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=-9.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 DDFC9C433E1 for ; Tue, 18 Aug 2020 20:00:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3A242076E for ; Tue, 18 Aug 2020 20:00:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=baylibre-com.20150623.gappssmtp.com header.i=@baylibre-com.20150623.gappssmtp.com header.b="mY9/qM2M" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726749AbgHRUAD (ORCPT ); Tue, 18 Aug 2020 16:00:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726673AbgHRUAC (ORCPT ); Tue, 18 Aug 2020 16:00:02 -0400 Received: from mail-qk1-x741.google.com (mail-qk1-x741.google.com [IPv6:2607:f8b0:4864:20::741]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01B6AC061389 for ; Tue, 18 Aug 2020 13:00:02 -0700 (PDT) Received: by mail-qk1-x741.google.com with SMTP id j187so19460302qke.11 for ; Tue, 18 Aug 2020 13:00:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=/ZDCPDwW9euB1yf1r32n/nOxApA5CLlHLcrrfHIoPe0=; b=mY9/qM2MC8h80QmH/L2o3ebU+oUQNUCW63wm7YBmbeK4YBE5Xe3Rjqtwof4g90Gl5j Nashil2BSJxW/GC+DcTms+MTs3zm8+LkClOf/U2jUP/YJlxAmvLXG+Y1SxzjQuQdOmRe FaeRrNHm7nBp0Ire6IgS6r1s0gdLxjr1afa0E+smJ3xN4nEInrIvlWBT7CW0TEmor1mO FIgviwqTSYceSMveg047w1orQVPvufjnGz94qi/TKhCr8AbTj6GPs3BxF/aFHmnO4n+M XlWMZtYVdzdVxOkWy4H/ual/TZMNFFmE2xwQGOV4ybgkF4mcBltQ5wgUueSnWH61nlUt zm4w== 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=/ZDCPDwW9euB1yf1r32n/nOxApA5CLlHLcrrfHIoPe0=; b=PwNh+kK+tshG/aumBZPJELtspHN6VVteBgRxnRaP7xpILukT0qQwSjrIwMkInlGW1e L0CY0WQyLiqXA4bR4sJUVDbmMB476vcTNIKJ/XzyyoW8jejyAds307AflvUPbxZcMuTR dHfLMKnH/5z/ODTEx5FrPt7PgiIwW6Z2OsAmuNboLAPp9YU3Mfpk4LSJkIq64zwSo51f sXKbCL6id+XD5yETiQ/a9L6HMGAfnQxTZx6OBPa/d54JXqu3O/qhLncSutCCCTDBx5NJ ZDk04TrqpIRWmz/wUOcRFCoWP25a/dg9jKaC9LCTdMcBjlQpkbcvRu0pEbGN57VPBDTh uXhg== X-Gm-Message-State: AOAM533oYMOAgLaf0ZUB2kkRxjXLdEHcNQYhAX2O4NIzVMcxsMnargob KV1Mt/Odj9FohiABvZVIY/XHtVKY+oUYD3fGq1mP3g== X-Google-Smtp-Source: ABdhPJzURAYX1VluYbg81khU/4BFMEQ5XggeNrYg7amfOd007KJmuQPkzQNHuZnA3kRR7pjm2ZwfV6zrZkG75TYorqc= X-Received: by 2002:a37:a495:: with SMTP id n143mr19146148qke.330.1597780801253; Tue, 18 Aug 2020 13:00:01 -0700 (PDT) MIME-Version: 1.0 References: <20200801112446.149549-1-refactormyself@gmail.com> <20200801112446.149549-9-refactormyself@gmail.com> In-Reply-To: <20200801112446.149549-9-refactormyself@gmail.com> From: Bartosz Golaszewski Date: Tue, 18 Aug 2020 21:59:50 +0200 Message-ID: Subject: Re: [RFC PATCH 08/17] gpio: Drop uses of pci_read_config_*() return value To: Bjorn Helgaas Cc: Linus Walleij , "Saheed O. Bolarinwa" , bjorn@helgaas.com, Shuah Khan , linux-kernel-mentees@lists.linuxfoundation.org, linux-pci@vger.kernel.org, LKML , linux-gpio Content-Type: text/plain; charset="UTF-8" Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Sat, Aug 1, 2020 at 2:24 PM Saheed O. Bolarinwa wrote: > > The return value of pci_read_config_*() may not indicate a device error. > However, the value read by these functions is more likely to indicate > this kind of error. This presents two overlapping ways of reporting > errors and complicates error checking. > > It is possible to move to one single