Commit 0e28997e authored by Kent Overstreet's avatar Kent Overstreet Committed by Jens Axboe
Browse files

btrfs: remove bio splitting and merge_bvec_fn() calls 



Btrfs has been doing bio splitting from btrfs_map_bio(), by checking
device limits as well as calling ->merge_bvec_fn() etc. That is not
necessary any more, because generic_make_request() is now able to
handle arbitrarily sized bios. So clean up unnecessary code paths.

Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: linux-btrfs@vger.kernel.org
Signed-off-by: default avatarKent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
[dpark: add more description in commit message]
Signed-off-by: default avatarDongsu Park <dpark@posteo.net>
Signed-off-by: default avatarMing Lin <ming.l@ssi.samsung.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 749b61da

fs/btrfs/volumes.c

+0 −72
Original line number Diff line number Diff line
@@ -5870,34 +5870,6 @@ static noinline void btrfs_schedule_bio(struct btrfs_root *root, 
				 &device->work);

}



static int bio_size_ok(struct block_device *bdev, struct bio *bio,

		       sector_t sector)

{

	struct bio_vec *prev;

	struct request_queue *q = bdev_get_queue(bdev);

	unsigned int max_sectors = queue_max_sectors(q);

	struct bvec_merge_data bvm = {

		.bi_bdev = bdev,

		.bi_sector = sector,

		.bi_rw = bio->bi_rw,

	};



	if (WARN_ON(bio->bi_vcnt == 0))

		return 1;



	prev = &bio->bi_io_vec[bio->bi_vcnt - 1];

	if (bio_sectors(bio) > max_sectors)

		return 0;



	if (!q->merge_bvec_fn)

		return 1;



	bvm.bi_size = bio->bi_iter.bi_size - prev->bv_len;

	if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len)

		return 0;

	return 1;

}



static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,

			      struct bio *bio, u64 physical, int dev_nr,

			      int rw, int async)
@@ -5931,38 +5903,6 @@ static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio, 
		btrfsic_submit_bio(rw, bio);

}



static int breakup_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,

			      struct bio *first_bio, struct btrfs_device *dev,

			      int dev_nr, int rw, int async)

{

	struct bio_vec *bvec = first_bio->bi_io_vec;

	struct bio *bio;

	int nr_vecs = bio_get_nr_vecs(dev->bdev);

	u64 physical = bbio->stripes[dev_nr].physical;



again:

	bio = btrfs_bio_alloc(dev->bdev, physical >> 9, nr_vecs, GFP_NOFS);

	if (!bio)

		return -ENOMEM;



	while (bvec <= (first_bio->bi_io_vec + first_bio->bi_vcnt - 1)) {

		if (bio_add_page(bio, bvec->bv_page, bvec->bv_len,

				 bvec->bv_offset) < bvec->bv_len) {

			u64 len = bio->bi_iter.bi_size;



			atomic_inc(&bbio->stripes_pending);

			submit_stripe_bio(root, bbio, bio, physical, dev_nr,

					  rw, async);

			physical += len;

			goto again;

		}

		bvec++;

	}



	submit_stripe_bio(root, bbio, bio, physical, dev_nr, rw, async);

	return 0;

}



static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)

{

	atomic_inc(&bbio->error);
@@ -6035,18 +5975,6 @@ int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio, 
			continue;

		}



		/*

		 * Check and see if we're ok with this bio based on it's size

		 * and offset with the given device.

		 */

		if (!bio_size_ok(dev->bdev, first_bio,

				 bbio->stripes[dev_nr].physical >> 9)) {

			ret = breakup_stripe_bio(root, bbio, first_bio, dev,

						 dev_nr, rw, async_submit);

			BUG_ON(ret);

			continue;

		}



		if (dev_nr < total_devs - 1) {

			bio = btrfs_bio_clone(first_bio, GFP_NOFS);

			BUG_ON(!bio); /* -ENOMEM */

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