1 files changed, 16 insertions, 10 deletions

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 9373b58dfab1..b3a1f2b70b31 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -43,11 +43,12 @@ 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;
+        struct blk_plug plug;
 
         if (!q)
                 return -ENXIO;
@@ -57,15 +58,16 @@ 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;
@@ -81,9 +83,10 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
         bb.flags = 1 << BIO_UPTODATE;
         bb.wait = &wait;
 
+        blk_start_plug(&plug);
         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 +101,12 @@ 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;
                 }
 
@@ -117,6 +122,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
                 atomic_inc(&bb.done);
                 submit_bio(type, bio);
         }
+        blk_finish_plug(&plug);
 
         /* Wait for bios in-flight */
         if (!atomic_dec_and_test(&bb.done))