1 files changed, 153 insertions, 28 deletions

diff --git a/drivers/input/input.c b/drivers/input/input.c
index 53a0ddee787..ce01332f7b3 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -534,8 +534,11 @@ EXPORT_SYMBOL(input_grab_device);
 static void __input_release_device(struct input_handle *handle)
 {
         struct input_dev *dev = handle->dev;
+        struct input_handle *grabber;
 
-        if (dev->grab == handle) {
+        grabber = rcu_dereference_protected(dev->grab,
+                                            lockdep_is_held(&dev->mutex));
+        if (grabber == handle) {
                 rcu_assign_pointer(dev->grab, NULL);
                 /* Make sure input_pass_event() notices that grab is gone */
                 synchronize_rcu();
@@ -1723,7 +1726,7 @@ EXPORT_SYMBOL_GPL(input_class);
 /**
  * input_allocate_device - allocate memory for new input device
  *
- * Returns prepared struct input_dev or NULL.
+ * Returns prepared struct input_dev or %NULL.
  *
  * NOTE: Use input_free_device() to free devices that have not been
  * registered; input_unregister_device() should be used for already
@@ -1750,6 +1753,70 @@ struct input_dev *input_allocate_device(void)
 }
 EXPORT_SYMBOL(input_allocate_device);
 
+struct input_devres {
+        struct input_dev *input;
+};
+
+static int devm_input_device_match(struct device *dev, void *res, void *data)
+{
+        struct input_devres *devres = res;
+
+        return devres->input == data;
+}
+
+static void devm_input_device_release(struct device *dev, void *res)
+{
+        struct input_devres *devres = res;
+        struct input_dev *input = devres->input;
+
+        dev_dbg(dev, "%s: dropping reference to %s\n",
+                __func__, dev_name(&input->dev));
+        input_put_device(input);
+}
+
+/**
+ * devm_input_allocate_device - allocate managed input device
+ * @dev: device owning the input device being created
+ *
+ * Returns prepared struct input_dev or %NULL.
+ *
+ * Managed input devices do not need to be explicitly unregistered or
+ * freed as it will be done automatically when owner device unbinds from
+ * its driver (or binding fails). Once managed input device is allocated,
+ * it is ready to be set up and registered in the same fashion as regular
+ * input device. There are no special devm_input_device_[un]register()
+ * variants, regular ones work with both managed and unmanaged devices.
+ *
+ * NOTE: the owner device is set up as parent of input device and users
+ * should not override it.
+ */
+
+struct input_dev *devm_input_allocate_device(struct device *dev)
+{
+        struct input_dev *input;
+        struct input_devres *devres;
+
+        devres = devres_alloc(devm_input_device_release,
+                              sizeof(struct input_devres), GFP_KERNEL);
+        if (!devres)
+                return NULL;
+
+        input = input_allocate_device();
+        if (!input) {
+                devres_free(devres);
+                return NULL;
+        }
+
+        input->dev.parent = dev;
+        input->devres_managed = true;
+
+        devres->input = input;
+        devres_add(dev, devres);
+
+        return input;
+}
+EXPORT_SYMBOL(devm_input_allocate_device);
+
 /**
  * input_free_device - free memory occupied by input_dev structure
  * @dev: input device to free
@@ -1766,8 +1833,14 @@ EXPORT_SYMBOL(input_allocate_device);
  */
 void input_free_device(struct input_dev *dev)
 {
-        if (dev)
+        if (dev) {
+                if (dev->devres_managed)
+                        WARN_ON(devres_destroy(dev->dev.parent,
+                                                devm_input_device_release,
+                                                devm_input_device_match,
+                                                dev));
                 input_put_device(dev);
+        }
 }
 EXPORT_SYMBOL(input_free_device);
 
@@ -1888,6 +1961,38 @@ static void input_cleanse_bitmasks(struct input_dev *dev)
         INPUT_CLEANSE_BITMASK(dev, SW, sw);
 }
 
