net: avoid limits overflow

Robin Holt tried to boot a 16TB machine and found some limits were
reached : sysctl_tcp_mem[2], sysctl_udp_mem[2]

We can switch infrastructure to use long "instead" of "int", now
atomic_long_t primitives are available for free.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reported-by: Robin Holt <holt@sgi.com>
Reviewed-by: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 4 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3357f69e353d..6d8ab1c4efc3 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -259,8 +259,11 @@ static void tcp_fixup_sndbuf(struct sock *sk)
         int sndmem = tcp_sk(sk)->rx_opt.mss_clamp + MAX_TCP_HEADER + 16 +
                      sizeof(struct sk_buff);
 
-        if (sk->sk_sndbuf < 3 * sndmem)
-                sk->sk_sndbuf = min(3 * sndmem, sysctl_tcp_wmem[2]);
+        if (sk->sk_sndbuf < 3 * sndmem) {
+                sk->sk_sndbuf = 3 * sndmem;
+                if (sk->sk_sndbuf > sysctl_tcp_wmem[2])
+                        sk->sk_sndbuf = sysctl_tcp_wmem[2];
+        }
 }
 
 /* 2. Tuning advertised window (window_clamp, rcv_ssthresh)
@@ -396,7 +399,7 @@ static void tcp_clamp_window(struct sock *sk)
         if (sk->sk_rcvbuf < sysctl_tcp_rmem[2] &&
             !(sk->sk_userlocks & SOCK_RCVBUF_LOCK) &&
             !tcp_memory_pressure &&
-            atomic_read(&tcp_memory_allocated) < sysctl_tcp_mem[0]) {
+            atomic_long_read(&tcp_memory_allocated) < sysctl_tcp_mem[0]) {
                 sk->sk_rcvbuf = min(atomic_read(&sk->sk_rmem_alloc),
                                     sysctl_tcp_rmem[2]);
         }
@@ -4861,7 +4864,7 @@ static int tcp_should_expand_sndbuf(struct sock *sk)
                 return 0;
 
         /* If we are under soft global TCP memory pressure, do not expand.  */
-        if (atomic_read(&tcp_memory_allocated) >= sysctl_tcp_mem[0])
+        if (atomic_long_read(&tcp_memory_allocated) >= sysctl_tcp_mem[0])
                 return 0;
 
         /* If we filled the congestion window, do not expand.  */