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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 B00A9C433E2 for ; Tue, 14 Jul 2020 13:27:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8AD0D22203 for ; Tue, 14 Jul 2020 13:27:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594733272; bh=k7p+YmhYNfSbib77plqQ7Xlc47tKB9s8ynT/cIsFVLM=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=IvjcqZnT+39XFAHbT8B5o8zN6iBqQxxSBcAXGA4orexXR1yhlpguONFzQhLBzjgAI +tB7U4PbTr0noeoiRc/1+tJCMxlrsXf5gn81sAPys4CIRkBfXAMNjvasT4cb3B5lwa AmmDwQMuZIe0H+PI0v8Fw/H/GRlietLt9IpecQwU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725997AbgGNN1w (ORCPT ); Tue, 14 Jul 2020 09:27:52 -0400 Received: from mail-oi1-f194.google.com ([209.85.167.194]:42115 "EHLO mail-oi1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726766AbgGNN1v (ORCPT ); Tue, 14 Jul 2020 09:27:51 -0400 Received: by mail-oi1-f194.google.com with SMTP id t4so13892886oij.9; Tue, 14 Jul 2020 06:27:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Co+8zho8E5dTiD8cmg9/ZPavIQVoRg7kJl84C1fgX4o=; b=Ak9rNiX58SVp3TwDXHkgLVMlvgVRokwbqMW6fzzw5RNsaFtIHKYJCHapp+PhKvXx5q c+tyQf6H3zW3IU7YIGzxoSspg1ZMNrvhPr8VvlcJrmPyfV/w3w1KXHD9ebDk/sTIij/X /foWTxlOrHmpPODKPrjxMTzRsXYttF2kvT80OV4cyjzyn2H9a/OHC6bKrmyjffJ8bXRU XMBYJpa1FubjV3wB5RsI2MRHh15bpznOoeLuPB5BwrNXHYnRkBMjx6ZiRuKGawmANhiQ oXYGnGr72PODH5NtfHBVvy7xExgD1+Q8e3CVWkJOIq1JK36G6X2GfxT1KRJFeutH8Zw4 J5pg== X-Gm-Message-State: AOAM533sZufFYQ/PG1NgUlIttecXG7r6ttGXBXgWEsA4WC2G/XzxBjeM 7qXENwWJSmZJCvlgDAQk3e6z2ZKMulTqvubMOa0= X-Google-Smtp-Source: ABdhPJzZCW5CAcdX22oZWNLapJZK91sy3IBs2TtUsKH0mXhc58jY+otLhQKYqyJqpqYGmfziPk7jXv4Of2khk72Y9k0= X-Received: by 2002:aca:4a89:: with SMTP id x131mr3775944oia.103.1594733270598; Tue, 14 Jul 2020 06:27:50 -0700 (PDT) MIME-Version: 1.0 References: <20200713175529.29715-1-refactormyself@gmail.com> <20200713175529.29715-4-refactormyself@gmail.com> In-Reply-To: <20200713175529.29715-4-refactormyself@gmail.com> From: "Rafael J. Wysocki" Date: Tue, 14 Jul 2020 15:27:38 +0200 Message-ID: Subject: Re: [PATCH 8/14 v3] PCI/ACPI: Check the return value of pcie_capability_read_*() To: "Saheed O. Bolarinwa" Cc: Shuah Khan , ACPI Devel Maling List , Linux PCI , linux-kernel-mentees@lists.linuxfoundation.org, Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Jul 13, 2020 at 6:55 PM Saheed O. Bolarinwa wrote: > > From: Bolarinwa Olayemi Saheed > > On failure pcie_capability_read_dword() sets it's last parameter, > val to 0. > However, with Patch 14/14, it is possible that val is set to ~0 on > failure. This would introduce a bug because (x & x) == (~0 & x). > > This bug can be avoided if the return value of pcie_capability_read_word > is checked to confirm success. > > Check the return value of pcie_capability_read_word() to ensure success. > > Suggested-by: Bjorn Helgaas > Signed-off-by: Bolarinwa Olayemi Saheed Acked-by: Rafael J. Wysocki > --- > drivers/pci/pci-acpi.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c > index 7224b1e5f2a8..39eb816bc3b8 100644 > --- a/drivers/pci/pci-acpi.c > +++ b/drivers/pci/pci-acpi.c > @@ -248,12 +248,13 @@ static bool pcie_root_rcb_set(struct pci_dev *dev) > { > struct pci_dev *rp = pcie_find_root_port(dev); > u16 lnkctl; > + int ret; > > if (!rp) > return false; > > - pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl); > - if (lnkctl & PCI_EXP_LNKCTL_RCB) > + ret = pcie_capability_read_word(rp, PCI_EXP_LNKCTL, &lnkctl); > + if (!ret && (lnkctl & PCI_EXP_LNKCTL_RCB)) > return true; > > return false; > @@ -792,12 +793,13 @@ bool pciehp_is_native(struct pci_dev *bridge) > { > const struct pci_host_bridge *host; > u32 slot_cap; > + int ret; > > if (!IS_ENABLED(CONFIG_HOTPLUG_PCI_PCIE)) > return false; > > - pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap); > - if (!(slot_cap & PCI_EXP_SLTCAP_HPC)) > + ret = pcie_capability_read_dword(bridge, PCI_EXP_SLTCAP, &slot_cap); > + if (ret || !(slot_cap & PCI_EXP_SLTCAP_HPC)) > return false; > > if (pcie_ports_native) > -- > 2.18.2 >