X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=include%2Flinux%2Fskbuff.h;h=7cdfb4d52847e6f733df1538f48fc73508e3d13e;hb=35926ff5fba8;hp=c9525bce80f60b7882a3a643a44e249c819fc658;hpb=cba7a98a474a4f2a9316473734ba76829191a78a;p=pandora-kernel.git

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)