6 files changed, 37 insertions, 67 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))
diff --git a/block/ioctl.c b/block/ioctl.c
index 500e4c73cc52..d3e6b5827a34 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -112,22 +112,9 @@ static int blkdev_reread_part(struct block_device *bdev)
         return res;
 }
 
-static void blk_ioc_discard_endio(struct bio *bio, int err)
-{
-        if (err) {
-                if (err == -EOPNOTSUPP)
-                        set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
-                clear_bit(BIO_UPTODATE, &bio->bi_flags);
-        }
-        complete(bio->bi_private);
-}
-
 static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
                              uint64_t len)
 {
-        struct request_queue *q = bdev_get_queue(bdev);
-        int ret = 0;
-
         if (start & 511)
                 return -EINVAL;
         if (len & 511)
@@ -137,40 +124,8 @@ static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
 
         if (start + len > (bdev->bd_inode->i_size >> 9))
                 return -EINVAL;
-
-        if (!q->prepare_discard_fn)
-                return -EOPNOTSUPP;
-
-        while (len && !ret) {
-                DECLARE_COMPLETION_ONSTACK(wait);
-                struct bio *bio;
-
-                bio = bio_alloc(GFP_KERNEL, 0);
-
-                bio->bi_end_io = blk_ioc_discard_endio;
-                bio->bi_bdev = bdev;
-                bio->bi_private = &wait;
-                bio->bi_sector = start;
-
-                if (len > queue_max_hw_sectors(q)) {
-                        bio->bi_size = queue_max_hw_sectors(q) << 9;
-                        len -= queue_max_hw_sectors(q);
-                        start += queue_max_hw_sectors(q);
-                } else {
-                        bio->bi_size = len << 9;
-                        len = 0;
-                }
-                submit_bio(DISCARD_NOBARRIER, bio);
-
-                wait_for_completion(&wait);
-
-                if (bio_flagged(bio, BIO_EOPNOTSUPP))
-                        ret = -EOPNOTSUPP;
-                else if (!bio_flagged(bio, BIO_UPTODATE))
-                        ret = -EIO;
-                bio_put(bio);
-        }
-        return ret;
+        return blkdev_issue_discard(bdev, start, len, GFP_KERNEL,
+                                    DISCARD_FL_WAIT);
 }
 
 static int put_ushort(unsigned long arg, unsigned short val)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 72a2b9c28e9f..535f85ba104f 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1511,7 +1511,8 @@ static int remove_extent_backref(struct btrfs_trans_handle *trans,
 static void btrfs_issue_discard(struct block_device *bdev,
                                 u64 start, u64 len)
 {
-        blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL);
+        blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL,
+                             DISCARD_FL_BARRIER);
 }
 #endif
 
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index fba795798d3a..fbc43241f2ef 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -857,7 +857,8 @@ static void gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset,
                                         goto start_new_extent;
                                 if ((start + nr_sects) != blk) {
                                         rv = blkdev_issue_discard(bdev, start,
-                                                            nr_sects, GFP_NOFS);
+                                                            nr_sects, GFP_NOFS,
+                                                            DISCARD_FL_BARRIER);
                                         if (rv)
                                                 goto fail;
                                         nr_sects = 0;
@@ -871,7 +872,8 @@ start_new_extent:
                 }
         }
         if (nr_sects) {
-                rv = blkdev_issue_discard(bdev, start, nr_sects, GFP_NOFS);
+                rv = blkdev_issue_discard(bdev, start, nr_sects, GFP_NOFS,
+                                         DISCARD_FL_BARRIER);
                 if (rv)
                         goto fail;
         }
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 86c2bdff3b89..e23a86cae5ac 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -998,15 +998,18 @@ static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
 }
 
 extern int blkdev_issue_flush(struct block_device *, sector_t *);
-extern int blkdev_issue_discard(struct block_device *,
-                                sector_t sector, sector_t nr_sects, gfp_t);
+#define DISCARD_FL_WAIT         0x01    /* wait for completion */
+#define DISCARD_FL_BARRIER      0x02    /* issue DISCARD_BARRIER request */
+extern int blkdev_issue_discard(struct block_device *, sector_t sector,
+                sector_t nr_sects, gfp_t, int flags);
 
 static inline int sb_issue_discard(struct super_block *sb,
                                    sector_t block, sector_t nr_blocks)
 {
         block <<= (sb->s_blocksize_bits - 9);
         nr_blocks <<= (sb->s_blocksize_bits - 9);
-        return blkdev_issue_discard(sb->s_bdev, block, nr_blocks, GFP_KERNEL);
+        return blkdev_issue_discard(sb->s_bdev, block, nr_blocks, GFP_KERNEL,
+                                    DISCARD_FL_BARRIER);
 }
 
 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 8ffdc0d23c53..74f1102e8749 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -161,7 +161,8 @@ static int discard_swap(struct swap_info_struct *si)
                 }
 
                 err = blkdev_issue_discard(si->bdev, start_block,
-                                                nr_blocks, GFP_KERNEL);
+                                                nr_blocks, GFP_KERNEL,
+                                                DISCARD_FL_BARRIER);
                 if (err)
                         break;
 
@@ -200,7 +201,8 @@ static void discard_swap_cluster(struct swap_info_struct *si,
                         start_block <<= PAGE_SHIFT - 9;
                         nr_blocks <<= PAGE_SHIFT - 9;
                         if (blkdev_issue_discard(si->bdev, start_block,
-                                                        nr_blocks, GFP_NOIO))
+                                                        nr_blocks, GFP_NOIO,
+                                                        DISCARD_FL_BARRIER))
                                 break;
                 }