1 files changed, 19 insertions, 12 deletions

diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index 30022b4e2f63..6593ab39cfe9 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -348,6 +348,9 @@ static void blkdev_discard_end_io(struct bio *bio, int err)
                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
         }
 
+        if (bio->bi_private)
+                complete(bio->bi_private);
+
         bio_put(bio);
 }
 
@@ -357,21 +360,20 @@ static void blkdev_discard_end_io(struct bio *bio, int err)
  * @sector:     start sector
  * @nr_sects:   number of sectors to discard
  * @gfp_mask:   memory allocation flags (for bio_alloc)
+ * @flags:      DISCARD_FL_* flags to control behaviour
  *
  * Description:
- *    Issue a discard request for the sectors in question. Does not wait.
+ *    Issue a discard request for the sectors in question.
  */
-int blkdev_issue_discard(struct block_device *bdev,
-                         sector_t sector, sector_t nr_sects, gfp_t gfp_mask)
+int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
+                sector_t nr_sects, gfp_t gfp_mask, int flags)
 {
-        struct request_queue *q;
-        struct bio *bio;
+        DECLARE_COMPLETION_ONSTACK(wait);
+        struct request_queue *q = bdev_get_queue(bdev);
+        int type = flags & DISCARD_FL_BARRIER ?
+                DISCARD_BARRIER : DISCARD_NOBARRIER;
         int ret = 0;
 
-        if (bdev->bd_disk == NULL)
-                return -ENXIO;
-
-        q = bdev_get_queue(bdev);
         if (!q)
                 return -ENXIO;
 
@@ -379,12 +381,14 @@ int blkdev_issue_discard(struct block_device *bdev,
                 return -EOPNOTSUPP;
 
         while (nr_sects && !ret) {
-                bio = bio_alloc(gfp_mask, 0);
+                struct bio *bio = bio_alloc(gfp_mask, 0);
                 if (!bio)
                         return -ENOMEM;
 
                 bio->bi_end_io = blkdev_discard_end_io;
                 bio->bi_bdev = bdev;
+                if (flags & DISCARD_FL_WAIT)
+                        bio->bi_private = &wait;
 
                 bio->bi_sector = sector;
 
@@ -396,10 +400,13 @@ int blkdev_issue_discard(struct block_device *bdev,
                         bio->bi_size = nr_sects << 9;
                         nr_sects = 0;
                 }
+
                 bio_get(bio);
-                submit_bio(DISCARD_BARRIER, bio);
+                submit_bio(type, bio);
+
+                if (flags & DISCARD_FL_WAIT)
+                        wait_for_completion(&wait);
 
-                /* Check if it failed immediately */
                 if (bio_flagged(bio, BIO_EOPNOTSUPP))
                         ret = -EOPNOTSUPP;
                 else if (!bio_flagged(bio, BIO_UPTODATE))