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[68.61.232.219]) by smtp.gmail.com with ESMTPSA id k6sm20286278ioh.28.2019.09.13.13.01.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 13 Sep 2019 13:01:08 -0700 (PDT) Received: from manet.1015granger.net (manet.1015granger.net [192.168.1.51]) by gateway.1015granger.net (8.14.7/8.14.7) with ESMTP id x8DK17QV017642; Fri, 13 Sep 2019 20:01:07 GMT Subject: [PATCH] SUNRPC: Fix congestion window race with disconnect From: Chuck Lever To: anna.schumaker@netapp.com, trondmy@hammerspace.com Cc: linux-nfs@vger.kernel.org Date: Fri, 13 Sep 2019 16:01:07 -0400 Message-ID: <20190913195959.2400.92744.stgit@manet.1015granger.net> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org If the congestion window closes just as the transport disconnects, a reconnect is never driven because: 1. The XPRT_CONG_WAIT flag prevents tasks from taking the write lock 2. There's no wake-up of the first task on the xprt->sending queue To address this, clear the congestion wait flag as part of completing a disconnect. Fixes: 75891f502f5f ("SUNRPC: Support for congestion control ... ") Signed-off-by: Chuck Lever --- net/sunrpc/xprt.c | 7 +++++++ 1 file changed, 7 insertions(+) Hi Anna, Trond - Please consider including this fix in next week's merge window. Thanks! diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 2e71f54..0f94a3c 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -456,6 +456,12 @@ void xprt_release_rqst_cong(struct rpc_task *task) } EXPORT_SYMBOL_GPL(xprt_release_rqst_cong); +static void xprt_clear_congestion_window_wait_locked(struct rpc_xprt *xprt) +{ + if (test_and_clear_bit(XPRT_CWND_WAIT, &xprt->state)) + __xprt_lock_write_next_cong(xprt); +} + /* * Clear the congestion window wait flag and wake up the next * entry on xprt->sending @@ -671,6 +677,7 @@ void xprt_disconnect_done(struct rpc_xprt *xprt) spin_lock(&xprt->transport_lock); xprt_clear_connected(xprt); xprt_clear_write_space_locked(xprt); + xprt_clear_congestion_window_wait_locked(xprt); xprt_wake_pending_tasks(xprt, -ENOTCONN); spin_unlock(&xprt->transport_lock); }