[PATCH][next] fbdev/fb.h: Use struct_size() helper in kzalloc()

[Gustavo A. R. Silva]

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@xxxxxxxxxx>
---
 include/linux/fb.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/fb.h b/include/linux/fb.h
index 3b4b2f0c6994..2b530e6d86e4 100644
--- 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;
-- 
2.27.0