From d0bf4a9e92b9a93ffeeacbd7b6cb83e0ee3dc2ef Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 29 Sep 2014 13:29:15 -0700 Subject: net: cleanup and document skb fclone layout Lets use a proper structure to clearly document and implement skb fast clones. Then, we might experiment more easily alternative layouts. This patch adds a new skb_fclone_busy() helper, used by tcp and xfrm, to stop leaking of implementation details. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/skbuff.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'include/linux/skbuff.h') diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 262efdbc346b..d8f7d74d5a4d 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -781,6 +781,31 @@ struct sk_buff *alloc_skb_with_frags(unsigned long header_len, int *errcode, gfp_t gfp_mask); +/* Layout of fast clones : [skb1][skb2][fclone_ref] */ +struct sk_buff_fclones { + struct sk_buff skb1; + + struct sk_buff skb2; + + atomic_t fclone_ref; +}; + +/** + * skb_fclone_busy - check if fclone is busy + * @skb: buffer + * + * Returns true is skb is a fast clone, and its clone is not freed. + */ +static inline bool skb_fclone_busy(const struct sk_buff *skb) +{ + const struct sk_buff_fclones *fclones; + + fclones = container_of(skb, struct sk_buff_fclones, skb1); + + return skb->fclone == SKB_FCLONE_ORIG && + fclones->skb2.fclone == SKB_FCLONE_CLONE; +} + static inline struct sk_buff *alloc_skb_fclone(unsigned int size, gfp_t priority) { -- cgit v1.2.3-59-g8ed1b