block: change the blk_queue_split calling convention

The double indirect bio leads to somewhat suboptimal code generation.
Instead return the (original or split) bio, and make sure the
request_queue arguments to the lower level helpers is passed after the
bio to avoid constant reshuffling of the argument passing registers.

Also give it and the helpers used to implement it more descriptive names.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220727162300.3089193-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

7 files changed, 9 insertions, 9 deletions

diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 6d8dd14458c6..8f7f144e54f3 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1608,7 +1608,7 @@ void drbd_submit_bio(struct bio *bio)
 {
 	struct drbd_device *device = bio->bi_bdev->bd_disk->private_data;
 
-	blk_queue_split(&bio);
+	bio = bio_split_to_limits(bio);
 
 	/*
 	 * what we "blindly" assume:
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 01a15dbd9cde..4cea3b08087e 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2399,7 +2399,7 @@ static void pkt_submit_bio(struct bio *bio)
 	struct pktcdvd_device *pd = bio->bi_bdev->bd_disk->queue->queuedata;
 	struct bio *split;
 
-	blk_queue_split(&bio);
+	bio = bio_split_to_limits(bio);
 
 	pkt_dbg(2, pd, "start = %6llx stop = %6llx\n",
 		(unsigned long long)bio->bi_iter.bi_sector,
diff --git a/drivers/block/ps3vram.c b/drivers/block/ps3vram.c
index d1e0fefec90b..e1d080f680ed 100644
--- a/drivers/block/ps3vram.c
+++ b/drivers/block/ps3vram.c
@@ -586,7 +586,7 @@ static void ps3vram_submit_bio(struct bio *bio)
 
 	dev_dbg(&dev->core, "%s\n", __func__);
 
-	blk_queue_split(&bio);
+	bio = bio_split_to_limits(bio);
 
 	spin_lock_irq(&priv->lock);
 	busy = !bio_list_empty(&priv->list);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 99642f69bfa7..fbcffcfb2304 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1181,7 +1181,7 @@ static sector_t max_io_len(struct dm_target *ti, sector_t sector)
 	 * Does the target need to split IO even further?
 	 * - varied (per target) IO splitting is a tenet of DM; this
 	 *   explains why stacked chunk_sectors based splitting via
-	 *   blk_queue_split() isn't possible here.
+	 *   bio_split_to_limits() isn't possible here.
 	 */
 	if (!ti->max_io_len)
 		return len;
@@ -1751,10 +1751,10 @@ static void dm_split_and_process_bio(struct mapped_device *md,
 	is_abnormal = is_abnormal_io(bio);
 	if (unlikely(is_abnormal)) {
 		/*
-		 * Use blk_queue_split() for abnormal IO (e.g. discard, etc)
+		 * Use bio_split_to_limits() for abnormal IO (e.g. discard, etc)
 		 * otherwise associated queue_limits won't be imposed.
 		 */
-		blk_queue_split(&bio);
+		bio = bio_split_to_limits(bio);
 	}
 
 	init_clone_info(&ci, md, map, bio, is_abnormal);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 35b895813c88..afaf36b2f6ab 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -442,7 +442,7 @@ static void md_submit_bio(struct bio *bio)
 		return;
 	}
 
-	blk_queue_split(&bio);
+	bio = bio_split_to_limits(bio);
 
 	if (mddev->ro == 1 && unlikely(rw == WRITE)) {
 		if (bio_sectors(bio) != 0)
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 64f44d98daaf..6ef497c75a16 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -346,7 +346,7 @@ static void nvme_ns_head_submit_bio(struct bio *bio)
 	 * different queue via blk_steal_bios(), so we need to use the bio_split
 	 * pool from the original queue to allocate the bvecs from.
 	 */
-	blk_queue_split(&bio);
+	bio = bio_split_to_limits(bio);
 
 	srcu_idx = srcu_read_lock(&head->srcu);
 	ns = nvme_find_path(head);
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 4d8d1759775a..5187705bd0f3 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -863,7 +863,7 @@ dcssblk_submit_bio(struct bio *bio)
 	unsigned long source_addr;
 	unsigned long bytes_done;
 
-	blk_queue_split(&bio);
+	bio = bio_split_to_limits(bio);
 
 	bytes_done = 0;
 	dev_info = bio->bi_bdev->bd_disk->private_data;