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 40b01b9bbd
      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>
This commit is contained in:
Tejun Heo
2008-03-04 11:18:17 +01:00
committed by Jens Axboe
parent 7a85f8896f
commit e3790c7d42
4 changed files with 34 additions and 8 deletions

View File

@@ -862,9 +862,10 @@ static int ata_scsi_dev_config(struct scsi_device *sdev,
struct request_queue *q = sdev->request_queue;
void *buf;
/* set the min alignment */
/* set the min alignment and padding */
blk_queue_update_dma_alignment(sdev->request_queue,
ATA_DMA_PAD_SZ - 1);
blk_queue_dma_pad(sdev->request_queue, ATA_DMA_PAD_SZ - 1);
/* configure draining */
buf = kmalloc(ATAPI_MAX_DRAIN, q->bounce_gfp | GFP_KERNEL);