Merge branch 'mptcp-rework-fwd-memory-allocation-and-one-cleanup'

Mat Martineau says:

====================
mptcp: Rework fwd memory allocation and one cleanup

These patches from the MPTCP tree rework forward memory allocation for
MPTCP (with some supporting changes in the net core), and also clean up
an unused function parameter.

Patch 1 updates TCP code but does not change any behavior, and creates
some macros for reclaim thresholds that will be reused in the MPTCP
code.

Patch 2 adds sk_forward_alloc_get() to the networking core to support
MPTCP's forward allocation with the diag interface.

Patch 3 reworks forward memory for MPTCP.

Patch 4 removes an unused arg and has no functional changes.
====================

Link: https://lore.kernel.org/r/20211026232916.179450-1-mathew.j.martineau@linux.intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/sock.h

@@ -1210,6 +1210,8 @@ struct proto {
 	unsigned int		inuse_idx;
 #endif
 
+	int			(*forward_alloc_get)(const struct sock *sk);
+
 	bool			(*stream_memory_free)(const struct sock *sk, int wake);
 	bool			(*stream_memory_read)(const struct sock *sk);
 	/* Memory pressure */
@@ -1217,6 +1219,7 @@ struct proto {
 	void			(*leave_memory_pressure)(struct sock *sk);
 	atomic_long_t		*memory_allocated;	/* Current allocated memory. */
 	struct percpu_counter	*sockets_allocated;	/* Current number of sockets. */
+
 	/*
 	 * Pressure flag: try to collapse.
 	 * Technical note: it is used by multiple contexts non atomically.
@@ -1294,6 +1297,14 @@ static inline void sk_refcnt_debug_release(const struct sock *sk)
 
 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 (!sk->sk_prot->forward_alloc_get)
+		return sk->sk_forward_alloc;
+
+	return sk->sk_prot->forward_alloc_get(sk);
+}
+
 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))
@@ -1573,6 +1584,11 @@ static inline void sk_mem_charge(struct sock *sk, int size)
 	sk->sk_forward_alloc -= size;
 }
 
+/* the following macros control memory reclaiming in sk_mem_uncharge()
+ */
+#define SK_RECLAIM_THRESHOLD	(1 << 21)
+#define SK_RECLAIM_CHUNK	(1 << 20)
+
 static inline void sk_mem_uncharge(struct sock *sk, int size)
 {
 	int reclaimable;
@@ -1589,8 +1605,8 @@ static inline void sk_mem_uncharge(struct sock *sk, int size)
 	 * If we reach 2 MBytes, reclaim 1 MBytes right now, there is
 	 * no need to hold that much forward allocation anyway.
 	 */
-	if (unlikely(reclaimable >= 1 << 21))
-		__sk_mem_reclaim(sk, 1 << 20);
+	if (unlikely(reclaimable >= SK_RECLAIM_THRESHOLD))
+		__sk_mem_reclaim(sk, SK_RECLAIM_CHUNK);
 }
 
 static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb)

net/ipv4/af_inet.c

@@ -150,7 +150,7 @@ void inet_sock_destruct(struct sock *sk)
 	WARN_ON(atomic_read(&sk->sk_rmem_alloc));
 	WARN_ON(refcount_read(&sk->sk_wmem_alloc));
 	WARN_ON(sk->sk_wmem_queued);
-	WARN_ON(sk->sk_forward_alloc);
+	WARN_ON(sk_forward_alloc_get(sk));
 
 	kfree(rcu_dereference_protected(inet->inet_opt, 1));
 	dst_release(rcu_dereference_protected(sk->sk_dst_cache, 1));

net/ipv4/inet_diag.c

@@ -271,7 +271,7 @@ 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->sk_forward_alloc,
+			.idiag_fmem = sk_forward_alloc_get(sk),
 			.idiag_tmem = sk_wmem_alloc_get(sk),
 		};
 

net/mptcp/protocol.h

@@ -227,7 +227,7 @@ struct mptcp_sock {
 	u64		ack_seq;
 	u64		rcv_wnd_sent;
 	u64		rcv_data_fin_seq;
-	int		wmem_reserved;
+	int		rmem_fwd_alloc;
 	struct sock	*last_snd;
 	int		snd_burst;
 	int		old_wspace;
@@ -272,19 +272,6 @@ struct mptcp_sock {
 	char		ca_name[TCP_CA_NAME_MAX];
 };
 
-#define mptcp_lock_sock(___sk, cb) do {					\
-	struct sock *__sk = (___sk); /* silence macro reuse warning */	\
-	might_sleep();							\
-	spin_lock_bh(&__sk->sk_lock.slock);				\
-	if (__sk->sk_lock.owned)					\
-		__lock_sock(__sk);					\
-	cb;								\
-	__sk->sk_lock.owned = 1;					\
-	spin_unlock(&__sk->sk_lock.slock);				\
-	mutex_acquire(&__sk->sk_lock.dep_map, 0, 0, _RET_IP_);		\
-	local_bh_enable();						\
-} while (0)
-
 #define mptcp_data_lock(sk) spin_lock_bh(&(sk)->sk_lock.slock)
 #define mptcp_data_unlock(sk) spin_unlock_bh(&(sk)->sk_lock.slock)
 

net/sched/em_meta.c

@@ -457,7 +457,7 @@ META_COLLECTOR(int_sk_fwd_alloc)
 		*err = -1;
 		return;
 	}
-	dst->value = sk->sk_forward_alloc;
+	dst->value = sk_forward_alloc_get(sk);
 }
 
 META_COLLECTOR(int_sk_sndbuf)