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Message-ID: <20090305210105.GC12835@hmsreliant.think-freely.org>
Date: Thu, 5 Mar 2009 16:01:05 -0500
From: Neil Horman <nhorman@...driver.com>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, kuznet@....inr.ac.ru, pekkas@...core.fi,
jmorris@...ei.org, yoshfuji@...ux-ipv6.org, kaber@...sh.net
Subject: Re: [Patch 3/5] Network Drop Monitor: Adding kfree_skb_clean for
non-drops and modifying end-of-line points for skbs
Ok, as requested, new version of this patch to add in bifurcation of kfree_skb
into two versions, one for legitimate kfree's, and one for drops
Modification Notes:
1) Renamed kfree_skb_clean to consume_skb, to better identify points where we
are finished with an skb
2) checkpatch cleanups
Thanks!
Neil
Signed-off-by: Neil Horman <nhorman@...driver.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(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 1f659e8..1fbab2a 100644
--- 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
index 5e2ac0c..d0de644 100644
--- 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
index e5e2111..6acbf9e 100644
--- 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"
@@ -442,11 +443,32 @@ 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
* @skb_size: minimum receive buffer size
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 3f6b735..e89f7b7 100644
--- 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
index 4bd178a..05b7abb 100644
--- 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
index d8cc006..74776de 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -584,7 +584,7 @@ drop_n_restore:
skb->len = skb_len;
}
drop:
- kfree_skb(skb);
+ consume_skb(skb);
return 0;
}
--
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