[PATCH] Add a klist to struct bus_type for its drivers.

- Use it in bus_for_each_drv().
- Use the klist spinlock instead of the bus rwsem.

Signed-off-by: Patrick Mochel <mochel@digitalimplant.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index c8da37230b3ec81465f8264e4ae1d22851f1ce5b..736dc1f5a3166c172f2f8b70944e4cc7a4012c44 100644 (file)
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -135,30 +135,6 @@ static struct kobj_type ktype_bus = {
 decl_subsys(bus, &ktype_bus, NULL);
 
 
-static int __bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
-                             void * data, int (*fn)(struct device_driver *, void *))
-{
-       struct list_head *head;
-       struct device_driver *drv;
-       int error = 0;
-
-       if (!(bus = get_bus(bus)))
-               return -EINVAL;
-
-       head = &bus->drivers.list;
-       drv = list_prepare_entry(start, head, kobj.entry);
-       list_for_each_entry_continue(drv, head, kobj.entry) {
-               get_driver(drv);
-               error = fn(drv, data);
-               put_driver(drv);
-               if (error)
-                       break;
-       }
-       put_bus(bus);
-       return error;
-}
-
-
 static struct device * next_device(struct klist_iter * i)
 {
        struct klist_node * n = klist_next(i);
@@ -203,6 +179,14 @@ int bus_for_each_dev(struct bus_type * bus, struct device * start,
        return error;
 }
 
+
+
+static struct device_driver * next_driver(struct klist_iter * i)
+{
+       struct klist_node * n = klist_next(i);
+       return n ? container_of(n, struct device_driver, knode_bus) : NULL;
+}
+
 /**
  *     bus_for_each_drv - driver iterator
  *     @bus:   bus we're dealing with.
@@ -226,12 +210,19 @@ int bus_for_each_dev(struct bus_type * bus, struct device * start,
 int bus_for_each_drv(struct bus_type * bus, struct device_driver * start,
                     void * data, int (*fn)(struct device_driver *, void *))
 {
-       int ret;
+       struct klist_iter i;
+       struct device_driver * drv;
+       int error = 0;
 
-       down_read(&bus->subsys.rwsem);
-       ret = __bus_for_each_drv(bus, start, data, fn);
-       up_read(&bus->subsys.rwsem);
-       return ret;
+       if (!bus)
+               return -EINVAL;
+
+       klist_iter_init_node(&bus->klist_drivers, &i,
+                            start ? &start->knode_bus : NULL);
+       while ((drv = next_driver(&i)) && !error)
+               error = fn(drv, data);
+       klist_iter_exit(&i);
+       return error;
 }
 
 static int device_add_attrs(struct bus_type * bus, struct device * dev)
@@ -376,6 +367,7 @@ int bus_add_driver(struct device_driver * drv)
                down_write(&bus->subsys.rwsem);
                driver_attach(drv);
                up_write(&bus->subsys.rwsem);
+               klist_add_tail(&bus->klist_drivers, &drv->knode_bus);
                module_add_driver(drv->owner, drv);
 
                driver_add_attrs(bus, drv);
@@ -397,6 +389,7 @@ void bus_remove_driver(struct device_driver * drv)
 {
        if (drv->bus) {
                driver_remove_attrs(drv->bus, drv);
+               klist_remove(&drv->knode_bus);
                down_write(&drv->bus->subsys.rwsem);
                pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
                driver_detach(drv);
@@ -536,6 +529,7 @@ int bus_register(struct bus_type * bus)
                goto bus_drivers_fail;
 
        klist_init(&bus->klist_devices);
+       klist_init(&bus->klist_drivers);
        bus_add_attrs(bus);
 
        pr_debug("bus type '%s' registered\n", bus->name);

diff --git a/include/linux/device.h b/include/linux/device.h
index e36953cf7f142b730c12da1685cff1333fd32cb5..ea9ab33dfe71b1ca6bf9e181973cb9b56fd55d49 100644 (file)
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -53,6 +53,7 @@ struct bus_type {
        struct kset             drivers;
        struct kset             devices;
        struct klist            klist_devices;
+       struct klist            klist_drivers;
 
        struct bus_attribute    * bus_attrs;
        struct device_attribute * dev_attrs;
@@ -105,6 +106,7 @@ struct device_driver {
        struct completion       unloaded;
        struct kobject          kobj;
        struct list_head        devices;
+       struct klist_node       knode_bus;
 
        struct module           * owner;