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From: Jiang Liu <liuj97@gmail.com>
To: Bjorn Helgaas <bhelgaas@google.com>,
	Don Dutile <ddutile@redhat.com>, Yinghai Lu <yinghai@kernel.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>,
	Taku Izumi <izumi.taku@jp.fujitsu.com>,
	"Rafael J . Wysocki" <rjw@sisk.pl>,
	Yijing Wang <wangyijing@huawei.com>,
	Xinwei Hu <huxinwei@huawei.com>,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
	Jiang Liu <liuj97@gmail.com>
Subject: [RFC PATCH v1 15/22] PCI/eeepc: use PCI bus lock to avoid race conditions
Date: Wed,  8 Aug 2012 00:10:55 +0800	[thread overview]
Message-ID: <1344355862-2726-16-git-send-email-jiang.liu@huawei.com> (raw)
In-Reply-To: <1344355862-2726-1-git-send-email-jiang.liu@huawei.com>

This patch uses PCI bus lock mechanism to avoid race conditions when doing
PCI device hotplug through eeepc driver. It also fixes a PCI device reference
count leakage issue because acpi_get_pci_dev() holds a reference to the
device returned.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
---
 drivers/platform/x86/eeepc-laptop.c |   20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/platform/x86/eeepc-laptop.c b/drivers/platform/x86/eeepc-laptop.c
index dab91b4..25c4176 100644
--- a/drivers/platform/x86/eeepc-laptop.c
+++ b/drivers/platform/x86/eeepc-laptop.c
@@ -606,16 +606,16 @@ static void eeepc_rfkill_hotplug(struct eeepc_laptop *eeepc, acpi_handle handle)
 			goto out_unlock;
 		}
 
-		bus = port->subordinate;
+		bus = pci_lock_subordinate(port, PCI_BUS_STATE_WORKING);
 
 		if (!bus) {
 			pr_warn("Unable to find PCI bus 1?\n");
-			goto out_unlock;
+			goto out_put_dev;
 		}
 
 		if (pci_bus_read_config_dword(bus, 0, PCI_VENDOR_ID, &l)) {
 			pr_err("Unable to read PCI config space?\n");
-			goto out_unlock;
+			goto out_unlock_bus;
 		}
 
 		absent = (l == 0xffffffff);
@@ -627,7 +627,7 @@ static void eeepc_rfkill_hotplug(struct eeepc_laptop *eeepc, acpi_handle handle)
 				absent ? "absent" : "present");
 			pr_warn("skipped wireless hotplug as probably "
 				"inappropriate for this model\n");
-			goto out_unlock;
+			goto out_unlock_bus;
 		}
 
 		if (!blocked) {
@@ -635,7 +635,7 @@ static void eeepc_rfkill_hotplug(struct eeepc_laptop *eeepc, acpi_handle handle)
 			if (dev) {
 				/* Device already present */
 				pci_dev_put(dev);
-				goto out_unlock;
+				goto out_unlock_bus;
 			}
 			dev = pci_scan_single_device(bus, 0);
 			if (dev) {
@@ -650,6 +650,11 @@ static void eeepc_rfkill_hotplug(struct eeepc_laptop *eeepc, acpi_handle handle)
 				pci_dev_put(dev);
 			}
 		}
+
+out_unlock_bus:
+		pci_bus_unlock(bus);
+out_put_dev:
+		pci_dev_put(port);
 	}
 
 out_unlock:
@@ -757,7 +762,7 @@ static struct hotplug_slot_ops eeepc_hotplug_slot_ops = {
 static int eeepc_setup_pci_hotplug(struct eeepc_laptop *eeepc)
 {
 	int ret = -ENOMEM;
-	struct pci_bus *bus = pci_find_bus(0, 1);
+	struct pci_bus *bus = pci_get_bus(0, 1);
 
 	if (!bus) {
 		pr_err("Unable to find wifi PCI bus\n");
@@ -785,6 +790,8 @@ static int eeepc_setup_pci_hotplug(struct eeepc_laptop *eeepc)
 		goto error_register;
 	}
 
+	pci_bus_put(bus);
+
 	return 0;
 
 error_register:
@@ -793,6 +800,7 @@ error_info:
 	kfree(eeepc->hotplug_slot);
 	eeepc->hotplug_slot = NULL;
 error_slot:
+	pci_bus_put(bus);
 	return ret;
 }
 
