[PATCH net-next] mlxsw: spectrum_nve: Use struct_size() in kzalloc()

[PATCH net-next] mlxsw: spectrum_nve: Use struct_size() in kzalloc()

[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 issue was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_nve.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_nve.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_nve.c
index fb1c48c698f2..9019548d731b 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_nve.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_nve.c
@@ -267,8 +267,8 @@ mlxsw_sp_nve_mc_record_create(struct mlxsw_sp *mlxsw_sp,
 	struct mlxsw_sp_nve_mc_record *mc_record;
 	int err;
 
-	mc_record = kzalloc(sizeof(*mc_record) + num_max_entries *
-			    sizeof(struct mlxsw_sp_nve_mc_entry), GFP_KERNEL);
+	mc_record = kzalloc(struct_size(mc_record, entries, num_max_entries),
+			    GFP_KERNEL);
 	if (!mc_record)
 		return ERR_PTR(-ENOMEM);
 
-- 
2.20.1

Re: [PATCH net-next] mlxsw: spectrum_nve: Use struct_size() in kzalloc()

[Ido Schimmel]

On Tue, Jan 15, 2019 at 05:14:29PM -0600, 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[];
> };
> 
> 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 issue was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Reviewed-by: Ido Schimmel <idosch@mellanox.com>

Re: [PATCH net-next] mlxsw: spectrum_nve: Use struct_size() in kzalloc()

[David Miller]

From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Tue, 15 Jan 2019 17:14:29 -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 = 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 issue was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Applied.