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, INCLUDES_PATCH,MAILING_LIST_MULTI,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 22F7FC43387 for ; Wed, 16 Jan 2019 15:50:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F0B7320657 for ; Wed, 16 Jan 2019 15:50:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404846AbfAPPux (ORCPT ); Wed, 16 Jan 2019 10:50:53 -0500 Received: from mga05.intel.com ([192.55.52.43]:59242 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726834AbfAPPux (ORCPT ); Wed, 16 Jan 2019 10:50:53 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Jan 2019 07:50:53 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,486,1539673200"; d="scan'208";a="126520213" Received: from gregmoor-mobl.amr.corp.intel.com ([10.254.11.196]) by orsmga002.jf.intel.com with ESMTP; 16 Jan 2019 07:50:50 -0800 Message-ID: Subject: Re: [PATCH v12 01/16] tracing: Use str_has_prefix() in synth_event_create() From: Tom Zanussi To: Joe Perches , Tom Zanussi , rostedt@goodmis.org Cc: tglx@linutronix.de, mhiramat@kernel.org, namhyung@kernel.org, vedang.patel@intel.com, bigeasy@linutronix.de, joel@joelfernandes.org, mathieu.desnoyers@efficios.com, julia@ni.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Date: Wed, 16 Jan 2019 09:50:49 -0600 In-Reply-To: <7c07519607d08c0afe448a03fb2010bce13cd77f.camel@perches.com> References: <7c07519607d08c0afe448a03fb2010bce13cd77f.camel@perches.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 (3.28.5-1.fc28) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Joe, On Tue, 2019-01-15 at 20:59 -0800, Joe Perches wrote: > On Tue, 2019-01-15 at 16:05 -0600, Tom Zanussi wrote: > > Since we now have a str_has_prefix() that returns the length, we > > can > > use that instead of explicitly calculating it. > > [] > > diff --git a/kernel/trace/trace_events_hist.c > > b/kernel/trace/trace_events_hist.c > > [] > > @@ -1200,8 +1200,7 @@ static int synth_event_create(int argc, const > > char **argv) > > > > /* This interface accepts group name prefix */ > > if (strchr(name, '/')) { > > - len = sizeof(SYNTH_SYSTEM "/") - 1; > > - if (strncmp(name, SYNTH_SYSTEM "/", len)) > > + if ((len = str_has_prefix(name, SYNTH_SYSTEM "/")) == > > 0) > > Since this is a single test, and not multiple if/else if > blocks, I believe this would read better on two lines > > len = str_has_prefix(name, SYNTH_SYSTEM "/"); > if (len == 0) > > > return -EINVAL; > > name += len; > > } > And I was so happy to have finally found a legitimate reason to put an assignment inside an if statement, sigh. OK, I'll change it. ;-) Thanks, Tom