq_unmap_user(struct bio *); 707 extern int blk_rq_map_kern(struct request_queue *, struct request *, void *, unsigned int, gfp_t); 708 extern int blk_rq_map_user_iov(struct request_queue *, struct request *, 709 struct rq_map_data *, struct sg_iovec *, int, 710 unsigned int, gfp_t); 711 extern int blk_execute_rq(struct request_queue *, struct gendisk *, 712 struct request *, int); 713 extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *, 714 struct request *, int, rq_end_io_fn *); 715 extern void blk_unplug(struct request_queue *q); 716 717 static inline struct request_queue *bdev_get_queue(struct block_device *bdev) 718 { 719 return bdev->bd_disk->queue; 720 } 721 722 /* 723 * blk_rq_pos() : the current sector 724 * blk_rq_bytes() : bytes left in the entire request 725 * blk_rq_cur_bytes() : bytes left in the current segment 726 * blk_rq_err_bytes() : bytes left till the next error boundary 727 * blk_rq_sectors() : sectors left in the entire request 728 * blk_rq_cur_sectors() : sectors left in the current segment 729 */ 730 static inline sector_t blk_rq_pos(const struct request *rq) 731 { 732 return rq->__sector; 733 } 734 735 static inline unsigned int blk_rq_bytes(const struct request *rq) 736 { 737 return rq->__data_len; 738 } 739 740 static inline int blk_rq_cur_bytes(const struct request *rq) 741 { 742 return rq->bio ? bio_cur_bytes(rq->bio) : 0; 743 } 744 745 extern unsigned int blk_rq_err_bytes(const struct request *rq); 746 747 static inline unsigned int blk_rq_sectors(const struct request *rq) 748 { 749 return blk_rq_bytes(rq) >> 9; 750 } 751 752 static inline unsigned int blk_rq_cur_sectors(const struct request *rq) 753 { 754 return blk_rq_cur_bytes(rq) >> 9; 755 } 756 757 /* 758 * Request issue related functions. 759 */ 760 extern struct request *blk_peek_request(struct request_queue *q); 761 extern void blk_start_request(struct request *rq); 762 extern struct request *blk_fetch_request(struct request_queue *q); 763 764 /* 765 * Request completion related functions. 766 * 767 * blk_update_request() completes given number of bytes and updates 768 * the request without completing it. 769 * 770 * blk_end_request() and friends. __blk_end_request() must be called 771 * with the request queue spinlock acquired. 772 * 773 * Several drivers define their own end_request and call 774 * blk_end_request() for parts of the original function. 775 * This prevents code duplication in drivers. 776 */ 777 extern bool blk_update_request(struct request *rq, int error, 778 unsigned int nr_bytes); 779 extern bool blk_end_request(struct request *rq, int error, 780 unsigned int nr_bytes); 781 extern void blk_end_request_all(struct request *rq, int error); 782 extern bool blk_end_request_cur(struct request *rq, int error); 783 extern bool blk_end_request_err(struct request *rq, int error); 784 extern bool __blk_end_request(struct request *rq, int error, 785 unsigned int nr_bytes); 786 extern void __blk_end_request_all(struct request *rq, int error); 787 extern bool __blk_end_request_cur(struct request *rq, int error); 788 extern bool __blk_end_request_err(struct request *rq, int error); 789 790 extern void blk_complete_request(struct request *); 791 extern void __blk_complete_request(struct request *); 792 extern void blk_abort_request(struct request *); 793 extern void blk_abort_queue(struct request_queue *); 794 extern void blk_unprep_request(struct request *); 795 796 /* 797 * Access functions for manipulating queue properties 798 */ 799 extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn, 800 spinlock_t *lock, int node_id); 801 extern struct request_queue *blk_init_allocated_queue_node(struct request_queue *, 802 request_fn_proc *, 803 spinlock_t *, int node_id); 804 extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *); 805 extern struct request_queue *blk_init_allocated_queue(struct request_queue *, 806 request_fn_proc *, spinlock_t *); 807 extern void blk_cleanup_queue(struct request_queue *); 808 extern void blk_queue_make_request(struct