inet: Hide route peer accesses behind helpers.

We encode the pointer(s) into an unsigned long with one state bit.

The state bit is used so we can store the inetpeer tree root to use
when resolving the peer later.

Later the peer roots will be per-FIB table, and this change works to
facilitate that.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 54 insertions, 0 deletions

diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h
index b84b32f..d432489 100644
--- a/include/net/inetpeer.h
+++ b/include/net/inetpeer.h
@@ -71,6 +71,60 @@ struct inet_peer_base {
 	int			total;
 };
 
+#define INETPEER_BASE_BIT	0x1UL
+
+static inline struct inet_peer *inetpeer_ptr(unsigned long val)
+{
+	BUG_ON(val & INETPEER_BASE_BIT);
+	return (struct inet_peer *) val;
+}
+
+static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
+{
+	if (!(val & INETPEER_BASE_BIT))
+		return NULL;
+	val &= ~INETPEER_BASE_BIT;
+	return (struct inet_peer_base *) val;
+}
+
+static inline bool inetpeer_ptr_is_peer(unsigned long val)
+{
+	return !(val & INETPEER_BASE_BIT);
+}
+
+static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
+{
+	/* This implicitly clears INETPEER_BASE_BIT */
+	*val = (unsigned long) peer;
+}
+
+static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
+{
+	unsigned long val = (unsigned long) peer;
+	unsigned long orig = *ptr;
+
+	if (!(orig & INETPEER_BASE_BIT) || !val ||
+	    cmpxchg(ptr, orig, val) != orig)
+		return false;
+	return true;
+}
+
+static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
+{
+	*ptr = (unsigned long) base | INETPEER_BASE_BIT;
+}
+
+static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
+{
+	unsigned long val = *from;
+
+	*to = val;
+	if (inetpeer_ptr_is_peer(val)) {
+		struct inet_peer *peer = inetpeer_ptr(val);
+		atomic_inc(&peer->refcnt);
+	}
+}
+
 extern void inet_peer_base_init(struct inet_peer_base *);
 
 void			inet_initpeers(void) __init;