From 879040742cf09f2360a9ac41846288707e4e567c Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Thu, 28 Aug 2008 15:05:58 +0900 Subject: 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 Cc: Jens Axboe Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/blkdev.h') 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) { -- cgit v1.2.1