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