nvmet-tcp: fix lockdep complaint on nvmet_tcp_wq flush during queue teardown

We probably need nvmet_tcp_wq to have MEM_RECLAIM as we are
sending/receiving for the socket from works on this workqueue.
Also this eliminates lockdep complaints:
--
[ 6174.010200] workqueue: WQ_MEM_RECLAIM
nvmet-wq:nvmet_tcp_release_queue_work [nvmet_tcp] is flushing
!WQ_MEM_RECLAIM nvmet_tcp_wq:nvmet_tcp_io_work [nvmet_tcp]
[ 6174.010216] WARNING: CPU: 20 PID: 14456 at kernel/workqueue.c:2628
check_flush_dependency+0x110/0x14c

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index 0a95425..dc3b4dc 100644 (file)
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -1839,7 +1839,8 @@ static int __init nvmet_tcp_init(void)
 {
        int ret;
 
-       nvmet_tcp_wq = alloc_workqueue("nvmet_tcp_wq", WQ_HIGHPRI, 0);
+       nvmet_tcp_wq = alloc_workqueue("nvmet_tcp_wq",
+                               WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
        if (!nvmet_tcp_wq)
                return -ENOMEM;