[PATCH 1/6] afs: Use struct_size() in kzalloc()

From: David Howells
Date: Thu Jan 17 2019 - 10:27:41 EST

From: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>

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 = kzalloc(sizeof(struct foo) + sizeof(void *) * count, 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, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>

fs/afs/server_list.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/afs/server_list.c b/fs/afs/server_list.c
index 95d0761cdb34..155dc14caef9 100644
--- a/fs/afs/server_list.c
+++ b/fs/afs/server_list.c
@@ -42,9 +42,7 @@ struct afs_server_list *afs_alloc_server_list(struct afs_cell *cell,
if (vldb->fs_mask[i] & type_mask)

- slist = kzalloc(sizeof(struct afs_server_list) +
- sizeof(struct afs_server_entry) * nr_servers,
+ slist = kzalloc(struct_size(slist, servers, nr_servers), GFP_KERNEL);
if (!slist)
goto error;