Commit 29adeb4f authored Aug 26, 2018 by Gustavo A. R. Silva Committed by Heiko Stuebner Aug 29, 2018

drm/rockchip: Use struct_size() in devm_kzalloc()



One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
	int stuff;
        void *entry[];
};

instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

or, like in this particular case:

size = sizeof(struct foo) + sizeof(void *) * count;
instance = devm_kzalloc(dev, size, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = devm_kzalloc(dev, struct_size(instance, entry, count),
GFP_KERNEL);

This issue was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20180826184712.GA9330@embeddedor.com

parent dc879f61

drivers/gpu/drm/rockchip/rockchip_drm_vop.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -32,6 +32,7 @@
		#include <linux/of_device.h>
		#include <linux/pm_runtime.h>
		#include <linux/component.h>
		#include <linux/overflow.h>

		#include <linux/reset.h>
		#include <linux/delay.h>
		@@ -1579,7 +1580,6 @@ static int vop_bind(struct device dev, struct device master, void *data)
		struct drm_device *drm_dev = data;
		struct vop *vop;
		struct resource *res;
		size_t alloc_size;
		int ret, irq;

		vop_data = of_device_get_match_data(dev);
		@@ -1587,8 +1587,8 @@ static int vop_bind(struct device dev, struct device master, void *data)
		return -ENODEV;

		/* Allocate vop struct and its vop_win array */
		alloc_size = sizeof(vop) + sizeof(vop->win) * vop_data->win_size;
		vop = devm_kzalloc(dev, alloc_size, GFP_KERNEL);
		vop = devm_kzalloc(dev, struct_size(vop, win, vop_data->win_size),
		GFP_KERNEL);
		if (!vop)
		return -ENOMEM;

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