PCI device list locking - take 3

@@ -93,7 +93,11 @@
 			continue;
 
 		device_add(&dev->dev);
+
+		spin_lock(&pci_bus_lock);
 		list_add_tail(&dev->global_list, &pci_devices);
+		spin_unlock(&pci_bus_lock);
+
 		pci_proc_attach_device(dev);
 		pci_create_sysfs_dev_files(dev);
 

@@ -108,7 +112,9 @@
 		 * it and then scan for unattached PCI devices.
 		 */
 		if (dev->subordinate && list_empty(&dev->subordinate->node)) {
+			spin_lock(&pci_bus_lock);
 			list_add_tail(&dev->subordinate->node, &dev->bus->children);
+			spin_unlock(&pci_bus_lock);
 			pci_bus_add_devices(dev->subordinate);
 		}
 	}

@@ -173,6 +173,24 @@
 }
 EXPORT_SYMBOL(pci_visit_dev);
 
+static void pci_destroy_dev(struct pci_dev *dev)
+{
+	device_unregister(&dev->dev);
+
+	/* Remove the device from the device lists, and prevent any further
+	 * list accesses from this device */
+	spin_lock(&pci_bus_lock);
+	list_del(&dev->bus_list);
+	list_del(&dev->global_list);
+	dev->bus_list.next = dev->bus_list.prev = NULL;
+	dev->global_list.next = dev->global_list.prev = NULL;
+	spin_unlock(&pci_bus_lock);
+
+	pci_free_resources(dev);
+	pci_proc_detach_device(dev);
+	pci_put_dev(dev);
+}
+
 /**
  * pci_remove_device_safe - remove an unused hotplug device
  * @dev: the device to remove

@@ -186,11 +204,7 @@
 {
 	if (pci_dev_driver(dev))
 		return -EBUSY;
-	device_unregister(&dev->dev);
-	list_del(&dev->bus_list);
-	list_del(&dev->global_list);
-	pci_free_resources(dev);
-	pci_proc_detach_device(dev);
+	pci_destroy_dev(dev);
 	return 0;
 }
 EXPORT_SYMBOL(pci_remove_device_safe);

@@ -237,17 +251,15 @@
 		pci_remove_behind_bridge(dev);
 		pci_proc_detach_bus(b);
 
+		spin_lock(&pci_bus_lock);
 		list_del(&b->node);
+		spin_unlock(&pci_bus_lock);
+
 		kfree(b);
 		dev->subordinate = NULL;
 	}
 
-	device_unregister(&dev->dev);
-	list_del(&dev->bus_list);
-	list_del(&dev->global_list);
-	pci_free_resources(dev);
-	pci_proc_detach_device(dev);
-	pci_put_dev(dev);
+	pci_destroy_dev(dev);
 }
 
 /**

@@ -59,3 +59,6 @@
 extern int pci_visit_dev(struct pci_visit *fn,
 			 struct pci_dev_wrapped *wrapped_dev,
 			 struct pci_bus_wrapped *wrapped_parent);
+
+/* Lock for read/write access to pci device and bus lists */
+extern spinlock_t pci_bus_lock;

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222 lines not on this page · raw message

@@ -566,6 +566,10 @@
 int pci_find_capability (struct pci_dev *dev, int cap);
 struct pci_bus * pci_find_next_bus(const struct pci_bus *from);
 
+struct pci_dev *pci_get_device (unsigned int vendor, unsigned int device, struct pci_dev *from);
+struct pci_dev *pci_get_subsys (unsigned int vendor, unsigned int device,
+				unsigned int ss_vendor, unsigned int ss_device,
+				struct pci_dev *from);
 int pci_bus_read_config_byte (struct pci_bus *bus, unsigned int devfn, int where, u8 *val);
 int pci_bus_read_config_word (struct pci_bus *bus, unsigned int devfn, int where, u16 *val);
 int pci_bus_read_config_dword (struct pci_bus *bus, unsigned int devfn, int where, u32 *val);

@@ -686,6 +690,13 @@
 
 static inline struct pci_dev *pci_find_subsys(unsigned int vendor, unsigned int device,
 unsigned int ss_vendor, unsigned int ss_device, const struct pci_dev *from)
+{ return NULL; }
+
+static inline struct pci_dev *pci_get_device (unsigned int vendor, unsigned int device, struct pci_dev *from)
+{ return NULL; }
+
+static inline struct pci_dev *pci_get_subsys (unsigned int vendor, unsigned int device,
+unsigned int ss_vendor, unsigned int ss_device, struct pci_dev *from)
 { return NULL; }
 
 static inline void pci_set_master(struct pci_dev *dev) { }