net: correct off-by-one write allocations reports

commit 2b85a34e91
(net: No more expensive sock_hold()/sock_put() on each tx)
changed initial sk_wmem_alloc value.

We need to take into account this offset when reporting
sk_wmem_alloc to user, in PROC_FS files or various
ioctls (SIOCOUTQ/TIOCOUTQ)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipx/af_ipx.c

@@ -1835,7 +1835,7 @@ static int ipx_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 
 	switch (cmd) {
 	case TIOCOUTQ:
-		amount = sk->sk_sndbuf - atomic_read(&sk->sk_wmem_alloc);
+		amount = sk->sk_sndbuf - sk_wmem_alloc_get(sk);
 		if (amount < 0)
 			amount = 0;
 		rc = put_user(amount, (int __user *)argp);

net/ipx/ipx_proc.c

@@ -280,8 +280,8 @@ static int ipx_seq_socket_show(struct seq_file *seq, void *v)
 	}
 
 	seq_printf(seq, "%08X  %08X  %02X     %03d\n",
-		   atomic_read(&s->sk_wmem_alloc),
-		   atomic_read(&s->sk_rmem_alloc),
+		   sk_wmem_alloc_get(s),
+		   sk_rmem_alloc_get(s),
 		   s->sk_state, SOCK_INODE(s->sk_socket)->i_uid);
 out:
 	return 0;