From patchwork Fri Jun 16 17:23:59 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 776877 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3wq6fw2Nk1z9s8N for ; Sat, 17 Jun 2017 03:24:08 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751546AbdFPRYG (ORCPT ); Fri, 16 Jun 2017 13:24:06 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:56426 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750827AbdFPRYF (ORCPT ); Fri, 16 Jun 2017 13:24:05 -0400 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1dLuxr-0006Rl-Tg; Fri, 16 Jun 2017 19:23:20 +0200 From: Sebastian Andrzej Siewior To: Eric Dumazet Cc: netdev@vger.kernel.org, "David S. Miller" , Thomas Gleixner , Sebastian Andrzej Siewior Subject: [PATCH 1/2] net/core: use local_bh_disable() in netif_rx_ni() Date: Fri, 16 Jun 2017 19:23:59 +0200 Message-Id: <20170616172400.10809-1-bigeasy@linutronix.de> X-Mailer: git-send-email 2.11.0 MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In 2004 [0] netif_rx_ni() gained a preempt_disable() section around netif_rx() and its do_softirq() + testing for it. The do_softirq() part is required because netif_rx() raises the softirq but does not invoke it. The preempt_disable() is required to avoid running the BH in parallel. All this can be avoided be putting this into a local_bh_disable()ed section. The local_bh_enable() part will invoke do_softirq() if required. [0] Make netif_rx_ni preempt-safe http://oss.sgi.com/projects/netdev/archive/2004-10/msg02211.html Signed-off-by: Sebastian Andrzej Siewior --- net/core/dev.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index b8d6dd9e8b5c..b1f8a89322bd 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3928,11 +3928,9 @@ int netif_rx_ni(struct sk_buff *skb) trace_netif_rx_ni_entry(skb); - preempt_disable(); + local_bh_disable(); err = netif_rx_internal(skb); - if (local_softirq_pending()) - do_softirq(); - preempt_enable(); + local_bh_enable(); return err; }