From 07a29b134ce8e47aef15ea71eab8e6b3734a9720 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Fri, 8 Dec 2023 13:53:20 +0100 Subject: 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: Hannes Reinecke Tested-by: Shin'ichiro Kawasaki Reviewed-by: Sagi Grimberg Signed-off-by: Keith Busch --- drivers/nvme/target/tcp.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c index 4dc60cbcb205..6a1e6bb80062 100644 --- a/drivers/nvme/target/tcp.c +++ b/drivers/nvme/target/tcp.c @@ -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; -- cgit