From patchwork Wed Sep 19 02:40:38 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yijing Wang X-Patchwork-Id: 184907 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 7FE592C0083 for ; Wed, 19 Sep 2012 12:42:08 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755146Ab2ISCmH (ORCPT ); Tue, 18 Sep 2012 22:42:07 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:52728 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755259Ab2ISCmH (ORCPT ); Tue, 18 Sep 2012 22:42:07 -0400 Received: from 172.24.2.119 (EHLO szxeml206-edg.china.huawei.com) ([172.24.2.119]) by szxrg02-dlp.huawei.com (MOS 4.3.4-GA FastPath queued) with ESMTP id APF89171; Wed, 19 Sep 2012 10:42:02 +0800 (CST) Received: from SZXEML419-HUB.china.huawei.com (10.82.67.158) by szxeml206-edg.china.huawei.com (172.24.2.59) with Microsoft SMTP Server (TLS) id 14.1.323.3; Wed, 19 Sep 2012 10:41:14 +0800 Received: from localhost (10.135.76.84) by szxeml419-hub.china.huawei.com (10.82.67.158) with Microsoft SMTP Server id 14.1.323.3; Wed, 19 Sep 2012 10:41:06 +0800 From: Yijing Wang To: Bjorn Helgaas , Huang Ying , Chen Gong CC: , Hanjun Guo , , Yijing Wang Subject: [PATCH 2/6] PCI/AER: introduce pci_bus_ops_get() function to avoid a small race condition window Date: Wed, 19 Sep 2012 10:40:38 +0800 Message-ID: <1348022442-7816-3-git-send-email-wangyijing@huawei.com> X-Mailer: git-send-email 1.7.11.msysgit.1 In-Reply-To: <1348022442-7816-1-git-send-email-wangyijing@huawei.com> References: <1348022442-7816-1-git-send-email-wangyijing@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.135.76.84] X-CFilter-Loop: Reflected Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org When we rmmod aer_inject module, there is a race condition window between pci_bus_ops_pop() and pci_bus_set_ops() in aer_inject_exit, eg. pci_read_aer/pci_write_aer was called between them. So introduce pci_bus_ops_get() to avoid this. Signed-off-by: Yijing Wang --- drivers/pci/pcie/aer/aer_inject.c | 21 ++++++++++++++++++--- 1 files changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pcie/aer/aer_inject.c b/drivers/pci/pcie/aer/aer_inject.c index 0f00a27..442147b 100644 --- a/drivers/pci/pcie/aer/aer_inject.c +++ b/drivers/pci/pcie/aer/aer_inject.c @@ -67,6 +67,8 @@ struct pci_bus_ops { struct pci_ops *ops; }; +#define to_pci_bus_ops(n) container_of(n, struct pci_bus_ops, list) + static LIST_HEAD(einjected); static LIST_HEAD(pci_bus_ops_list); @@ -160,6 +162,18 @@ static struct pci_bus_ops *pci_bus_ops_pop(void) return bus_ops; } +static struct pci_bus_ops *pci_bus_ops_get(struct pci_bus_ops *from) +{ + struct pci_bus_ops *bus_ops = NULL; + struct list_head *n; + + n = from ? from->list.next : pci_bus_ops_list.next; + if (n != &pci_bus_ops_list) + bus_ops = to_pci_bus_ops(n); + + return bus_ops; +} + static u32 *find_pci_config_dword(struct aer_error *err, int where, int *prw1cs) { @@ -540,14 +554,15 @@ static void __exit aer_inject_exit(void) { struct aer_error *err, *err_next; unsigned long flags; - struct pci_bus_ops *bus_ops; + struct pci_bus_ops *bus_ops = NULL; misc_deregister(&aer_inject_device); - while ((bus_ops = pci_bus_ops_pop())) { + while ((bus_ops = pci_bus_ops_get(bus_ops))) pci_bus_set_ops(bus_ops->bus, bus_ops->ops); + + while ((bus_ops = pci_bus_ops_pop())) kfree(bus_ops); - } spin_lock_irqsave(&inject_lock, flags); list_for_each_entry_safe(err, err_next, &einjected, list) {