way of checking for error if the > dependency on the return value of these functions is removed, then it > can later be made to return void. > > Remove all uses of the return value of pci_read_config_*(). > Check the actual value read for ~0. In this case, ~0 is an invalid > value thus it indicates some kind of error. > > Suggested-by: Bjorn Helgaas > Signed-off-by: Saheed O. Bolarinwa > --- > drivers/gpio/gpio-amd8111.c | 7 +++++-- > drivers/gpio/gpio-rdc321x.c | 21 ++++++++++++--------- > 2 files changed, 17 insertions(+), 11 deletions(-) > > diff --git a/drivers/gpio/gpio-amd8111.c b/drivers/gpio/gpio-amd8111.c > index fdcebe59510d..7b9882380cbc 100644 > --- a/drivers/gpio/gpio-amd8111.c > +++ b/drivers/gpio/gpio-amd8111.c > @@ -198,9 +198,12 @@ static int __init amd_gpio_init(void) > goto out; > > found: > - err = pci_read_config_dword(pdev, 0x58, &gp.pmbase); > - if (err) > + pci_read_config_dword(pdev, 0x58, &gp.pmbase); > + if (gp.pmbase == (u32)~0) { > + err = -ENODEV; > goto out; > + } > + > err = -EIO; > gp.pmbase &= 0x0000FF00; > if (gp.pmbase == 0) > diff --git a/drivers/gpio/gpio-rdc321x.c b/drivers/gpio/gpio-rdc321x.c > index 01ed2517e9fd..03f1ff07b844 100644 > --- a/drivers/gpio/gpio-rdc321x.c > +++ b/drivers/gpio/gpio-rdc321x.c > @@ -85,10 +85,13 @@ static int rdc_gpio_config(struct gpio_chip *chip, > gpch = gpiochip_get_data(chip); > > spin_lock(&gpch->lock); > - err = pci_read_config_dword(gpch->sb_pdev, gpio < 32 ? > - gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, ®); > - if (err) > + pci_read_config_dword(gpch->sb_pdev, > + (gpio < 32) ? gpch->reg1_ctrl_base > + : gpch->reg2_ctrl_base, ®); > + if (reg == (u32)~0) { > + err = -ENODEV; > goto unlock; > + } > > reg |= 1 << (gpio & 0x1f); > > @@ -166,17 +169,17 @@ static int rdc321x_gpio_probe(struct platform_device *pdev) > /* This might not be, what others (BIOS, bootloader, etc.) > wrote to these registers before, but it's a good guess. Still > better than just using 0xffffffff. */ > - err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev, > + pci_read_config_dword(rdc321x_gpio_dev->sb_pdev, > rdc321x_gpio_dev->reg1_data_base, > &rdc321x_gpio_dev->data_reg[0]); > - if (err) > - return err; > + if (rdc321x_gpio_dev->data_reg[0] == (u32)~0) > + return -ENODEV; > > - err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev, > + pci_read_config_dword(rdc321x_gpio_dev->sb_pdev, > rdc321x_gpio_dev->reg2_data_base, > &rdc321x_gpio_dev->data_reg[1]); > - if (err) > - return err; > + if (rdc321x_gpio_dev->data_reg[1] == (u32)~0) > + return -ENODEV; > > dev_info(&pdev->dev, "registering %d GPIOs\n", > rdc321x_gpio_dev->chip.ngpio); > -- > 2.18.4 > Bjorn, I don't know the pci sub-system at all. Does this look good to you? Bartosz 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=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 A64DCC433E1 for ; Tue, 18 Aug 2020 20:08:23 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1C1C520786 for ; Tue, 18 Aug 2020 20:08:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=baylibre-com.20150623.gappssmtp.com header.i=@baylibre-com.20150623.gappssmtp.com header.b="mY9/qM2M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1C1C520786 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=baylibre.