[PATCH 4/4] dm: fix dm_wq_work() to only use __split_and_process_bio() if appropriate

Mike Snitzer
2019-01-19T18:05:18Z

Otherwise targets that don't support/expect IO splitting could resubmit
bios using code paths with unnecessary IO splitting complexity.

Depends-on: 24113d487843 ("dm: avoid indirect call in __dm_make_request")
Fixes: 978e51ba38e00 ("dm: optimize bio-based NVMe IO submission")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
drivers/md/dm.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 6e29c2d99b99..aa7e429646b3 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1727,6 +1727,15 @@ static blk_qc_t __process_bio(struct mapped_device *md,
return ret;
}

+static blk_qc_t dm_process_bio(struct mapped_device *md,
+ struct dm_table *map, struct bio *bio)
+{
+ if (dm_get_md_type(md) == DM_TYPE_NVME_BIO_BASED)
+ return __process_bio(md, map, bio);
+ else
+ return __split_and_process_bio(md, map, bio);
+}
+
static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio)
{
struct mapped_device *md = q->queuedata;
@@ -1747,10 +1756,7 @@ static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio)
return ret;
}

- if (dm_get_md_type(md) == DM_TYPE_NVME_BIO_BASED)
- ret = __process_bio(md, map, bio);
- else
- ret = __split_and_process_bio(md, map, bio);
+ ret = dm_process_bio(md, map, bio);

dm_put_live_table(md, srcu_idx);
return ret;
@@ -2429,9 +2435,9 @@ static void dm_wq_work(struct work_struct *work)
break;

if (dm_request_based(md))
- generic_make_request(c);
+ (void) generic_make_request(c);
else
- __split_and_process_bio(md, map, c);
+ (void) dm_process_bio(md, map, c);
}

dm_put_live_table(md, srcu_idx);
--
2.15.0