[PATCH 14/18] HID: logitech-hidpp: use guard() for send_mutex

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Manual mutex_lock() and mutex_unlock() calls force early loop exits to
break to a shared unlock path instead of returning directly. Convert
hidpp_send_message_sync() to use guard(mutex) so lock release is bound
to the function scope and busy-retry exits can return immediately.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/hid/hid-logitech-hidpp.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 3a3baeb9fbb9..bf13e5fbe142 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -361,24 +361,22 @@ static int hidpp_send_message_sync(struct hidpp_device *hidpp,
 	int ret;
 	int max_retries = 3;
 
-	mutex_lock(&hidpp->send_mutex);
+	guard(mutex)(&hidpp->send_mutex);
 
 	do {
 		ret = __do_hidpp_send_message_sync(hidpp, message, response);
 		if (response->report_id == REPORT_ID_HIDPP_SHORT &&
 		    ret != HIDPP_ERROR_BUSY)
-			break;
+			return ret;
 		if ((response->report_id == REPORT_ID_HIDPP_LONG ||
 		     response->report_id == REPORT_ID_HIDPP_VERY_LONG) &&
 		    ret != HIDPP20_ERROR_BUSY)
-			break;
+			return ret;
 
 		dbg_hid("%s:got busy hidpp error %02X, retrying\n", __func__, ret);
 	} while (--max_retries);
 
-	mutex_unlock(&hidpp->send_mutex);
 	return ret;
-
 }
 
 /*
-- 
2.56.0.506.g506a7eabc5-goog