dm bufio: use multi-page bio vector

The kernel supports multi page bio vector entries, so we can use them
in dm-bufio as an optimization.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index cca43ed..ae55264 100644 (file)
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -1312,19 +1312,14 @@ static void use_bio(struct dm_buffer *b, enum req_op op, sector_t sector,
 {
        struct bio *bio;
        char *ptr;
-       unsigned int vec_size, len;
+       unsigned int len;
 
-       vec_size = b->c->block_size >> PAGE_SHIFT;
-       if (unlikely(b->c->sectors_per_block_bits < PAGE_SHIFT - SECTOR_SHIFT))
-               vec_size += 2;
-
-       bio = bio_kmalloc(vec_size, GFP_NOWAIT | __GFP_NORETRY | __GFP_NOWARN);
+       bio = bio_kmalloc(1, GFP_NOWAIT | __GFP_NORETRY | __GFP_NOWARN);
        if (!bio) {
-dmio:
                use_dmio(b, op, sector, n_sectors, offset);
                return;
        }
-       bio_init(bio, b->c->bdev, bio->bi_inline_vecs, vec_size, op);
+       bio_init(bio, b->c->bdev, bio->bi_inline_vecs, 1, op);
        bio->bi_iter.bi_sector = sector;
        bio->bi_end_io = bio_complete;
        bio->bi_private = b;
@@ -1332,18 +1327,7 @@ dmio:
        ptr = (char *)b->data + offset;
        len = n_sectors << SECTOR_SHIFT;
 
-       do {
-               unsigned int this_step = min((unsigned int)(PAGE_SIZE - offset_in_page(ptr)), len);
-
-               if (!bio_add_page(bio, virt_to_page(ptr), this_step,
-                                 offset_in_page(ptr))) {
-                       bio_put(bio);
-                       goto dmio;
-               }
-
-               len -= this_step;
-               ptr += this_step;
-       } while (len > 0);
+       __bio_add_page(bio, virt_to_page(ptr), len, offset_in_page(ptr));
 
        submit_bio(bio);
 }