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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>
This commit is contained in:
Martin K. Petersen 2010-01-11 03:21:51 -05:00 committed by Jens Axboe
parent ce289321b7
commit e03a72e136
3 changed files with 18 additions and 32 deletions
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26
block/blk-settings.c
View File

@ -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);

7
fs/partitions/check.c
View File

@ -412,9 +412,10 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno,
pdev = part_to_dev(p);
p->start_sect = start;
p->alignment_offset = queue_sector_alignment_offset(disk->queue, start);
p->discard_alignment = queue_sector_discard_alignment(disk->queue,
start);
p->alignment_offset =
queue_limit_alignment_offset(&disk->queue->limits, start);
p->discard_alignment =
queue_limit_discard_alignment(&disk->queue->limits, start);
p->nr_sects = len;
p->partno = partno;
p->policy = get_disk_ro(disk);

17
include/linux/blkdev.h
View File

@ -1112,18 +1112,13 @@ static inline int queue_alignment_offset(struct request_queue *q)
return q->limits.alignment_offset;
}
static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t offset)
static inline int queue_limit_alignment_offset(struct queue_limits *lim, sector_t sector)
{
unsigned int granularity = max(lim->physical_block_size, lim->io_min);
unsigned int alignment = (sector << 9) & (granularity - 1);
offset &= granularity - 1;
return (granularity + lim->alignment_offset - offset) & (granularity - 1);
}
static inline int queue_sector_alignment_offset(struct request_queue *q,
sector_t sector)
{
return queue_limit_alignment_offset(&q->limits, sector << 9);
return (granularity + lim->alignment_offset - alignment)
& (granularity - 1);
}
static inline int bdev_alignment_offset(struct block_device *bdev)
@ -1147,10 +1142,8 @@ static inline int queue_discard_alignment(struct request_queue *q)
return q->limits.discard_alignment;
}
static inline int queue_sector_discard_alignment(struct request_queue *q,
sector_t sector)
static inline int queue_limit_discard_alignment(struct queue_limits *lim, sector_t sector)
{
struct queue_limits *lim = &q->limits;
unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
return (lim->discard_granularity + lim->discard_alignment - alignment)