[LV-k25-commit] CVS: kernel-2.5/drivers/base bus.c,1.2,1.3

[Kenn H. <ke...@us...>]

Update of /cvsroot/linux-vax/kernel-2.5/drivers/base
In directory sc8-pr-cvs1:/tmp/cvs-serv1632/drivers/base

Modified Files:
	bus.c 
Log Message:
Merge with 2.5.20.  Also catch up on some file deletions in 2.5.17 to 
2.5.19 that I missed earlier.


Index: bus.c
===================================================================
RCS file: /cvsroot/linux-vax/kernel-2.5/drivers/base/bus.c,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- bus.c	12 Jan 2003 22:46:40 -0000	1.2
+++ bus.c	14 Jan 2003 23:55:17 -0000	1.3
@@ -24,6 +24,91 @@
 };
 
 /**
+ * bus_for_each_dev - walk list of devices and do something to each
+ * @bus:	bus in question
+ * @data:	data for the callback
+ * @callback:	caller-defined action to perform on each device
+ *
+ * Why do we do this? So we can guarantee proper locking and reference
+ * counting on devices as we touch each one.
+ *
+ * Algorithm:
+ * Take the bus lock and get the first node in the list. We increment
+ * the reference count and unlock the bus. If we have a device from a 
+ * previous iteration, we decrement the reference count. 
+ * After we call the callback, we get the next node in the list and loop.
+ * At the end, if @dev is not null, we still have it pinned, so we need
+ * to let it go.
+ */
+int bus_for_each_dev(struct bus_type * bus, void * data, 
+		     int (*callback)(struct device * dev, void * data))
+{
+	struct device * next;
+	struct device * dev = NULL;
+	struct list_head * node;
+	int error = 0;
+
+	get_bus(bus);
+	read_lock(&bus->lock);
+	node = bus->devices.next;
+	while (node != &bus->devices) {
+		next = list_entry(node,struct device,bus_list);
+		get_device(next);
+		read_unlock(&bus->lock);
+
+		if (dev)
+			put_device(dev);
+		dev = next;
+		if ((error = callback(dev,data))) {
+			put_device(dev);
+			break;
+		}
+		read_lock(&bus->lock);
+		node = dev->bus_list.next;
+	}
+	read_unlock(&bus->lock);
+	if (dev)
+		put_device(dev);
+	put_bus(bus);
+	return error;
+}
+
+int bus_for_each_drv(struct bus_type * bus, void * data,
+		     int (*callback)(struct device_driver * drv, void * data))
+{
+	struct device_driver * next;
+	struct device_driver * drv = NULL;
+	struct list_head * node;
+	int error = 0;
+
+	/* pin bus in memory */
+	get_bus(bus);
+
+	read_lock(&bus->lock);
+	node = bus->drivers.next;
+	while (node != &bus->drivers) {
+		next = list_entry(node,struct device_driver,bus_list);
+		get_driver(next);
+		read_unlock(&bus->lock);
+
+		if (drv)
+			put_driver(drv);
+		drv = next;
+		if ((error = callback(drv,data))) {
+			put_driver(drv);
+			break;
+		}
+		read_lock(&bus->lock);
+		node = drv->bus_list.next;
+	}
+	read_unlock(&bus->lock);
+	if (drv)
+		put_driver(drv);
+	put_bus(bus);
+	return error;
+}
+
+/**
  * bus_add_device - add device to bus
  * @dev:	device being added
  *
@@ -120,6 +205,8 @@
 
 core_initcall(bus_init);
 
+EXPORT_SYMBOL(bus_for_each_dev);
+EXPORT_SYMBOL(bus_for_each_drv);
 EXPORT_SYMBOL(bus_add_device);
 EXPORT_SYMBOL(bus_remove_device);
 EXPORT_SYMBOL(bus_register);