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HID: Remove the semaphore driver_lock

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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: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Binoy Jayan <binoy.jayan@linaro.org>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Binoy Jayan 2017-06-14 12:59:51 +05:30 committed by Jiri Kosina
parent a9d0683e0b
commit 6f68f0ac72
2 changed files with 5 additions and 13 deletions
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15
drivers/hid/hid-core.c
View file

@ -2487,11 +2487,9 @@ 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;
@ -2518,8 +2516,7 @@ 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;
}
@ -2529,11 +2526,9 @@ 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;
@ -2549,8 +2544,7 @@ 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;
}
@ -3008,7 +3002,6 @@ 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);

3
include/linux/hid.h
View file

@ -526,7 +526,6 @@ struct hid_device { /* device report descriptor */
struct hid_report_enum report_enum[HID_REPORT_TYPES];
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 device dev; /* device */
struct hid_driver *driver;
@ -551,7 +550,7 @@ struct hid_device { /* device report descriptor */
unsigned int status; /* see STAT flags above */
unsigned claimed; /* Claimed by hidinput, hiddev? */
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 */
void *hiddev; /* The hiddev structure */