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| author |   FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> | 2008-08-28 15:05:58 +0900 |
|---|---|---|
| committer |   Jens Axboe <jens.axboe@oracle.com> | 2008-10-09 08:56:11 +0200 |
| commit | 879040742cf09f2360a9ac41846288707e4e567c (patch) | |
| tree | 7768750efd0d8ef28a183f8cd781b0c878212795 /include/linux/blkdev.h | |
| parent | bio: convert bio_copy_kern to use bio_copy_user (diff) | |
| download | linux-dev-879040742cf09f2360a9ac41846288707e4e567c.tar.xz linux-dev-879040742cf09f2360a9ac41846288707e4e567c.zip | |
block: add blk_rq_aligned helper function
This adds blk_rq_aligned helper function to see if alignment and
padding requirement is satisfied for DMA transfer. This also converts
blk_rq_map_kern and __blk_rq_map_user to use the helper function.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'include/linux/blkdev.h')
| -rw-r--r-- | include/linux/blkdev.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 358ac423ed2f..9c2549260427 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -899,6 +899,13 @@ static inline int queue_dma_alignment(struct request_queue *q) return q ? q->dma_alignment : 511; } +static inline int blk_rq_aligned(struct request_queue *q, void *addr, + unsigned int len) +{ + unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask; + return !((unsigned long)addr & alignment) && !(len & alignment); +} + /* assumes size > 256 */ static inline unsigned int blksize_bits(unsigned int size) { |