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;
struct boo entry[];
};
size = sizeof(struct foo) + count * sizeof(struct boo);
instance = alloc(size, GFP_KERNEL)
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
size = struct_size(instance, entry, count);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
net/netfilter/ipvs/ip_vs_ctl.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 7d6318664eb2..bcd9112f47d9 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2734,8 +2734,7 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
int size;
get = (struct ip_vs_get_services *)arg;
- size = sizeof(*get) +
- sizeof(struct ip_vs_service_entry) * get->num_services;
+ size = struct_size(get, entrytable, get->num_services);
if (*len != size) {
pr_err("length: %u != %u\n", *len, size);
ret = -EINVAL;
@@ -2776,8 +2775,7 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
int size;
get = (struct ip_vs_get_dests *)arg;
- size = sizeof(*get) +
- sizeof(struct ip_vs_dest_entry) * get->num_dests;
+ size = struct_size(get, entrytable, get->num_dests);
if (*len != size) {
pr_err("length: %u != %u\n", *len, size);
ret = -EINVAL;
--
2.20.1
