1 #ifndef _LINUX_BLKDEV_H
2 #define _LINUX_BLKDEV_H
4 #include <linux/config.h>
5 #include <linux/major.h>
6 #include <linux/genhd.h>
7 #include <linux/list.h>
8 #include <linux/timer.h>
9 #include <linux/workqueue.h>
10 #include <linux/pagemap.h>
11 #include <linux/backing-dev.h>
12 #include <linux/wait.h>
13 #include <linux/mempool.h>
14 #include <linux/bio.h>
15 #include <linux/module.h>
16 #include <linux/stringify.h>
18 #include <asm/scatterlist.h>
21 typedef struct request_queue request_queue_t;
22 struct elevator_queue;
23 typedef struct elevator_queue elevator_t;
24 struct request_pm_state;
26 #define BLKDEV_MIN_RQ 4
27 #define BLKDEV_MAX_RQ 128 /* Default maximum */
30 * This is the per-process anticipatory I/O scheduler state.
32 struct as_io_context {
35 void (*dtor)(struct as_io_context *aic); /* destructor */
36 void (*exit)(struct as_io_context *aic); /* called on task exit */
39 atomic_t nr_queued; /* queued reads & sync writes */
40 atomic_t nr_dispatched; /* number of requests gone to the drivers */
42 /* IO History tracking */
44 unsigned long last_end_request;
45 unsigned long ttime_total;
46 unsigned long ttime_samples;
47 unsigned long ttime_mean;
49 unsigned int seek_samples;
50 sector_t last_request_pos;
56 struct cfq_io_context {
57 void (*dtor)(struct cfq_io_context *);
58 void (*exit)(struct cfq_io_context *);
60 struct io_context *ioc;
63 * circular list of cfq_io_contexts belonging to a process io context
65 struct list_head list;
66 struct cfq_queue *cfqq;
70 * This is the per-process I/O subsystem state. It is refcounted and
71 * kmalloc'ed. Currently all fields are modified in process io context
72 * (apart from the atomic refcount), so require no locking.
79 * For request batching
81 unsigned long last_waited; /* Time last woken after wait for request */
82 int nr_batch_requests; /* Number of requests left in the batch */
86 struct as_io_context *aic;
87 struct cfq_io_context *cic;
90 void put_io_context(struct io_context *ioc);
91 void exit_io_context(void);
92 struct io_context *get_io_context(int gfp_flags);
93 void copy_io_context(struct io_context **pdst, struct io_context **psrc);
94 void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
99 wait_queue_head_t wait[2];
100 wait_queue_head_t drain;
103 #define BLK_MAX_CDB 16
106 * try to put the fields that are referenced together in the same cacheline
109 struct list_head queuelist; /* looking for ->queue? you must _not_
110 * access it directly, use
111 * blkdev_dequeue_request! */
112 unsigned long flags; /* see REQ_ bits below */
114 /* Maintain bio traversal state for part by part I/O submission.
115 * hard_* are block layer internals, no driver should touch them!
118 sector_t sector; /* next sector to submit */
119 unsigned long nr_sectors; /* no. of sectors left to submit */
120 /* no. of sectors left to submit in the current segment */
121 unsigned int current_nr_sectors;
123 sector_t hard_sector; /* next sector to complete */
124 unsigned long hard_nr_sectors; /* no. of sectors left to complete */
125 /* no. of sectors left to complete in the current segment */
126 unsigned int hard_cur_sectors;
131 void *elevator_private;
133 int rq_status; /* should split this into a few status bits */
134 struct gendisk *rq_disk;
136 unsigned long start_time;
138 /* Number of scatter-gather DMA addr+len pairs after
139 * physical address coalescing is performed.
141 unsigned short nr_phys_segments;
143 /* Number of scatter-gather addr+len pairs after
144 * physical and DMA remapping hardware coalescing is performed.
145 * This is the number of scatter-gather entries the driver
146 * will actually have to deal with after DMA mapping is done.
