block: use blkdev_issue_discard in blk_ioctl_discard

blk_ioctl_discard duplicates large amounts of code from blkdev_issue_discard,
the only difference between the two is that blkdev_issue_discard needs to
send a barrier discard request and blk_ioctl_discard a non-barrier one,
and blk_ioctl_discard needs to wait on the request.  To facilitates this
add a flags argument to blkdev_issue_discard to control both aspects of the
behaviour.  This will be very useful later on for using the waiting
funcitonality for other callers.

Based on an earlier patch from Matthew Wilcox <matthew@wil.cx>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 4 insertions, 2 deletions

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;
                 }