netpoll: move setting of NETPOLL_RX_DROP into netpoll_poll_dev

Today netpoll depends on setting NETPOLL_RX_DROP before networking
drivers receive packets in interrupt context so that the packets can
be dropped.  Move this setting into netpoll_poll_dev from
poll_one_napi so that if ndo_poll_controller happens to receive
packets we will drop the packets on the floor instead of letting the
packets bounce through the networking stack and potentially cause problems.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index a664f7829a6d16db4579789ca5b8c40654cc78d7..ef4f45df539f89d6e7a93f00fc6e4f23a81a2c12 100644 (file)
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -144,8 +144,7 @@ static __sum16 checksum_udp(struct sk_buff *skb, struct udphdr *uh,
  * network adapter, forcing superfluous retries and possibly timeouts.
  * Thus, we set our budget to greater than 1.
  */
-static int poll_one_napi(struct netpoll_info *npinfo,
-                        struct napi_struct *napi, int budget)
+static int poll_one_napi(struct napi_struct *napi, int budget)
 {
        int work;
 
@@ -156,16 +155,12 @@ static int poll_one_napi(struct netpoll_info *npinfo,
        if (!test_bit(NAPI_STATE_SCHED, &napi->state))
                return budget;
 
-       npinfo->rx_flags |= NETPOLL_RX_DROP;
-       atomic_inc(&trapped);
        set_bit(NAPI_STATE_NPSVC, &napi->state);
 
        work = napi->poll(napi, budget);
        trace_napi_poll(napi);
 
        clear_bit(NAPI_STATE_NPSVC, &napi->state);
-       atomic_dec(&trapped);
-       npinfo->rx_flags &= ~NETPOLL_RX_DROP;
 
        return budget - work;
 }
@@ -178,8 +173,7 @@ static void poll_napi(struct net_device *dev)
        list_for_each_entry(napi, &dev->napi_list, dev_list) {
                if (napi->poll_owner != smp_processor_id() &&
                    spin_trylock(&napi->poll_lock)) {
-                       budget = poll_one_napi(rcu_dereference_bh(dev->npinfo),
-                                              napi, budget);
+                       budget = poll_one_napi(napi, budget);
                        spin_unlock(&napi->poll_lock);
 
                        if (!budget)
@@ -215,6 +209,9 @@ static void netpoll_poll_dev(struct net_device *dev)
                return;
        }
 
+       ni->rx_flags |= NETPOLL_RX_DROP;
+       atomic_inc(&trapped);
+
        ops = dev->netdev_ops;
        if (!ops->ndo_poll_controller) {
                up(&ni->dev_lock);
@@ -226,6 +223,9 @@ static void netpoll_poll_dev(struct net_device *dev)
 
        poll_napi(dev);
 
+       atomic_dec(&trapped);
+       ni->rx_flags &= ~NETPOLL_RX_DROP;
+
        up(&ni->dev_lock);
 
        if (dev->flags & IFF_SLAVE) {