Return-Path: Received: from mail-io0-f193.google.com ([209.85.223.193]:33273 "EHLO mail-io0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751514AbdAaSio (ORCPT ); Tue, 31 Jan 2017 13:38:44 -0500 Subject: [PATCH v2 4/7] sunrpc: Allow xprt->ops->timer method to sleep From: Chuck Lever To: anna.schumaker@netapp.com Cc: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Tue, 31 Jan 2017 13:38:41 -0500 Message-ID: <20170131183841.5325.33330.stgit@manet.1015granger.net> In-Reply-To: <20170131183345.5325.47072.stgit@manet.1015granger.net> References: <20170131183345.5325.47072.stgit@manet.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: The transport lock is needed to protect the xprt_adjust_cwnd() call in xs_udp_timer, but it is not necessary for accessing the rq_reply_bytes_recvd or tk_status fields. It is correct to sublimate the lock into UDP's xs_udp_timer method, where it is required. The ->timer method has to take the transport lock if needed, but it can now sleep safely, or even call back into the RPC scheduler. This is more a clean-up than a fix, but the "issue" was introduced by my transport switch patches back in 2005. Fixes: 46c0ee8bc4ad ("RPC: separate xprt_timer implementations") Signed-off-by: Chuck Lever --- net/sunrpc/xprt.c | 2 -- net/sunrpc/xprtsock.c | 2 ++ 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 9a6be03..b530a28 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -897,13 +897,11 @@ static void xprt_timer(struct rpc_task *task) return; dprintk("RPC: %5u xprt_timer\n", task->tk_pid); - spin_lock_bh(&xprt->transport_lock); if (!req->rq_reply_bytes_recvd) { if (xprt->ops->timer) xprt->ops->timer(xprt, task); } else task->tk_status = 0; - spin_unlock_bh(&xprt->transport_lock); } /** diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index af392d9..d9bb644 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1734,7 +1734,9 @@ static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t */ static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task) { + spin_lock_bh(&xprt->transport_lock); xprt_adjust_cwnd(xprt, task, -ETIMEDOUT); + spin_unlock_bh(&xprt->transport_lock); } static unsigned short xs_get_random_port(void)