path: root/block/blk-settings.c
diff options
authorTejun Heo <htejun@gmail.com>2008-03-04 11:18:17 +0100
committerJens Axboe <jens.axboe@oracle.com>2008-03-04 11:18:17 +0100
commite3790c7d42a545e8fe8b38b513613ca96687b670 (patch)
tree0b849ba46007c4d7f7a34271a76d58e7406cbad7 /block/blk-settings.c
parent7a85f8896f4b4a4a0249563b92af9e3161a6b467 (diff)
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-settings.c')
1 files changed, 17 insertions, 0 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index da923fed1f2..a9f37f530b1 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -293,6 +293,23 @@ void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
+ * blk_queue_dma_pad - set pad mask
+ * @q: the request queue for the device
+ * @mask: pad mask
+ *
+ * Set pad mask. Direct IO requests are padded to the mask specified.
+ *
+ * Appending pad buffer to a request modifies ->data_len such that it
+ * includes the pad buffer. The original requested data length can be
+ * obtained using blk_rq_raw_data_len().
+ **/
+void blk_queue_dma_pad(struct request_queue *q, unsigned int mask)
+ q->dma_pad_mask = mask;
* blk_queue_dma_drain - Set up a drain buffer for excess dma.
* @q: the request queue for the device
* @dma_drain_needed: fn which returns non-zero if drain is necessary