Move the code for rounding down a sector into a new function.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
---
block/blk-lib.c | 32 +++++++++++++++++++++++++-------
1 file changed, 25 insertions(+), 7 deletions(-)
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 9ebf653..2f4c6b2 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -26,6 +26,26 @@ static void bio_batch_end_io(struct bio *bio)
bio_put(bio);
}
+/*
+ * Return the largest number that is less than or equal to @s and for which
+ * the remainder of the division by @granularity is @alignment.
+ */
+static sector_t blk_round_sect_down(sector_t s, u32 granularity, u32 alignment)
+{
+ sector_t tmp = s, res = s;
+ u32 remainder;
+
+ WARN_ON_ONCE(alignment >= granularity);
+
+ remainder = sector_div(tmp, granularity);
+ if (remainder == alignment)
+ return res;
+ res -= remainder - alignment;
+ if (remainder < alignment)
+ res -= granularity;
+ return min(res, s);
+}
+
/**
* blkdev_issue_discard - queue a discard
* @bdev: blockdev to issue discard for
@@ -73,7 +93,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
blk_start_plug(&plug);
while (nr_sects) {
unsigned int req_sects;
- sector_t end_sect, tmp;
+ sector_t end_sect;
bio = bio_alloc(gfp_mask, 1);
if (!bio) {
@@ -89,12 +109,10 @@ 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;
- 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;
+ if (req_sects < nr_sects) {
+ end_sect = blk_round_sect_down(end_sect, granularity,
+ alignment);
+ WARN_ON_ONCE(end_sect < sector);
req_sects = end_sect - sector;
}
--
2.1.4
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