From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754666Ab1HWAtG (ORCPT ); Mon, 22 Aug 2011 20:49:06 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:38360 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753119Ab1HWAtF (ORCPT ); Mon, 22 Aug 2011 20:49:05 -0400 X-Authority-Analysis: v=1.1 cv=s3eDhkhcaTLnj7IEXy8aaXUiY7FbET0mf+/2Xe0elbc= c=1 sm=0 a=WwlJiVmu3h4A:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=WeO8DyxonXgUeFibRtwA:9 a=xGH53cSU8azWbwAAuZAA:7 a=PUjeQqilurYA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Subject: Re: [PATCH v3] trace: Add per_cpu ring buffer control files From: Steven Rostedt To: Vaibhav Nagarnaik Cc: Michael Rubin , David Sharp , linux-kernel@vger.kernel.org In-Reply-To: <1314050999-10409-1-git-send-email-vnagarnaik@google.com> References: <1313531179-9323-4-git-send-email-vnagarnaik@google.com> <1314050999-10409-1-git-send-email-vnagarnaik@google.com> Content-Type: text/plain; charset="ISO-8859-15" Date: Mon, 22 Aug 2011 20:49:00 -0400 Message-ID: <1314060540.15704.143.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.32.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2011-08-22 at 15:09 -0700, Vaibhav Nagarnaik wrote: > > @@ -3740,10 +3757,6 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, > !cpumask_test_cpu(cpu, buffer_b->cpumask)) > goto out; > > - /* At least make sure the two buffers are somewhat the same */ > - if (buffer_a->pages != buffer_b->pages) > - goto out; > - > ret = -EAGAIN; > > if (ring_buffer_flags != RB_BUFFERS_ON) > @@ -3758,6 +3771,12 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, > cpu_buffer_a = buffer_a->buffers[cpu]; > cpu_buffer_b = buffer_b->buffers[cpu]; I would move the cpu_buffer_(ab) assignments up instead, as I want the EINVAL to have dominance. The record_disable just says that we are temporarily out of commission, when in fact it could be invalid. Thus the invalid conditions need to be treated first. -- Steve > > + ret = -EINVAL; > + /* At least make sure the two buffers are somewhat the same */ > + if (cpu_buffer_a->pages != cpu_buffer_b->pages) > + goto out; > + > + ret = -EAGAIN; > if (atomic_read(&cpu_buffer_a->record_disabled)) > goto out; >