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authorShaohua Li <shli@kernel.org>2012-12-14 11:15:36 +0800
committerJens Axboe <axboe@kernel.dk>2012-12-14 20:46:04 +0100
commit8dd2cb7e880d2f77fba53b523c99133ad5054cfd (patch)
treeea51e89f8c8bf9ca8e888d68ecf6732a52e8e99d /block
parent75274551c81796b636c5acb0c2597dec7ec2e6c4 (diff)
downloadvexpress-lsk-8dd2cb7e880d2f77fba53b523c99133ad5054cfd.tar.gz
block: discard granularity might not be power of 2
In MD raid case, discard granularity might not be power of 2, for example, a 4-disk raid5 has 3*chunk_size discard granularity. Correct the calculation for such cases. Reported-by: Neil Brown <neilb@suse.de> Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-lib.c23
-rw-r--r--block/blk-settings.c6
2 files changed, 16 insertions, 13 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 9373b58dfab..5677fd33d7d 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -43,8 +43,8 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
DECLARE_COMPLETION_ONSTACK(wait);
struct request_queue *q = bdev_get_queue(bdev);
int type = REQ_WRITE | REQ_DISCARD;
- unsigned int max_discard_sectors;
- unsigned int granularity, alignment, mask;
+ sector_t max_discard_sectors;
+ sector_t granularity, alignment;
struct bio_batch bb;
struct bio *bio;
int ret = 0;
@@ -57,15 +57,16 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
/* Zero-sector (unknown) and one-sector granularities are the same. */
granularity = max(q->limits.discard_granularity >> 9, 1U);
- mask = granularity - 1;
- alignment = (bdev_discard_alignment(bdev) >> 9) & mask;
+ alignment = bdev_discard_alignment(bdev) >> 9;
+ alignment = sector_div(alignment, granularity);
/*
* Ensure that max_discard_sectors is of the proper
* granularity, so that requests stay aligned after a split.
*/
max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
- max_discard_sectors = round_down(max_discard_sectors, granularity);
+ sector_div(max_discard_sectors, granularity);
+ max_discard_sectors *= granularity;
if (unlikely(!max_discard_sectors)) {
/* Avoid infinite loop below. Being cautious never hurts. */
return -EOPNOTSUPP;
@@ -83,7 +84,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
while (nr_sects) {
unsigned int req_sects;
- sector_t end_sect;
+ sector_t end_sect, tmp;
bio = bio_alloc(gfp_mask, 1);
if (!bio) {
@@ -98,10 +99,12 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
* misaligned, stop the discard at the previous aligned sector.
*/
end_sect = sector + req_sects;
- if (req_sects < nr_sects && (end_sect & mask) != alignment) {
- end_sect =
- round_down(end_sect - alignment, granularity)
- + alignment;
+ tmp = end_sect;
+ if (req_sects < nr_sects &&
+ sector_div(tmp, granularity) != alignment) {
+ end_sect = end_sect - alignment;
+ sector_div(end_sect, granularity);
+ end_sect = end_sect * granularity + alignment;
req_sects = end_sect - sector;
}
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 779bb7646bc..c50ecf0ea3b 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -611,7 +611,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
bottom = b->discard_granularity + alignment;
/* Verify that top and bottom intervals line up */
- if (max(top, bottom) & (min(top, bottom) - 1))
+ if ((max(top, bottom) % min(top, bottom)) != 0)
t->discard_misaligned = 1;
}
@@ -619,8 +619,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
b->max_discard_sectors);
t->discard_granularity = max(t->discard_granularity,
b->discard_granularity);
- t->discard_alignment = lcm(t->discard_alignment, alignment) &
- (t->discard_granularity - 1);
+ t->discard_alignment = lcm(t->discard_alignment, alignment) %
+ t->discard_granularity;
}
return ret;