request_queue *, make_request_fn *); 809 extern void blk_queue_bounce_limit(struct request_queue *, u64); 810 extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int); 811 extern void blk_queue_max_segments(struct request_queue *, unsigned short); 812 extern void blk_queue_max_segment_size(struct request_queue *, unsigned int); 813 extern void blk_queue_max_discard_sectors(struct request_queue *q, 814 unsigned int max_discard_sectors); 815 extern void blk_queue_logical_block_size(struct request_queue *, unsigned short); 816 extern void blk_queue_physical_block_size(struct request_queue *, unsigned int); 817 extern void blk_queue_alignment_offset(struct request_queue *q, 818 unsigned int alignment); 819 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min); 820 extern void blk_queue_io_min(struct request_queue *q, unsigned int min); 821 extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt); 822 extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt); 823 extern void blk_set_default_limits(struct queue_limits *lim); 824 extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, 825 sector_t offset); 826 extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev, 827 sector_t offset); 828 extern void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, 829 sector_t offset); 830 extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b); 831 extern void blk_queue_dma_pad(struct request_queue *, unsigned int); 832 extern void blk_queue_update_dma_pad(struct request_queue *, unsigned int); 833 extern int blk_queue_dma_drain(struct request_queue *q, 834 dma_drain_needed_fn *dma_drain_needed, 835 void *buf, unsigned int size); 836 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn); 837 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long); 838 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn); 839 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn); 840 extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *); 841 extern void blk_queue_dma_alignment(struct request_queue *, int); 842 extern void blk_queue_update_dma_alignment(struct request_queue *, int); 843 extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *); 844 extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *); 845 extern void blk_queue_rq_timeout(struct request_queue *, unsigned int); 846 extern void blk_queue_flush(struct request_queue *q, unsigned int flush); 847 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev); 848 849 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *); 850 extern void blk_dump_rq_flags(struct request *, char *); 851 extern void generic_unplug_device(struct request_queue *); 852 extern long nr_blockdev_pages(void); 853 854 int blk_get_queue(struct request_queue *); 855 struct request_queue *blk_alloc_queue(gfp_t); 856 struct request_queue *blk_alloc_queue_node(gfp_t, int); 857 extern void blk_put_queue(struct request_queue *); 858 859 /* 860 * tag stuff 861 */ 862 #define blk_rq_tagged(rq) ((rq)->cmd_flags & REQ_QUEUED) 863 extern int blk_queue_start_tag(struct request_queue *, struct request *); 864 extern struct request *blk_queue_find_tag(struct request_queue *, int); 865 extern void blk_queue_end_tag(struct request_queue *, struct request *); 866 extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *); 867 extern void blk_queue_free_tags(struct request_queue *); 868 extern int blk_queue_resize_tags(struct request_queue *, int); 869 extern void blk_queue_invalidate_tags(struct request_queue *); 870 extern struct blk_queue_tag *blk_init_tags(int); 871 extern void blk_free_tags(struct blk_queue_tag *); 872 873 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt, 874 int tag) 875 { 876 if (unlikely(bqt == NULL || tag >= bqt->real_max_depth)) 877 return NULL; 878 return bqt->tag_index[tag]; 879 } 880 881 #define BLKDEV_DISCARD_SECURE 0x01 /* secure discard */ 882 883 extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *); 884 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector, 885 sector_t nr_sects, gfp_t