diff options
| 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 | |
| parent | 4d8ab62e087d9300883b82c2662e73e6eef803a3 (diff) | |
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>
| -rw-r--r-- | block/blk-map.c | 12 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 7 |
2 files changed, 9 insertions, 10 deletions
diff --git a/block/blk-map.c b/block/blk-map.c index dad6a2907835..572140cda5ff 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -45,7 +45,6 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq, unsigned int len, gfp_t gfp_mask) { unsigned long uaddr; - unsigned int alignment; struct bio *bio, *orig_bio; int reading, ret; @@ -56,8 +55,7 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq, * direct dma. else, set up kernel bounce buffers */ uaddr = (unsigned long) ubuf; - alignment = queue_dma_alignment(q) | q->dma_pad_mask; - if (!(uaddr & alignment) && !(len & alignment) && !map_data) + if (blk_rq_aligned(q, ubuf, len) && !map_data) bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask); else bio = bio_copy_user(q, map_data, uaddr, len, reading, gfp_mask); @@ -274,8 +272,6 @@ EXPORT_SYMBOL(blk_rq_unmap_user); int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, unsigned int len, gfp_t gfp_mask) { - unsigned long kaddr; - unsigned int alignment; int reading = rq_data_dir(rq) == READ; int do_copy = 0; struct bio *bio; @@ -285,11 +281,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, if (!len || !kbuf) return -EINVAL; - kaddr = (unsigned long)kbuf; - alignment = queue_dma_alignment(q) | q->dma_pad_mask; - do_copy = ((kaddr & alignment) || (len & alignment) || - object_is_on_stack(kbuf)); - + do_copy = !blk_rq_aligned(q, kbuf, len) || object_is_on_stack(kbuf); if (do_copy) bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); else 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) { |