diff options
| author | Patrick McHardy <kaber@trash.net> | 2013-04-17 10:46:58 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-04-19 22:57:57 +0400 |
| commit | 0ebd0ac5ff01ebf412e1bd3c33620ef7ffc5d866 (patch) | |
| tree | 0f91f0bb25b2674c97ac97ff05e572f6d2394562 | |
| parent | e32123e59871b9389d5b3fe9318611c7f1d1307a (diff) | |
| download | linux-0ebd0ac5ff01ebf412e1bd3c33620ef7ffc5d866.tar.xz | |
net: add function to allocate sk_buff head without data area
Add a function to allocate a sk_buff 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@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/skbuff.h | 6 | ||||
| -rw-r--r-- | net/core/skbuff.c | 30 |
2 files changed, 35 insertions, 1 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f5bed7b31954..2e0ced1af3b1 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -651,6 +651,12 @@ static inline struct sk_buff *alloc_skb_fclone(unsigned int size, return __alloc_skb(size, priority, SKB_ALLOC_FCLONE, 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 struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src); extern int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask); extern struct sk_buff *skb_clone(struct sk_buff *skb, diff --git a/net/core/skbuff.c b/net/core/skbuff.c index a92d9e7d10f7..898cf5c566f9 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -179,6 +179,33 @@ out: * */ +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; + + /* + * 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 @@ -584,7 +611,8 @@ 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); } /** |