[SRU][K:master-next][PATCH v3 2/2] pktcdvd: check for NULL returna fter calling bio_split_to_limits()

[Alexander Mikhalitsyn]

From: Jens Axboe <axboe at kernel.dk>

BugLink: https://bugs.launchpad.net/bugs/2020901

The revert of the removal of this driver happened after we fixed up
the split limits for NOWAIT issue, hence it got missed. Ensure that
we check for a NULL bio after splitting, in case it should be retried.

Marking this as fixing both commits, so that stable backport will do
this correctly.

Cc: stable at vger.kernel.org
Fixes: 9cea62b2cbab ("block: don't allow splitting of a REQ_NOWAIT bio")
Fixes: 4b83e99ee709 ("Revert "pktcdvd: remove driver."")
Signed-off-by: Jens Axboe <axboe at kernel.dk>
(backported from 3e9900f3bd7ba30d60f82b162b70a1dffe4e8e24)
[amikhalitsyn: adjust context bio_split_to_limits -> blk_queue_split]
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn at canonical.com>
---
 drivers/block/pktcdvd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 789093375344..1988bb05c0c7 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2400,6 +2400,8 @@ static void pkt_submit_bio(struct bio *bio)
 	struct bio *split;
 
 	blk_queue_split(&bio);
+	if (!bio)
+		return;
 
 	pkt_dbg(2, pd, "start = %6llx stop = %6llx\n",
 		(unsigned long long)bio->bi_iter.bi_sector,
-- 
2.34.1