+static void __input_unregister_device(struct input_dev *dev)
+{
+        struct input_handle *handle, *next;
+
+        input_disconnect_device(dev);
+
+        mutex_lock(&input_mutex);
+
+        list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
+                handle->handler->disconnect(handle);
+        WARN_ON(!list_empty(&dev->h_list));
+
+        del_timer_sync(&dev->timer);
+        list_del_init(&dev->node);
+
+        input_wakeup_procfs_readers();
+
+        mutex_unlock(&input_mutex);
+
+        device_del(&dev->dev);
+}
+
+static void devm_input_device_unregister(struct device *dev, void *res)
+{
+        struct input_devres *devres = res;
+        struct input_dev *input = devres->input;
+
+        dev_dbg(dev, "%s: unregistering device %s\n",
+                __func__, dev_name(&input->dev));
+        __input_unregister_device(input);
+}
+
 /**
  * input_register_device - register device with input core
  * @dev: device to be registered
@@ -1903,11 +2008,21 @@ static void input_cleanse_bitmasks(struct input_dev *dev)
 int input_register_device(struct input_dev *dev)
 {
         static atomic_t input_no = ATOMIC_INIT(0);
+        struct input_devres *devres = NULL;
         struct input_handler *handler;
         unsigned int packet_size;
         const char *path;
         int error;
 
+        if (dev->devres_managed) {
+                devres = devres_alloc(devm_input_device_unregister,
+                                      sizeof(struct input_devres), GFP_KERNEL);
+                if (!devres)
+                        return -ENOMEM;
+
+                devres->input = dev;
+        }
+
         /* Every input device generates EV_SYN/SYN_REPORT events. */
         __set_bit(EV_SYN, dev->evbit);
 
@@ -1923,8 +2038,10 @@ int input_register_device(struct input_dev *dev)
 
         dev->max_vals = max(dev->hint_events_per_packet, packet_size) + 2;
         dev->vals = kcalloc(dev->max_vals, sizeof(*dev->vals), GFP_KERNEL);
-        if (!dev->vals)
-                return -ENOMEM;
+        if (!dev->vals) {
+                error = -ENOMEM;
+                goto err_devres_free;
+        }
 
         /*
          * If delay and period are pre-set by the driver, then autorepeating
@@ -1949,7 +2066,7 @@ int input_register_device(struct input_dev *dev)
 
         error = device_add(&dev->dev);
         if (error)
-                return error;
+                goto err_free_vals;
 
         path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
         pr_info("%s as %s\n",
@@ -1958,10 +2075,8 @@ int input_register_device(struct input_dev *dev)
         kfree(path);
 
         error = mutex_lock_interruptible(&input_mutex);
-        if (error) {
-                device_del(&dev->dev);
-                return error;
-        }
+        if (error)
+                goto err_device_del;
 
         list_add_tail(&dev->node, &input_dev_list);
 
@@ -1972,7 +2087,21 @@ int input_register_device(struct input_dev *dev)
 
         mutex_unlock(&input_mutex);
 
+        if (dev->devres_managed) {
+                dev_dbg(dev->dev.parent, "%s: registering %s with devres.\n",
+                        __func__, dev_name(&dev->dev));
+                devres_add(dev->dev.parent, devres);
+        }
         return 0;
+
+err_device_del:
+        device_del(&dev->dev);
+err_free_vals:
+        kfree(dev->vals);
+        dev->vals = NULL;
+err_devres_free:
+        devres_free(devres);
+        return error;
 }
 EXPORT_SYMBOL(input_register_device);
 
@@ -1985,24 +2114,20 @@ EXPORT_SYMBOL(input_register_device);
  */
 void input_unregister_device(struct input_dev *dev)
 {
-        struct input_handle *handle, *next;
-
-        input_disconnect_device(dev);
-
-        mutex_lock(&input_mutex);
-
-        list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
-                handle->handler->disconnect(handle);
-        WARN_ON(!list_empty(&dev->h_list));
-
-        del_timer_sync(&dev->timer);
-        list_del_init(&dev->node);
-
-        input_wakeup_procfs_readers();
-
-        mutex_unlock(&input_mutex);
-
-        device_unregister(&dev->dev);
+        if (dev->devres_managed) {
+                WARN_ON(devres_destroy(dev->dev.parent,
+                                        devm_input_device_unregister,
+                                        devm_input_device_match,
+                                        dev));
+                __input_unregister_device(dev);
+                /*
+                 * We do not do input_put_device() here because it will be done
+                 * when 2nd devres fires up.
+                 */
+        } else {
+                __input_unregister_device(dev);
+                input_put_device(dev);
+        }
 }
 EXPORT_SYMBOL(input_unregister_device);