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[143.89.191.97]) by smtp.gmail.com with ESMTPSA id i15-20020aa7908f000000b006661562429fsm10510857pfa.97.2023.09.26.10.22.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Sep 2023 10:22:35 -0700 (PDT) From: Chengfeng Ye To: hch@lst.de, sagi@grimberg.me, kch@nvidia.com Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Chengfeng Ye Subject: [PATCH] nvmet-rdma: use spin_lock_bh() on rsp_wr_wait_lock Date: Tue, 26 Sep 2023 17:22:08 +0000 Message-Id: <20230926172208.55478-1-dg573847474@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" It seems to me that read_cqe.done could be executed under softirq context, as done callbacks always do, and it acquires rsp_wr_wait_lock along the following call chain. nvmet_rdma_read_data_done() --> nvmet_rdma_release_rsp() --> spin_lock(&queue->rsp_wr_wait_lock) So it seems more reasonable to use spin_lock_bh() on it, otherwise there could be following potential deadlocks. nvmet_rdma_queue_response() --> nvmet_rdma_release_rsp() --> spin_lock(&queue->rsp_wr_wait_lock) --> nvmet_rdma_read_data_done() --> nvmet_rdma_release_rsp() --> spin_lock(&queue->rsp_wr_wait_lock) nvmet_rdma_cm_handler() --> nvmet_rdma_handle_command() --> spin_lock(&queue->rsp_wr_wait_lock) --> nvmet_rdma_read_data_done() --> nvmet_rdma_release_rsp() --> spin_lock(&queue->rsp_wr_wait_lock) Signed-off-by: Chengfeng Ye --- drivers/nvme/target/rdma.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c index 4597bca43a6d..a01ed29fbd8a 100644 --- a/drivers/nvme/target/rdma.c +++ b/drivers/nvme/target/rdma.c @@ -520,7 +520,7 @@ static int nvmet_rdma_post_recv(struct nvmet_rdma_devic= e *ndev, =20 static void nvmet_rdma_process_wr_wait_list(struct nvmet_rdma_queue *queue) { - spin_lock(&queue->rsp_wr_wait_lock); + spin_lock_bh(&queue->rsp_wr_wait_lock); while (!list_empty(&queue->rsp_wr_wait_list)) { struct nvmet_rdma_rsp *rsp; bool ret; @@ -529,16 +529,16 @@ static void nvmet_rdma_process_wr_wait_list(struct nv= met_rdma_queue *queue) struct nvmet_rdma_rsp, wait_list); list_del(&rsp->wait_list); =20 - spin_unlock(&queue->rsp_wr_wait_lock); + spin_unlock_bh(&queue->rsp_wr_wait_lock); ret =3D nvmet_rdma_execute_command(rsp); - spin_lock(&queue->rsp_wr_wait_lock); + spin_lock_bh(&queue->rsp_wr_wait_lock); =20 if (!ret) { list_add(&rsp->wait_list, &queue->rsp_wr_wait_list); break; } } - spin_unlock(&queue->rsp_wr_wait_lock); + spin_unlock_bh(&queue->rsp_wr_wait_lock); } =20 static u16 nvmet_rdma_check_pi_status(struct ib_mr *sig_mr) @@ -994,9 +994,9 @@ static void nvmet_rdma_handle_command(struct nvmet_rdma= _queue *queue, goto out_err; =20 if (unlikely(!nvmet_rdma_execute_command(cmd))) { - spin_lock(&queue->rsp_wr_wait_lock); + spin_lock_bh(&queue->rsp_wr_wait_lock); list_add_tail(&cmd->wait_list, &queue->rsp_wr_wait_list); - spin_unlock(&queue->rsp_wr_wait_lock); + spin_unlock_bh(&queue->rsp_wr_wait_lock); } =20 return; --=20 2.17.1