[PATCH 17/18] HID: logitech-hidpp: manage send_mutex with devm_mutex_init()

[Dmitry Torokhov]

Manually initializing and destroying the HID++ command mutex in probe
and remove destroys the mutex before devres tears down managed child
resources such as the delayed input device and battery power supply.
Switching to devm_mutex_init() eliminates manual teardown boilerplate
while keeping the mutex valid throughout child device teardown.

Initialize the command mutex with devm_mutex_init() during probe,
returning early on allocation failure, and drop manual mutex
destruction from the error path and device removal handler.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
---
 drivers/hid/hid-logitech-hidpp.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index d0ec973a4b49..7ff7b7d8e2d2 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -4732,9 +4732,12 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	INIT_WORK(&hidpp->work, hidpp_connect_event);
 	INIT_WORK(&hidpp->reset_hi_res_work, hidpp_reset_hi_res_handler);
-	mutex_init(&hidpp->send_mutex);
 	init_waitqueue_head(&hidpp->wait);
 
+	ret = devm_mutex_init(&hdev->dev, &hidpp->send_mutex);
+	if (ret)
+		return ret;
+
 	/* indicates we are handling the battery properties in the kernel */
 	ret = sysfs_create_group(&hdev->dev.kobj, &ps_attribute_group);
 	if (ret)
@@ -4810,7 +4813,6 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	hid_hw_stop(hdev);
 hid_hw_start_fail:
 	sysfs_remove_group(&hdev->dev.kobj, &ps_attribute_group);
-	mutex_destroy(&hidpp->send_mutex);
 	return ret;
 }
 
@@ -4827,7 +4829,6 @@ static void hidpp_remove(struct hid_device *hdev)
 	disable_work_sync(&hidpp->reset_hi_res_work);
 
 	hid_hw_stop(hdev);
-	mutex_destroy(&hidpp->send_mutex);
 }
 
 #define LDJ_DEVICE(product) \
-- 
2.56.0.506.g506a7eabc5-goog