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authorMartin K. Petersen <martin.petersen@oracle.com>2010-01-11 03:21:51 -0500
committerJens Axboe <jens.axboe@oracle.com>2010-01-11 14:30:09 +0100
commite03a72e13648ac6277bf2bab6b8324d51f89c0fa (patch)
treea01a2e072a5b225f22bd8bfa75f5270a527a4e4b /block/blk-settings.c
parentce289321b7dc1eb108e3df0dec872b7429ef49f7 (diff)
downloadlinux-linaro-stable-e03a72e13648ac6277bf2bab6b8324d51f89c0fa.tar.gz
block: Stop using byte offsets
All callers of the stacking functions use 512-byte sector units rather than byte offsets. Simplify the code so the stacking functions take sectors when specifying data offsets. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-settings.c')
-rw-r--r--block/blk-settings.c26
1 files changed, 9 insertions, 17 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 5eeb9e0d256e..78549c723783 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -507,7 +507,7 @@ static unsigned int lcm(unsigned int a, unsigned int b)
* blk_stack_limits - adjust queue_limits for stacked devices
* @t: the stacking driver limits (top device)
* @b: the underlying queue limits (bottom, component device)
- * @offset: offset to beginning of data within component device
+ * @start: first data sector within component device
*
* Description:
* This function is used by stacking drivers like MD and DM to ensure
@@ -525,10 +525,9 @@ static unsigned int lcm(unsigned int a, unsigned int b)
* the alignment_offset is undefined.
*/
int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
- sector_t offset)
+ sector_t start)
{
- sector_t alignment;
- unsigned int top, bottom, ret = 0;
+ unsigned int top, bottom, alignment, ret = 0;
t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
@@ -548,7 +547,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
t->misaligned |= b->misaligned;
- alignment = queue_limit_alignment_offset(b, offset);
+ alignment = queue_limit_alignment_offset(b, start);
/* Bottom device has different alignment. Check that it is
* compatible with the current top alignment.
@@ -611,11 +610,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
/* Discard alignment and granularity */
if (b->discard_granularity) {
- unsigned int granularity = b->discard_granularity;
- offset &= granularity - 1;
-
- alignment = (granularity + b->discard_alignment - offset)
- & (granularity - 1);
+ alignment = queue_limit_discard_alignment(b, start);
if (t->discard_granularity != 0 &&
t->discard_alignment != alignment) {
@@ -657,7 +652,7 @@ int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
start += get_start_sect(bdev);
- return blk_stack_limits(t, &bq->limits, start << 9);
+ return blk_stack_limits(t, &bq->limits, start);
}
EXPORT_SYMBOL(bdev_stack_limits);
@@ -668,9 +663,8 @@ EXPORT_SYMBOL(bdev_stack_limits);
* @offset: offset to beginning of data within component device
*
* Description:
- * Merges the limits for two queues. Returns 0 if alignment
- * didn't change. Returns -1 if adding the bottom device caused
- * misalignment.
+ * Merges the limits for a top level gendisk and a bottom level
+ * block_device.
*/
void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
sector_t offset)
@@ -678,9 +672,7 @@ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
struct request_queue *t = disk->queue;
struct request_queue *b = bdev_get_queue(bdev);
- offset += get_start_sect(bdev) << 9;
-
- if (blk_stack_limits(&t->limits, &b->limits, offset) < 0) {
+ if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) {
char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
disk_name(disk, 0, top);