Patchwork [v3,6/8] ACPI, PCI: add acpi_pci_roots protection

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Submitter Taku Izumi
Date Sept. 18, 2012, 6:24 a.m.
Message ID <20120918152440.117dd1cb.izumi.taku@jp.fujitsu.com>
Download mbox | patch
Permalink /patch/184622/
State Accepted
Headers show

Comments

Taku Izumi - Sept. 18, 2012, 6:24 a.m.
Use mutex to protect acpi_pci_roots list against PCI host bridge 
hotplug operations.

Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
---
 drivers/acpi/pci_root.c |   27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)


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Bjorn Helgaas - Sept. 20, 2012, 7:32 p.m.
On Tue, Sep 18, 2012 at 12:24 AM, Taku Izumi <izumi.taku@jp.fujitsu.com> wrote:
>
> Use mutex to protect acpi_pci_roots list against PCI host bridge
> hotplug operations.
>
> Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
> ---
>  drivers/acpi/pci_root.c |   27 ++++++++++++++++++---------
>  1 file changed, 18 insertions(+), 9 deletions(-)
>
> Index: Bjorn-next-0903/drivers/acpi/pci_root.c
> ===================================================================
> --- Bjorn-next-0903.orig/drivers/acpi/pci_root.c
> +++ Bjorn-next-0903/drivers/acpi/pci_root.c
> @@ -112,12 +112,17 @@ EXPORT_SYMBOL(acpi_pci_unregister_driver
>  acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus)
>  {
>         struct acpi_pci_root *root;
> +       struct acpi_handle *handle = NULL;

This should be "acpi_handle handle", not "struct acpi_handle *handle".

> +       mutex_lock(&acpi_pci_root_lock);
>         list_for_each_entry(root, &acpi_pci_roots, node)
>                 if ((root->segment == (u16) seg) &&
> -                   (root->secondary.start == (u16) bus))
> -                       return root->device->handle;
> -       return NULL;
> +                   (root->secondary.start == (u16) bus)) {
> +                       handle = root->device->handle;
> +                       break;
> +               }
> +       mutex_unlock(&acpi_pci_root_lock);
> +       return handle;
>  }
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Patch

Index: Bjorn-next-0903/drivers/acpi/pci_root.c
===================================================================
--- Bjorn-next-0903.orig/drivers/acpi/pci_root.c
+++ Bjorn-next-0903/drivers/acpi/pci_root.c
@@ -112,12 +112,17 @@  EXPORT_SYMBOL(acpi_pci_unregister_driver
 acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus)
 {
 	struct acpi_pci_root *root;
+	struct acpi_handle *handle = NULL;
 	
+	mutex_lock(&acpi_pci_root_lock);
 	list_for_each_entry(root, &acpi_pci_roots, node)
 		if ((root->segment == (u16) seg) &&
-		    (root->secondary.start == (u16) bus))
-			return root->device->handle;
-	return NULL;		
+		    (root->secondary.start == (u16) bus)) {
+			handle = root->device->handle;
+			break;
+		}
+	mutex_unlock(&acpi_pci_root_lock);
+	return handle;
 }
 
 EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle);
@@ -509,8 +514,9 @@  static int __devinit acpi_pci_root_add(s
 	 * TBD: Need PCI interface for enumeration/configuration of roots.
 	 */
 
-	/* TBD: Locking */
+	mutex_lock(&acpi_pci_root_lock);
 	list_add_tail(&root->node, &acpi_pci_roots);
+	mutex_unlock(&acpi_pci_root_lock);
 
 	printk(KERN_INFO PREFIX "%s [%s] (domain %04x %pR)\n",
 	       acpi_device_name(device), acpi_device_bid(device),
@@ -529,7 +535,7 @@  static int __devinit acpi_pci_root_add(s
 			    "Bus %04x:%02x not present in PCI namespace\n",
 			    root->segment, (unsigned int)root->secondary.start);
 		result = -ENODEV;
-		goto end;
+		goto out_del_root;
 	}
 
 	/*
@@ -539,7 +545,7 @@  static int __devinit acpi_pci_root_add(s
 	 */
 	result = acpi_pci_bind_root(device);
 	if (result)
-		goto end;
+		goto out_del_root;
 
 	/*
 	 * PCI Routing Table
@@ -617,9 +623,11 @@  static int __devinit acpi_pci_root_add(s
 
 	return 0;
 
+out_del_root:
+	mutex_lock(&acpi_pci_root_lock);
+	list_del(&root->node);
+	mutex_unlock(&acpi_pci_root_lock);
 end:
-	if (!list_empty(&root->node))
-		list_del(&root->node);
 	kfree(root);
 	return result;
 }
@@ -649,11 +657,12 @@  static int acpi_pci_root_remove(struct a
 	list_for_each_entry(driver, &acpi_pci_drivers, node)
 		if (driver->remove)
 			driver->remove(root);
-	mutex_unlock(&acpi_pci_root_lock);
 
 	device_set_run_wake(root->bus->bridge, false);
 	pci_acpi_remove_bus_pm_notifier(device);
 
+	list_del(&root->node);
+	mutex_unlock(&acpi_pci_root_lock);
 	kfree(root);
 	return 0;
 }