blkdev: generalize flags for blkdev_issue_fn functions

The patch just convert all blkdev_issue_xxx function to common
set of flags. Wait/allocation semantics preserved.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 0d0c323..ef3d980 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -100,9 +100,11 @@
 		if (ext4_should_writeback_data(inode) &&
 		    (journal->j_fs_dev != journal->j_dev) &&
 		    (journal->j_flags & JBD2_BARRIER))
-			blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
+			blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL,
+					NULL, BLKDEV_IFL_WAIT);
 		jbd2_log_wait_commit(journal, commit_tid);
 	} else if (journal->j_flags & JBD2_BARRIER)
-		blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
+		blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL,
+			BLKDEV_IFL_WAIT);
 	return ret;
 }