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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 B7AF4C433DF for ; Tue, 19 May 2020 21:47:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 95C0C205CB for ; Tue, 19 May 2020 21:47:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728565AbgESVry (ORCPT ); Tue, 19 May 2020 17:47:54 -0400 Received: from mga11.intel.com ([192.55.52.93]:42118 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726283AbgESVrv (ORCPT ); Tue, 19 May 2020 17:47:51 -0400 IronPort-SDR: UiMcuVdmfvQq7KNx2qK/V6S9FRDUZlOl22R8N1u96/WmrtbxzalWE92osiK5FH2kkreYbkCD5+ T8gBmUpfKUoQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 May 2020 14:47:49 -0700 IronPort-SDR: oDcEPABCJkhYOpRStiTW/3J9LSPf4JJPp/dhLlrBGxXzbgAHqly5KeS19Si6LhwmQ0saSvFSgw wlOskq7V2jgA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,411,1583222400"; d="scan'208";a="264453871" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by orsmga003.jf.intel.com with ESMTP; 19 May 2020 14:47:46 -0700 Received: from andy by smile with local (Exim 4.93) (envelope-from ) id 1jbA5V-007ipx-7Z; Wed, 20 May 2020 00:47:49 +0300 Date: Wed, 20 May 2020 00:47:49 +0300 From: Andy Shevchenko To: Reinette Chatre Cc: tglx@linutronix.de, fenghua.yu@intel.com, bp@alien8.de, tony.luck@intel.com, kuo-lang.tseng@intel.com, ravi.v.shankar@intel.com, mingo@redhat.com, babu.moger@amd.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V6 4/4] x86/resctrl: Use appropriate API for strings terminated by newline Message-ID: <20200519214749.GM1634618@smile.fi.intel.com> References: <79faf008e6460a2bc8a3cc02313f7900552b1475.1589922949.git.reinette.chatre@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <79faf008e6460a2bc8a3cc02313f7900552b1475.1589922949.git.reinette.chatre@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 19, 2020 at 02:28:31PM -0700, Reinette Chatre wrote: > The user input to files in the resctrl filesystem are expected to be > terminated with a newline. Testing the user input includes a test for > the presence of a newline and then replacing the newline with NUL > byte followed by comparison using strcmp(). > > sysfs_streq() exists to test if strings are equal, treating both NUL and > newline-then-NUL as equivalent string terminations. Even more, > sysfs_match_string() exists to match a given string in an array using > sysfs_streq(). > > Replace existing strcmp() comparisons of strings that are terminated > with a newline with more appropriate sysfs_streq() via the > sysfs_match_string() API that can perform the match across the different > mode strings that are already maintained in an array. FWIW, Reviewed-by: Andy Shevchenko > Suggested-by: Andy Shevchenko > Signed-off-by: Reinette Chatre > --- > Changes since V5: > - Remove the early check of the sysfs_match_string() return code. (Andy) > > arch/x86/kernel/cpu/resctrl/rdtgroup.c | 28 ++++++++++---------------- > 1 file changed, 11 insertions(+), 17 deletions(-) > > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > index 088a1536bccc..07e0f150c56e 100644 > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > @@ -1414,13 +1414,11 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of, > char *buf, size_t nbytes, loff_t off) > { > struct rdtgroup *rdtgrp; > - enum rdtgrp_mode mode; > int ret = 0; > + int user_m; > > - /* Valid input requires a trailing newline */ > - if (nbytes == 0 || buf[nbytes - 1] != '\n') > + if (nbytes == 0) > return -EINVAL; > - buf[nbytes - 1] = '\0'; > > rdtgrp = rdtgroup_kn_lock_live(of->kn); > if (!rdtgrp) { > @@ -1430,29 +1428,25 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of, > > rdt_last_cmd_clear(); > > - mode = rdtgrp->mode; > + user_m = sysfs_match_string(rdt_mode_str, buf); > > - if ((!strcmp(buf, "shareable") && mode == RDT_MODE_SHAREABLE) || > - (!strcmp(buf, "exclusive") && mode == RDT_MODE_EXCLUSIVE) || > - (!strcmp(buf, "pseudo-locksetup") && > - mode == RDT_MODE_PSEUDO_LOCKSETUP) || > - (!strcmp(buf, "pseudo-locked") && mode == RDT_MODE_PSEUDO_LOCKED)) > + /* Do nothing and return success if user asks for current mode */ > + if (user_m == rdtgrp->mode) > goto out; > > - if (mode == RDT_MODE_PSEUDO_LOCKED) { > + if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED) { > rdt_last_cmd_puts("Cannot change pseudo-locked group\n"); > ret = -EINVAL; > goto out; > } > > - if (!strcmp(buf, "shareable")) { > + if (user_m == RDT_MODE_SHAREABLE) { > if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) { > ret = rdtgroup_locksetup_exit(rdtgrp); > if (ret) > goto out; > } > - rdtgrp->mode = RDT_MODE_SHAREABLE; > - } else if (!strcmp(buf, "exclusive")) { > + } else if (user_m == RDT_MODE_EXCLUSIVE) { > if (!rdtgroup_mode_test_exclusive(rdtgrp)) { > ret = -EINVAL; > goto out; > @@ -1462,16 +1456,16 @@ static ssize_t rdtgroup_mode_write(struct kernfs_open_file *of, > if (ret) > goto out; > } > - rdtgrp->mode = RDT_MODE_EXCLUSIVE; > - } else if (!strcmp(buf, "pseudo-locksetup")) { > + } else if (user_m == RDT_MODE_PSEUDO_LOCKSETUP) { > ret = rdtgroup_locksetup_enter(rdtgrp); > if (ret) > goto out; > - rdtgrp->mode = RDT_MODE_PSEUDO_LOCKSETUP; > } else { > rdt_last_cmd_puts("Unknown or unsupported mode\n"); > ret = -EINVAL; > + goto out; > } > + rdtgrp->mode = user_m; > > out: > rdtgroup_kn_unlock(of->kn); > -- > 2.21.0 > -- With Best Regards, Andy Shevchenko