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Commit 6f68f0ac authored by Binoy Jayan's avatar Binoy Jayan Committed by Jiri Kosina
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HID: Remove the semaphore driver_lock 



The semaphore 'driver_lock' is used as a simple mutex, and also unnecessary as
suggested by Arnd. Hence removing it, as the concurrency between the probe and
remove is already handled in the driver core.

Suggested-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarBinoy Jayan <binoy.jayan@linaro.org>
Acked-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent a9d0683e

drivers/hid/hid-core.c

+4 −11
Original line number Original line Diff line number Diff line
@@ -2487,11 +2487,9 @@ static int hid_device_probe(struct device *dev) 
	const struct hid_device_id *id;

	const struct hid_device_id *id;

	int ret = 0;

	int ret = 0;





	if (down_interruptible(&hdev->driver_lock))

		return -EINTR;

	if (down_interruptible(&hdev->driver_input_lock)) {

	if (down_interruptible(&hdev->driver_input_lock)) {

		ret = -EINTR;

		ret = -EINTR;

		goto unlock_driver_lock;

		goto end;

	}

	}

	hdev->io_started = false;

	hdev->io_started = false;
@@ -2518,8 +2516,7 @@ static int hid_device_probe(struct device *dev) 
unlock:

unlock:

	if (!hdev->io_started)

	if (!hdev->io_started)

		up(&hdev->driver_input_lock);

		up(&hdev->driver_input_lock);

unlock_driver_lock:

end:

	up(&hdev->driver_lock);

	return ret;

	return ret;

}

}
@@ -2529,11 +2526,9 @@ static int hid_device_remove(struct device *dev) 
	struct hid_driver *hdrv;

	struct hid_driver *hdrv;

	int ret = 0;

	int ret = 0;





	if (down_interruptible(&hdev->driver_lock))

		return -EINTR;

	if (down_interruptible(&hdev->driver_input_lock)) {

	if (down_interruptible(&hdev->driver_input_lock)) {

		ret = -EINTR;

		ret = -EINTR;

		goto unlock_driver_lock;

		goto end;

	}

	}

	hdev->io_started = false;

	hdev->io_started = false;
@@ -2549,8 +2544,7 @@ static int hid_device_remove(struct device *dev) 




	if (!hdev->io_started)

	if (!hdev->io_started)

		up(&hdev->driver_input_lock);

		up(&hdev->driver_input_lock);

unlock_driver_lock:

end:

	up(&hdev->driver_lock);

	return ret;

	return ret;

}

}
@@ -3008,7 +3002,6 @@ struct hid_device *hid_allocate_device(void) 
	init_waitqueue_head(&hdev->debug_wait);

	init_waitqueue_head(&hdev->debug_wait);

	INIT_LIST_HEAD(&hdev->debug_list);

	INIT_LIST_HEAD(&hdev->debug_list);

	spin_lock_init(&hdev->debug_list_lock);

	spin_lock_init(&hdev->debug_list_lock);

	sema_init(&hdev->driver_lock, 1);

	sema_init(&hdev->driver_input_lock, 1);

	sema_init(&hdev->driver_input_lock, 1);

	mutex_init(&hdev->ll_open_lock);

	mutex_init(&hdev->ll_open_lock);

include/linux/hid.h

+1 −2
Original line number Original line Diff line number Diff line
@@ -526,7 +526,6 @@ struct hid_device { /* device report descriptor */ 
	struct hid_report_enum report_enum[HID_REPORT_TYPES];

	struct hid_report_enum report_enum[HID_REPORT_TYPES];

	struct work_struct led_work;					/* delayed LED worker */

	struct work_struct led_work;					/* delayed LED worker */





	struct semaphore driver_lock;					/* protects the current driver, except during input */

	struct semaphore driver_input_lock;				/* protects the current driver */

	struct semaphore driver_input_lock;				/* protects the current driver */

	struct device dev;						/* device */

	struct device dev;						/* device */

	struct hid_driver *driver;

	struct hid_driver *driver;
@@ -551,7 +550,7 @@ struct hid_device { /* device report descriptor */ 
	unsigned int status;						/* see STAT flags above */

	unsigned int status;						/* see STAT flags above */

	unsigned claimed;						/* Claimed by hidinput, hiddev? */

	unsigned claimed;						/* Claimed by hidinput, hiddev? */

	unsigned quirks;						/* Various quirks the device can pull on us */

	unsigned quirks;						/* Various quirks the device can pull on us */

	bool io_started;						/* Protected by driver_lock. If IO has started */

	bool io_started;						/* If IO has started */





	struct list_head inputs;					/* The list of inputs */

	struct list_head inputs;					/* The list of inputs */

	void *hiddev;							/* The hiddev structure */

	void *hiddev;							/* The hiddev structure */