* [PATCH net-next] flow_offload: use struct_size() in kzalloc()
@ 2019-05-23 22:56 Gustavo A. R. Silva
2019-05-25 17:59 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2019-05-23 22:56 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 = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), 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@embeddedor.com>
---
net/core/flow_offload.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/net/core/flow_offload.c b/net/core/flow_offload.c
index 5ce7d47a960e..3d93e51b83e0 100644
--- a/net/core/flow_offload.c
+++ b/net/core/flow_offload.c
@@ -7,8 +7,7 @@ struct flow_rule *flow_rule_alloc(unsigned int num_actions)
{
struct flow_rule *rule;
- rule = kzalloc(sizeof(struct flow_rule) +
- sizeof(struct flow_action_entry) * num_actions,
+ rule = kzalloc(struct_size(rule, action.entries, num_actions),
GFP_KERNEL);
if (!rule)
return NULL;
--
2.21.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net-next] flow_offload: use struct_size() in kzalloc()
2019-05-23 22:56 [PATCH net-next] flow_offload: use struct_size() in kzalloc() Gustavo A. R. Silva
@ 2019-05-25 17:59 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2019-05-25 17:59 UTC (permalink / raw)
To: gustavo; +Cc: netdev, linux-kernel
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Thu, 23 May 2019 17:56:53 -0500
> 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 = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), 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@embeddedor.com>
Applied.
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