On Tue, 2017-10-31 at 23:10 +0900, David S. Miller wrote:
> Only IPSEC routes have a non-NULL dst->child pointer. And IPSEC
> routes are identified by a non-NULL dst->xfrm pointer.
>
> Signed-off-by: David S. Miller <da...@davemloft.net>
> ---
> include/net/xfrm.h | 9 +++++++++
> net/core/dst.c | 8 +++++---
> net/ipv4/xfrm4_mode_tunnel.c | 2 +-
> net/ipv6/xfrm6_mode_tunnel.c | 2 +-
> net/ipv6/xfrm6_policy.c | 2 +-
> net/xfrm/xfrm_output.c | 2 +-
> net/xfrm/xfrm_policy.c | 12 ++++++------
> security/selinux/xfrm.c | 2 +-
> 8 files changed, 25 insertions(+), 14 deletions(-)
>
> diff --git a/include/net/xfrm.h b/include/net/xfrm.h
> index f002a2c5e33c..be599f9bb60d 100644
> --- a/include/net/xfrm.h
> +++ b/include/net/xfrm.h
> @@ -993,6 +993,15 @@ struct xfrm_dst {
> u32 path_cookie;
> };
>
> +static inline struct dst_entry *xfrm_dst_child(const struct dst_entry *dst)
> +{
> +#ifdef CONFIG_XFRM
> + if (dst->xfrm)
> + return dst->child;
> +#endif
> + return NULL;
> +}
> +
> #ifdef CONFIG_XFRM
> static inline void xfrm_dst_destroy(struct xfrm_dst *xdst)
> {
> diff --git a/net/core/dst.c b/net/core/dst.c
> index 662a2d4a3d19..6a3c21b8fc8d 100644
> --- a/net/core/dst.c
> +++ b/net/core/dst.c
> @@ -116,12 +116,14 @@ EXPORT_SYMBOL(dst_alloc);
>
> struct dst_entry *dst_destroy(struct dst_entry * dst)
> {
> - struct dst_entry *child;
> + struct dst_entry *child = NULL;
>
> smp_rmb();
>
> - child = dst->child;
> -
> +#ifdef CONFIG_XFRM
> + if (dst->xfrm)
> + child = dst->child;
> +#endif
Why not using here :
child = xfrm_dst_child(dst);
This avoid the #ifdef and uses the new helper quite well.
