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 = 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, entry, 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 <[email protected]>
---
drivers/net/ethernet/intel/i40e/i40e_client.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e_client.c b/drivers/net/ethernet/intel/i40e/i40e_client.c
index 5f3b8b9ff511..e81530ca08d0 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_client.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_client.c
@@ -578,11 +578,9 @@ static int i40e_client_setup_qvlist(struct i40e_info *ldev,
struct i40e_hw *hw = &pf->hw;
struct i40e_qv_info *qv_info;
u32 v_idx, i, reg_idx, reg;
- u32 size;
- size = sizeof(struct i40e_qvlist_info) +
- (sizeof(struct i40e_qv_info) * (qvlist_info->num_vectors - 1));
- ldev->qvlist_info = kzalloc(size, GFP_KERNEL);
+ ldev->qvlist_info = kzalloc(struct_size(ldev->qvlist_info, qv_info,
+ qvlist_info->num_vectors - 1), GFP_KERNEL);
if (!ldev->qvlist_info)
return -ENOMEM;
ldev->qvlist_info->num_vectors = qvlist_info->num_vectors;
--
2.21.0
On Thu, 2019-03-28 at 12:52 -0500, Gustavo A. R. Silva wrote:
> 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 = 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, entry, 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 <[email protected]>
> ---
> drivers/net/ethernet/intel/i40e/i40e_client.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
Thanks Gustavo, I will queue this up.