148 unsigned short nr_hw_segments;
155 struct request_list *rl;
157 struct completion *waiting;
161 * when request is used as a packet command carrier
163 unsigned int cmd_len;
164 unsigned char cmd[BLK_MAX_CDB];
166 unsigned int data_len;
169 unsigned int sense_len;
172 unsigned int timeout;
175 * For Power Management requests
177 struct request_pm_state *pm;
181 * first three bits match BIO_RW* bits, important
184 __REQ_RW, /* not set, read. set, write */
185 __REQ_FAILFAST, /* no low level driver retries */
186 __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */
187 __REQ_HARDBARRIER, /* may not be passed by drive either */
188 __REQ_CMD, /* is a regular fs rw request */
189 __REQ_NOMERGE, /* don't touch this for merging */
190 __REQ_STARTED, /* drive already may have started this one */
191 __REQ_DONTPREP, /* don't call prep for this one */
192 __REQ_QUEUED, /* uses queueing */
194 * for ATA/ATAPI devices
196 __REQ_PC, /* packet command (special) */
197 __REQ_BLOCK_PC, /* queued down pc from block layer */
198 __REQ_SENSE, /* sense retrival */
200 __REQ_FAILED, /* set if the request failed */
201 __REQ_QUIET, /* don't worry about errors */
202 __REQ_SPECIAL, /* driver suplied command */
205 __REQ_DRIVE_TASKFILE,
206 __REQ_PREEMPT, /* set for "ide_preempt" requests */
207 __REQ_PM_SUSPEND, /* suspend request */
208 __REQ_PM_RESUME, /* resume request */
209 __REQ_PM_SHUTDOWN, /* shutdown request */
210 __REQ_BAR_PREFLUSH, /* barrier pre-flush done */
211 __REQ_BAR_POSTFLUSH, /* barrier post-flush */
212 __REQ_NR_BITS, /* stops here */
215 #define REQ_RW (1 << __REQ_RW)
216 #define REQ_FAILFAST (1 << __REQ_FAILFAST)
217 #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER)
218 #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER)
219 #define REQ_CMD (1 << __REQ_CMD)
220 #define REQ_NOMERGE (1 << __REQ_NOMERGE)
221 #define REQ_STARTED (1 << __REQ_STARTED)
222 #define REQ_DONTPREP (1 << __REQ_DONTPREP)
223 #define REQ_QUEUED (1 << __REQ_QUEUED)
224 #define REQ_PC (1 << __REQ_PC)
225 #define REQ_BLOCK_PC (1 << __REQ_BLOCK_PC)
226 #define REQ_SENSE (1 << __REQ_SENSE)
227 #define REQ_FAILED (1 << __REQ_FAILED)
228 #define REQ_QUIET (1 << __REQ_QUIET)
229 #define REQ_SPECIAL (1 << __REQ_SPECIAL)
230 #define REQ_DRIVE_CMD (1 << __REQ_DRIVE_CMD)
231 #define REQ_DRIVE_TASK (1 << __REQ_DRIVE_TASK)
232 #define REQ_DRIVE_TASKFILE (1 << __REQ_DRIVE_TASKFILE)
233 #define REQ_PREEMPT (1 << __REQ_PREEMPT)
234 #define REQ_PM_SUSPEND (1 << __REQ_PM_SUSPEND)
235 #define REQ_PM_RESUME (1 << __REQ_PM_RESUME)
236 #define REQ_PM_SHUTDOWN (1 << __REQ_PM_SHUTDOWN)
237 #define REQ_BAR_PREFLUSH (1 << __REQ_BAR_PREFLUSH)
238 #define REQ_BAR_POSTFLUSH (1 << __REQ_BAR_POSTFLUSH)
241 * State information carried for REQ_PM_SUSPEND and REQ_PM_RESUME
242 * requests. Some step values could eventually be made generic.
244 struct request_pm_state
246 /* PM state machine step value, currently driver specific */
248 /* requested PM state value (S1, S2, S3, S4, ...) */
250 void* data; /* for driver use */
253 #include <linux/elevator.h>
255 typedef int (merge_request_fn) (request_queue_t *, struct request *,
257 typedef int (merge_requests_fn) (request_queue_t *, struct request *,
259 typedef void (request_fn_proc) (request_queue_t *q);
260 typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
261 typedef int (prep_rq_fn) (request_queue_t *, struct request *);
262 typedef void (unplug_fn) (request_queue_t *);
265 typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
266 typedef void (activity_fn) (void *data, int rw);
267 typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
269 enum blk_queue_state {
274 #define BLK_TAGS_PER_LONG (sizeof(unsigned long) * 8)
275 #define BLK_TAGS_MASK (BLK_TAGS_PER_LONG - 1)
277 struct blk_queue_tag {
278 struct request **tag_index; /* map of busy tags */
279 unsigned long *tag_map; /* bit map of free/busy tags */
280 struct list_head busy_list; /* fifo list of busy tags */
281 int busy; /* current depth */
282 int max_depth; /* what we will send to device */
283 int real_max_depth; /* what the array can hold */
284 atomic_t refcnt; /* map can be shared */
290 * Together with queue_head for cacheline sharing
292 struct list_head queue_head;
293 struct request *last_merge;
294 elevator_t *elevator;
297 * the queue request freelist, one for reads and one for writes
299 struct request_list rq;
301 request_fn_proc *request_fn;
302 merge_request_fn *back_merge_fn;
303 merge_request_fn *front_merge_fn;
304 merge_requests_fn *merge_requests_fn;
305 make_request_fn *make_request_fn;
306 prep_rq_fn *prep_rq_fn;
307 unplug_fn *unplug_fn;
308 merge_bvec_fn *merge_bvec_fn;
309 activity_fn *activity_fn;
310 issue_flush_fn *issue_flush_fn;
313 * Auto-unplugging state
315 struct timer_list unplug_timer;
316 int unplug_thresh; /* After this many requests */
317 unsigned long unplug_delay; /* After this many jiffies */
318 struct work_struct unplug_work;
320 struct backing_dev_info backing_dev_info;
323 * The queue owner gets to use this for whatever they like.