gfp_mask, unsigned long flags); 886 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, 887 sector_t nr_sects, gfp_t gfp_mask); 888 static inline int sb_issue_discard(struct super_block *sb, sector_t block, 889 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags) 890 { 891 return blkdev_issue_discard(sb->s_bdev, block << (sb->s_blocksize_bits - 9), 892 nr_blocks << (sb->s_blocksize_bits - 9), 893 gfp_mask, flags); 894 } 895 896 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm); 897 898 enum blk_default_limits { 899 BLK_MAX_SEGMENTS = 128, 900 BLK_SAFE_MAX_SECTORS = 255, 901 BLK_DEF_MAX_SECTORS = 1024, 902 BLK_MAX_SEGMENT_SIZE = 65536, 903 BLK_SEG_BOUNDARY_MASK = 0xFFFFFFFFUL, 904 }; 905 906 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist) 907 908 static inline unsigned long queue_bounce_pfn(struct request_queue *q) 909 { 910 return q->limits.bounce_pfn; 911 } 912 913 static inline unsigned long queue_segment_boundary(struct request_queue *q) 914 { 915 return q->limits.seg_boundary_mask; 916 } 917 918 static inline unsigned int queue_max_sectors(struct request_queue *q) 919 { 920 return q->limits.max_sectors; 921 } 922 923 static inline unsigned int queue_max_hw_sectors(struct request_queue *q) 924 { 925 return q->limits.max_hw_sectors; 926 } 927 928 static inline unsigned short queue_max_segments(struct request_queue *q) 929 { 930 return q->limits.max_segments; 931 } 932 933 static inline unsigned int queue_max_segment_size(struct request_queue *q) 934 { 935 return q->limits.max_segment_size; 936 } 937 938 static inline unsigned short queue_logical_block_size(struct request_queue *q) 939 { 940 int retval = 512; 941 942 if (q && q->limits.logical_block_size) 943 retval = q->limits.logical_block_size; 944 945 return retval; 946 } 947 948 static inline unsigned short bdev_logical_block_size(struct block_device *bdev) 949 { 950 return queue_logical_block_size(bdev_get_queue(bdev)); 951 } 952 953 static inline unsigned int queue_physical_block_size(struct request_queue *q) 954 { 955 return q->limits.physical_block_size; 956 } 957 958 static inline unsigned int bdev_physical_block_size(struct block_device *bdev) 959 { 960 return queue_physical_block_size(bdev_get_queue(bdev)); 961 } 962 963 static inline unsigned int queue_io_min(struct request_queue *q) 964 { 965 return q->limits.io_min; 966 } 967 968 static inline int bdev_io_min(struct block_device *bdev) 969 { 970 return queue_io_min(bdev_get_queue(bdev)); 971 } 972 973 static inline unsigned int queue_io_opt(struct request_queue *q) 974 { 975 return q->limits.io_opt; 976 } 977 978 static inline int bdev_io_opt(struct block_device *bdev) 979 { 980 return queue_io_opt(bdev_get_queue(bdev)); 981 } 982 983 static inline int queue_alignment_offset(struct request_queue *q) 984 { 985 if (q->limits.misaligned) 986 return -1; 987 988 return q->limits.alignment_offset; 989 } 990 991 static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector) 992 { 993 unsigned int granularity = max(lim->physical_block_size, lim->io_min); 994 unsigned int alignment = (sector << 9) & (granularity - 1); 995 996 return (granularity + lim->alignment_offset - alignment) 997 & (granularity - 1); 998 } 999 1000 static inline int bdev_alignment_offset(struct block_device *bdev) 1001 { 1002 struct request_queue *q = bdev_get_queue(bdev); 1003 1004 if (q->limits.misaligned) 1005 return -1; 1006 1007 if (bdev != bdev->bd_contains) 1008 return bdev->bd_part->alignment_offset; 1009 1010 return q->limits.alignment_offset; 1011 } 1012 1013 static inline int queue_discard_alignment(struct request_queue *q) 1014 { 1015 if (q->limits.discard_misaligned) 1016 return -1; 1017 1018 return q->limits.discard_alignment; 1019 } 1020 1021 static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector) 1022 { 1023 unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1); 1024 1025 return (lim->discard_granularity + lim->discard_alignment - alignment) 1026 & (lim->discard_granularity - 1); 1027 } 1028 1029 static inline