[ Upstream commit 7da413a1 ]

alloc_workqueue is not checked for errors and as a result,
a potential NULL dereference could occur.
Signed-off-by: Allen Pais <allen.pais@oracle.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>