From 31deaeb11ba7a885116c9c30892b9f763c04d59c Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Fri, 8 Dec 2023 13:53:21 +0100 Subject: [PATCH] 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: Hannes Reinecke Tested-by: Shin'ichiro Kawasaki Reviewed-by: Sagi Grimberg Signed-off-by: Keith Busch --- drivers/nvme/target/rdma.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c index 4597bca43a6d..667f9c04f35d 100644 --- a/drivers/nvme/target/rdma.c +++ b/drivers/nvme/target/rdma.c @@ -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;