md: fast clone bio in bio_clone_mddev()

Firstly bio_clone_mddev() is used in raid normal I/O and isn't
in resync I/O path.

Secondly all the direct access to bvec table in raid happens on
resync I/O except for write behind of raid1, in which we still
use bio_clone() for allocating new bvec table.

So this patch replaces bio_clone() with bio_clone_fast()
in bio_clone_mddev().

Also kill bio_clone_mddev() and call bio_clone_fast() directly, as
suggested by Christoph Hellwig.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Shaohua Li <shli@fb.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 691d6d9bf740..ad5c9483bd50 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1108,7 +1108,7 @@ read_again:
         r1_bio->read_disk = rdisk;
         r1_bio->start_next_window = 0;
 
-        read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
+        read_bio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
         bio_trim(read_bio, r1_bio->sector - bio->bi_iter.bi_sector,
                  max_sectors);
 
@@ -1376,7 +1376,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
                 }
 
                 if (!mbio) {
-                        mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
+                        mbio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set);
                         bio_trim(mbio, offset, max_sectors);
                 }
 
@@ -2286,7 +2286,8 @@ static int narrow_write_error(struct r1bio *r1_bio, int i)
 
                         wbio->bi_vcnt = vcnt;
                 } else {
-                        wbio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
+                        wbio = bio_clone_fast(r1_bio->master_bio, GFP_NOIO,
+                                              mddev->bio_set);
                 }
 
                 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
@@ -2424,7 +2425,8 @@ read_more:
                 const unsigned long do_sync
                         = r1_bio->master_bio->bi_opf & REQ_SYNC;
                 r1_bio->read_disk = disk;
-                bio = bio_clone_mddev(r1_bio->master_bio, GFP_NOIO, mddev);
+                bio = bio_clone_fast(r1_bio->master_bio, GFP_NOIO,
+                                     mddev->bio_set);
                 bio_trim(bio, r1_bio->sector - bio->bi_iter.bi_sector,
                          max_sectors);
                 r1_bio->bios[r1_bio->read_disk] = bio;