Merge branch 'net-cleanup-datagram-receive-helpers'

Paolo Abeni says:

====================
net: cleanup datagram receive helpers

Several receive helpers have an optional destructor argument, which uglify
the code a bit and is taxed by retpoline overhead.

This series refactor the code so that we can drop such optional argument,
cleaning the helpers a bit and avoiding an indirect call in fast path.

The first patch refactor a bit the caller, so that the second patch
actually dropping the argument is more straight-forward

v1 -> v2:
 - call scm_stat_del() only when not peeking - Kirill
 - fix build issue with CONFIG_INET_ESPINTCP
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 17 deletions

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 9d0518d9bdd4..3385a7a0b231 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -690,7 +690,8 @@ static void unix_show_fdinfo(struct seq_file *m, struct socket *sock)
 
 	if (sk) {
 		u = unix_sk(sock->sk);
-		seq_printf(m, "scm_fds: %u\n", READ_ONCE(u->scm_stat.nr_fds));
+		seq_printf(m, "scm_fds: %u\n",
+			   atomic_read(&u->scm_stat.nr_fds));
 	}
 }
 #else
@@ -1602,10 +1603,8 @@ static void scm_stat_add(struct sock *sk, struct sk_buff *skb)
 	struct scm_fp_list *fp = UNIXCB(skb).fp;
 	struct unix_sock *u = unix_sk(sk);
 
-	lockdep_assert_held(&sk->sk_receive_queue.lock);
-
 	if (unlikely(fp && fp->count))
-		u->scm_stat.nr_fds += fp->count;
+		atomic_add(fp->count, &u->scm_stat.nr_fds);
 }
 
 static void scm_stat_del(struct sock *sk, struct sk_buff *skb)
@@ -1613,10 +1612,8 @@ static void scm_stat_del(struct sock *sk, struct sk_buff *skb)
 	struct scm_fp_list *fp = UNIXCB(skb).fp;
 	struct unix_sock *u = unix_sk(sk);
 
-	lockdep_assert_held(&sk->sk_receive_queue.lock);
-
 	if (unlikely(fp && fp->count))
-		u->scm_stat.nr_fds -= fp->count;
+		atomic_sub(fp->count, &u->scm_stat.nr_fds);
 }
 
 /*
@@ -1805,10 +1802,8 @@ restart_locked:
 	if (sock_flag(other, SOCK_RCVTSTAMP))
 		__net_timestamp(skb);
 	maybe_add_creds(skb, sock, other);
-	spin_lock(&other->sk_receive_queue.lock);
 	scm_stat_add(other, skb);
-	__skb_queue_tail(&other->sk_receive_queue, skb);
-	spin_unlock(&other->sk_receive_queue.lock);
+	skb_queue_tail(&other->sk_receive_queue, skb);
 	unix_state_unlock(other);
 	other->sk_data_ready(other);
 	sock_put(other);
@@ -1910,10 +1905,8 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg,
 			goto pipe_err_free;
 
 		maybe_add_creds(skb, sock, other);
-		spin_lock(&other->sk_receive_queue.lock);
 		scm_stat_add(other, skb);
-		__skb_queue_tail(&other->sk_receive_queue, skb);
-		spin_unlock(&other->sk_receive_queue.lock);
+		skb_queue_tail(&other->sk_receive_queue, skb);
 		unix_state_unlock(other);
 		other->sk_data_ready(other);
 		sent += size;
@@ -2113,9 +2106,12 @@ static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg,
 
 		skip = sk_peek_offset(sk, flags);
 		skb = __skb_try_recv_datagram(sk, &sk->sk_receive_queue, flags,
-					      scm_stat_del, &skip, &err, &last);
-		if (skb)
+					      &skip, &err, &last);
+		if (skb) {
+			if (!(flags & MSG_PEEK))
+				scm_stat_del(sk, skb);
 			break;
+		}
 
 		mutex_unlock(&u->iolock);
 
@@ -2409,9 +2405,7 @@ unlock:
 			sk_peek_offset_bwd(sk, chunk);
 
 			if (UNIXCB(skb).fp) {
-				spin_lock(&sk->sk_receive_queue.lock);
 				scm_stat_del(sk, skb);
-				spin_unlock(&sk->sk_receive_queue.lock);
 				unix_detach_fds(&scm, skb);
 			}