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authorAlexander Duyck <alexander.h.duyck@intel.com>2012-05-03 01:09:42 +0000
committerDavid S. Miller <davem@davemloft.net>2012-05-03 13:18:37 -0400
commit3a7c1ee4ab89f9250b8f82656a7be0ae14aa3691 (patch)
tree9dc10e067f2364fd3590b38cd5db495cd09c32e6 /include/linux
parent715dc1f342713816d1be1c37643a2c9e6ee181a7 (diff)
skb: Add skb_head_is_locked helper function
This patch adds support for a skb_head_is_locked helper function. It is meant to be used any time we are considering transferring the head from skb->head to a paged frag. If the head is locked it means we cannot remove the head from the skb so it must be copied or we must take the skb as a whole. Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/skbuff.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 988fc49667b..37f539129d8 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2566,5 +2566,19 @@ static inline bool skb_is_recycleable(const struct sk_buff *skb, int skb_size)
return true;
}
+
+/**
+ * skb_head_is_locked - Determine if the skb->head is locked down
+ * @skb: skb to check
+ *
+ * The head on skbs build around a head frag can be removed if they are
+ * not cloned. This function returns true if the skb head is locked down
+ * due to either being allocated via kmalloc, or by being a clone with
+ * multiple references to the head.
+ */
+static inline bool skb_head_is_locked(const struct sk_buff *skb)
+{
+ return !skb->head_frag || skb_cloned(skb);
+}
#endif /* __KERNEL__ */
#endif /* _LINUX_SKBUFF_H */