Commit 54d9a1b4 authored by Alasdair G Kergon's avatar Alasdair G Kergon
Browse files

dm: simplify dm_request loop 



Refactor the code in dm_request().

Require the new DMF_BLOCK_FOR_SUSPEND flag on readahead bios we will
discard so we don't drop such bios while processing a barrier.

Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 1eb787ec

drivers/md/dm.c

+7 −11
Original line number Diff line number Diff line
@@ -929,7 +929,6 @@ static int dm_merge_bvec(struct request_queue *q, 
 */

static int dm_request(struct request_queue *q, struct bio *bio)

{

	int r = -EIO;

	int rw = bio_data_dir(bio);

	struct mapped_device *md = q->queuedata;

	int cpu;
@@ -957,11 +956,14 @@ static int dm_request(struct request_queue *q, struct bio *bio) 
	while (test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) {

		up_read(&md->io_lock);



		if (bio_rw(bio) != READA)

			r = queue_io(md, bio);

		if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) &&

		    bio_rw(bio) == READA) {

			bio_io_error(bio);

			return 0;

		}



		if (r <= 0)

			goto out_req;

		if (!queue_io(md, bio))

			return 0;



		/*

		 * We're in a while loop, because someone could suspend
@@ -973,12 +975,6 @@ static int dm_request(struct request_queue *q, struct bio *bio) 
	__split_and_process_bio(md, bio);

	up_read(&md->io_lock);

	return 0;



out_req:

	if (r < 0)

		bio_io_error(bio);



	return 0;

}



static void dm_unplug_all(struct request_queue *q)