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authorTejun Heo2008-03-04 04:18:17 -0600
committerJens Axboe2008-03-04 04:18:17 -0600
commite3790c7d42a545e8fe8b38b513613ca96687b670 (patch)
tree0b849ba46007c4d7f7a34271a76d58e7406cbad7 /block/blk-map.c
parent7a85f8896f4b4a4a0249563b92af9e3161a6b467 (diff)
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block: separate out padding from alignment
Block layer alignment was used for two different purposes - memory alignment and padding. This causes problems in lower layers because drivers which only require memory alignment ends up with adjusted rq->data_len. Separate out padding such that padding occurs iff driver explicitly requests it. Tomo: restorethe code to update bio in blk_rq_map_user introduced by the commit 40b01b9bbdf51ae543a04744283bf2d56c4a6afa according to padding alignment. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-map.c')
-rw-r--r--block/blk-map.c20
1 files changed, 13 insertions, 7 deletions
diff --git a/block/blk-map.c b/block/blk-map.c
index f5598322954..4e17dfd0035 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -43,6 +43,7 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
43 void __user *ubuf, unsigned int len) 43 void __user *ubuf, unsigned int len)
44{ 44{
45 unsigned long uaddr; 45 unsigned long uaddr;
46 unsigned int alignment;
46 struct bio *bio, *orig_bio; 47 struct bio *bio, *orig_bio;
47 int reading, ret; 48 int reading, ret;
48 49
@@ -53,8 +54,8 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
53 * direct dma. else, set up kernel bounce buffers 54 * direct dma. else, set up kernel bounce buffers
54 */ 55 */
55 uaddr = (unsigned long) ubuf; 56 uaddr = (unsigned long) ubuf;
56 if (!(uaddr & queue_dma_alignment(q)) && 57 alignment = queue_dma_alignment(q) | q->dma_pad_mask;
57 !(len & queue_dma_alignment(q))) 58 if (!(uaddr & alignment) && !(len & alignment))
58 bio = bio_map_user(q, NULL, uaddr, len, reading); 59 bio = bio_map_user(q, NULL, uaddr, len, reading);
59 else 60 else
60 bio = bio_copy_user(q, uaddr, len, reading); 61 bio = bio_copy_user(q, uaddr, len, reading);
@@ -141,15 +142,20 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
141 142
142 /* 143 /*
143 * __blk_rq_map_user() copies the buffers if starting address 144 * __blk_rq_map_user() copies the buffers if starting address
144 * or length isn't aligned. As the copied buffer is always 145 * or length isn't aligned to dma_pad_mask. As the copied
145 * page aligned, we know that there's enough room for padding. 146 * buffer is always page aligned, we know that there's enough
146 * Extend the last bio and update rq->data_len accordingly. 147 * room for padding. Extend the last bio and update
148 * rq->data_len accordingly.
147 * 149 *
148 * On unmap, bio_uncopy_user() will use unmodified 150 * On unmap, bio_uncopy_user() will use unmodified
149 * bio_map_data pointed to by bio->bi_private. 151 * bio_map_data pointed to by bio->bi_private.
150 */ 152 */
151 if (len & queue_dma_alignment(q)) { 153 if (len & q->dma_pad_mask) {
152 unsigned int pad_len = (queue_dma_alignment(q) & ~len) + 1; 154 unsigned int pad_len = (q->dma_pad_mask & ~len) + 1;
155 struct bio *bio = rq->biotail;
156
157 bio->bi_io_vec[bio->bi_vcnt - 1].bv_len += pad_len;
158 bio->bi_size += pad_len;
153 159
154 rq->extra_len += pad_len; 160 rq->extra_len += pad_len;
155 } 161 }