unsigned int queue_discard_zeroes_data(struct request_queue *q) 1030 { 1031 if (q->limits.discard_zeroes_data == 1) 1032 return 1; 1033 1034 return 0; 1035 } 1036 1037 static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev) 1038 { 1039 return queue_discard_zeroes_data(bdev_get_queue(bdev)); 1040 } 1041 1042 static inline int queue_dma_alignment(struct request_queue *q) 1043 { 1044 return q ? q->dma_alignment : 511; 1045 } 1046 1047 static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr, 1048 unsigned int len) 1049 { 1050 unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask; 1051 return !(addr & alignment) && !(len & alignment); 1052 } 1053 1054 /* assumes size > 256 */ 1055 static inline unsigned int blksize_bits(unsigned int size) 1056 { 1057 unsigned int bits = 8; 1058 do { 1059 bits++; 1060 size >>= 1; 1061 } while (size > 256); 1062 return bits; 1063 } 1064 1065 static inline unsigned int block_size(struct block_device *bdev) 1066 { 1067 return bdev->bd_block_size; 1068 } 1069 1070 typedef struct {struct page *v;} Sector; 1071 1072 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *); 1073 1074 static inline void put_dev_sector(Sector p) 1075 { 1076 page_cache_release(p.v); 1077 } 1078 1079 struct work_struct; 1080 int kblockd_schedule_work(struct request_queue *q, struct work_struct *work); 1081 int kblockd_schedule_delayed_work(struct request_queue *q, struct delayed_work *dwork, unsigned long delay); 1082 1083 #ifdef CONFIG_BLK_CGROUP 1084 /* 1085 * This should not be using sched_clock(). A real patch is in progress 1086 * to fix this up, until that is in place we need to disable preemption 1087 * around sched_clock() in this function and set_io_start_time_ns(). 1088 */ 1089 static inline void set_start_time_ns(struct request *req) 1090 { 1091 preempt_disable(); 1092 req->start_time_ns = sched_clock(); 1093 preempt_enable(); 1094 } 1095 1096 static inline void set_io_start_time_ns(struct request *req) 1097 { 1098 preempt_disable(); 1099 req->io_start_time_ns = sched_clock(); 1100 preempt_enable(); 1101 } 1102 1103 static inline uint64_t rq_start_time_ns(struct request *req) 1104 { 1105 return req->start_time_ns; 1106 } 1107 1108 static inline uint64_t rq_io_start_time_ns(struct request *req) 1109 { 1110 return req->io_start_time_ns; 1111 } 1112 #else 1113 static inline void set_start_time_ns(struct request *req) {} 1114 static inline void set_io_start_time_ns(struct request *req) {} 1115 static inline uint64_t rq_start_time_ns(struct request *req) 1116 { 1117 return 0; 1118 } 1119 static inline uint64_t rq_io_start_time_ns(struct request *req) 1120 { 1121 return 0; 1122 } 1123 #endif 1124 1125 #ifdef CONFIG_BLK_DEV_THROTTLING 1126 extern int blk_throtl_init(struct request_queue *q); 1127 extern void blk_throtl_exit(struct request_queue *q); 1128 extern int blk_throtl_bio(struct request_queue *q, struct bio **bio); 1129 extern void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay); 1130 extern void throtl_shutdown_timer_wq(struct request_queue *q); 1131 #else /* CONFIG_BLK_DEV_THROTTLING */ 1132 static inline int blk_throtl_bio(struct request_queue *q, struct bio **bio) 1133 { 1134 return 0; 1135 } 1136 1137 static inline int blk_throtl_init(struct request_queue *q) { return 0; } 1138 static inline int blk_throtl_exit(struct request_queue *q) { return 0; } 1139 static inline void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay) {} 1140 static inline void throtl_shutdown_timer_wq(struct request_queue *q) {} 1141 #endif /* CONFIG_BLK_DEV_THROTTLING */ 1142 1143 #define MODULE_ALIAS_BLOCKDEV(major,minor) \ 1144 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor)) 1145 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \ 1146 MODULE_ALIAS("block-major-" __stringify(major) "-*") 1147 1148 #if defined(CONFIG_BLK_DEV_INTEGRITY) 1149 1150 #define INTEGRITY_FLAG_READ 2 /* verify data integrity on read */ 1151 #define INTEGRITY_FLAG_WRITE 4 /* generate data integrity on write */ 1152 1153 struct blk_integrity_exchg { 1154 void *prot_buf; 1155 void *data_buf; 1156 sector_t sector; 1157 unsigned int data_size; 1158 unsigned short sector_size; 1159 const char *disk_name; 1160 }; 1161 1162 typedef void (integrity_gen_fn) (struct blk_integrity_exchg *); 1163 typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *); 1164 typedef void (integrity_set_tag_fn) (void *, void *, unsigned int); 1165 typedef void (integrity_get_tag_fn) (void *, void *, unsigned int); 1166 1167 struct blk_integrity { 1168 integrity_gen_fn *generate_fn; 1169 integrity_vrfy_fn *verify_fn; 1170 integrity_set_tag_fn *set_tag_fn; 1171 integrity_get_tag_fn *get_tag_fn; 1172 1173 unsigned short flags; 1174 unsigned short tuple_size; 1175 unsigned short sector_size; 1176 unsigned short tag_size; 1177 1178 const char *name; 1179 1180 struct kobject kobj; 1181 }; 1182 1183 extern int blk_integrity_register(struct gendisk *, struct blk_integrity *); 1184 extern void blk_integrity_unregister(struct gendisk *); 1185 extern int blk_integrity_compare(struct gendisk *, struct gendisk *); 1186 extern int blk_rq_map_integrity_sg(struct request_queue *, struct bio *, 1187 struct scatterlist *); 1188 extern int blk_rq_count_integrity_sg(struct request_queue *, struct bio *); 1189 extern int blk_integrity_merge_rq(struct request_queue *, struct request *, 1190 struct request *); 1191 extern int blk_integrity_merge_bio(struct request_queue *, struct request *, 1192 struct bio *); 1193 1194 static inline 1195 struct blk_integrity *bdev_get_integrity(struct block_device *bdev) 1196 { 1197 return bdev->bd_disk->integrity; 1198 } 1199 1200 static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk) 1201 { 1202 return disk->integrity; 1203 } 1204 1205 static inline int blk_integrity_rq(struct request *rq) 1206 { 1207 if (rq->bio == NULL) 1208 return 0; 1209 1210 return bio_integrity(rq->bio); 1211 } 1212 1213 static inline void blk_queue_max_integrity_segments(struct request_queue *q, 1214 unsigned int segs) 1215 { 1216 q->limits.max_integrity_segments = segs; 1217 } 1218 1219 static inline unsigned short 1220 queue_max_integrity_segments(struct request_queue *q) 1221 { 1222 return q->limits.max_integrity_segments; 1223 } 1224 1225 #else /* CONFIG_BLK_DEV_INTEGRITY */ 1226 1227 #define blk_integrity_rq(rq) (0) 1228 #define blk_rq_count_integrity_sg(a, b) (0) 1229 #define blk_rq_map_integrity_sg(a, b, c) (0) 1230 #define bdev_get_integrity(a) (0) 1231 #define blk_get_integrity(a) (0) 1232 #define blk_integrity_compare(a, b) (0) 1233 #define blk_integrity_register(a, b) (0) 1234 #define blk_integrity_unregister(a) do { } while (0); 1235 #define blk_queue_max_integrity_segments(a, b) do { } while (0); 1236 #define queue_max_integrity_segments(a) (0) 1237 #define blk_integrity_merge_rq(a, b, c) (0) 1238 #define blk_integrity_merge_bio(a, b, c) (0) 1239 1240 #endif /* CONFIG_BLK_DEV_INTEGRITY */ 1241 1242 struct block_device_operations { 1243 int (*open) (struct block_device *, fmode_t); 1244 int (*release) (struct gendisk *, fmode_t); 1245 int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long); 1246 int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long); 1247 int (*direct_access) (struct block_device *, sector_t, 1248 void **, unsigned long *); 1249 int (*media_changed) (struct gendisk *); 1250 void (*unlock_native_capacity) (struct gendisk *); 1251 int (*revalidate_disk) (struct gendisk *); 1252 int (*getgeo)(struct block_device *, struct hd_geometry *); 1253 /* this callback is with swap_lock and sometimes page table lock held */ 1254 void (*swap_slot_free_notify) (struct block_device *, unsigned long); 1255 struct module *owner; 1256 }; 1257 1258 extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int, 1259 unsigned long); 1260 #else /* CONFIG_BLOCK */ 1261 /* 1262 * stubs for when the block layer is configured out 1263 */ 1264 #define buffer_heads_over_limit 0 1265 1266 static inline long nr_blockdev_pages(void) 1267 { 1268 return 0; 1269 } 1270 1271 #endif /* CONFIG_BLOCK */ 1272 1273 #endif 1274