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>
diff --git a/block/blk-map.c b/block/blk-map.c
index dad6a29..572140c 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -45,7 +45,6 @@
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 @@
* 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 @@
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 @@
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