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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FAKE_REPLY_C,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 8287FECE58C for ; Mon, 7 Oct 2019 22:34:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58F5C21721 for ; Mon, 7 Oct 2019 22:34:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570487672; bh=LGBSGuz5q9yo8hI9Okbu1av/OqHVYJvDjRBLyWdeHjQ=; h=Date:From:To:Cc:Subject:In-Reply-To:List-ID:From; b=p+N5smlevJo2Rnl1Sc0uDk/s3N1sx/4X02wV0BxxmSi5R/96fKKjMF3y8f+Fw8MLw 6Mks5eJafWjrZQRmg1EjjWpW9TmbERWwW7CO3c/siuV/xLx3SjyyjlH6cD11tPdI8M PnIpZx4qtgbaxsT1TubBwAI7+R+c/g4/9xT65myg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728980AbfJGWeb (ORCPT ); Mon, 7 Oct 2019 18:34:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:49326 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728893AbfJGWeb (ORCPT ); Mon, 7 Oct 2019 18:34:31 -0400 Received: from localhost (unknown [69.71.4.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AFD78206C0; Mon, 7 Oct 2019 22:34:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570487670; bh=LGBSGuz5q9yo8hI9Okbu1av/OqHVYJvDjRBLyWdeHjQ=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=l+VHYoudpyoV9iaA3IzzJYmS6Xzj05+MpEYQxm0RayzX19zv2bvuOo1THZKU44DF0 +/RKCBHtGlDq0ii3iA7U7ajRxB4C4h0kF6M54zbmqTza1xkHLgFRZLMgxVEyQGgCe8 ErahbP+R9O9kkCL6iBNowjUgn9RLtJi/JXtbCF9A= Date: Mon, 7 Oct 2019 17:34:28 -0500 From: Bjorn Helgaas To: "Rafael J. Wysocki" Cc: linux-nvme , Keith Busch , Mario Limonciello , Kai-Heng Feng , Keith Busch , Christoph Hellwig , Sagi Grimberg , Linux PM , Linux Kernel Mailing List , Rajat Jain , Linux PCI , Heiner Kallweit Subject: Re: [PATCH v3 1/2] PCI: PCIe: ASPM: Introduce pcie_aspm_enabled() Message-ID: <20191007223428.GA72605@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1618955.HVa0YQSOW5@kreacher> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org [+cc Heiner] On Thu, Aug 08, 2019 at 11:55:07PM +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > Add a function checking whether or not PCIe ASPM has been enabled for > a given device. > > It will be used by the NVMe driver to decide how to handle the > device during system suspend. > > Signed-off-by: Rafael J. Wysocki > --- > > v2 -> v3: > * Make the new function return bool. > * Change its name back to pcie_aspm_enabled(). > * Fix kerneldoc comment formatting. > > -> v2: > * Move the PCI/PCIe ASPM changes to a separate patch. > * Add the _mask suffix to the new function name. > * Add EXPORT_SYMBOL_GPL() to the new function. > * Avoid adding an unnecessary blank line. > > --- > drivers/pci/pcie/aspm.c | 20 ++++++++++++++++++++ > include/linux/pci.h | 3 +++ > 2 files changed, 23 insertions(+) > > Index: linux-pm/drivers/pci/pcie/aspm.c > =================================================================== > --- linux-pm.orig/drivers/pci/pcie/aspm.c > +++ linux-pm/drivers/pci/pcie/aspm.c > @@ -1170,6 +1170,26 @@ static int pcie_aspm_get_policy(char *bu > module_param_call(policy, pcie_aspm_set_policy, pcie_aspm_get_policy, > NULL, 0644); > > +/** > + * pcie_aspm_enabled - Check if PCIe ASPM has been enabled for a device. > + * @pci_device: Target device. > + */ > +bool pcie_aspm_enabled(struct pci_dev *pci_device) > +{ > + struct pci_dev *bridge = pci_upstream_bridge(pci_device); > + bool ret; > + > + if (!bridge) > + return false; > + > + mutex_lock(&aspm_lock); > + ret = bridge->link_state ? !!bridge->link_state->aspm_enabled : false; > + mutex_unlock(&aspm_lock); Why do we need to acquire aspm_lock here? We aren't modifying anything, and I don't think we're preventing a race. If this races with another thread that changes aspm_enabled, we'll return either the old state or the new one, and I think that's still the case even if we don't acquire aspm_lock. > + return ret; > +} > +EXPORT_SYMBOL_GPL(pcie_aspm_enabled); > + > #ifdef CONFIG_PCIEASPM_DEBUG > static ssize_t link_state_show(struct device *dev, > struct device_attribute *attr, > Index: linux-pm/include/linux/pci.h > =================================================================== > --- linux-pm.orig/include/linux/pci.h > +++ linux-pm/include/linux/pci.h > @@ -1567,8 +1567,11 @@ extern bool pcie_ports_native; > > #ifdef CONFIG_PCIEASPM > bool pcie_aspm_support_enabled(void); > +bool pcie_aspm_enabled(struct pci_dev *pci_device); > #else > static inline bool pcie_aspm_support_enabled(void) { return false; } > +static inline bool pcie_aspm_enabled(struct pci_dev *pci_device) > +{ return false; } > #endif > > #ifdef CONFIG_PCIEAER > > >