[dm-devel] [PATCH v2 4/4] dm: unconditionally call blk_queue_split() in dm_process_bio()

[Mike Snitzer]

blk_queue_split() has become compulsory from .submit_bio -- regardless
of whether it is recursing.  Update DM core to always call
blk_queue_split().

dm_queue_split() is removed because __split_and_process_bio() handles
splitting as needed.

Signed-off-by: Mike Snitzer <snitzer at redhat.com>
---
 drivers/md/dm.c | 45 +--------------------------------------------
 1 file changed, 1 insertion(+), 44 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index fb0255d25e4b..0bae9f26dc8e 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1530,22 +1530,6 @@ static int __send_write_zeroes(struct clone_info *ci, struct dm_target *ti)
 	return __send_changing_extent_only(ci, ti, get_num_write_zeroes_bios(ti));
 }
 
-static bool is_abnormal_io(struct bio *bio)
-{
-	bool r = false;
-
-	switch (bio_op(bio)) {
-	case REQ_OP_DISCARD:
-	case REQ_OP_SECURE_ERASE:
-	case REQ_OP_WRITE_SAME:
-	case REQ_OP_WRITE_ZEROES:
-		r = true;
-		break;
-	}
-
-	return r;
-}
-
 static bool __process_abnormal_io(struct clone_info *ci, struct dm_target *ti,
 				  int *result)
 {
@@ -1723,23 +1707,6 @@ static blk_qc_t __process_bio(struct mapped_device *md, struct dm_table *map,
 	return ret;
 }
 
-static void dm_queue_split(struct mapped_device *md, struct dm_target *ti, struct bio **bio)
-{
-	unsigned len, sector_count;
-
-	sector_count = bio_sectors(*bio);
-	len = min_t(sector_t, max_io_len((*bio)->bi_iter.bi_sector, ti), sector_count);
-
-	if (sector_count > len) {
-		struct bio *split = bio_split(*bio, len, GFP_NOIO, &md->queue->bio_split);
-
-		bio_chain(split, *bio);
-		trace_block_split(md->queue, split, (*bio)->bi_iter.bi_sector);
-		submit_bio_noacct(*bio);
-		*bio = split;
-	}
-}
-
 static blk_qc_t dm_process_bio(struct mapped_device *md,
 			       struct dm_table *map, struct bio *bio)
 {
@@ -1759,17 +1726,7 @@ static blk_qc_t dm_process_bio(struct mapped_device *md,
 		}
 	}
 
-	/*
-	 * If in ->queue_bio we need to use blk_queue_split(), otherwise
-	 * queue_limits for abnormal requests (e.g. discard, writesame, etc)
-	 * won't be imposed.
-	 */
-	if (current->bio_list) {
-		if (is_abnormal_io(bio))
-			blk_queue_split(&bio);
-		else
-			dm_queue_split(md, ti, &bio);
-	}
+	blk_queue_split(&bio);
 
 	if (dm_get_md_type(md) == DM_TYPE_NVME_BIO_BASED)
 		return __process_bio(md, map, bio, ti);
-- 
2.15.0