* [PATCH net-next] mpls_iptunnel: use struct_size() helper
@ 2019-02-08 1:10 Gustavo A. R. Silva
2019-02-09 6:57 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2019-02-08 1:10 UTC (permalink / raw)
To: David S. Miller; +Cc: netdev, linux-kernel, Gustavo A. R. Silva
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[];
};
instance = alloc(sizeof(struct foo) + count * sizeof(struct boo));
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = alloc(struct_size(instance, entry, count));
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
net/mpls/mpls_iptunnel.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
index 94f53a9b7d1a..dda8930f20e7 100644
--- a/net/mpls/mpls_iptunnel.c
+++ b/net/mpls/mpls_iptunnel.c
@@ -183,8 +183,8 @@ static int mpls_build_state(struct nlattr *nla,
&n_labels, NULL, extack))
return -EINVAL;
- newts = lwtunnel_state_alloc(sizeof(*tun_encap_info) +
- n_labels * sizeof(u32));
+ newts = lwtunnel_state_alloc(struct_size(tun_encap_info, label,
+ n_labels));
if (!newts)
return -ENOMEM;
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net-next] mpls_iptunnel: use struct_size() helper
2019-02-08 1:10 [PATCH net-next] mpls_iptunnel: use struct_size() helper Gustavo A. R. Silva
@ 2019-02-09 6:57 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2019-02-09 6:57 UTC (permalink / raw)
To: gustavo; +Cc: netdev, linux-kernel
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Thu, 7 Feb 2019 19:10:52 -0600
> 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[];
> };
>
> instance = alloc(sizeof(struct foo) + count * sizeof(struct boo));
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = alloc(struct_size(instance, entry, count));
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Applied.
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