Commit 31deaeb1 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Keith Busch
Browse files

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



nvmet_rdma_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 07a29b13

drivers/nvme/target/rdma.c

+16 −3
Original line number Diff line number Diff line
@@ -37,6 +37,8 @@ 
#define NVMET_RDMA_MAX_MDTS			8

#define NVMET_RDMA_MAX_METADATA_MDTS		5



#define NVMET_RDMA_BACKLOG 128



struct nvmet_rdma_srq;



struct nvmet_rdma_cmd {
@@ -1583,8 +1585,19 @@ static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id, 
	}



	if (queue->host_qid == 0) {

		/* Let inflight controller teardown complete */

		flush_workqueue(nvmet_wq);

		struct nvmet_rdma_queue *q;

		int pending = 0;



		/* Check for pending controller teardown */

		mutex_lock(&nvmet_rdma_queue_mutex);

		list_for_each_entry(q, &nvmet_rdma_queue_list, queue_list) {

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

			    q->state == NVMET_RDMA_Q_DISCONNECTING)

				pending++;

		}

		mutex_unlock(&nvmet_rdma_queue_mutex);

		if (pending > NVMET_RDMA_BACKLOG)

			return NVME_SC_CONNECT_CTRL_BUSY;

	}



	ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn);
@@ -1880,7 +1893,7 @@ static int nvmet_rdma_enable_port(struct nvmet_rdma_port *port) 
		goto out_destroy_id;

	}



	ret = rdma_listen(cm_id, 128);

	ret = rdma_listen(cm_id, NVMET_RDMA_BACKLOG);

	if (ret) {

		pr_err("listening to %pISpcs failed (%d)\n", addr, ret);

		goto out_destroy_id;