net: dismiss sk_forward_alloc_get()

After the previous patch we can remove the forward_alloc_get
proto callback, basically reverting commit 292e607 ("net: introduce
sk_forward_alloc_get()") and commit 66d58f0 ("net: use
sk_forward_alloc_get() in sk_get_meminfo()").

Signed-off-by: Paolo Abeni <[email protected]>

Author: Paolo Abeni

include/net/sock.h

@@ -1283,10 +1283,6 @@ struct proto {
 	unsigned int		inuse_idx;
 #endif
 
-#if IS_ENABLED(CONFIG_MPTCP)
-	int			(*forward_alloc_get)(const struct sock *sk);
-#endif
-
 	bool			(*stream_memory_free)(const struct sock *sk, int wake);
 	bool			(*sock_is_readable)(struct sock *sk);
 	/* Memory pressure */
@@ -1347,15 +1343,6 @@ int sock_load_diag_module(int family, int protocol);
 
 INDIRECT_CALLABLE_DECLARE(bool tcp_stream_memory_free(const struct sock *sk, int wake));
 
-static inline int sk_forward_alloc_get(const struct sock *sk)
-{
-#if IS_ENABLED(CONFIG_MPTCP)
-	if (sk->sk_prot->forward_alloc_get)
-		return sk->sk_prot->forward_alloc_get(sk);
-#endif
-	return READ_ONCE(sk->sk_forward_alloc);
-}
-
 static inline bool __sk_stream_memory_free(const struct sock *sk, int wake)
 {
 	if (READ_ONCE(sk->sk_wmem_queued) >= READ_ONCE(sk->sk_sndbuf))

net/core/sock.c

@@ -3858,7 +3858,7 @@ void sk_get_meminfo(const struct sock *sk, u32 *mem)
 	mem[SK_MEMINFO_RCVBUF] = READ_ONCE(sk->sk_rcvbuf);
 	mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk);
 	mem[SK_MEMINFO_SNDBUF] = READ_ONCE(sk->sk_sndbuf);
-	mem[SK_MEMINFO_FWD_ALLOC] = sk_forward_alloc_get(sk);
+	mem[SK_MEMINFO_FWD_ALLOC] = READ_ONCE(sk->sk_forward_alloc);
 	mem[SK_MEMINFO_WMEM_QUEUED] = READ_ONCE(sk->sk_wmem_queued);
 	mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc);
 	mem[SK_MEMINFO_BACKLOG] = READ_ONCE(sk->sk_backlog.len);

net/ipv4/af_inet.c

@@ -153,7 +153,7 @@ void inet_sock_destruct(struct sock *sk)
 	WARN_ON_ONCE(atomic_read(&sk->sk_rmem_alloc));
 	WARN_ON_ONCE(refcount_read(&sk->sk_wmem_alloc));
 	WARN_ON_ONCE(sk->sk_wmem_queued);
-	WARN_ON_ONCE(sk_forward_alloc_get(sk));
+	WARN_ON_ONCE(sk->sk_forward_alloc);
 
 	kfree(rcu_dereference_protected(inet->inet_opt, 1));
 	dst_release(rcu_dereference_protected(sk->sk_dst_cache, 1));

net/ipv4/inet_diag.c

@@ -282,7 +282,7 @@ int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk,
 		struct inet_diag_meminfo minfo = {
 			.idiag_rmem = sk_rmem_alloc_get(sk),
 			.idiag_wmem = READ_ONCE(sk->sk_wmem_queued),
-			.idiag_fmem = sk_forward_alloc_get(sk),
+			.idiag_fmem = READ_ONCE(sk->sk_forward_alloc),
 			.idiag_tmem = sk_wmem_alloc_get(sk),
 		};
 

net/sched/em_meta.c

@@ -460,7 +460,7 @@ META_COLLECTOR(int_sk_fwd_alloc)
 		*err = -1;
 		return;
 	}
-	dst->value = sk_forward_alloc_get(sk);
+	dst->value = READ_ONCE(sk->sk_forward_alloc);
 }
 
 META_COLLECTOR(int_sk_sndbuf)