324 * ll_rw_blk doesn't touch it.
331 * queue needs bounce pages for pages above this limit
333 unsigned long bounce_pfn;
337 * various queue flags, see QUEUE_* below
339 unsigned long queue_flags;
342 * protects queue structures from reentrancy
344 spinlock_t *queue_lock;
354 unsigned long nr_requests; /* Max # of requests */
355 unsigned int nr_congestion_on;
356 unsigned int nr_congestion_off;
357 unsigned int nr_batching;
359 unsigned short max_sectors;
360 unsigned short max_hw_sectors;
361 unsigned short max_phys_segments;
362 unsigned short max_hw_segments;
363 unsigned short hardsect_size;
364 unsigned int max_segment_size;
366 unsigned long seg_boundary_mask;
367 unsigned int dma_alignment;
369 struct blk_queue_tag *queue_tags;
373 unsigned int in_flight;
378 unsigned int sg_timeout;
379 unsigned int sg_reserved_size;
381 struct list_head drain_list;
384 #define RQ_INACTIVE (-1)
386 #define RQ_SCSI_BUSY 0xffff
387 #define RQ_SCSI_DONE 0xfffe
388 #define RQ_SCSI_DISCONNECTING 0xffe0
390 #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */
391 #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
392 #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */
393 #define QUEUE_FLAG_READFULL 3 /* write queue has been filled */
394 #define QUEUE_FLAG_WRITEFULL 4 /* read queue has been filled */
395 #define QUEUE_FLAG_DEAD 5 /* queue being torn down */
396 #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
397 #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
398 #define QUEUE_FLAG_ORDERED 8 /* supports ordered writes */
399 #define QUEUE_FLAG_DRAIN 9 /* draining queue for sched switch */
401 #define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
402 #define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
403 #define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
405 #define blk_fs_request(rq) ((rq)->flags & REQ_CMD)
406 #define blk_pc_request(rq) ((rq)->flags & REQ_BLOCK_PC)
407 #define blk_noretry_request(rq) ((rq)->flags & REQ_FAILFAST)
408 #define blk_rq_started(rq) ((rq)->flags & REQ_STARTED)
410 #define blk_account_rq(rq) (blk_rq_started(rq) && blk_fs_request(rq))
412 #define blk_pm_suspend_request(rq) ((rq)->flags & REQ_PM_SUSPEND)
413 #define blk_pm_resume_request(rq) ((rq)->flags & REQ_PM_RESUME)
414 #define blk_pm_request(rq) \
415 ((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME))
417 #define blk_barrier_rq(rq) ((rq)->flags & REQ_HARDBARRIER)
418 #define blk_barrier_preflush(rq) ((rq)->flags & REQ_BAR_PREFLUSH)
419 #define blk_barrier_postflush(rq) ((rq)->flags & REQ_BAR_POSTFLUSH)
421 #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist)
423 #define rq_data_dir(rq) ((rq)->flags & 1)
425 static inline int blk_queue_full(struct request_queue *q, int rw)
428 return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
429 return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
432 static inline void blk_set_queue_full(struct request_queue *q, int rw)
435 set_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
437 set_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
440 static inline void blk_clear_queue_full(struct request_queue *q, int rw)
443 clear_bit(QUEUE_FLAG_READFULL, &q->queue_flags);
445 clear_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags);
450 * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
451 * it already be started by driver.
