[PATCH] PCI: Add pci_walk_bus function to PCI core (nonrecursive)

The PCI error recovery infrastructure needs to be able to contact all the drivers affected by a PCI error event, which may mean traversing all the devices under a given PCI-PCI bridge. This patch adds a function to the PCI core that traverses all the PCI devices on a PCI bus and under any PCI-PCI bridges on that bus (and so on), calling a given function for each device. This provides a way for the error recovery code to iterate through all devices that are affected by an error event. This version is not implemented as a recursive function. Instead, when we reach a PCI-PCI bridge, we set the pointers to start doing the devices on the bus under the bridge, and when we reach the end of a bus's devices, we use the bus->self pointer to go back up to the next higher bus and continue doing its devices. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] PCI: Add pci_walk_bus function to PCI core (nonrecursive)
The PCI error recovery infrastructure needs to be able to contact all the drivers affected by a PCI error event, which may mean traversing all the devices under a given PCI-PCI bridge. This patch adds a function to the PCI core that traverses all the PCI devices on a PCI bus and under any PCI-PCI bridges on that bus (and so on), calling a given function for each device. This provides a way for the error recovery code to iterate through all devices that are affected by an error event. This version is not implemented as a recursive function. Instead, when we reach a PCI-PCI bridge, we set the pointers to start doing the devices on the bus under the bridge, and when we reach the end of a bus's devices, we use the bus->self pointer to go back up to the next higher bus and continue doing its devices. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Paul Mackerras · Greg Kroah-Hartman
1 parent 1d2450a4a6
Showing 2 changed files with 51 additions and 0 deletions Side-by-side Diff
drivers/pci/bus.c
include/linux/pci.h
@@ -151,6 +151,54 @@
 	}
 }
  
+/** pci_walk_bus - walk devices on/under bus, calling callback.
+ *  @top      bus whose devices should be walked
+ *  @cb       callback to be called for each device found
+ *  @userdata arbitrary pointer to be passed to callback.
+ *
+ *  Walk the given bus, including any bridged devices
+ *  on buses under this bus.  Call the provided callback
+ *  on each device found.
+ */
+void pci_walk_bus(struct pci_bus *top, void (*cb)(struct pci_dev *, void *),
+		  void *userdata)
+{
+	struct pci_dev *dev;
+	struct pci_bus *bus;
+	struct list_head *next;
+
+	bus = top;
+	spin_lock(&pci_bus_lock);
+	next = top->devices.next;
+	for (;;) {
+		if (next == &bus->devices) {
+			/* end of this bus, go up or finish */
+			if (bus == top)
+				break;
+			next = bus->self->bus_list.next;
+			bus = bus->self->bus;
+			continue;
+		}
+		dev = list_entry(next, struct pci_dev, bus_list);
+		pci_dev_get(dev);
+		if (dev->subordinate) {
+			/* this is a pci-pci bridge, do its devices next */
+			next = dev->subordinate->devices.next;
+			bus = dev->subordinate;
+		} else
+			next = dev->bus_list.next;
+		spin_unlock(&pci_bus_lock);
+
+		/* Run device routines with the bus unlocked */
+		cb(dev, userdata);
+
+		spin_lock(&pci_bus_lock);
+		pci_dev_put(dev);
+	}
+	spin_unlock(&pci_bus_lock);
+}
+EXPORT_SYMBOL_GPL(pci_walk_bus);
+
 EXPORT_SYMBOL(pci_bus_alloc_resource);
 EXPORT_SYMBOL_GPL(pci_bus_add_device);
 EXPORT_SYMBOL(pci_bus_add_devices);
@@ -434,6 +434,9 @@
 const struct pci_device_id *pci_match_id(const struct pci_device_id *ids, struct pci_dev *dev);
 int pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max, int pass);
  
+void pci_walk_bus(struct pci_bus *top, void (*cb)(struct pci_dev *, void *),
+		  void *userdata);
+
 /* kmem_cache style wrapper around pci_alloc_consistent() */
  
 #include <linux/dmapool.h>
...	...	@@ -151,6 +151,54 @@
151	151	}
152	152	}
153	153
	154	+/** pci_walk_bus - walk devices on/under bus, calling callback.
	155	+ * @top bus whose devices should be walked
	156	+ * @cb callback to be called for each device found
	157	+ * @userdata arbitrary pointer to be passed to callback.
	158	+ *
	159	+ * Walk the given bus, including any bridged devices
	160	+ * on buses under this bus. Call the provided callback
	161	+ * on each device found.
	162	+ */
	163	+void pci_walk_bus(struct pci_bus top, void (cb)(struct pci_dev , void ),
	164	+ void *userdata)
	165	+{
	166	+ struct pci_dev *dev;
	167	+ struct pci_bus *bus;
	168	+ struct list_head *next;
	169	+
	170	+ bus = top;
	171	+ spin_lock(&pci_bus_lock);
	172	+ next = top->devices.next;
	173	+ for (;;) {
	174	+ if (next == &bus->devices) {
	175	+ /* end of this bus, go up or finish */
	176	+ if (bus == top)
	177	+ break;
	178	+ next = bus->self->bus_list.next;
	179	+ bus = bus->self->bus;
	180	+ continue;
	181	+ }
	182	+ dev = list_entry(next, struct pci_dev, bus_list);
	183	+ pci_dev_get(dev);
	184	+ if (dev->subordinate) {
	185	+ /* this is a pci-pci bridge, do its devices next */
	186	+ next = dev->subordinate->devices.next;
	187	+ bus = dev->subordinate;
	188	+ } else
	189	+ next = dev->bus_list.next;
	190	+ spin_unlock(&pci_bus_lock);
	191	+
	192	+ /* Run device routines with the bus unlocked */
	193	+ cb(dev, userdata);
	194	+
	195	+ spin_lock(&pci_bus_lock);
	196	+ pci_dev_put(dev);
	197	+ }
	198	+ spin_unlock(&pci_bus_lock);
	199	+}
	200	+EXPORT_SYMBOL_GPL(pci_walk_bus);
	201	+
154	202	EXPORT_SYMBOL(pci_bus_alloc_resource);
155	203	EXPORT_SYMBOL_GPL(pci_bus_add_device);
156	204	EXPORT_SYMBOL(pci_bus_add_devices);
...	...	@@ -434,6 +434,9 @@
434	434	const struct pci_device_id pci_match_id(const struct pci_device_id ids, struct pci_dev *dev);
435	435	int pci_scan_bridge(struct pci_bus bus, struct pci_dev dev, int max, int pass);
436	436
	437	+void pci_walk_bus(struct pci_bus top, void (cb)(struct pci_dev , void ),
	438	+ void *userdata);
	439	+
437	440	/* kmem_cache style wrapper around pci_alloc_consistent() */
438	441
439	442	#include <linux/dmapool.h>