From patchwork Thu Feb 20 20:45:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 1241648 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linutronix.de Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48Nn2j3Jfzz9sRf for ; Fri, 21 Feb 2020 07:57:01 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729249AbgBTU4m (ORCPT ); Thu, 20 Feb 2020 15:56:42 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:44147 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729128AbgBTU4h (ORCPT ); Thu, 20 Feb 2020 15:56:37 -0500 Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1j4srb-0007T7-5m; Thu, 20 Feb 2020 21:56:03 +0100 Received: from nanos.tec.linutronix.de (localhost [IPv6:::1]) by nanos.tec.linutronix.de (Postfix) with ESMTP id 97E9410408C; Thu, 20 Feb 2020 21:56:02 +0100 (CET) Message-Id: <20200220204617.637603528@linutronix.de> User-Agent: quilt/0.65 Date: Thu, 20 Feb 2020 21:45:20 +0100 From: Thomas Gleixner To: LKML Cc: David Miller , bpf@vger.kernel.org, netdev@vger.kernel.org, Alexei Starovoitov , Daniel Borkmann , Sebastian Sewior , Peter Zijlstra , Clark Williams , Steven Rostedt , Juri Lelli , Ingo Molnar , Mathieu Desnoyers , Vinicius Costa Gomes , Jakub Kicinski Subject: [patch V2 03/20] bpf/tracing: Remove redundant preempt_disable() in __bpf_trace_run() References: <20200220204517.863202864@linutronix.de> MIME-Version: 1.0 X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1, SHORTCIRCUIT=-0.0001 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org __bpf_trace_run() disables preemption around the BPF_PROG_RUN() invocation. This is redundant because __bpf_trace_run() is invoked from a trace point via __DO_TRACE() which already disables preemption _before_ invoking any of the functions which are attached to a trace point. Remove it. Signed-off-by: Thomas Gleixner --- kernel/trace/bpf_trace.c | 2 -- 1 file changed, 2 deletions(-) --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1476,9 +1476,7 @@ static __always_inline void __bpf_trace_run(struct bpf_prog *prog, u64 *args) { rcu_read_lock(); - preempt_disable(); (void) BPF_PROG_RUN(prog, args); - preempt_enable(); rcu_read_unlock(); }