Commit 8295cda7 authored by Alex Elder's avatar Alex Elder
Browse files

rbd: encapsulate handling for a single request 



In rbd_rq_fn(), requests are fetched from the block layer and each
request is processed, looping through the request's list of bio's
until they've all been consumed.

Separate the handling for a single request into its own function to
make it a bit easier to see what's going on.

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent 8986cb37

drivers/block/rbd.c

+63 −56
Original line number Diff line number Diff line
@@ -1583,6 +1583,64 @@ static struct rbd_req_coll *rbd_alloc_coll(int num_reqs) 
	return coll;

}



static int rbd_dev_do_request(struct request *rq,

				struct rbd_device *rbd_dev,

				struct ceph_snap_context *snapc,

				u64 ofs, unsigned int size,

				struct bio *bio_chain)

{

	int num_segs;

	struct rbd_req_coll *coll;

	unsigned int bio_offset;

	int cur_seg = 0;



	dout("%s 0x%x bytes at 0x%llx\n",

		rq_data_dir(rq) == WRITE ? "write" : "read",

		size, (unsigned long long) blk_rq_pos(rq) * SECTOR_SIZE);



	num_segs = rbd_get_num_segments(&rbd_dev->header, ofs, size);

	if (num_segs <= 0)

		return num_segs;



	coll = rbd_alloc_coll(num_segs);

	if (!coll)

		return -ENOMEM;



	bio_offset = 0;

	do {

		u64 limit = rbd_segment_length(rbd_dev, ofs, size);

		unsigned int clone_size;

		struct bio *bio_clone;



		BUG_ON(limit > (u64)UINT_MAX);

		clone_size = (unsigned int)limit;

		dout("bio_chain->bi_vcnt=%hu\n", bio_chain->bi_vcnt);



		kref_get(&coll->kref);



		/* Pass a cloned bio chain via an osd request */



		bio_clone = bio_chain_clone_range(&bio_chain,

					&bio_offset, clone_size,

					GFP_ATOMIC);

		if (bio_clone)

			(void)rbd_do_op(rq, rbd_dev, snapc,

					ofs, clone_size,

					bio_clone, coll, cur_seg);

		else

			rbd_coll_end_req_index(rq, coll, cur_seg,

						(s32)-ENOMEM,

						clone_size);

		size -= clone_size;

		ofs += clone_size;



		cur_seg++;

	} while (size > 0);

	kref_put(&coll->kref, rbd_coll_release);



	return 0;

}



/*

 * block device queue callback

 */
@@ -1596,10 +1654,8 @@ static void rbd_rq_fn(struct request_queue *q) 
		bool do_write;

		unsigned int size;

		u64 ofs;

		int num_segs, cur_seg = 0;

		struct rbd_req_coll *coll;

		struct ceph_snap_context *snapc;

		unsigned int bio_offset;

		int result;



		dout("fetched request\n");
@@ -1637,60 +1693,11 @@ static void rbd_rq_fn(struct request_queue *q) 
		ofs = blk_rq_pos(rq) * SECTOR_SIZE;

		bio = rq->bio;



		dout("%s 0x%x bytes at 0x%llx\n",

		     do_write ? "write" : "read",

		     size, (unsigned long long) blk_rq_pos(rq) * SECTOR_SIZE);



		num_segs = rbd_get_num_segments(&rbd_dev->header, ofs, size);

		if (num_segs <= 0) {

			spin_lock_irq(q->queue_lock);

			__blk_end_request_all(rq, num_segs);

		result = rbd_dev_do_request(rq, rbd_dev, snapc, ofs, size, bio);

		ceph_put_snap_context(snapc);

			continue;

		}

		coll = rbd_alloc_coll(num_segs);

		if (!coll) {

			spin_lock_irq(q->queue_lock);

			__blk_end_request_all(rq, -ENOMEM);

			ceph_put_snap_context(snapc);

			continue;

		}



		bio_offset = 0;

		do {

			u64 limit = rbd_segment_length(rbd_dev, ofs, size);

			unsigned int chain_size;

			struct bio *bio_chain;



			BUG_ON(limit > (u64) UINT_MAX);

			chain_size = (unsigned int) limit;

			dout("rq->bio->bi_vcnt=%hu\n", rq->bio->bi_vcnt);



			kref_get(&coll->kref);



			/* Pass a cloned bio chain via an osd request */



			bio_chain = bio_chain_clone_range(&bio,

						&bio_offset, chain_size,

						GFP_ATOMIC);

			if (bio_chain)

				(void) rbd_do_op(rq, rbd_dev, snapc,

						ofs, chain_size,

						bio_chain, coll, cur_seg);

			else

				rbd_coll_end_req_index(rq, coll, cur_seg,

						       (s32)-ENOMEM,

						       chain_size);

			size -= chain_size;

			ofs += chain_size;



			cur_seg++;

		} while (size > 0);

		kref_put(&coll->kref, rbd_coll_release);



		spin_lock_irq(q->queue_lock);



		ceph_put_snap_context(snapc);

		if (!size || result < 0)

			__blk_end_request_all(rq, result);

	}

}