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authorGeert Uytterhoeven <geert@linux-m68k.org>2013-11-04 14:00:06 +0100
committerJens Axboe <axboe@kernel.dk>2013-11-08 09:04:46 -0700
commit97597dc08f58e25bc74154b7d1c387a4c0432950 (patch)
tree0d904cb15553db7ee1c624dfa1ae4706da779bfe /block/blk-lib.c
parentf8c5e94486671ffcac696886c246baa6ba89b5cf (diff)
downloadlinux-linaro-stable-97597dc08f58e25bc74154b7d1c387a4c0432950.tar.gz
block: Do not call sector_div() with a 64-bit divisor
do_div() (called by sector_div() if CONFIG_LBDAF=y) is meant for divisions of 64-bit number by 32-bit numbers. Passing 64-bit divisor types caused issues in the past on 32-bit platforms, cfr. commit ea077b1b96e073eac5c3c5590529e964767fc5f7 ("m68k: Truncate base in do_div()"). As queue_limits.max_discard_sectors and .discard_granularity are unsigned int, max_discard_sectors and granularity should be unsigned int. As bdev_discard_alignment() returns int, alignment should be int. Now 2 calls to sector_div() can be replaced by 32-bit arithmetic: - The 64-bit modulo operation can become a 32-bit modulo operation, - The 64-bit division and multiplication can be replaced by a 32-bit modulo operation and a subtraction. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-lib.c')
-rw-r--r--block/blk-lib.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
index d6f50d572565..9b5b561cb928 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;
- sector_t max_discard_sectors;
- sector_t granularity, alignment;
+ unsigned int max_discard_sectors, granularity;
+ int alignment;
struct bio_batch bb;
struct bio *bio;
int ret = 0;
@@ -58,16 +58,14 @@ 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);
- alignment = bdev_discard_alignment(bdev) >> 9;
- alignment = sector_div(alignment, granularity);
+ alignment = (bdev_discard_alignment(bdev) >> 9) % 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);
- sector_div(max_discard_sectors, granularity);
- max_discard_sectors *= granularity;
+ max_discard_sectors -= max_discard_sectors % granularity;
if (unlikely(!max_discard_sectors)) {
/* Avoid infinite loop below. Being cautious never hurts. */
return -EOPNOTSUPP;