[PATCH v4 3/7] ACPI: button: Access input device's users under appropriate mutex

[Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx>]

Inspecting input device's 'users' member should be done under device's
mutex, so add appropriate invocations.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx>
---
 drivers/acpi/button.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
index 78cfc70cb320..ff7ab291f678 100644
--- a/drivers/acpi/button.c
+++ b/drivers/acpi/button.c
@@ -456,13 +456,16 @@ static int acpi_button_resume(struct device *dev)
 {
 	struct acpi_device *device = to_acpi_device(dev);
 	struct acpi_button *button = acpi_driver_data(device);
+	struct input_dev *input = button->input;
 
 	button->suspended = false;
-	if (button->type == ACPI_BUTTON_TYPE_LID && button->input->users) {
+	mutex_lock(&input->mutex);
+	if (button->type == ACPI_BUTTON_TYPE_LID && input->users) {
 		button->last_state = !!acpi_lid_evaluate_state(device);
 		button->last_time = ktime_get();
 		acpi_lid_initialize_state(device);
 	}
+	mutex_unlock(&input->mutex);
 	return 0;
 }
 #endif
-- 
2.17.1