From patchwork Mon Mar 29 14:40:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 12170255 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81967C433DB for ; Mon, 29 Mar 2021 14:41:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5294561864 for ; Mon, 29 Mar 2021 14:41:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231151AbhC2Okq (ORCPT ); Mon, 29 Mar 2021 10:40:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:40504 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231150AbhC2OkY (ORCPT ); Mon, 29 Mar 2021 10:40:24 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6403E61933; Mon, 29 Mar 2021 14:40:24 +0000 (UTC) Subject: [PATCH v1 6/6] svcrdma: Clean up dto_q critical section in svc_rdma_recvfrom() From: Chuck Lever To: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Date: Mon, 29 Mar 2021 10:40:23 -0400 Message-ID: <161702882362.5937.2325805207945484450.stgit@klimt.1015granger.net> In-Reply-To: <161702808762.5937.3596341039481819410.stgit@klimt.1015granger.net> References: <161702808762.5937.3596341039481819410.stgit@klimt.1015granger.net> User-Agent: StGit/1.0-5-g755c MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org This, to me, seems less cluttered and less redundant. I was hoping it could help reduce lock contention on the dto_q lock by reducing the size of the critical section, but alas, the only improvement is readability. Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c index 357e3ae01991..1cf0b04b632a 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -794,22 +794,20 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp) rqstp->rq_xprt_ctxt = NULL; + ctxt = NULL; spin_lock(&rdma_xprt->sc_rq_dto_lock); ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_rq_dto_q); - if (!ctxt) { + if (ctxt) + list_del(&ctxt->rc_list); + else /* No new incoming requests, terminate the loop */ clear_bit(XPT_DATA, &xprt->xpt_flags); - spin_unlock(&rdma_xprt->sc_rq_dto_lock); - svc_xprt_received(xprt); - return 0; - } - list_del(&ctxt->rc_list); spin_unlock(&rdma_xprt->sc_rq_dto_lock); - percpu_counter_inc(&svcrdma_stat_recv); - - /* Start receiving the next incoming message */ svc_xprt_received(xprt); + if (!ctxt) + return 0; + percpu_counter_inc(&svcrdma_stat_recv); ib_dma_sync_single_for_cpu(rdma_xprt->sc_pd->device, ctxt->rc_recv_sge.addr, ctxt->rc_byte_len, DMA_FROM_DEVICE);