[SRU][K:master-next][PATCH v2 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

commit 3e9900f3bd7ba30d60f82b162b70a1dffe4e8e24 upstream.

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>
[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