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author | Martin K. Petersen <martin.petersen@oracle.com> | 2012-09-18 12:19:27 -0400 |
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committer | Jens Axboe <axboe@kernel.dk> | 2012-09-20 14:31:45 +0200 |
commit | 4363ac7c13a9a4b763c6e8d9fdbfc2468f3b8ca4 (patch) | |
tree | 010b05699eb9544b9cdfe5e1b3affdaea80132e7 /include/linux/blkdev.h | |
parent | f31dc1cd490539e2b62a126bc4dc2495b165d772 (diff) | |
download | linux-stable-4363ac7c13a9a4b763c6e8d9fdbfc2468f3b8ca4.tar.gz linux-stable-4363ac7c13a9a4b763c6e8d9fdbfc2468f3b8ca4.tar.bz2 linux-stable-4363ac7c13a9a4b763c6e8d9fdbfc2468f3b8ca4.zip |
block: Implement support for WRITE SAME
The WRITE SAME command supported on some SCSI devices allows the same
block to be efficiently replicated throughout a block range. Only a
single logical block is transferred from the host and the storage device
writes the same data to all blocks described by the I/O.
This patch implements support for WRITE SAME in the block layer. The
blkdev_issue_write_same() function can be used by filesystems and block
drivers to replicate a buffer across a block range. This can be used to
efficiently initialize software RAID devices, etc.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/blkdev.h')
-rw-r--r-- | include/linux/blkdev.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 90f7abe8f183..1756001210d2 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -270,6 +270,7 @@ struct queue_limits { unsigned int io_min; unsigned int io_opt; unsigned int max_discard_sectors; + unsigned int max_write_same_sectors; unsigned int discard_granularity; unsigned int discard_alignment; @@ -614,9 +615,20 @@ static inline bool blk_check_merge_flags(unsigned int flags1, if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE)) return false; + if ((flags1 & REQ_WRITE_SAME) != (flags2 & REQ_WRITE_SAME)) + return false; + return true; } +static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b) +{ + if (bio_data(a) == bio_data(b)) + return true; + + return false; +} + /* * q->prep_rq_fn return values */ @@ -818,6 +830,9 @@ static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q, if (unlikely(cmd_flags & REQ_DISCARD)) return q->limits.max_discard_sectors; + if (unlikely(cmd_flags & REQ_WRITE_SAME)) + return q->limits.max_write_same_sectors; + return q->limits.max_sectors; } @@ -886,6 +901,8 @@ extern void blk_queue_max_segments(struct request_queue *, unsigned short); extern void blk_queue_max_segment_size(struct request_queue *, unsigned int); extern void blk_queue_max_discard_sectors(struct request_queue *q, unsigned int max_discard_sectors); +extern void blk_queue_max_write_same_sectors(struct request_queue *q, + unsigned int max_write_same_sectors); extern void blk_queue_logical_block_size(struct request_queue *, unsigned short); extern void blk_queue_physical_block_size(struct request_queue *, unsigned int); extern void blk_queue_alignment_offset(struct request_queue *q, @@ -1016,6 +1033,8 @@ static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt, extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *); extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask, unsigned long flags); +extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, + sector_t nr_sects, gfp_t gfp_mask, struct page *page); extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask); static inline int sb_issue_discard(struct super_block *sb, sector_t block, @@ -1193,6 +1212,16 @@ static inline unsigned int bdev_discard_zeroes_data(struct block_device *bdev) return queue_discard_zeroes_data(bdev_get_queue(bdev)); } +static inline unsigned int bdev_write_same(struct block_device *bdev) +{ + struct request_queue *q = bdev_get_queue(bdev); + + if (q) + return q->limits.max_write_same_sectors; + + return 0; +} + static inline int queue_dma_alignment(struct request_queue *q) { return q ? q->dma_alignment : 511; |