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authorFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>2008-08-28 15:05:58 +0900
committerJens Axboe <jens.axboe@oracle.com>2008-10-09 08:56:11 +0200
commit879040742cf09f2360a9ac41846288707e4e567c (patch)
tree7768750efd0d8ef28a183f8cd781b0c878212795 /include
parent4d8ab62e087d9300883b82c2662e73e6eef803a3 (diff)
downloadlinux-879040742cf09f2360a9ac41846288707e4e567c.tar.bz2
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')
-rw-r--r--include/linux/blkdev.h7
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)
{