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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E4FC9C433F5 for ; Thu, 21 Oct 2021 15:23:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA0BF60C49 for ; Thu, 21 Oct 2021 15:23:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231912AbhJUPZX (ORCPT ); Thu, 21 Oct 2021 11:25:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231795AbhJUPZW (ORCPT ); Thu, 21 Oct 2021 11:25:22 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33F3DC061764; Thu, 21 Oct 2021 08:23:06 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id a15-20020a17090a688f00b001a132a1679bso3423769pjd.0; Thu, 21 Oct 2021 08:23:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=u8MgP9EyHiwfzS+PfrhohOi5W9AFD7yrctxjYPpGCNs=; b=WVm5YA3svbpKDgEwEWf79YIA2d+HMr3vgMUHlvL/Q51sZB1k2BjB9D7OsHHe/c6ZKR 3jo0jGxj8JujkkKMJhKYdcEd/cKgCG0WMlt9XvJeSW+eGf4jQaIAEAeYa55sICeLOZaV htM63ArD0dzfszA64bl2Zs+CReRT/73uwp0oWQt18dn/jQqZQcB8udEnM7Cj6mWPDiuE +4kAM3z3gaanSnhrYgy4hAfp6xgol2yZl7O0uBcvhdh1I+5SN3IPuyoCebu8a/jyf57v prYMYOkeURk7aJQt/MlEV0Wq7OhpA/mwL0HPnkGLFh6zkUpJ9CRl1VMFMi7W9FYDW+jz SLzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=u8MgP9EyHiwfzS+PfrhohOi5W9AFD7yrctxjYPpGCNs=; b=Nni676keI8Kib+udjH0zD31AIRYHuq6+JObt/qbLAn+RCBE+s3ZsBVJMswX4hAH12S 4ezBYlmRucBb155CyLAmsQMzRyL3N+m68IgLqSDFBL5D9f6RhEFai+uxR0DDikdlfSRo MrDMjyrSr8QqqklZsPDjzcfChPZk0foVl9huNrmAIm4EfRBBVzzEYY4PdMnjo0Mp2ffL 4cRq58KdNMjMVxJuCsPv+9h08dRNr5yQTzMDBzkgbTPd4uagG6FH9BFy2STYcnk16jFO OQeopQsKrZPkJzJwKEkvwt/0V2HrOyO9oaFSbgHDyJTQigsW1/0eryrmqs26FLQkC6T/ 1ceQ== X-Gm-Message-State: AOAM531Pp+0Hf6s3QUuORI9rz9exeMQ1+6zsuseTnM9H3XVfro++X+Kr 8YCUcLC9nO9Y/Zv3NgDfUxQ= X-Google-Smtp-Source: ABdhPJyM7v0zXEyGqjciHtSAM+WG0z/jW2TYz2BvKHQIg0x3oAjMjTZKgmIFXVMU8//fhdvqmoiD5g== X-Received: by 2002:a17:90a:4b47:: with SMTP id o7mr7491151pjl.198.1634829785570; Thu, 21 Oct 2021 08:23:05 -0700 (PDT) Received: from theprophet ([2406:7400:63:29a4:d874:a949:6890:f95f]) by smtp.gmail.com with ESMTPSA id f84sm6347400pfa.25.2021.10.21.08.23.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Oct 2021 08:23:05 -0700 (PDT) Date: Thu, 21 Oct 2021 20:52:53 +0530 From: Naveen Naidu To: bhelgaas@google.com Cc: linux-kernel-mentees@lists.linuxfoundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, Lukas Wunner , Kuppuswamy Sathyanarayanan , Amey Narkhede Subject: Re: [PATCH v3 18/25] PCI: pciehp: Use RESPONSE_IS_PCI_ERROR() to check read from hardware Message-ID: <20211021152253.pqc6xp3vnv5fpczj@theprophet> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/10, Naveen Naidu wrote: > An MMIO read from a PCI device that doesn't exist or doesn't respond > causes a PCI error. There's no real data to return to satisfy the > CPU read, so most hardware fabricates ~0 data. > > Use RESPONSE_IS_PCI_ERROR() to check the response we get when we read > data from hardware. > > This helps unify PCI error response checking and make error checks > consistent and easier to find. > > Compile tested only. > > Signed-off-by: Naveen Naidu > --- > drivers/pci/hotplug/pciehp_hpc.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c > index 3024d7e85e6a..f472f83f6cce 100644 > --- a/drivers/pci/hotplug/pciehp_hpc.c > +++ b/drivers/pci/hotplug/pciehp_hpc.c > @@ -89,7 +89,7 @@ static int pcie_poll_cmd(struct controller *ctrl, int timeout) > > do { > pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status); > - if (slot_status == (u16) ~0) { > + if (RESPONSE_IS_PCI_ERROR(slot_status)) { > ctrl_info(ctrl, "%s: no response from device\n", > __func__); > return 0; > @@ -165,7 +165,7 @@ static void pcie_do_write_cmd(struct controller *ctrl, u16 cmd, > pcie_wait_cmd(ctrl); > > pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl); > - if (slot_ctrl == (u16) ~0) { > + if (RESPONSE_IS_PCI_ERROR(slot_ctrl)) { > ctrl_info(ctrl, "%s: no response from device\n", __func__); > goto out; > } > @@ -236,7 +236,7 @@ int pciehp_check_link_active(struct controller *ctrl) > int ret; > > ret = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status); > - if (ret == PCIBIOS_DEVICE_NOT_FOUND || lnk_status == (u16)~0) > + if (ret == PCIBIOS_DEVICE_NOT_FOUND || RESPONSE_IS_PCI_ERROR(lnk_status)) > return -ENODEV; > > ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA); > @@ -443,7 +443,7 @@ int pciehp_card_present(struct controller *ctrl) > int ret; > > ret = pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status); > - if (ret == PCIBIOS_DEVICE_NOT_FOUND || slot_status == (u16)~0) > + if (ret == PCIBIOS_DEVICE_NOT_FOUND || RESPONSE_IS_PCI_ERROR(slot_status)) > return -ENODEV; > > return !!(slot_status & PCI_EXP_SLTSTA_PDS); > @@ -621,7 +621,7 @@ static irqreturn_t pciehp_isr(int irq, void *dev_id) > > read_status: > pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &status); > - if (status == (u16) ~0) { > + if (RESPONSE_IS_PCI_ERROR(status)) { > ctrl_info(ctrl, "%s: no response from device\n", __func__); > if (parent) > pm_runtime_put(parent); > -- > 2.25.1 > Lukas, I have not added your Acked-by tag from the v1 [1] of the patch series, since the RESPONSE_IS_PCI_ERROR macro definition slightly changed. I hope this was the right thing to do. [1]: https://lore.kernel.org/linux-pci/20211011194740.GA14357@wunner.de/ Also, regarding your comments from v1 patch series [1] about re-naming the RESPONSE_IS_PCI_ERROR to RESPONSE_IS_PCI_TIMEOUT. We could indeed change the change to RESPONSE_IS_PCI_TIMEOUT for pciehp, but then I'm afraid that picehp would be the odd one out. I mean, since in all the other places we are using RESPONE_IS_PCI_TIMEOUT to see if any error occured while reading from a device. RESPONSE_IS_PCI_ERROR stills gives an idea to the readers that some PCI error occured. It was my understanding that timeout is also a kind of PCI error (I might be horribly wrong here, given my very less experience with PCI subsystem) so it would be okay to use RESPONSE_IS_PCI_ERROR here. If that is not the case please let me know. But I am not sure what to do here? If RESPONSE_IS_PCI_ERROR does not fit here, should the right option would be to revert/remove this patch from the series? Thanks, Naveen