Clean up common ifaddr management:

- Unify reference count and lock initialization in a single function,
  ifa_init().
- Move tear-down from a macro (IFAFREE) to a function ifa_free().
- Move reference count bump from a macro (IFAREF) to a function ifa_ref().
- Instead of using a u_int protected by a mutex to refcount(9) for
  reference count management.

The ifa_mtx is now used for exactly one ioctl, and possibly should be
removed.

MFC after:	3 weeks

4 files changed, 47 insertions, 35 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index c5e1a56f61c6..fa708e97b134 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -758,7 +758,7 @@ if_attach_internal(struct ifnet *ifp, int vmove)
 		socksize = roundup2(socksize, sizeof(long));
 		ifasize = sizeof(*ifa) + 2 * socksize;
 		ifa = malloc(ifasize, M_IFADDR, M_WAITOK | M_ZERO);
-		IFA_LOCK_INIT(ifa);
+		ifa_init(ifa);
 		sdl = (struct sockaddr_dl *)(ifa + 1);
 		sdl->sdl_len = socksize;
 		sdl->sdl_family = AF_LINK;
@@ -775,7 +775,6 @@ if_attach_internal(struct ifnet *ifp, int vmove)
 		sdl->sdl_len = masklen;
 		while (namelen != 0)
 			sdl->sdl_data[--namelen] = 0xff;
-		ifa->ifa_refcnt = 1;
 		TAILQ_INSERT_HEAD(&ifp->if_addrhead, ifa, ifa_link);
 		/* Reliably crash if used uninitialized. */
 		ifp->if_broadcastaddr = NULL;
@@ -896,7 +895,7 @@ if_purgeaddrs(struct ifnet *ifp)
 		}
 #endif /* INET6 */
 		TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
-		IFAFREE(ifa);
+		ifa_free(ifa);
 	}
 }
 
@@ -1013,7 +1012,7 @@ if_detach_internal(struct ifnet *ifp, int vmove)
 		if (!TAILQ_EMPTY(&ifp->if_addrhead)) {
 			ifa = TAILQ_FIRST(&ifp->if_addrhead);
 			TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
-			IFAFREE(ifa);
+			ifa_free(ifa);
 		}
 	}
 
@@ -1420,6 +1419,34 @@ if_rtdel(struct radix_node *rn, void *arg)
 }
 
 /*
+ * Reference count functions for ifaddrs.
+ */
+void
+ifa_init(struct ifaddr *ifa)
+{
+
+	mtx_init(&ifa->ifa_mtx, "ifaddr", NULL, MTX_DEF);
+	refcount_init(&ifa->ifa_refcnt, 1);
+}
+
+void
+ifa_ref(struct ifaddr *ifa)
+{
+
+	refcount_acquire(&ifa->ifa_refcnt);
+}
+
+void
+ifa_free(struct ifaddr *ifa)
+{
+
+	if (refcount_release(&ifa->ifa_refcnt)) {
+		mtx_destroy(&ifa->ifa_mtx);
+		free(ifa, M_IFADDR);
+	}
+}
+
+/*
  * XXX: Because sockaddr_dl has deeper structure than the sockaddr
  * structs used to represent other address families, it is necessary
  * to perform a different comparison.
@@ -1711,10 +1738,10 @@ link_rtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
 		return;
 	ifa = ifaof_ifpforaddr(dst, ifp);
 	if (ifa) {
-		IFAREF(ifa);		/* XXX */
+		ifa_ref(ifa);		/* XXX */
 		oifa = rt->rt_ifa;
 		rt->rt_ifa = ifa;
-		IFAFREE(oifa);
+		ifa_free(oifa);
 		if (ifa->ifa_rtrequest && ifa->ifa_rtrequest != link_rtrequest)
 			ifa->ifa_rtrequest(cmd, rt, info);
 	}
diff --git a/sys/net/if_var.h b/sys/net/if_var.h
index 556aace8fae1..cbd274afc9fb 100644
--- a/sys/net/if_var.h
+++ b/sys/net/if_var.h
@@ -706,11 +706,14 @@ struct ifaddr {
 /* for compatibility with other BSDs */
 #define	ifa_list	ifa_link
 
-#define	IFA_LOCK_INIT(ifa)	\
-    mtx_init(&(ifa)->ifa_mtx, "ifaddr", NULL, MTX_DEF)
+#ifdef _KERNEL
 #define	IFA_LOCK(ifa)		mtx_lock(&(ifa)->ifa_mtx)
 #define	IFA_UNLOCK(ifa)		mtx_unlock(&(ifa)->ifa_mtx)
-#define	IFA_DESTROY(ifa)	mtx_destroy(&(ifa)->ifa_mtx)
+
+void	ifa_free(struct ifaddr *ifa);
+void	ifa_init(struct ifaddr *ifa);
+void	ifa_ref(struct ifaddr *ifa);
+#endif
 
