1 files changed, 96 insertions, 16 deletions

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 253868e03c70..1d76e2349654 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -27,6 +27,9 @@
 #define to_driver(obj) container_of(obj, struct device_driver, kobj)
 
 
+static int __must_check bus_rescan_devices_helper(struct device *dev,
+                                                void *data);
+
 static ssize_t
 drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
 {
@@ -60,8 +63,19 @@ static struct sysfs_ops driver_sysfs_ops = {
 
 static void driver_release(struct kobject * kobj)
 {
-        struct device_driver * drv = to_driver(kobj);
-        complete(&drv->unloaded);
+        /*
+         * Yes this is an empty release function, it is this way because struct
+         * device is always a static object, not a dynamic one.  Yes, this is
+         * not nice and bad, but remember, drivers are code, reference counted
+         * by the module count, not a device, which is really data.  And yes,
+         * in the future I do want to have all drivers be created dynamically,
+         * and am working toward that goal, but it will take a bit longer...
+         *
+         * But do not let this example give _anyone_ the idea that they can
+         * create a release function without any code in it at all, to do that
+         * is almost always wrong.  If you have any questions about this,
+         * please send an email to <greg@kroah.com>
+         */
 }
 
 static struct kobj_type ktype_driver = {
@@ -133,7 +147,6 @@ static decl_subsys(bus, &ktype_bus, NULL);
 
 
 #ifdef CONFIG_HOTPLUG
-
 /* Manually detach a device from its associated driver. */
 static int driver_helper(struct device *dev, void *data)
 {
@@ -199,6 +212,33 @@ static ssize_t driver_bind(struct device_driver *drv,
 }
 static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
 
+static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
+{
+        return sprintf(buf, "%d\n", bus->drivers_autoprobe);
+}
+
+static ssize_t store_drivers_autoprobe(struct bus_type *bus,
+                                       const char *buf, size_t count)
+{
+        if (buf[0] == '0')
+                bus->drivers_autoprobe = 0;
+        else
+                bus->drivers_autoprobe = 1;
+        return count;
+}
+
+static ssize_t store_drivers_probe(struct bus_type *bus,
+                                   const char *buf, size_t count)
+{
+        struct device *dev;
+
+        dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
+        if (!dev)
+                return -ENODEV;
+        if (bus_rescan_devices_helper(dev, NULL) != 0)
+                return -EINVAL;
+        return count;
+}
 #endif
 
 static struct device * next_device(struct klist_iter * i)
@@ -418,21 +458,21 @@ out_put:
  *      - Add device to bus's list of devices.
  *      - Try to attach to driver.
  */
-int bus_attach_device(struct device * dev)
+void bus_attach_device(struct device * dev)
 {
         struct bus_type *bus = dev->bus;
         int ret = 0;
 
         if (bus) {
                 dev->is_registered = 1;
-                ret = device_attach(dev);
-                if (ret >= 0) {
+                if (bus->drivers_autoprobe)
+                        ret = device_attach(dev);
+                WARN_ON(ret < 0);
+                if (ret >= 0)
                         klist_add_tail(&dev->knode_bus, &bus->klist_devices);
-                        ret = 0;
-                } else
+                else
                         dev->is_registered = 0;
         }
-        return ret;
 }
 
 /**
@@ -515,9 +555,41 @@ static void remove_bind_files(struct device_driver *drv)
         driver_remove_file(drv, &driver_attr_bind);
         driver_remove_file(drv, &driver_attr_unbind);
 }
+
+static int add_probe_files(struct bus_type *bus)
+{
+        int retval;
+
+        bus->drivers_probe_attr.attr.name = "drivers_probe";
+        bus->drivers_probe_attr.attr.mode = S_IWUSR;
+        bus->drivers_probe_attr.attr.owner = bus->owner;
+        bus->drivers_probe_attr.store = store_drivers_probe;
+        retval = bus_create_file(bus, &bus->drivers_probe_attr);
+        if (retval)
+                goto out;
+
+        bus->drivers_autoprobe_attr.attr.name = "drivers_autoprobe";
+        bus->drivers_autoprobe_attr.attr.mode = S_IWUSR | S_IRUGO;
+        bus->drivers_autoprobe_attr.attr.owner = bus->owner;
+        bus->drivers_autoprobe_attr.show = show_drivers_autoprobe;
+        bus->drivers_autoprobe_attr.store = store_drivers_autoprobe;
+        retval = bus_create_file(bus, &bus->drivers_autoprobe_attr);
+        if (retval)
+                bus_remove_file(bus, &bus->drivers_probe_attr);
+out:
+        return retval;
+}
+
+static void remove_probe_files(struct bus_type *bus)
+{
+        bus_remove_file(bus, &bus->drivers_autoprobe_attr);
+        bus_remove_file(bus, &bus->drivers_probe_attr);
+}
 #else
 static inline int add_bind_files(struct device_driver *drv) { return 0; }
 static inline void remove_bind_files(struct device_driver *drv) {}
+static inline int add_probe_files(struct bus_type *bus) { return 0; }
+static inline void remove_probe_files(struct bus_type *bus) {}
 #endif
 
 /**
@@ -531,7 +603,7 @@ int bus_add_driver(struct device_driver *drv)
         int error = 0;
 
         if (!bus)
-                return 0;
+                return -EINVAL;
 
         pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
         error = kobject_set_name(&drv->kobj, "%s", drv->name);
@@ -541,9 +613,11 @@ int bus_add_driver(struct device_driver *drv)
         if ((error = kobject_register(&drv->kobj)))
                 goto out_put_bus;
 
-        error = driver_attach(drv);
-        if (error)
-                goto out_unregister;
+        if (drv->bus->drivers_autoprobe) {
+                error = driver_attach(drv);
+                if (error)
+                        goto out_unregister;
+        }
         klist_add_tail(&drv->knode_bus, &bus->klist_drivers);
         module_add_driver(drv->owner, drv);
 
@@ -605,8 +679,6 @@ static int __must_check bus_rescan_devices_helper(struct device *dev,
                 ret = device_attach(dev);
                 if (dev->parent)
                         up(&dev->parent->sem);
-                if (ret > 0)
-                        ret = 0;
         }
         return ret < 0 ? ret : 0;
 }
@@ -762,6 +834,12 @@ int bus_register(struct bus_type * bus)
 
         klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put);
         klist_init(&bus->klist_drivers, NULL, NULL);
+
+        bus->drivers_autoprobe = 1;
+        retval = add_probe_files(bus);
+        if (retval)
+                goto bus_probe_files_fail;
+
         retval = bus_add_attrs(bus);
         if (retval)
                 goto bus_attrs_fail;
@@ -770,6 +848,8 @@ int bus_register(struct bus_type * bus)
         return 0;
 
 bus_attrs_fail:
+        remove_probe_files(bus);
+bus_probe_files_fail:
         kset_unregister(&bus->drivers);
 bus_drivers_fail:
         kset_unregister(&bus->devices);
@@ -779,7 +859,6 @@ out:
         return retval;
 }
 
-
 /**
  *      bus_unregister - remove a bus from the system
  *      @bus:   bus.
@@ -791,6 +870,7 @@ void bus_unregister(struct bus_type * bus)
 {
         pr_debug("bus %s: unregistering\n", bus->name);
         bus_remove_attrs(bus);
+        remove_probe_files(bus);
         kset_unregister(&bus->drivers);
         kset_unregister(&bus->devices);
         subsystem_unregister(&bus->subsys);