-- 
1.7.9.5


  parent reply	other threads:[~2012-08-07 16:10 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-07 16:10 [RFC PATCH v1 00/22] introduce PCI bus lock to serialize PCI hotplug operations Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 01/22] PCI: use pci_get_domain_bus_and_slot() to avoid race conditions Jiang Liu
2012-09-11 22:00   ` Bjorn Helgaas
2012-09-12  8:37     ` Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 02/22] PCI: trivial cleanups for drivers/pci/remove.c Jiang Liu
2012-09-11 22:03   ` Bjorn Helgaas
2012-09-12  8:50     ` Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 03/22] PCI: change PCI device management code to better follow device model Jiang Liu
2012-09-11 22:03   ` Bjorn Helgaas
2012-08-07 16:10 ` [RFC PATCH v1 04/22] PCI: split PCI bus device registration into two stages Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 05/22] PCI: introduce pci_bus_{get|put}() to manage PCI bus reference count Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 06/22] PCI: use a global lock to serialize PCI root bridge hotplug operations Jiang Liu
2012-09-11 22:57   ` Bjorn Helgaas
2012-09-12 15:42     ` Jiang Liu
2012-09-12 16:51       ` Bjorn Helgaas
2012-09-13 16:00         ` [PATCH 1/2] PCI: introduce root bridge hotplug safe interfaces to walk root buses Jiang Liu
2012-09-13 17:40           ` Bjorn Helgaas
2012-09-17 15:55             ` Jiang Liu
2012-09-17 16:24               ` Bjorn Helgaas
2012-09-18 21:39                 ` Bjorn Helgaas
2012-09-21 16:07                   ` [PATCH v4] PCI: introduce two interfaces to walk PCI buses Jiang Liu
2012-09-26 20:14                     ` Bjorn Helgaas
2012-09-13 16:00         ` [PATCH 2/2] PCI: remove host bridge hotplug unsafe interface pci_get_next_bus() Jiang Liu
2012-09-17 15:51         ` [RFC PATCH v1 06/22] PCI: use a global lock to serialize PCI root bridge hotplug operations Jiang Liu
2012-09-20 18:49         ` Paul E. McKenney
2012-08-07 16:10 ` [RFC PATCH v1 07/22] PCI: introduce PCI bus lock to serialize PCI " Jiang Liu
2012-09-11 23:24   ` Bjorn Helgaas
2012-08-07 16:10 ` [RFC PATCH v1 08/22] PCI: introduce hotplug safe search interfaces for PCI bus/device Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 09/22] PCI: enhance PCI probe logic to support PCI bus lock mechanism Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 10/22] PCI: enhance PCI bus specific " Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 11/22] PCI: enhance PCI resource assignment " Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 12/22] PCI: enhance PCI remove " Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 13/22] PCI: make each PCI device hold a reference to its parent PCI bus Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 14/22] PCI/sysfs: use PCI bus lock to avoid race conditions Jiang Liu
2012-08-07 16:10 ` Jiang Liu [this message]
2012-09-11 23:18   ` [RFC PATCH v1 15/22] PCI/eeepc: " Bjorn Helgaas
2012-09-12 14:24     ` [PATCH] eeepc-laptop: fix device reference count leakage in eeepc_rfkill_hotplug() Jiang Liu
2012-09-12 19:59       ` Bjorn Helgaas
2012-08-07 16:10 ` [RFC PATCH v1 16/22] PCI/asus-wmi: use PCI bus lock to avoid race conditions Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 17/22] PCI/pciehp: " Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 18/22] PCI/acpiphp: " Jiang Liu
2012-08-07 16:10 ` [RFC PATCH v1 19/22] PCI/x86: enable PCI bus lock mechanism for x86 platforms Jiang Liu
2012-09-11 23:22   ` Bjorn Helgaas
2012-09-12  9:56     ` Jiang Liu
2012-08-07 16:11 ` [RFC PATCH v1 20/22] PCI/IA64: enable PCI bus lock mechanism for IA64 platforms Jiang Liu
2012-08-07 16:11 ` [RFC PATCH v1 21/22] PCI: cleanups for PCI bus lock implementation Jiang Liu
2012-09-11 23:21   ` Bjorn Helgaas
2012-09-12  8:58     ` Jiang Liu
2012-08-07 16:11 ` [RFC PATCH v1 22/22] PCI: unexport pci_root_buses Jiang Liu
2012-08-07 18:11 ` [RFC PATCH v1 00/22] introduce PCI bus lock to serialize PCI hotplug operations Don Dutile
2012-08-08 15:49   ` Jiang Liu

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