netns xfrm: add struct xfrm_policy::xp_net

Again, to avoid complications with passing netns when not necessary.
Again, ->xp_net is set-once field, once set it never changes.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index cf2bf3a..3eccefa 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -228,13 +228,14 @@
  * SPD calls.
  */
 
-struct xfrm_policy *xfrm_policy_alloc(gfp_t gfp)
+struct xfrm_policy *xfrm_policy_alloc(struct net *net, gfp_t gfp)
 {
 	struct xfrm_policy *policy;
 
 	policy = kzalloc(sizeof(struct xfrm_policy), gfp);
 
 	if (policy) {
+		write_pnet(&policy->xp_net, net);
 		INIT_LIST_HEAD(&policy->walk.all);
 		INIT_HLIST_NODE(&policy->bydst);
 		INIT_HLIST_NODE(&policy->byidx);
@@ -1153,7 +1154,7 @@
 
 static struct xfrm_policy *clone_policy(struct xfrm_policy *old, int dir)
 {
-	struct xfrm_policy *newp = xfrm_policy_alloc(GFP_ATOMIC);
+	struct xfrm_policy *newp = xfrm_policy_alloc(xp_net(old), GFP_ATOMIC);
 
 	if (newp) {
 		newp->selector = old->selector;
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 65cdaa5..765c01e 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -1080,7 +1080,7 @@
 
 static struct xfrm_policy *xfrm_policy_construct(struct xfrm_userpolicy_info *p, struct nlattr **attrs, int *errp)
 {
-	struct xfrm_policy *xp = xfrm_policy_alloc(GFP_KERNEL);
+	struct xfrm_policy *xp = xfrm_policy_alloc(&init_net, GFP_KERNEL);
 	int err;
 
 	if (!xp) {
@@ -2291,7 +2291,7 @@
 	if (p->dir > XFRM_POLICY_OUT)
 		return NULL;
 
-	xp = xfrm_policy_alloc(GFP_KERNEL);
+	xp = xfrm_policy_alloc(&init_net, GFP_KERNEL);
 	if (xp == NULL) {
 		*dir = -ENOBUFS;
 		return NULL;