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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 99686C169C4 for ; Sun, 3 Feb 2019 14:04:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E7AA20823 for ; Sun, 3 Feb 2019 14:04:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729834AbfBCOEF (ORCPT ); Sun, 3 Feb 2019 09:04:05 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52932 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727958AbfBCNtp (ORCPT ); Sun, 3 Feb 2019 08:49:45 -0500 Received: from cable-78.29.236.164.coditel.net ([78.29.236.164] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gqI9X-0003tv-3Y; Sun, 03 Feb 2019 13:49:43 +0000 Received: from ben by deadeye with local (Exim 4.92-RC4) (envelope-from ) id 1gqI9U-0006pV-HP; Sun, 03 Feb 2019 14:49:40 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Julian Wiedmann" , "David S. Miller" Date: Sun, 03 Feb 2019 14:45:08 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 031/305] s390/qeth: invoke softirqs after napi_schedule() In-Reply-To: X-SA-Exim-Connect-IP: 78.29.236.164 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.63-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Julian Wiedmann commit 4d19db777a2f32c9b76f6fd517ed8960576cb43e upstream. Calling napi_schedule() from process context does not ensure that the NET_RX softirq is run in a timely fashion. So trigger it manually. This is no big issue with current code. A call to ndo_open() is usually followed by a ndo_set_rx_mode() call, and for qeth this contains a spin_unlock_bh(). Except for OSN, where qeth_l2_set_rx_mode() bails out early. Nevertheless it's best to not depend on this behaviour, and just fix the issue at its source like all other drivers do. For instance see commit 83a0c6e58901 ("i40e: Invoke softirqs after napi_reschedule"). Fixes: a1c3ed4c9ca0 ("qeth: NAPI support for l2 and l3 discipline") Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- drivers/s390/net/qeth_l2_main.c | 3 +++ drivers/s390/net/qeth_l3_main.c | 3 +++ 2 files changed, 6 insertions(+) --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -856,7 +856,10 @@ static int __qeth_l2_open(struct net_dev if (qdio_stop_irq(card->data.ccwdev, 0) >= 0) { napi_enable(&card->napi); + local_bh_disable(); napi_schedule(&card->napi); + /* kick-start the NAPI softirq: */ + local_bh_enable(); } else rc = -EIO; return rc; --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -3127,7 +3127,10 @@ static int __qeth_l3_open(struct net_dev if (qdio_stop_irq(card->data.ccwdev, 0) >= 0) { napi_enable(&card->napi); + local_bh_disable(); napi_schedule(&card->napi); + /* kick-start the NAPI softirq: */ + local_bh_enable(); } else rc = -EIO; return rc;