From e3790c7d42a545e8fe8b38b513613ca96687b670 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 4 Mar 2008 11:18:17 +0100 Subject: 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 Signed-off-by: FUJITA Tomonori Signed-off-by: Jens Axboe --- block/blk-settings.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'block/blk-settings.c') 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 @@ -292,6 +292,23 @@ void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b) } EXPORT_SYMBOL(blk_queue_stack_limits); +/** + * 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; +} +EXPORT_SYMBOL(blk_queue_dma_pad); + /** * blk_queue_dma_drain - Set up a drain buffer for excess dma. * @q: the request queue for the device -- cgit v1.2.3