block: move down direct IO plugging

Move unplugging for direct I/O from around ->direct_IO() down to
do_blockdev_direct_IO(). This implicitly adds plugging for direct
writes.

CC: Li Shaohua <shli@fusionio.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 1faf4cb56f39..f86c720dba0e 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1062,6 +1062,7 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
         unsigned long user_addr;
         size_t bytes;
         struct buffer_head map_bh = { 0, };
+        struct blk_plug plug;
 
         if (rw & WRITE)
                 rw = WRITE_ODIRECT;
@@ -1177,6 +1178,8 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
                                 PAGE_SIZE - user_addr / PAGE_SIZE);
         }
 
+        blk_start_plug(&plug);
+
         for (seg = 0; seg < nr_segs; seg++) {
                 user_addr = (unsigned long)iov[seg].iov_base;
                 sdio.size += bytes = iov[seg].iov_len;
@@ -1235,6 +1238,8 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
         if (sdio.bio)
                 dio_bio_submit(dio, &sdio);
 
+        blk_finish_plug(&plug);
+
         /*
          * It is possible that, we return short IO due to end of file.
          * In that case, we need to release all the pages we got hold on.