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-kernel-mentees-bounces@lists.linuxfoundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id CBA5E86AA1; Tue, 18 Aug 2020 20:08:22 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id prYXrHTJBFlf; Tue, 18 Aug 2020 20:08:21 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id BA88786A26; Tue, 18 Aug 2020 20:08:21 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id A4E0DC07FF; Tue, 18 Aug 2020 20:08:21 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 122FCC0051 for ; Tue, 18 Aug 2020 20:08:20 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 0101C2002B for ; Tue, 18 Aug 2020 20:08:19 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id maB-YeIKYoco for ; Tue, 18 Aug 2020 20:08:17 +0000 (UTC) X-Greylist: delayed 00:08:15 by SQLgrey-1.7.6 Received: from mail-qk1-f196.google.com (mail-qk1-f196.google.com [209.85.222.196]) by silver.osuosl.org (Postfix) with ESMTPS id 5FEB21FF98 for ; Tue, 18 Aug 2020 20:08:17 +0000 (UTC) Received: by mail-qk1-f196.google.com with SMTP id b79so19487264qkg.9 for ; Tue, 18 Aug 2020 13:08:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=/ZDCPDwW9euB1yf1r32n/nOxApA5CLlHLcrrfHIoPe0=; b=mY9/qM2MC8h80QmH/L2o3ebU+oUQNUCW63wm7YBmbeK4YBE5Xe3Rjqtwof4g90Gl5j Nashil2BSJxW/GC+DcTms+MTs3zm8+LkClOf/U2jUP/YJlxAmvLXG+Y1SxzjQuQdOmRe FaeRrNHm7nBp0Ire6IgS6r1s0gdLxjr1afa0E+smJ3xN4nEInrIvlWBT7CW0TEmor1mO FIgviwqTSYceSMveg047w1orQVPvufjnGz94qi/TKhCr8AbTj6GPs3BxF/aFHmnO4n+M XlWMZtYVdzdVxOkWy4H/ual/TZMNFFmE2xwQGOV4ybgkF4mcBltQ5wgUueSnWH61nlUt zm4w== 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=/ZDCPDwW9euB1yf1r32n/nOxApA5CLlHLcrrfHIoPe0=; b=clAVC+zdWGi6ojXG0snZvinZTYzMWoNYwG5WbcbjB9L3HQ/OrrdzYP3E7Ob7SnUtjS dMe9jXzpl2KpK/ubkrZoDqrWdJwTCGZYWUrJeY61FVzPa++o2PwYg+9p+Rfalcg28j2l lDVlf8HqeSyIoo8Es6OwiH0+XunxjkkUhzBYQamm67VNYLus7eDGQ/8Kx63uapBmcwy0 p9R+CXz2AP7oAwe72nZv2htPAUtUAwJ1T8jmMPPaIJm0IzxyepPkXppAxi2Sr+75bVnq 3Jym2aGDcyqVzQdg/hM5DTb5MR8ODkGZPXUIbtE18uKGaLBQz0vi2FmS8ZqvEbUXikBC 2C6Q== X-Gm-Message-State: AOAM533HGvDSMksxOOcG9xAW9EScJgx0XFTHYLNu1fZNieaSzEdF+EA0 DCLj6rJxVOPBDlKdPj2mgnBNhxxqmvDMrLzMxw8lfo/gHCM= X-Google-Smtp-Source: ABdhPJzURAYX1VluYbg81khU/4BFMEQ5XggeNrYg7amfOd007KJmuQPkzQNHuZnA3kRR7pjm2ZwfV6zrZkG75TYorqc= X-Received: by 2002:a37:a495:: with SMTP id n143mr19146148qke.330.1597780801253; Tue, 18 Aug 2020 13:00:01 -0700 (PDT) MIME-Version: 1.0 References: <20200801112446.149549-1-refactormyself@gmail.com> <20200801112446.149549-9-refactormyself@gmail.com> In-Reply-To: <20200801112446.149549-9-refactormyself@gmail.com> From: Bartosz Golaszewski Date: Tue, 18 Aug 2020 21:59:50 +0200 Message-ID: To: Bjorn Helgaas Cc: "Saheed O. Bolarinwa" , Linus Walleij , LKML , linux-gpio , linux-pci@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [Linux-kernel-mentees] [RFC PATCH 08/17] gpio: Drop uses of pci_read_config_*() return value X-BeenThere: linux-kernel-mentees@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-kernel-mentees-bounces@lists.linuxfoundation.org Sender: "Linux-kernel-mentees" On