[PATCH 15/62] Input: synaptics-rmi4 - fix a locking bug in an error path

[Bart Van Assche]

Lock f54->data_mutex before the first 'goto error' statement since
jumping to the 'error' label causes that mutex to be unlocked.

This bug has been detected by the Clang thread-safety checker.

Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Cc: Nick Dyer <nick@xxxxxxxxxxxxx>
Cc: linux-input@xxxxxxxxxxxxxxx
Fixes: 3a762dbd5347 ("[media] Input: synaptics-rmi4 - add support for F54 diagnostics")
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
 drivers/input/rmi4/rmi_f54.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/input/rmi4/rmi_f54.c b/drivers/input/rmi4/rmi_f54.c
index ac4041a69fcd..fd57ebb1cb50 100644
--- a/drivers/input/rmi4/rmi_f54.c
+++ b/drivers/input/rmi4/rmi_f54.c
@@ -539,6 +539,9 @@ static void rmi_f54_work(struct work_struct *work)
 	int i;
 
 	report_size = rmi_f54_get_report_size(f54);
+
+	mutex_lock(&f54->data_mutex);
+
 	if (report_size == 0) {
 		dev_err(&fn->dev, "Bad report size, report type=%d\n",
 				f54->report_type);
@@ -546,8 +549,6 @@ static void rmi_f54_work(struct work_struct *work)
 		goto error;     /* retry won't help */
 	}
 
-	mutex_lock(&f54->data_mutex);
-
 	/*
 	 * Need to check if command has completed.
 	 * If not try again later.