Merge branch 'for-4.14/driver-lock-removal' into for-linus

- Arnd pointed out that driver_lock semaphore is superfluous, as
  driver core already provides all the necessary concurency protection.
  Removal patch from Binoy Jayan

1 files changed, 4 insertions, 11 deletions

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index d946d561e064..9bc91160819b 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -2488,11 +2488,9 @@ static int hid_device_probe(struct device *dev)
 	const struct hid_device_id *id;
 	int ret = 0;
 
-	if (down_interruptible(&hdev->driver_lock))
-		return -EINTR;
 	if (down_interruptible(&hdev->driver_input_lock)) {
 		ret = -EINTR;
-		goto unlock_driver_lock;
+		goto end;
 	}
 	hdev->io_started = false;
 
@@ -2519,8 +2517,7 @@ static int hid_device_probe(struct device *dev)
 unlock:
 	if (!hdev->io_started)
 		up(&hdev->driver_input_lock);
-unlock_driver_lock:
-	up(&hdev->driver_lock);
+end:
 	return ret;
 }
 
@@ -2530,11 +2527,9 @@ static int hid_device_remove(struct device *dev)
 	struct hid_driver *hdrv;
 	int ret = 0;
 
-	if (down_interruptible(&hdev->driver_lock))
-		return -EINTR;
 	if (down_interruptible(&hdev->driver_input_lock)) {
 		ret = -EINTR;
-		goto unlock_driver_lock;
+		goto end;
 	}
 	hdev->io_started = false;
 
@@ -2550,8 +2545,7 @@ static int hid_device_remove(struct device *dev)
 
 	if (!hdev->io_started)
 		up(&hdev->driver_input_lock);
-unlock_driver_lock:
-	up(&hdev->driver_lock);
+end:
 	return ret;
 }
 
@@ -3009,7 +3003,6 @@ struct hid_device *hid_allocate_device(void)
 	init_waitqueue_head(&hdev->debug_wait);
 	INIT_LIST_HEAD(&hdev->debug_list);
 	spin_lock_init(&hdev->debug_list_lock);
-	sema_init(&hdev->driver_lock, 1);
 	sema_init(&hdev->driver_input_lock, 1);
 	mutex_init(&hdev->ll_open_lock);