diff options
Diffstat (limited to 'include/linux/skbuff.h')
| -rw-r--r-- | include/linux/skbuff.h | 58 |
1 files changed, 54 insertions, 4 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index c9525bce80f6..7cdfb4d52847 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -264,7 +264,7 @@ typedef unsigned char *sk_buff_data_t; * @transport_header: Transport layer header * @network_header: Network layer header * @mac_header: Link layer header - * @_skb_dst: destination entry + * @_skb_refdst: destination entry (with norefcount bit) * @sp: the security path, used for xfrm * @cb: Control buffer. Free for use by every layer. Put private vars here * @len: Length of actual data @@ -328,7 +328,7 @@ struct sk_buff { */ char cb[48] __aligned(8); - unsigned long _skb_dst; + unsigned long _skb_refdst; #ifdef CONFIG_XFRM struct sec_path *sp; #endif @@ -419,14 +419,64 @@ struct sk_buff { #include <asm/system.h> +/* + * skb might have a dst pointer attached, refcounted or not. + * _skb_refdst low order bit is set if refcount was _not_ taken + */ +#define SKB_DST_NOREF 1UL +#define SKB_DST_PTRMASK ~(SKB_DST_NOREF) + +/** + * skb_dst - returns skb dst_entry + * @skb: buffer + * + * Returns skb dst_entry, regardless of reference taken or not. + */ static inline struct dst_entry *skb_dst(const struct sk_buff *skb) { - return (struct dst_entry *)skb->_skb_dst; + /* If refdst was not refcounted, check we still are in a + * rcu_read_lock section + */ + WARN_ON((skb->_skb_refdst & SKB_DST_NOREF) && + !rcu_read_lock_held() && + !rcu_read_lock_bh_held()); + return (struct dst_entry *)(skb->_skb_refdst & SKB_DST_PTRMASK); } +/** + * skb_dst_set - sets skb dst + * @skb: buffer + * @dst: dst entry + * + * Sets skb dst, assuming a reference was taken on dst and should + * be released by skb_dst_drop() + */ static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst) { - skb->_skb_dst = (unsigned long)dst; + skb->_skb_refdst = (unsigned long)dst; +} + +/** + * skb_dst_set_noref - sets skb dst, without a reference + * @skb: buffer + * @dst: dst entry + * + * Sets skb dst, assuming a reference was not taken on dst + * skb_dst_drop() should not dst_release() this dst + */ +static inline void skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst) +{ + WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held()); + skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF; +} + +/** + * skb_dst_is_noref - Test if skb dst isnt refcounted + * @skb: buffer + */ +static inline bool skb_dst_is_noref(const struct sk_buff *skb) +{ + return (skb->_skb_refdst & SKB_DST_NOREF) && skb_dst(skb); } static inline struct rtable *skb_rtable(const struct sk_buff *skb) |