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Commit 68cc444d authored by Kees Cook's avatar Kees Cook Committed by David S. Miller
Browse files

mdio-mux-gpio: Remove VLA usage 

In the quest to remove all stack VLA usage from the kernel[1], this
allocates the values buffer during the callback instead of putting it
on the stack.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com



Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a6e65e5d

drivers/net/phy/mdio-mux-gpio.c

+14 −8
Original line number Diff line number Diff line
@@ -20,23 +20,23 @@ 
struct mdio_mux_gpio_state {

	struct gpio_descs *gpios;

	void *mux_handle;

	int values[];

};



static int mdio_mux_gpio_switch_fn(int current_child, int desired_child,

				   void *data)

{

	struct mdio_mux_gpio_state *s = data;

	int values[s->gpios->ndescs];

	unsigned int n;



	if (current_child == desired_child)

		return 0;



	for (n = 0; n < s->gpios->ndescs; n++)

		values[n] = (desired_child >> n) & 1;

		s->values[n] = (desired_child >> n) & 1;



	gpiod_set_array_value_cansleep(s->gpios->ndescs, s->gpios->desc,

				       values);

				       s->values);



	return 0;

}
@@ -44,15 +44,21 @@ static int mdio_mux_gpio_switch_fn(int current_child, int desired_child, 
static int mdio_mux_gpio_probe(struct platform_device *pdev)

{

	struct mdio_mux_gpio_state *s;

	struct gpio_descs *gpios;

	int r;



	s = devm_kzalloc(&pdev->dev, sizeof(*s), GFP_KERNEL);

	if (!s)

	gpios = gpiod_get_array(&pdev->dev, NULL, GPIOD_OUT_LOW);

	if (IS_ERR(gpios))

		return PTR_ERR(gpios);



	s = devm_kzalloc(&pdev->dev, struct_size(s, values, gpios->ndescs),

			 GFP_KERNEL);

	if (!s) {

		gpiod_put_array(gpios);

		return -ENOMEM;

	}



	s->gpios = gpiod_get_array(&pdev->dev, NULL, GPIOD_OUT_LOW);

	if (IS_ERR(s->gpios))

		return PTR_ERR(s->gpios);

	s->gpios = gpios;



	r = mdio_mux_init(&pdev->dev, pdev->dev.of_node,

			  mdio_mux_gpio_switch_fn, &s->mux_handle, s, NULL);