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 mmp_path {
...
struct mmp_overlay overlays[0];
};
size = sizeof(struct mmp_path) + count * sizeof(struct mmp_overlay);
instance = kzalloc(size, GFP_KERNEL)
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kzalloc(struct_size(instance, overlays, count), GFP_KERNEL)
Notice that, in this case, variable size is not necessary, hence it
is removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
drivers/video/fbdev/mmp/core.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/video/fbdev/mmp/core.c b/drivers/video/fbdev/mmp/core.c
index 0ffc1b7b7052..154127256a2c 100644
--- a/drivers/video/fbdev/mmp/core.c
+++ b/drivers/video/fbdev/mmp/core.c
@@ -153,13 +153,11 @@ EXPORT_SYMBOL_GPL(mmp_get_path);
struct mmp_path *mmp_register_path(struct mmp_path_info *info)
{
int i;
- size_t size;
struct mmp_path *path = NULL;
struct mmp_panel *panel;
- size = sizeof(struct mmp_path)
- + sizeof(struct mmp_overlay) * info->overlay_num;
- path = kzalloc(size, GFP_KERNEL);
+ path = kzalloc(struct_size(path, overlays, info->overlay_num),
+ GFP_KERNEL);
if (!path)
return NULL;
--
2.22.0
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