Sat, Aug 1, 2020 at 2:24 PM Saheed O. Bolarinwa wrote: > > The return value of pci_read_config_*() may not indicate a device error. > However, the value read by these functions is more likely to indicate > this kind of error. This presents two overlapping ways of reporting > errors and complicates error checking. > > It is possible to move to one single way of checking for error if the > dependency on the return value of these functions is removed, then it > can later be made to return void. > > Remove all uses of the return value of pci_read_config_*(). > Check the actual value read for ~0. In this case, ~0 is an invalid > value thus it indicates some kind of error. > > Suggested-by: Bjorn Helgaas > Signed-off-by: Saheed O. Bolarinwa > --- > drivers/gpio/gpio-amd8111.c | 7 +++++-- > drivers/gpio/gpio-rdc321x.c | 21 ++++++++++++--------- > 2 files changed, 17 insertions(+), 11 deletions(-) > > diff --git a/drivers/gpio/gpio-amd8111.c b/drivers/gpio/gpio-amd8111.c > index fdcebe59510d..7b9882380cbc 100644 > --- a/drivers/gpio/gpio-amd8111.c > +++ b/drivers/gpio/gpio-amd8111.c > @@ -198,9 +198,12 @@ static int __init amd_gpio_init(void) > goto out; > > found: > - err = pci_read_config_dword(pdev, 0x58, &gp.pmbase); > - if (err) > + pci_read_config_dword(pdev, 0x58, &gp.pmbase); > + if (gp.pmbase == (u32)~0) { > + err = -ENODEV; > goto out; > + } > + > err = -EIO; > gp.pmbase &= 0x0000FF00; > if (gp.pmbase == 0) > diff --git a/drivers/gpio/gpio-rdc321x.c b/drivers/gpio/gpio-rdc321x.c > index 01ed2517e9fd..03f1ff07b844 100644 > --- a/drivers/gpio/gpio-rdc321x.c > +++ b/drivers/gpio/gpio-rdc321x.c > @@ -85,10 +85,13 @@ static int rdc_gpio_config(struct gpio_chip *chip, > gpch = gpiochip_get_data(chip); > > spin_lock(&gpch->lock); > - err = pci_read_config_dword(gpch->sb_pdev, gpio < 32 ? > - gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, ®); > - if (err) > + pci_read_config_dword(gpch->sb_pdev, > + (gpio < 32) ? gpch->reg1_ctrl_base > + : gpch->reg2_ctrl_base, ®); > + if (reg == (u32)~0) { > + err = -ENODEV; > goto unlock; > + } > > reg |= 1 << (gpio & 0x1f); > > @@ -166,17 +169,17 @@ static int rdc321x_gpio_probe(struct platform_device *pdev) > /* This might not be, what others (BIOS, bootloader, etc.) > wrote to these registers before, but it's a good guess. Still > better than just using 0xffffffff. */ > - err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev, > + pci_read_config_dword(rdc321x_gpio_dev->sb_pdev, > rdc321x_gpio_dev->reg1_data_base, > &rdc321x_gpio_dev->data_reg[0]); > - if (err) > - return err; > + if (rdc321x_gpio_dev->data_reg[0] == (u32)~0) > + return -ENODEV; > > - err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev, > + pci_read_config_dword(rdc321x_gpio_dev->sb_pdev, > rdc321x_gpio_dev->reg2_data_base, > &rdc321x_gpio_dev->data_reg[1]); > - if (err) > - return err; > + if (rdc321x_gpio_dev->data_reg[1] == (u32)~0) > + return -ENODEV; > > dev_info(&pdev->dev, "registering %d GPIOs\n", > rdc321x_gpio_dev->chip.ngpio); > -- > 2.18.4 > Bjorn, I don't know the pci sub-system at all. Does this look good to you? Bartosz _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees