From patchwork Fri Aug 17 04:49:02 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Herrenschmidt X-Patchwork-Id: 958659 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 41sBTQ6lygz9s4v for ; Fri, 17 Aug 2018 15:24:26 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726134AbeHQI0G (ORCPT ); Fri, 17 Aug 2018 04:26:06 -0400 Received: from gate.crashing.org ([63.228.1.57]:48469 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726327AbeHQI0G (ORCPT ); Fri, 17 Aug 2018 04:26:06 -0400 Received: from pasglop.ozlabs.ibm.com (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id w7H4nAsJ017258; Thu, 16 Aug 2018 23:49:41 -0500 From: Benjamin Herrenschmidt To: Bjorn Helgaas , linux-pci@vger.kernel.org Cc: Hari Vyas , Ray Jui , Srinath Mannam , Guenter Roeck , Jens Axboe , Lukas Wunner , Konstantin Khlebnikov , Marta Rybczynska , Pierre-Yves Kerbrat , linux-kernel@vger.kernel.org, Benjamin Herrenschmidt Subject: [RFC PATCH 6/6] pci: Protect is_busmaster using the state lock Date: Fri, 17 Aug 2018 14:49:02 +1000 Message-Id: <20180817044902.31420-7-benh@kernel.crashing.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180817044902.31420-1-benh@kernel.crashing.org> References: <20180817044902.31420-1-benh@kernel.crashing.org> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org This wraps pci_set_master() and pci_clear_master() with the pci_dev state lock. The clearing of is_busmaster in pci_disable_device() is already covered. This also adds a comment explaining why is_busmaster must not be checked in pci_set_master() due to how the power management code uses it. Signed-off-by: Benjamin Herrenschmidt --- drivers/pci/pci.c | 9 +++++++++ include/linux/pci.h | 2 +- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 68152de2b5a0..13d988d5b2a3 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4052,11 +4052,18 @@ void __weak pcibios_set_master(struct pci_dev *dev) * * Enables bus-mastering on the device and calls pcibios_set_master() * to do the needed arch specific settings. + * + * Note: This must not check dev->is_busmaster because the power management + * code will call this in order to restore the config space to the + * state of is_busmaster, thus is_busmaster might be set but the + * config space bit cleared. */ void pci_set_master(struct pci_dev *dev) { + pci_dev_state_lock(dev); __pci_set_master(dev, true); pcibios_set_master(dev); + pci_dev_state_unlock(dev); } EXPORT_SYMBOL(pci_set_master); @@ -4066,7 +4073,9 @@ EXPORT_SYMBOL(pci_set_master); */ void pci_clear_master(struct pci_dev *dev) { + pci_dev_state_lock(dev); __pci_set_master(dev, false); + pci_dev_state_unlock(dev); } EXPORT_SYMBOL(pci_clear_master); diff --git a/include/linux/pci.h b/include/linux/pci.h index 0d4fc22df190..a5bac5b21454 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -375,7 +375,6 @@ struct pci_dev { unsigned int multifunction:1; /* Multi-function device */ unsigned int is_added:1; - unsigned int is_busmaster:1; /* Is busmaster */ unsigned int no_msi:1; /* May not use MSI */ unsigned int no_64bit_msi:1; /* May only use 32-bit MSIs */ unsigned int block_cfg_access:1; /* Config space access blocked */ @@ -450,6 +449,7 @@ struct pci_dev { struct mutex state_lock; /* Protect local state bits */ /* --- Fields below this line are protected by the state_lock mutex */ + unsigned int is_busmaster:1; /* Is busmaster */ }; static inline void pci_dev_state_lock(struct pci_dev *dev)