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| author | Martin K. Petersen <martin.petersen@oracle.com> | 2012-09-18 12:19:27 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2012-09-20 14:31:45 +0200 |
| commit | 4363ac7c13a9a4b763c6e8d9fdbfc2468f3b8ca4 (patch) | |
| tree | 010b05699eb9544b9cdfe5e1b3affdaea80132e7 /block/blk-settings.c | |
| parent | f31dc1cd490539e2b62a126bc4dc2495b165d772 (diff) | |
| download | linux-4363ac7c13a9a4b763c6e8d9fdbfc2468f3b8ca4.tar.bz2 | |
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 'block/blk-settings.c')
| -rw-r--r-- | block/blk-settings.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c index 565a6786032f..779bb7646bcd 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -113,6 +113,7 @@ void blk_set_default_limits(struct queue_limits *lim) lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK; lim->max_segment_size = BLK_MAX_SEGMENT_SIZE; lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS; + lim->max_write_same_sectors = 0; lim->max_discard_sectors = 0; lim->discard_granularity = 0; lim->discard_alignment = 0; @@ -144,6 +145,7 @@ void blk_set_stacking_limits(struct queue_limits *lim) lim->max_segments = USHRT_MAX; lim->max_hw_sectors = UINT_MAX; lim->max_sectors = UINT_MAX; + lim->max_write_same_sectors = UINT_MAX; } EXPORT_SYMBOL(blk_set_stacking_limits); @@ -286,6 +288,18 @@ void blk_queue_max_discard_sectors(struct request_queue *q, EXPORT_SYMBOL(blk_queue_max_discard_sectors); /** + * blk_queue_max_write_same_sectors - set max sectors for a single write same + * @q: the request queue for the device + * @max_write_same_sectors: maximum number of sectors to write per command + **/ +void blk_queue_max_write_same_sectors(struct request_queue *q, + unsigned int max_write_same_sectors) +{ + q->limits.max_write_same_sectors = max_write_same_sectors; +} +EXPORT_SYMBOL(blk_queue_max_write_same_sectors); + +/** * blk_queue_max_segments - set max hw segments for a request for this queue * @q: the request queue for the device * @max_segments: max number of segments @@ -510,6 +524,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors); t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors); + t->max_write_same_sectors = min(t->max_write_same_sectors, + b->max_write_same_sectors); t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, |