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
This commit is contained in:
Gustavo A. R. Silva 2018-08-26 13:47:12 -05:00 committed by Heiko Stuebner
parent dc879f61c4
commit 29adeb4f95

View File

@ -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;