From mboxrd@z Thu Jan 1 00:00:00 1970 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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 589AAC43381 for ; Mon, 18 Mar 2019 09:38:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 285C52075C for ; Mon, 18 Mar 2019 09:38:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552901924; bh=oYoYZV8mqzlxaxx93XOfSMg83lepof+eqoLletY2qOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=K/PrNkjxfpnrkCCPHGgGQGsb8G/HXOOpWoezoJcqQ44UnEX02lfZJj0d9oIJRG1nM to0DTlc45hKgRALXWJkzTY7gXO+h2f4nifELxY5eaKzUh9ShfGfFWdq1Evbp3A+8N6 Ecp/jOjLr93KptRHwf+F+xdO5nYFmR+v/ECT8hUo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387778AbfCRJhH (ORCPT ); Mon, 18 Mar 2019 05:37:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:45328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387757AbfCRJhA (ORCPT ); Mon, 18 Mar 2019 05:37:00 -0400 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 880B62075C; Mon, 18 Mar 2019 09:36:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552901820; bh=oYoYZV8mqzlxaxx93XOfSMg83lepof+eqoLletY2qOM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PcxdW74coIPwwfsawUxCwC7O8Q+K0vYtUoEmKxPKtOBCnVwP52f/fcLHkReK8u63W eFdXIPKhJe6mtDhGsy+0p+vOAFQbBob7sGRMI1xRmkO3TilwTvdACY6yazyvtFl0L2 D7A6wm0O+/z9EjK8NfkFu6T2SlZDmiYN4trQK2TM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Howells , Marc Dionne , "David S. Miller" Subject: [PATCH 4.9 23/31] rxrpc: Fix client call queueing, waiting for channel Date: Mon, 18 Mar 2019 10:25:58 +0100 Message-Id: <20190318084211.344832305@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190318084210.397476003@linuxfoundation.org> References: <20190318084210.397476003@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Howells [ Upstream commit 69ffaebb90369ce08657b5aea4896777b9d6e8fc ] rxrpc_get_client_conn() adds a new call to the front of the waiting_calls queue if the connection it's going to use already exists. This is bad as it allows calls to get starved out. Fix this by adding to the tail instead. Also change the other enqueue point in the same function to put it on the front (ie. when we have a new connection). This makes the point that in the case of a new connection the new call goes at the front (though it doesn't actually matter since the queue should be unoccupied). Fixes: 45025bceef17 ("rxrpc: Improve management and caching of client connection objects") Signed-off-by: David Howells Reviewed-by: Marc Dionne Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/rxrpc/conn_client.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/rxrpc/conn_client.c +++ b/net/rxrpc/conn_client.c @@ -355,7 +355,7 @@ static int rxrpc_get_client_conn(struct * normally have to take channel_lock but we do this before anyone else * can see the connection. */ - list_add_tail(&call->chan_wait_link, &candidate->waiting_calls); + list_add(&call->chan_wait_link, &candidate->waiting_calls); if (cp->exclusive) { call->conn = candidate; @@ -430,7 +430,7 @@ found_extant_conn: spin_lock(&conn->channel_lock); call->conn = conn; call->security_ix = conn->security_ix; - list_add(&call->chan_wait_link, &conn->waiting_calls); + list_add_tail(&call->chan_wait_link, &conn->waiting_calls); spin_unlock(&conn->channel_lock); _leave(" = 0 [extant %d]", conn->debug_id); return 0;