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| author |   David Woodhouse <David.Woodhouse@intel.com> | 2008-08-05 18:01:53 +0100 |
|---|---|---|
| committer |   Jens Axboe <jens.axboe@oracle.com> | 2008-10-09 08:56:01 +0200 |
| commit | fb2dce862d9f9a68e6b9374579056ec9eca02a63 (patch) | |
| tree | 888e0fd7248c9329fa1aa3981043a2dc2457d488 /include/linux/blkdev.h | |
| parent | Fix up comments about matching flags between bio and rq (diff) | |
| download | linux-dev-fb2dce862d9f9a68e6b9374579056ec9eca02a63.tar.xz linux-dev-fb2dce862d9f9a68e6b9374579056ec9eca02a63.zip | |
Add 'discard' request handling
Some block devices benefit from a hint that they can forget the contents
of certain sectors. Add basic support for this to the block core, along
with a 'blkdev_issue_discard()' helper function which issues such
requests.
The caller doesn't get to provide an end_io functio, since
blkdev_issue_discard() will automatically split the request up into
multiple bios if appropriate. Neither does the function wait for
completion -- it's expected that callers won't care about when, or even
_if_, the request completes. It's only a hint to the device anyway. By
definition, the file system doesn't _care_ about these sectors any more.
[With feedback from OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> and
Jens Axboe <jens.axboe@oracle.com]
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'include/linux/blkdev.h')
| -rw-r--r-- | include/linux/blkdev.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index e0ba018f5e88..26ececbbebe2 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -89,6 +89,7 @@ enum { enum rq_flag_bits { __REQ_RW, /* not set, read. set, write */ __REQ_FAILFAST, /* no low level driver retries */ + __REQ_DISCARD, /* request to discard sectors */ __REQ_SORTED, /* elevator knows about this request */ __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */ __REQ_HARDBARRIER, /* may not be passed by drive either */ @@ -111,6 +112,7 @@ enum rq_flag_bits { }; #define REQ_RW (1 << __REQ_RW) +#define REQ_DISCARD (1 << __REQ_DISCARD) #define REQ_FAILFAST (1 << __REQ_FAILFAST) #define REQ_SORTED (1 << __REQ_SORTED) #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER) @@ -252,6 +254,7 @@ typedef void (request_fn_proc) (struct request_queue *q); typedef int (make_request_fn) (struct request_queue *q, struct bio *bio); typedef int (prep_rq_fn) (struct request_queue *, struct request *); typedef void (unplug_fn) (struct request_queue *); +typedef int (prepare_discard_fn) (struct request_queue *, struct request *); struct bio_vec; struct bvec_merge_data { @@ -307,6 +310,7 @@ struct request_queue make_request_fn *make_request_fn; prep_rq_fn *prep_rq_fn; unplug_fn *unplug_fn; + prepare_discard_fn *prepare_discard_fn; merge_bvec_fn *merge_bvec_fn; prepare_flush_fn *prepare_flush_fn; softirq_done_fn *softirq_done_fn; @@ -546,6 +550,7 @@ enum { #define blk_sorted_rq(rq) ((rq)->cmd_flags & REQ_SORTED) #define blk_barrier_rq(rq) ((rq)->cmd_flags & REQ_HARDBARRIER) #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA) +#define blk_discard_rq(rq) ((rq)->cmd_flags & REQ_DISCARD) #define blk_bidi_rq(rq) ((rq)->next_rq != NULL) #define blk_empty_barrier(rq) (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors) /* rq->queuelist of dequeued request must be list_empty() */ @@ -796,6 +801,7 @@ extern void blk_queue_merge_bvec(struct request_queue *, merge_bvec_fn *); extern void blk_queue_dma_alignment(struct request_queue *, int); extern void blk_queue_update_dma_alignment(struct request_queue *, int); extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *); +extern void blk_queue_set_discard(struct request_queue *, prepare_discard_fn *); extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev); extern int blk_queue_ordered(struct request_queue *, unsigned, prepare_flush_fn *); extern int blk_do_ordered(struct request_queue *, struct request **); @@ -837,6 +843,16 @@ static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt, } extern int blkdev_issue_flush(struct block_device *, sector_t *); +extern int blkdev_issue_discard(struct block_device *, sector_t sector, + unsigned nr_sects); + +static inline int sb_issue_discard(struct super_block *sb, + sector_t block, unsigned nr_blocks) +{ + block <<= (sb->s_blocksize_bits - 9); + nr_blocks <<= (sb->s_blocksize_bits - 9); + return blkdev_issue_discard(sb->s_bdev, block, nr_blocks); +} /* * command filter functions |