 /*
  * The prefix structure contains information about one prefix
@@ -741,24 +744,6 @@ struct ifmultiaddr {
 };
 
 #ifdef _KERNEL
-#define	IFAFREE(ifa)					\
-	do {						\
-		IFA_LOCK(ifa);				\
-		KASSERT((ifa)->ifa_refcnt > 0,		\
-		    ("ifa %p !(ifa_refcnt > 0)", ifa));	\
-		if (--(ifa)->ifa_refcnt == 0) {		\
-			IFA_DESTROY(ifa);		\
-			free(ifa, M_IFADDR);		\
-		} else 					\
-			IFA_UNLOCK(ifa);		\
-	} while (0)
-
-#define IFAREF(ifa)					\
-	do {						\
-		IFA_LOCK(ifa);				\
-		++(ifa)->ifa_refcnt;			\
-		IFA_UNLOCK(ifa);			\
-	} while (0)
 
 extern	struct rwlock ifnet_lock;
 #define	IFNET_LOCK_INIT() \
diff --git a/sys/net/route.c b/sys/net/route.c
index aaa38d76c6b0..1705e98e0193 100644
--- a/sys/net/route.c
+++ b/sys/net/route.c
@@ -474,7 +474,7 @@ rtfree(struct rtentry *rt)
 		 * e.g other routes and ifaddrs.
 		 */
 		if (rt->rt_ifa)
-			IFAFREE(rt->rt_ifa);
+			ifa_free(rt->rt_ifa);
 		/*
 		 * The key is separatly alloc'd so free it (see rt_setgate()).
 		 * This also frees the gateway, as they are always malloc'd
@@ -1126,7 +1126,7 @@ rtrequest1_fib(int req, struct rt_addrinfo *info, struct rtentry **ret_nrt,
 		 * This moved from below so that rnh->rnh_addaddr() can
 		 * examine the ifa and  ifa->ifa_ifp if it so desires.
 		 */
-		IFAREF(ifa);
+		ifa_ref(ifa);
 		rt->rt_ifa = ifa;
 		rt->rt_ifp = ifa->ifa_ifp;
 		rt->rt_rmx.rmx_weight = 1;
@@ -1136,7 +1136,7 @@ rtrequest1_fib(int req, struct rt_addrinfo *info, struct rtentry **ret_nrt,
 		if (rn_mpath_capable(rnh) &&
 			rt_mpath_conflict(rnh, rt, netmask)) {
 			if (rt->rt_ifa) {
-				IFAFREE(rt->rt_ifa);
+				ifa_free(rt->rt_ifa);
 			}
 			Free(rt_key(rt));
 			RT_LOCK_DESTROY(rt);
@@ -1153,7 +1153,7 @@ rtrequest1_fib(int req, struct rt_addrinfo *info, struct rtentry **ret_nrt,
 		 */
 		if (rn == NULL) {
 			if (rt->rt_ifa)
-				IFAFREE(rt->rt_ifa);
+				ifa_free(rt->rt_ifa);
 			Free(rt_key(rt));
 			RT_LOCK_DESTROY(rt);
 			uma_zfree(V_rtzone, rt);
@@ -1409,8 +1409,8 @@ rtinit1(struct ifaddr *ifa, int cmd, int flags, int fibnum)
 			 */
 			if (memcmp(rt->rt_ifa->ifa_addr,
 			    ifa->ifa_addr, ifa->ifa_addr->sa_len)) {
-				IFAFREE(rt->rt_ifa);
-				IFAREF(ifa);
+				ifa_free(rt->rt_ifa);
+				ifa_ref(ifa);
 				rt->rt_ifp = ifa->ifa_ifp;
 				rt->rt_ifa = ifa;
 			}
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index 56bb3a7bf0c2..ab3855721587 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -694,7 +694,7 @@ route_output(struct mbuf *m, struct socket *so)
 			    rt->rt_ifa->ifa_rtrequest != NULL) {
 				rt->rt_ifa->ifa_rtrequest(RTM_DELETE, rt,
 				    &info);
-				IFAFREE(rt->rt_ifa);
+				ifa_free(rt->rt_ifa);
 			}
 			if (info.rti_info[RTAX_GATEWAY] != NULL) {
 				RT_UNLOCK(rt);
@@ -712,7 +712,7 @@ route_output(struct mbuf *m, struct socket *so)
 			}
 			if (info.rti_ifa != NULL &&
 			    info.rti_ifa != rt->rt_ifa) {
-				IFAREF(info.rti_ifa);
+				ifa_ref(info.rti_ifa);
 				rt->rt_ifa = info.rti_ifa;
 				rt->rt_ifp = info.rti_ifp;
 			}