gpio: bail out silently on NULL descriptors

linusw · linusw · commit 54d77198fdfb · 2016-05-30T16:56:41.000+02:00
In fdeb8e1 ("gpio: reflect base and ngpio into gpio_device") assumed that GPIO descriptors are either valid or error pointers, but gpiod_get_[index_]optional() actually return NULL descriptors and then all subsequent calls should just bail out. Cc: stable@vger.kernel.org Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Andrew Lunn <andrew@lunn.ch> Fixes: fdeb8e1 ("gpio: reflect base and ngpio into gpio_device") Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
@@ -1367,10 +1367,13 @@ static int __gpiod_request(struct gpio_desc *desc, const char *label)
 /*
  * This descriptor validation needs to be inserted verbatim into each
  * function taking a descriptor, so we need to use a preprocessor
- * macro to avoid endless duplication.
+ * macro to avoid endless duplication. If the desc is NULL it is an
+ * optional GPIO and calls should just bail out.
  */
 #define VALIDATE_DESC(desc) do { \
-	if (!desc || !desc->gdev) { \
+	if (!desc) \
+		return 0; \
+	if (!desc->gdev) { \
 		pr_warn("%s: invalid GPIO\n", __func__); \
 		return -EINVAL; \
 	} \
@@ -1381,7 +1384,9 @@ static int __gpiod_request(struct gpio_desc *desc, const char *label)
 	} } while (0)
 
 #define VALIDATE_DESC_VOID(desc) do { \
-	if (!desc || !desc->gdev) { \
+	if (!desc) \
+		return; \
+	if (!desc->gdev) { \
 		pr_warn("%s: invalid GPIO\n", __func__); \
 		return; \
 	} \
