block: fix single range discard merge

[mirror_ubuntu-bionic-kernel.git] / block / blk-lib.c

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 2bc544ce3d2e5a89c2c216c85d72e00f9172bb09..012425f5bd8c5e01e22e1cd2a146221f4e25a260 100644 (file)
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -29,9 +29,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 {
        struct request_queue *q = bdev_get_queue(bdev);
        struct bio *bio = *biop;
-       unsigned int granularity;
        unsigned int op;
-       int alignment;
        sector_t bs_mask;
 
        if (!q)
@@ -51,30 +49,15 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
        if ((sector | nr_sects) & bs_mask)
                return -EINVAL;
 
-       /* Zero-sector (unknown) and one-sector granularities are the same.  */
-       granularity = max(q->limits.discard_granularity >> 9, 1U);
-       alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
-
        while (nr_sects) {
-               unsigned int req_sects;
-               sector_t end_sect, tmp;
+               unsigned int req_sects = nr_sects;
+               sector_t end_sect;
 
-               /* Make sure bi_size doesn't overflow */
-               req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
+               req_sects = min(req_sects, bio_allowed_max_sectors(q));
+               if (!req_sects)
+                       goto fail;
 
-               /**
-                * If splitting a request, and the next starting sector would be
-                * 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;
-                       req_sects = end_sect - sector;
-               }
 
                bio = next_bio(bio, 0, gfp_mask);
                bio->bi_iter.bi_sector = sector;
@@ -96,6 +79,14 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 
        *biop = bio;
        return 0;
+
+fail:
+       if (bio) {
+               submit_bio_wait(bio);
+               bio_put(bio);
+       }
+       *biop = NULL;
+       return -EOPNOTSUPP;
 }
 EXPORT_SYMBOL(__blkdev_issue_discard);
 
@@ -164,7 +155,7 @@ static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
                return -EOPNOTSUPP;
 
        /* Ensure that max_write_same_sectors doesn't overflow bi_size */
-       max_write_same_sectors = UINT_MAX >> 9;
+       max_write_same_sectors = bio_allowed_max_sectors(q);
 
        while (nr_sects) {
                bio = next_bio(bio, 1, gfp_mask);