1 files changed, 89 insertions, 37 deletions

diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 8c0d33e182fd..8ab010ddf709 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -31,6 +31,81 @@ static struct device *next_device(struct klist_iter *i)
 }
 
 /**
+ * driver_set_override() - Helper to set or clear driver override.
+ * @dev: Device to change
+ * @override: Address of string to change (e.g. &device->driver_override);
+ *            The contents will be freed and hold newly allocated override.
+ * @s: NUL-terminated string, new driver name to force a match, pass empty
+ *     string to clear it ("" or "\n", where the latter is only for sysfs
+ *     interface).
+ * @len: length of @s
+ *
+ * Helper to set or clear driver override in a device, intended for the cases
+ * when the driver_override field is allocated by driver/bus code.
+ *
+ * Returns: 0 on success or a negative error code on failure.
+ */
+int driver_set_override(struct device *dev, const char **override,
+			const char *s, size_t len)
+{
+	const char *new, *old;
+	char *cp;
+
+	if (!override || !s)
+		return -EINVAL;
+
+	/*
+	 * The stored value will be used in sysfs show callback (sysfs_emit()),
+	 * which has a length limit of PAGE_SIZE and adds a trailing newline.
+	 * Thus we can store one character less to avoid truncation during sysfs
+	 * show.
+	 */
+	if (len >= (PAGE_SIZE - 1))
+		return -EINVAL;
+
+	/*
+	 * Compute the real length of the string in case userspace sends us a
+	 * bunch of \0 characters like python likes to do.
+	 */
+	len = strlen(s);
+
+	if (!len) {
+		/* Empty string passed - clear override */
+		device_lock(dev);
+		old = *override;
+		*override = NULL;
+		device_unlock(dev);
+		kfree(old);
+
+		return 0;
+	}
+
+	cp = strnchr(s, len, '\n');
+	if (cp)
+		len = cp - s;
+
+	new = kstrndup(s, len, GFP_KERNEL);
+	if (!new)
+		return -ENOMEM;
+
+	device_lock(dev);
+	old = *override;
+	if (cp != s) {
+		*override = new;
+	} else {
+		/* "\n" passed - clear override */
+		kfree(new);
+		*override = NULL;
+	}
+	device_unlock(dev);
+
+	kfree(old);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(driver_set_override);
+
+/**
  * driver_for_each_device - Iterator for devices bound to a driver.
  * @drv: Driver we're iterating.
  * @start: Device to begin with
@@ -40,7 +115,7 @@ static struct device *next_device(struct klist_iter *i)
  * Iterate over the @drv's list of devices calling @fn for each one.
  */
 int driver_for_each_device(struct device_driver *drv, struct device *start,
-			   void *data, int (*fn)(struct device *, void *))
+			   void *data, device_iter_t fn)
 {
 	struct klist_iter i;
 	struct device *dev;
@@ -73,9 +148,9 @@ EXPORT_SYMBOL_GPL(driver_for_each_device);
  * if it does.  If the callback returns non-zero, this function will
  * return to the caller and not iterate over any more devices.
  */
-struct device *driver_find_device(struct device_driver *drv,
+struct device *driver_find_device(const struct device_driver *drv,
 				  struct device *start, const void *data,
-				  int (*match)(struct device *dev, const void *data))
+				  device_match_t match)
 {
 	struct klist_iter i;
 	struct device *dev;
@@ -85,9 +160,12 @@ struct device *driver_find_device(struct device_driver *drv,
 
 	klist_iter_init_node(&drv->p->klist_devices, &i,
 			     (start ? &start->p->knode_driver : NULL));
-	while ((dev = next_device(&i)))
-		if (match(dev, data) && get_device(dev))
+	while ((dev = next_device(&i))) {
+		if (match(dev, data)) {
+			get_device(dev);
 			break;
+		}
+	}
 	klist_iter_exit(&i);
 	return dev;
 }
@@ -98,7 +176,7 @@ EXPORT_SYMBOL_GPL(driver_find_device);
  * @drv: driver.
  * @attr: driver attribute descriptor.
  */
-int driver_create_file(struct device_driver *drv,
+int driver_create_file(const struct device_driver *drv,
 		       const struct driver_attribute *attr)
 {
 	int error;
@@ -116,7 +194,7 @@ EXPORT_SYMBOL_GPL(driver_create_file);
  * @drv: driver.
  * @attr: driver attribute descriptor.
  */
-void driver_remove_file(struct device_driver *drv,
+void driver_remove_file(const struct device_driver *drv,
 			const struct driver_attribute *attr)
 {
 	if (drv)
@@ -124,13 +202,13 @@ void driver_remove_file(struct device_driver *drv,
 }
 EXPORT_SYMBOL_GPL(driver_remove_file);
 
-int driver_add_groups(struct device_driver *drv,
+int driver_add_groups(const struct device_driver *drv,
 		      const struct attribute_group **groups)
 {
 	return sysfs_create_groups(&drv->p->kobj, groups);
 }
 
-void driver_remove_groups(struct device_driver *drv,
+void driver_remove_groups(const struct device_driver *drv,
 			  const struct attribute_group **groups)
 {
 	sysfs_remove_groups(&drv->p->kobj, groups);
@@ -149,7 +227,7 @@ int driver_register(struct device_driver *drv)
 	int ret;
 	struct device_driver *other;
 
-	if (!drv->bus->p) {
+	if (!bus_is_registered(drv->bus)) {
 		pr_err("Driver '%s' was unable to register with bus_type '%s' because the bus was not initialized.\n",
 			   drv->name, drv->bus->name);
 		return -EINVAL;
@@ -177,6 +255,7 @@ int driver_register(struct device_driver *drv)
 		return ret;
 	}
 	kobject_uevent(&drv->p->kobj, KOBJ_ADD);
+	deferred_probe_extend_timeout();
 
 	return ret;
 }
@@ -198,30 +277,3 @@ void driver_unregister(struct device_driver *drv)
 	bus_remove_driver(drv);
 }
 EXPORT_SYMBOL_GPL(driver_unregister);
-
-/**
- * driver_find - locate driver on a bus by its name.
- * @name: name of the driver.
- * @bus: bus to scan for the driver.
- *
- * Call kset_find_obj() to iterate over list of drivers on
- * a bus to find driver by name. Return driver if found.
- *
- * This routine provides no locking to prevent the driver it returns
- * from being unregistered or unloaded while the caller is using it.
- * The caller is responsible for preventing this.
- */
-struct device_driver *driver_find(const char *name, struct bus_type *bus)
-{
-	struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
-	struct driver_private *priv;
-
-	if (k) {
-		/* Drop reference added by kset_find_obj() */
-		kobject_put(k);
-		priv = to_driver(k);
-		return priv->driver;
-	}
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(driver_find);