diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/skbuff.h | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 14b923ddb6df..ca8be45dd8be 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1159,6 +1159,45 @@ static inline struct dst_entry *skb_dst(const struct sk_buff *skb) return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK); } +static inline void skb_dst_check_unset(struct sk_buff *skb) +{ + DEBUG_NET_WARN_ON_ONCE((skb->_skb_refdst & SKB_DST_PTRMASK) && + !(skb->_skb_refdst & SKB_DST_NOREF)); +} + +/** + * skb_dstref_steal() - return current dst_entry value and clear it + * @skb: buffer + * + * Resets skb dst_entry without adjusting its reference count. Useful in + * cases where dst_entry needs to be temporarily reset and restored. + * Note that the returned value cannot be used directly because it + * might contain SKB_DST_NOREF bit. + * + * When in doubt, prefer skb_dst_drop() over skb_dstref_steal() to correctly + * handle dst_entry reference counting. + * + * Returns: original skb dst_entry. + */ +static inline unsigned long skb_dstref_steal(struct sk_buff *skb) +{ + unsigned long refdst = skb->_skb_refdst; + + skb->_skb_refdst = 0; + return refdst; +} + +/** + * skb_dstref_restore() - restore skb dst_entry removed via skb_dstref_steal() + * @skb: buffer + * @refdst: dst entry from a call to skb_dstref_steal() + */ +static inline void skb_dstref_restore(struct sk_buff *skb, unsigned long refdst) +{ + skb_dst_check_unset(skb); + skb->_skb_refdst = refdst; +} + /** * skb_dst_set - sets skb dst * @skb: buffer @@ -1169,6 +1208,7 @@ static inline struct dst_entry *skb_dst(const struct sk_buff *skb) */ static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst) { + skb_dst_check_unset(skb); skb->slow_gro |= !!dst; skb->_skb_refdst = (unsigned long)dst; } @@ -1185,6 +1225,7 @@ static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst) */ static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst) { + skb_dst_check_unset(skb); WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held()); skb->slow_gro |= !!dst; skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF; |