diff mbox series

[net-next,1/7] ipv4: nexthop: Reduce allocation size of 'struct nh_group'

Message ID 20200826164857.1029764-2-idosch@idosch.org
State Accepted
Delegated to: David Miller
Headers show
Series ipv4: nexthop: Various improvements | expand

Commit Message

Ido Schimmel Aug. 26, 2020, 4:48 p.m. UTC 
From: Ido Schimmel <idosch@nvidia.com>

The struct looks as follows:

struct nh_group {
	struct nh_group		*spare; /* spare group for removals */
	u16			num_nh;
	bool			mpath;
	bool			fdb_nh;
	bool			has_v4;
	struct nh_grp_entry	nh_entries[];
};

But its offset within 'struct nexthop' is also taken into account to
determine the allocation size.

Instead, use struct_size() to allocate only the required number of
bytes.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
---
 net/ipv4/nexthop.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

Comments

David Ahern Aug. 26, 2020, 7:06 p.m. UTC | #1 
On 8/26/20 10:48 AM, Ido Schimmel wrote:
> From: Ido Schimmel <idosch@nvidia.com>
> 
> The struct looks as follows:
> 
> struct nh_group {
> 	struct nh_group		*spare; /* spare group for removals */
> 	u16			num_nh;
> 	bool			mpath;
> 	bool			fdb_nh;
> 	bool			has_v4;
> 	struct nh_grp_entry	nh_entries[];
> };
> 
> But its offset within 'struct nexthop' is also taken into account to
> determine the allocation size.

must be a leftover from initial versions. Thanks for catching this.

> 
> Instead, use struct_size() to allocate only the required number of
> bytes.
> 
> Signed-off-by: Ido Schimmel <idosch@nvidia.com>
> ---
>  net/ipv4/nexthop.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
> index 134e92382275..d13730ff9aeb 100644
> --- a/net/ipv4/nexthop.c
> +++ b/net/ipv4/nexthop.c
> @@ -133,12 +133,9 @@ static struct nexthop *nexthop_alloc(void)
>  
>  static struct nh_group *nexthop_grp_alloc(u16 num_nh)
>  {
> -	size_t sz = offsetof(struct nexthop, nh_grp)
> -		    + sizeof(struct nh_group)
> -		    + sizeof(struct nh_grp_entry) * num_nh;
>  	struct nh_group *nhg;
>  
> -	nhg = kzalloc(sz, GFP_KERNEL);
> +	nhg = kzalloc(struct_size(nhg, nh_entries, num_nh), GFP_KERNEL);
>  	if (nhg)
>  		nhg->num_nh = num_nh;
>  
> 

Reviewed-by: David Ahern <dsahern@gmail.com>
diff mbox series

Patch

diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index 134e92382275..d13730ff9aeb 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -133,12 +133,9 @@  static struct nexthop *nexthop_alloc(void)
 
 static struct nh_group *nexthop_grp_alloc(u16 num_nh)
 {
-	size_t sz = offsetof(struct nexthop, nh_grp)
-		    + sizeof(struct nh_group)
-		    + sizeof(struct nh_grp_entry) * num_nh;
 	struct nh_group *nhg;
 
-	nhg = kzalloc(sz, GFP_KERNEL);
+	nhg = kzalloc(struct_size(nhg, nh_entries, num_nh), GFP_KERNEL);
 	if (nhg)
 		nhg->num_nh = num_nh;