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>

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 1faf4cb..f86c720 100644 (file)
--- 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.

diff --git a/mm/filemap.c b/mm/filemap.c
index 2b09529..3843445 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1412,12 +1412,8 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
                        retval = filemap_write_and_wait_range(mapping, pos,
                                        pos + iov_length(iov, nr_segs) - 1);
                        if (!retval) {
-                               struct blk_plug plug;
-
-                               blk_start_plug(&plug);
                                retval = mapping->a_ops->direct_IO(READ, iocb,
                                                        iov, pos, nr_segs);
-                               blk_finish_plug(&plug);
                        }
                        if (retval > 0) {
                                *ppos = pos + retval;