block: adjust blkdev_issue_discard for swap

Two mods to blkdev_issue_discard(), thinking ahead to its use on swap:

1. Add gfp_mask argument, so swap allocation can use it where GFP_KERNEL
   might deadlock but GFP_NOIO is safe.

2. Enlarge nr_sects argument from unsigned to sector_t: unsigned long is
   enough to cover a whole swap area, but sector_t suits any partition.

Change sb_issue_discard()'s nr_blocks to sector_t too; but no need seen
for a gfp_mask there, just pass GFP_KERNEL down to blkdev_issue_discard().

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index 988b63479b2f..5c99ff8d2db8 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -332,12 +332,13 @@ static void blkdev_discard_end_io(struct bio *bio, int err)
  * @bdev:       blockdev to issue discard for
  * @sector:     start sector
  * @nr_sects:   number of sectors to discard
+ * @gfp_mask:   memory allocation flags (for bio_alloc)
  *
  * Description:
  *    Issue a discard request for the sectors in question. Does not wait.
  */
-int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
-                         unsigned nr_sects)
+int blkdev_issue_discard(struct block_device *bdev,
+                         sector_t sector, sector_t nr_sects, gfp_t gfp_mask)
 {
         struct request_queue *q;
         struct bio *bio;
@@ -354,7 +355,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
                 return -EOPNOTSUPP;
 
         while (nr_sects && !ret) {
-                bio = bio_alloc(GFP_KERNEL, 0);
+                bio = bio_alloc(gfp_mask, 0);
                 if (!bio)
                         return -ENOMEM;