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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
parent7a85f8896f4b4a4a0249563b92af9e3161a6b467 (diff)
downloadvexpress-lsk-e3790c7d42a545e8fe8b38b513613ca96687b670.tar.gz
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>
-rw-r--r--block/blk-map.c20
-rw-r--r--block/blk-settings.c17
-rw-r--r--drivers/ata/libata-scsi.c3
-rw-r--r--include/linux/blkdev.h2
4 files changed, 34 insertions, 8 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,
void __user *ubuf, unsigned int len)
{
unsigned long uaddr;
+ unsigned int alignment;
struct bio *bio, *orig_bio;
int reading, ret;
@@ -53,8 +54,8 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
* direct dma. else, set up kernel bounce buffers
*/
uaddr = (unsigned long) ubuf;
- if (!(uaddr & queue_dma_alignment(q)) &&
- !(len & queue_dma_alignment(q)))
+ alignment = queue_dma_alignment(q) | q->dma_pad_mask;
+ if (!(uaddr & alignment) && !(len & alignment))
bio = bio_map_user(q, NULL, uaddr, len, reading);
else
bio = bio_copy_user(q, uaddr, len, reading);
@@ -141,15 +142,20 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
/*
* __blk_rq_map_user() copies the buffers if starting address
- * or length isn't aligned. As the copied buffer is always
- * page aligned, we know that there's enough room for padding.
- * Extend the last bio and update rq->data_len accordingly.
+ * or length isn't aligned to dma_pad_mask. As the copied
+ * buffer is always page aligned, we know that there's enough
+ * room for padding. Extend the last bio and update
+ * rq->data_len accordingly.
*
* On unmap, bio_uncopy_user() will use unmodified
* bio_map_data pointed to by bio->bi_private.
*/
- if (len & queue_dma_alignment(q)) {
- unsigned int pad_len = (queue_dma_alignment(q) & ~len) + 1;
+ if (len & q->dma_pad_mask) {
+ unsigned int pad_len = (q->dma_pad_mask & ~len) + 1;
+ struct bio *bio = rq->biotail;
+
+ bio->bi_io_vec[bio->bi_vcnt - 1].bv_len += pad_len;
+ bio->bi_size += pad_len;
rq->extra_len += pad_len;
}
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)
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
* @dma_drain_needed: fn which returns non-zero if drain is necessary
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index fe47922dd69..8f0e8f2bc62 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -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);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index b72526c13ca..6f79d40dd3c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -362,6 +362,7 @@ struct request_queue
unsigned long seg_boundary_mask;
void *dma_drain_buffer;
unsigned int dma_drain_size;
+ unsigned int dma_pad_mask;
unsigned int dma_alignment;
struct blk_queue_tag *queue_tags;
@@ -701,6 +702,7 @@ extern void blk_queue_max_hw_segments(struct request_queue *, unsigned short);
extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
extern void blk_queue_hardsect_size(struct request_queue *, unsigned short);
extern void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b);
+extern void blk_queue_dma_pad(struct request_queue *, unsigned int);
extern int blk_queue_dma_drain(struct request_queue *q,
dma_drain_needed_fn *dma_drain_needed,
void *buf, unsigned int size);