fbdev/fb.h: Use struct_size() helper in kzalloc()

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

This code was detected with the help of Coccinelle and, audited and
fixed manually.

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200617175647.GA26370@embeddedor

diff --git a/include/linux/fb.h b/include/linux/fb.h
index 3b4b2f0..2b530e6 100644 (file)
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -506,8 +506,9 @@ struct fb_info {
 };
 
 static inline struct apertures_struct *alloc_apertures(unsigned int max_num) {
-       struct apertures_struct *a = kzalloc(sizeof(struct apertures_struct)
-                       + max_num * sizeof(struct aperture), GFP_KERNEL);
+       struct apertures_struct *a;
+
+       a = kzalloc(struct_size(a, ranges, max_num), GFP_KERNEL);
        if (!a)
                return NULL;
        a->count = max_num;