staging: pi433: add comment to rx_lock mutex definition

Checkpatch reports: CHECK: struct mutex definition without comment.
Fix this by documenting what rx_mutex struct is used for in pi433
driver.

Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
Link: https://lore.kernel.org/r/20220103232616.GA11161@mail.google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c
index 29bd37669059bbb01d58efb392ffd195101b6b5d..68c09fa016ed335e7722bf0a463a8467207901cc 100644 (file)
--- a/drivers/staging/pi433/pi433_if.c
+++ b/drivers/staging/pi433/pi433_if.c
@@ -92,7 +92,7 @@ struct pi433_device {
        u32                     rx_bytes_to_drop;
        u32                     rx_bytes_dropped;
        unsigned int            rx_position;
-       struct mutex            rx_lock;
+       struct mutex            rx_lock; /* protects rx_* variable accesses */
        wait_queue_head_t       rx_wait_queue;
 
        /* fifo wait queue */