[NET]: Cleanup the allocation/freeing of the sock object

The sock object is allocated either from the generic cache with
the kmalloc, or from the proc->slab cache.

Move this logic into an isolated set of helpers and make the
sk_alloc/sk_free look a bit nicer.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/sock.c

@@ -870,6 +870,31 @@ static void sock_copy(struct sock *nsk, const struct sock *osk)
 #endif
 }
 
+static struct sock *sk_prot_alloc(struct proto *prot, gfp_t priority)
+{
+	struct sock *sk;
+	struct kmem_cache *slab;
+
+	slab = prot->slab;
+	if (slab != NULL)
+		sk = kmem_cache_alloc(slab, priority);
+	else
+		sk = kmalloc(prot->obj_size, priority);
+
+	return sk;
+}
+
+static void sk_prot_free(struct proto *prot, struct sock *sk)
+{
+	struct kmem_cache *slab;
+
+	slab = prot->slab;
+	if (slab != NULL)
+		kmem_cache_free(slab, sk);
+	else
+		kfree(sk);
+}
+
 /**
  *	sk_alloc - All socket objects are allocated here
  *	@net: the applicable net namespace
@@ -881,14 +906,9 @@ static void sock_copy(struct sock *nsk, const struct sock *osk)
 struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
 		      struct proto *prot, int zero_it)
 {
-	struct sock *sk = NULL;
-	struct kmem_cache *slab = prot->slab;
-
-	if (slab != NULL)
-		sk = kmem_cache_alloc(slab, priority);
-	else
-		sk = kmalloc(prot->obj_size, priority);
+	struct sock *sk;
 
+	sk = sk_prot_alloc(prot, priority);
 	if (sk) {
 		if (zero_it) {
 			memset(sk, 0, prot->obj_size);
@@ -911,10 +931,7 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t priority,
 	return sk;
 
 out_free:
-	if (slab != NULL)
-		kmem_cache_free(slab, sk);
-	else
-		kfree(sk);
+	sk_prot_free(prot, sk);
 	return NULL;
 }
 
@@ -940,10 +957,7 @@ void sk_free(struct sock *sk)
 
 	security_sk_free(sk);
 	put_net(sk->sk_net);
-	if (sk->sk_prot_creator->slab != NULL)
-		kmem_cache_free(sk->sk_prot_creator->slab, sk);
-	else
-		kfree(sk);
+	sk_prot_free(sk->sk_prot_creator, sk);
 	module_put(owner);
 }