Network Drop Monitor: Adding kfree_skb_clean for non-drops and modify…

…ing end-of-line points for skbs Signed-off-by: Neil Horman <nhorman@tuxdriver.com> include/linux/skbuff.h | 4 +++- net/core/datagram.c | 2 +- net/core/skbuff.c | 22 ++++++++++++++++++++++ net/ipv4/arp.c | 2 +- net/ipv4/udp.c | 2 +- net/packet/af_packet.c | 2 +- 6 files changed, 29 insertions(+), 5 deletions(-) Signed-off-by: David S. Miller <davem@davemloft.net>
mariux64 · Mar 13, 2009 · ead2ceb · ead2ceb
1 parent 4893d39
commit ead2ceb
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Showing 6 changed files with 29 additions and 5 deletions.
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
@@ -421,6 +421,7 @@ extern void skb_dma_unmap(struct device *dev, struct sk_buff *skb,
 #endif
 
 extern void kfree_skb(struct sk_buff *skb);
+extern void consume_skb(struct sk_buff *skb);
 extern void	       __kfree_skb(struct sk_buff *skb);
 extern struct sk_buff *__alloc_skb(unsigned int size,
 				   gfp_t priority, int fclone, int node);
@@ -459,7 +460,8 @@ extern int	       skb_to_sgvec(struct sk_buff *skb,
 extern int	       skb_cow_data(struct sk_buff *skb, int tailbits,
 				    struct sk_buff **trailer);
 extern int	       skb_pad(struct sk_buff *skb, int pad);
-#define dev_kfree_skb(a)	kfree_skb(a)
+#define dev_kfree_skb(a)	consume_skb(a)
+#define dev_consume_skb(a)	kfree_skb_clean(a)
 extern void	      skb_over_panic(struct sk_buff *skb, int len,
 				     void *here);
 extern void	      skb_under_panic(struct sk_buff *skb, int len,

diff --git a/net/core/datagram.c b/net/core/datagram.c
@@ -208,7 +208,7 @@ struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned flags,
 
 void skb_free_datagram(struct sock *sk, struct sk_buff *skb)
 {
-	kfree_skb(skb);
+	consume_skb(skb);
 	sk_mem_reclaim_partial(sk);
 }
 

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
@@ -65,6 +65,7 @@
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
+#include <trace/skb.h>
 
 #include "kmap_skb.h"
 
@@ -442,10 +443,31 @@ void kfree_skb(struct sk_buff *skb)
 		smp_rmb();
 	else if (likely(!atomic_dec_and_test(&skb->users)))
 		return;
+	trace_kfree_skb(skb, __builtin_return_address(0));
 	__kfree_skb(skb);
 }
 EXPORT_SYMBOL(kfree_skb);
 
+/**
+ *	consume_skb - free an skbuff
+ *	@skb: buffer to free
+ *
+ *	Drop a ref to the buffer and free it if the usage count has hit zero
+ *	Functions identically to kfree_skb, but kfree_skb assumes that the frame
+ *	is being dropped after a failure and notes that
+ */
+void consume_skb(struct sk_buff *skb)
+{
+	if (unlikely(!skb))
+		return;
+	if (likely(atomic_read(&skb->users) == 1))
+		smp_rmb();
+	else if (likely(!atomic_dec_and_test(&skb->users)))
+		return;
+	__kfree_skb(skb);
+}
+EXPORT_SYMBOL(consume_skb);
+
 /**
  *	skb_recycle_check - check if skb can be reused for receive
  *	@skb: buffer

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
@@ -892,7 +892,7 @@ static int arp_process(struct sk_buff *skb)
 out:
 	if (in_dev)
 		in_dev_put(in_dev);
-	kfree_skb(skb);
+	consume_skb(skb);
 	return 0;
 }
 

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
@@ -1184,7 +1184,7 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
 			sk = sknext;
 		} while (sknext);
 	} else
-		kfree_skb(skb);
+		consume_skb(skb);
 	spin_unlock(&hslot->lock);
 	return 0;
 }

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
@@ -584,7 +584,7 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev, struct packet
 		skb->len = skb_len;
 	}
 drop:
-	kfree_skb(skb);
+	consume_skb(skb);
 	return 0;
 }