Commit 56c5de44 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

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: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent f5f93541

drivers/md/dm-bufio.c

+4 −20
Original line number Diff line number Diff line
@@ -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 @@ static void use_bio(struct dm_buffer *b, enum req_op op, sector_t sector, 
	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);

}