From patchwork Sat May 15 05:24:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= X-Patchwork-Id: 12259459 X-Patchwork-Delegate: bhelgaas@google.com 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 A540CC433B4 for ; Sat, 15 May 2021 05:24:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D528613EB for ; Sat, 15 May 2021 05:24:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233013AbhEOF0C (ORCPT ); Sat, 15 May 2021 01:26:02 -0400 Received: from mail-ej1-f49.google.com ([209.85.218.49]:33514 "EHLO mail-ej1-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233005AbhEOF0B (ORCPT ); Sat, 15 May 2021 01:26:01 -0400 Received: by mail-ej1-f49.google.com with SMTP id z12so158784ejw.0 for ; Fri, 14 May 2021 22:24:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=B3UpkKoHQG0tf/oaVD2LnuLhgOWE3b/n2dCLRadGIF4=; b=ahth2oomvySxlOPGd0F0TyfCqfxt0RteEPKUxzAkRn41OL/6XkMAbBNdNP2rYLYfJE ZM4+Ga7k6K1VPU90w3frcK9QcxLyseLhtidLreZUOSZ6qjQ7u2/Ztr56ieP8T3MWqhVq fPZr0Eu/5aR+lqYnSm75WhbE7ZwLiu6u7mzEPTsqHjUtqK2gxFLeUrkcZ51pNQ4tNaHU vk1QWcGoiX1kkfEDBCoO31vdgMpAR8LRa13rg+CppkZPzzS2iiiTNcR3wDVg6YSvxb6X I/KBCrt+hCRnCRzQ8RLC+ecpR7xnel+W2G7EieS4aM9ABw/rd9kEwLFWrUIlODmy05Jr E1GQ== X-Gm-Message-State: AOAM531I7Dx4BhnIMeVcb3jhXxUy1hBC79E1Vs5Bm+z8Xz9ab7NMWwgA kTBLil5d6Nh2hTPSaRLp5Ic= X-Google-Smtp-Source: ABdhPJyGXrwiw6AUEQkiZNiiFMo18eHtQ1pD3BH99lSq0gDTyHGjespN0d9GO5o1Cd76Qnuv/DwQMA== X-Received: by 2002:a17:907:2646:: with SMTP id ar6mr19927960ejc.293.1621056288007; Fri, 14 May 2021 22:24:48 -0700 (PDT) Received: from workstation.lan ([95.155.85.46]) by smtp.gmail.com with ESMTPSA id kt21sm4821487ejb.5.2021.05.14.22.24.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 May 2021 22:24:47 -0700 (PDT) From: =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= To: Bjorn Helgaas Cc: Logan Gunthorpe , Joe Perches , "Oliver O'Halloran" , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Tyrel Datwyler , Russell Currey , Kurt Schwemmer , Vidya Sagar , Xiongfeng Wang , linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v2 12/14] PCI: Fix trailing newline handling of resource_alignment_param Date: Sat, 15 May 2021 05:24:32 +0000 Message-Id: <20210515052434.1413236-12-kw@linux.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210515052434.1413236-1-kw@linux.com> References: <20210515052434.1413236-1-kw@linux.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org The value of the "resource_alignment" can be specified using a kernel command-line argument (using the "pci=resource_alignment=") or through the corresponding sysfs object under the /sys/bus/pci path. Currently, when the value is set via the kernel command-line argument, and then subsequently accessed through sysfs object, the value read back will not be correct, as per: # grep -oE 'pci=resource_alignment.+' /proc/cmdline pci=resource_alignment=20@00:1f.2 # cat /sys/bus/pci/resource_alignment 20@00:1f. This is also true when the value is set through the sysfs object, but the trailing newline has not been included, as per: # echo -n 20@00:1f.2 > /sys/bus/pci/resource_alignment # cat /sys/bus/pci/resource_alignment 20@00:1f. When the value set through the sysfs object includes the trailing newline, then reading it back will work as intended, as per: # echo 20@00:1f.2 > /sys/bus/pci/resource_alignment # cat /sys/bus/pci/resource_alignment 20@00:1f.2 To fix this inconsistency, append a trailing newline in the show() function and strip the trailing line in the store() function if one is present. Also, allow for the value previously set using either a command-line argument or through the sysfs object to be cleared at run-time. Fixes: e499081da1a2 ("PCI: Force trailing new line to resource_alignment_param in sysfs") Signed-off-by: Krzysztof Wilczyński --- drivers/pci/pci.c | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 5ed316ea5831..7cde86bdcc8e 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6439,34 +6439,37 @@ static ssize_t resource_alignment_show(struct bus_type *bus, char *buf) spin_lock(&resource_alignment_lock); if (resource_alignment_param) - count = sysfs_emit(buf, "%s", resource_alignment_param); + count = sysfs_emit(buf, "%s\n", resource_alignment_param); spin_unlock(&resource_alignment_lock); - /* - * When set by the command line, resource_alignment_param will not - * have a trailing line feed, which is ugly. So conditionally add - * it here. - */ - if (count >= 2 && buf[count - 2] != '\n' && count < PAGE_SIZE - 1) { - buf[count - 1] = '\n'; - buf[count++] = 0; - } - return count; } static ssize_t resource_alignment_store(struct bus_type *bus, const char *buf, size_t count) { - char *param = kstrndup(buf, count, GFP_KERNEL); + char *param, *old, *end; + param = kstrndup(buf, count, GFP_KERNEL); if (!param) return -ENOMEM; + end = strchr(param, '\n'); + if (end) + *end = '\0'; + spin_lock(&resource_alignment_lock); - kfree(resource_alignment_param); - resource_alignment_param = param; + old = resource_alignment_param; + if (strlen(param)) { + resource_alignment_param = param; + } else { + kfree(resource_alignment_param); + resource_alignment_param = NULL; + } spin_unlock(&resource_alignment_lock); + + kfree(old); + return count; }