453 #define RQ_NOMERGE_FLAGS \
454 (REQ_NOMERGE | REQ_STARTED | REQ_HARDBARRIER | REQ_SOFTBARRIER)
455 #define rq_mergeable(rq) \
456 (!((rq)->flags & RQ_NOMERGE_FLAGS) && blk_fs_request((rq)))
459 * noop, requests are automagically marked as active/inactive by I/O
460 * scheduler -- see elv_next_request
462 #define blk_queue_headactive(q, head_active)
465 * q->prep_rq_fn return values
467 #define BLKPREP_OK 0 /* serve it */
468 #define BLKPREP_KILL 1 /* fatal error, kill */
469 #define BLKPREP_DEFER 2 /* leave on queue */
471 extern unsigned long blk_max_low_pfn, blk_max_pfn;
474 * standard bounce addresses:
476 * BLK_BOUNCE_HIGH : bounce all highmem pages
477 * BLK_BOUNCE_ANY : don't bounce anything
478 * BLK_BOUNCE_ISA : bounce pages above ISA DMA boundary
480 #define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
481 #define BLK_BOUNCE_ANY ((u64)blk_max_pfn << PAGE_SHIFT)
482 #define BLK_BOUNCE_ISA (ISA_DMA_THRESHOLD)
485 extern int init_emergency_isa_pool(void);
486 extern void blk_queue_bounce(request_queue_t *q, struct bio **bio);
488 static inline int init_emergency_isa_pool(void)
492 static inline void blk_queue_bounce(request_queue_t *q, struct bio **bio)
495 #endif /* CONFIG_MMU */
497 #define rq_for_each_bio(_bio, rq) \
499 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
503 unsigned block_size_bits;
506 extern int blk_register_queue(struct gendisk *disk);
507 extern void blk_unregister_queue(struct gendisk *disk);
508 extern void register_disk(struct gendisk *dev);
509 extern void generic_make_request(struct bio *bio);
510 extern void blk_put_request(struct request *);
511 extern void blk_attempt_remerge(request_queue_t *, struct request *);
512 extern void __blk_attempt_remerge(request_queue_t *, struct request *);
513 extern struct request *blk_get_request(request_queue_t *, int, int);
514 extern void blk_put_request(struct request *);
515 extern void blk_insert_request(request_queue_t *, struct request *, int, void *, int);
516 extern void blk_requeue_request(request_queue_t *, struct request *);
517 extern void blk_plug_device(request_queue_t *);
518 extern int blk_remove_plug(request_queue_t *);
519 extern void blk_recount_segments(request_queue_t *, struct bio *);
520 extern int blk_phys_contig_segment(request_queue_t *q, struct bio *, struct bio *);
521 extern int blk_hw_contig_segment(request_queue_t *q, struct bio *, struct bio *);
522 extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __user *);
523 extern void blk_start_queue(request_queue_t *q);
524 extern void blk_stop_queue(request_queue_t *q);
525 extern void blk_sync_queue(struct request_queue *q);
526 extern void __blk_stop_queue(request_queue_t *q);
527 extern void blk_run_queue(request_queue_t *);
528 extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
529 extern struct request *blk_rq_map_user(request_queue_t *, int, void __user *, unsigned int);
530 extern int blk_rq_unmap_user(struct request *, struct bio *, unsigned int);
531 extern int blk_execute_rq(request_queue_t *, struct gendisk *, struct request *);
533 static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
535 return bdev->bd_disk->queue;
538 static inline void blk_run_backing_dev(struct backing_dev_info *bdi,
541 if (bdi && bdi->unplug_io_fn)
542 bdi->unplug_io_fn(bdi, page);
545 static inline void blk_run_address_space(struct address_space *mapping)
548 blk_run_backing_dev(mapping->backing_dev_info, NULL);
552 * end_request() and friends. Must be called with the request queue spinlock
553 * acquired. All functions called within end_request() _must_be_ atomic.
555 * Several drivers define their own end_request and call
556 * end_that_request_first() and end_that_request_last()
557 * for parts of the original function. This prevents
558 * code duplication in drivers.
