[NET]: Memory barrier cleanups
Ralf Baechle [Thu, 7 Dec 2006 08:11:33 +0000 (00:11 -0800)]
I believe all the below memory barriers only matter on SMP so
therefore the smp_* variant of the barrier should be used.

I'm wondering if the barrier in net/ipv4/inet_timewait_sock.c should be
dropped entirely.  schedule_work's implementation currently implies a
memory barrier and I think sane semantics of schedule_work() should imply
a memory barrier, as needed so the caller shouldn't have to worry.
It's not quite obvious why the barrier in net/packet/af_packet.c is
needed; maybe it should be implied through flush_dcache_page?

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/wireless.c
net/ipv4/inet_timewait_sock.c
net/ipv4/tcp_input.c
net/packet/af_packet.c

index cb1b872..f69ab7b 100644 (file)
@@ -2130,7 +2130,7 @@ int iw_handler_set_spy(struct net_device *        dev,
         * The rtnl_lock() make sure we don't race with the other iw_handlers.
         * This make sure wireless_spy_update() "see" that the spy list
         * is temporarily disabled. */
-       wmb();
+       smp_wmb();
 
        /* Are there are addresses to copy? */
        if(wrqu->data.length > 0) {
@@ -2159,7 +2159,7 @@ int iw_handler_set_spy(struct net_device *        dev,
        }
 
        /* Make sure above is updated before re-enabling */
-       wmb();
+       smp_wmb();
 
        /* Enable addresses */
        spydata->spy_number = wrqu->data.length;
index 8c74f91..75373f3 100644 (file)
@@ -178,7 +178,7 @@ void inet_twdr_hangman(unsigned long data)
        need_timer = 0;
        if (inet_twdr_do_twkill_work(twdr, twdr->slot)) {
                twdr->thread_slots |= (1 << twdr->slot);
-               mb();
+               smp_mb();
                schedule_work(&twdr->twkill_work);
                need_timer = 1;
        } else {
index 9304034..c701f6a 100644 (file)
@@ -4235,7 +4235,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
                 * Change state from SYN-SENT only after copied_seq
                 * is initialized. */
                tp->copied_seq = tp->rcv_nxt;
-               mb();
+               smp_mb();
                tcp_set_state(sk, TCP_ESTABLISHED);
 
                security_inet_conn_established(sk, skb);
@@ -4483,7 +4483,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                case TCP_SYN_RECV:
                        if (acceptable) {
                                tp->copied_seq = tp->rcv_nxt;
-                               mb();
+                               smp_mb();
                                tcp_set_state(sk, TCP_ESTABLISHED);
                                sk->sk_state_change(sk);
 
index 08e68b6..da73e8a 100644 (file)
@@ -660,7 +660,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, struct packe
        sll->sll_ifindex = dev->ifindex;
 
        h->tp_status = status;
-       mb();
+       smp_mb();
 
        {
                struct page *p_start, *p_end;