Merge branch 'akpm' (Andrew's patch-bomb)

[pandora-kernel.git] / net / core / dev.c

diff --git a/net/core/dev.c b/net/core/dev.c
index c8569f8..0cb3fe8 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3156,6 +3156,23 @@ void netdev_rx_handler_unregister(struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(netdev_rx_handler_unregister);
 
+/*
+ * Limit the use of PFMEMALLOC reserves to those protocols that implement
+ * the special handling of PFMEMALLOC skbs.
+ */
+static bool skb_pfmemalloc_protocol(struct sk_buff *skb)
+{
+       switch (skb->protocol) {
+       case __constant_htons(ETH_P_ARP):
+       case __constant_htons(ETH_P_IP):
+       case __constant_htons(ETH_P_IPV6):
+       case __constant_htons(ETH_P_8021Q):
+               return true;
+       default:
+               return false;
+       }
+}
+
 static int __netif_receive_skb(struct sk_buff *skb)
 {
        struct packet_type *ptype, *pt_prev;
@@ -3165,14 +3182,27 @@ static int __netif_receive_skb(struct sk_buff *skb)
        bool deliver_exact = false;
        int ret = NET_RX_DROP;
        __be16 type;
+       unsigned long pflags = current->flags;
 
        net_timestamp_check(!netdev_tstamp_prequeue, skb);
 
        trace_netif_receive_skb(skb);
 
+       /*
+        * PFMEMALLOC skbs are special, they should
+        * - be delivered to SOCK_MEMALLOC sockets only
+        * - stay away from userspace
+        * - have bounded memory usage
+        *
+        * Use PF_MEMALLOC as this saves us from propagating the allocation
+        * context down to all allocation sites.
+        */
+       if (sk_memalloc_socks() && skb_pfmemalloc(skb))
+               current->flags |= PF_MEMALLOC;
+
        /* if we've gotten here through NAPI, check netpoll */
        if (netpoll_receive_skb(skb))
-               return NET_RX_DROP;
+               goto out;
 
        orig_dev = skb->dev;
 
@@ -3192,7 +3222,7 @@ another_round:
        if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
                skb = vlan_untag(skb);
                if (unlikely(!skb))
-                       goto out;
+                       goto unlock;
        }
 
 #ifdef CONFIG_NET_CLS_ACT
@@ -3202,6 +3232,9 @@ another_round:
        }
 #endif
 
+       if (sk_memalloc_socks() && skb_pfmemalloc(skb))
+               goto skip_taps;
+
        list_for_each_entry_rcu(ptype, &ptype_all, list) {
                if (!ptype->dev || ptype->dev == skb->dev) {
                        if (pt_prev)
@@ -3210,13 +3243,18 @@ another_round:
                }
        }
 
+skip_taps:
 #ifdef CONFIG_NET_CLS_ACT
        skb = handle_ing(skb, &pt_prev, &ret, orig_dev);
        if (!skb)
-               goto out;
+               goto unlock;
 ncls:
 #endif
 
+       if (sk_memalloc_socks() && skb_pfmemalloc(skb)
+                               && !skb_pfmemalloc_protocol(skb))
+               goto drop;
+
        rx_handler = rcu_dereference(skb->dev->rx_handler);
        if (vlan_tx_tag_present(skb)) {
                if (pt_prev) {
@@ -3226,7 +3264,7 @@ ncls:
                if (vlan_do_receive(&skb, !rx_handler))
                        goto another_round;
                else if (unlikely(!skb))
-                       goto out;
+                       goto unlock;
        }
 
        if (rx_handler) {
@@ -3236,7 +3274,7 @@ ncls:
                }
                switch (rx_handler(&skb)) {
                case RX_HANDLER_CONSUMED:
-                       goto out;
+                       goto unlock;
                case RX_HANDLER_ANOTHER:
                        goto another_round;
                case RX_HANDLER_EXACT:
@@ -3269,6 +3307,7 @@ ncls:
                else
                        ret = pt_prev->func(skb, skb->dev, pt_prev, orig_dev);
        } else {
+drop:
                atomic_long_inc(&skb->dev->rx_dropped);
                kfree_skb(skb);
                /* Jamal, now you will not able to escape explaining
@@ -3277,8 +3316,10 @@ ncls:
                ret = NET_RX_DROP;
        }
 
-out:
+unlock:
        rcu_read_unlock();
+out:
+       tsk_restore_flags(current, pflags, PF_MEMALLOC);
        return ret;
 }