From: Patrick McHardy <kaber@xxxxxxxxx>
Add a function to allocate a skbuff head without any data. This will be
used by memory mapped netlink to attach data from the mmaped area to the
skb.
Additionally change skb_release_all() to check whether the skb has a
data area to allow the skb destructor to clear the data pointer in
case only a head has been allocated.
Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
---
include/linux/skbuff.h | 6 ++++++
net/core/skbuff.c | 31 ++++++++++++++++++++++++++++++-
2 files changed, 36 insertions(+), 1 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 7b996ed..8cfc285 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -521,6 +521,12 @@ static inline struct sk_buff *alloc_skb_fclone(unsigned int size,
return __alloc_skb(size, priority, 1, NUMA_NO_NODE);
}
+extern struct sk_buff *__alloc_skb_head(gfp_t priority, int node);
+static inline struct sk_buff *alloc_skb_head(gfp_t priority)
+{
+ return __alloc_skb_head(priority, -1);
+}
+
extern bool skb_recycle_check(struct sk_buff *skb, int skb_size);
extern struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 2beda82..d632de9 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -153,6 +153,34 @@ static void skb_under_panic(struct sk_buff *skb, int sz, void *here)
*
*/
+struct sk_buff *__alloc_skb_head(gfp_t gfp_mask, int node)
+{
+ struct sk_buff *skb;
+
+ /* Get the HEAD */
+ skb = kmem_cache_alloc_node(skbuff_head_cache,
+ gfp_mask & ~__GFP_DMA, node);
+ if (!skb)
+ goto out;
+ prefetchw(skb);
+
+ /*
+ * Only clear those fields we need to clear, not those that we will
+ * actually initialise below. Hence, don't put any more fields after
+ * the tail pointer in struct sk_buff!
+ */
+ memset(skb, 0, offsetof(struct sk_buff, tail));
+ skb->data = NULL;
+ skb->truesize = sizeof(struct sk_buff);
+ atomic_set(&skb->users, 1);
+
+#ifdef NET_SKBUFF_DATA_USES_OFFSET
+ skb->mac_header = ~0U;
+#endif
+out:
+ return skb;
+}
+
/**
* __alloc_skb - allocate a network buffer
* @size: size to allocate
@@ -414,7 +442,8 @@ static void skb_release_head_state(struct sk_buff *skb)
static void skb_release_all(struct sk_buff *skb)
{
skb_release_head_state(skb);
- skb_release_data(skb);
+ if (likely(skb->data))
+ skb_release_data(skb);
}
/**
--
1.7.4.4
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