560 extern int end_that_request_first(struct request *, int, int);
561 extern int end_that_request_chunk(struct request *, int, int);
562 extern void end_that_request_last(struct request *);
563 extern void end_request(struct request *req, int uptodate);
566 * end_that_request_first/chunk() takes an uptodate argument. we account
567 * any value <= as an io error. 0 means -EIO for compatability reasons,
568 * any other < 0 value is the direct error type. An uptodate value of
569 * 1 indicates successful io completion
571 #define end_io_error(uptodate) (unlikely((uptodate) <= 0))
573 static inline void blkdev_dequeue_request(struct request *req)
575 BUG_ON(list_empty(&req->queuelist));
577 list_del_init(&req->queuelist);
580 elv_remove_request(req->q, req);
584 * Access functions for manipulating queue properties
586 extern request_queue_t *blk_init_queue(request_fn_proc *, spinlock_t *);
587 extern void blk_cleanup_queue(request_queue_t *);
588 extern void blk_queue_make_request(request_queue_t *, make_request_fn *);
589 extern void blk_queue_bounce_limit(request_queue_t *, u64);
590 extern void blk_queue_max_sectors(request_queue_t *, unsigned short);
591 extern void blk_queue_max_phys_segments(request_queue_t *, unsigned short);
592 extern void blk_queue_max_hw_segments(request_queue_t *, unsigned short);
593 extern void blk_queue_max_segment_size(request_queue_t *, unsigned int);
594 extern void blk_queue_hardsect_size(request_queue_t *, unsigned short);
595 extern void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b);
596 extern void blk_queue_segment_boundary(request_queue_t *, unsigned long);
597 extern void blk_queue_prep_rq(request_queue_t *, prep_rq_fn *pfn);
598 extern void blk_queue_merge_bvec(request_queue_t *, merge_bvec_fn *);
599 extern void blk_queue_dma_alignment(request_queue_t *, int);
600 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
601 extern void blk_queue_ordered(request_queue_t *, int);
602 extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
603 extern int blkdev_scsi_issue_flush_fn(request_queue_t *, struct gendisk *, sector_t *);
605 extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
606 extern void blk_dump_rq_flags(struct request *, char *);
607 extern void generic_unplug_device(request_queue_t *);
608 extern void __generic_unplug_device(request_queue_t *);
609 extern long nr_blockdev_pages(void);
610 extern void blk_wait_queue_drained(request_queue_t *, int);
611 extern void blk_finish_queue_drain(request_queue_t *);
613 int blk_get_queue(request_queue_t *);
614 request_queue_t *blk_alloc_queue(int);
615 #define blk_put_queue(q) blk_cleanup_queue((q))
620 #define blk_queue_tag_depth(q) ((q)->queue_tags->busy)
621 #define blk_queue_tag_queue(q) ((q)->queue_tags->busy < (q)->queue_tags->max_depth)
622 #define blk_rq_tagged(rq) ((rq)->flags & REQ_QUEUED)
623 extern int blk_queue_start_tag(request_queue_t *, struct request *);
624 extern struct request *blk_queue_find_tag(request_queue_t *, int);
625 extern void blk_queue_end_tag(request_queue_t *, struct request *);
626 extern int blk_queue_init_tags(request_queue_t *, int, struct blk_queue_tag *);
627 extern void blk_queue_free_tags(request_queue_t *);
628 extern int blk_queue_resize_tags(request_queue_t *, int);
629 extern void blk_queue_invalidate_tags(request_queue_t *);
630 extern long blk_congestion_wait(int rw, long timeout);
632 extern void blk_rq_bio_prep(request_queue_t *, struct request *, struct bio *);
633 extern int blkdev_issue_flush(struct block_device *, sector_t *);
635 #define MAX_PHYS_SEGMENTS 128
636 #define MAX_HW_SEGMENTS 128
637 #define MAX_SECTORS 255
639 #define MAX_SEGMENT_SIZE 65536
641 #define blkdev_entry_to_request(entry) list_entry((entry), struct request, queuelist)
643 extern void drive_stat_acct(struct request *, int, int);
645 static inline int queue_hardsect_size(request_queue_t *q)
649 if (q && q->hardsect_size)
650 retval = q->hardsect_size;
655 static inline int bdev_hardsect_size(struct block_device *bdev)
657 return queue_hardsect_size(bdev_get_queue(bdev));
660 static inline int queue_dma_alignment(request_queue_t *q)
664 if (q && q->dma_alignment)
665 retval = q->dma_alignment;
670 static inline int bdev_dma_aligment(struct block_device *bdev)
672 return queue_dma_alignment(bdev_get_queue(bdev));
675 #define blk_finished_io(nsects) do { } while (0)
676 #define blk_started_io(nsects) do { } while (0)
678 /* assumes size > 256 */
679 static inline unsigned int blksize_bits(unsigned int size)
681 unsigned int bits = 8;
685 } while (size > 256);
689 extern inline unsigned int block_size(struct block_device *bdev)
691 return bdev->bd_block_size;
694 typedef struct {struct page *v;} Sector;
696 unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
698 static inline void put_dev_sector(Sector p)
700 page_cache_release(p.v);
704 int kblockd_schedule_work(struct work_struct *work);
705 void kblockd_flush(void);
708 # include <asm/div64.h>
709 # define sector_div(a, b) do_div(a, b)
711 # define sector_div(n, b)( \
721 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
722 MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
723 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \
724 MODULE_ALIAS("block-major-" __stringify(major) "-*")