Commit 07a29b13 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Keith Busch
Browse files

nvmet-tcp: avoid circular locking dependency on install_queue() 



nvmet_tcp_install_queue() is driven from the ->io_work workqueue
function, but will call flush_workqueue() which might trigger
->release_work() which in itself calls flush_work on ->io_work.

To avoid that check for pending queue in disconnecting status,
and return 'controller busy' when we reached a certain threshold.

Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Tested-by: default avatarShin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarKeith Busch <kbusch@kernel.org>
parent 06c59d42

drivers/nvme/target/tcp.c

+15 −3
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 


#define NVMET_TCP_DEF_INLINE_DATA_SIZE	(4 * PAGE_SIZE)

#define NVMET_TCP_MAXH2CDATA		0x400000 /* 16M arbitrary limit */

#define NVMET_TCP_BACKLOG 128



static int param_store_val(const char *str, int *val, int min, int max)

{
@@ -2067,7 +2068,7 @@ static int nvmet_tcp_add_port(struct nvmet_port *nport) 
		goto err_sock;

	}



	ret = kernel_listen(port->sock, 128);

	ret = kernel_listen(port->sock, NVMET_TCP_BACKLOG);

	if (ret) {

		pr_err("failed to listen %d on port sock\n", ret);

		goto err_sock;
@@ -2133,8 +2134,19 @@ static u16 nvmet_tcp_install_queue(struct nvmet_sq *sq) 
		container_of(sq, struct nvmet_tcp_queue, nvme_sq);



	if (sq->qid == 0) {

		/* Let inflight controller teardown complete */

		flush_workqueue(nvmet_wq);

		struct nvmet_tcp_queue *q;

		int pending = 0;



		/* Check for pending controller teardown */

		mutex_lock(&nvmet_tcp_queue_mutex);

		list_for_each_entry(q, &nvmet_tcp_queue_list, queue_list) {

			if (q->nvme_sq.ctrl == sq->ctrl &&

			    q->state == NVMET_TCP_Q_DISCONNECTING)

				pending++;

		}

		mutex_unlock(&nvmet_tcp_queue_mutex);

		if (pending > NVMET_TCP_BACKLOG)

			return NVME_SC_CONNECT_CTRL_BUSY;

	}



	queue->nr_cmds = sq->size * 2;