use refcnt API for multicast addresses, add tracepoint:refcnt:ifmaddr probe

Replace hand-rolled reference counting with refcnt_init(9) and hook it up
with a new dt(4) probe.

OK bluhm mvs

5 files changed, 18 insertions, 15 deletions

diff --git a/sys/dev/dt/dt_prov_static.c b/sys/dev/dt/dt_prov_static.c
index 5bd926dfbcf..e446844f575 100644
--- a/sys/dev/dt/dt_prov_static.c
+++ b/sys/dev/dt/dt_prov_static.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dt_prov_static.c,v 1.18 2023/04/28 20:03:13 mvs Exp $ */
+/*	$OpenBSD: dt_prov_static.c,v 1.19 2023/06/28 11:49:49 kn Exp $ */
 
 /*
  * Copyright (c) 2019 Martin Pieuchot <mpi@openbsd.org>
@@ -93,6 +93,7 @@ DT_STATIC_PROBE2(smr, thread, "uint64_t", "uint64_t");
  */
 DT_STATIC_PROBE0(refcnt, none);
 DT_STATIC_PROBE3(refcnt, ifaddr, "void *", "int", "int");
+DT_STATIC_PROBE3(refcnt, ifmaddr, "void *", "int", "int");
 DT_STATIC_PROBE3(refcnt, inpcb, "void *", "int", "int");
 DT_STATIC_PROBE3(refcnt, rtentry, "void *", "int", "int");
 DT_STATIC_PROBE3(refcnt, tdb, "void *", "int", "int");
@@ -140,6 +141,7 @@ struct dt_probe *const dtps_static[] = {
 	/* refcnt */
 	&_DT_STATIC_P(refcnt, none),
 	&_DT_STATIC_P(refcnt, ifaddr),
+	&_DT_STATIC_P(refcnt, ifmaddr),
 	&_DT_STATIC_P(refcnt, inpcb),
 	&_DT_STATIC_P(refcnt, rtentry),
 	&_DT_STATIC_P(refcnt, tdb),
diff --git a/sys/net/if_var.h b/sys/net/if_var.h
index 4152d3a3704..a4eabc52ca0 100644
--- a/sys/net/if_var.h
+++ b/sys/net/if_var.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_var.h,v 1.127 2023/05/30 08:30:01 jsg Exp $	*/
+/*	$OpenBSD: if_var.h,v 1.128 2023/06/28 11:49:49 kn Exp $	*/
 /*	$NetBSD: if.h,v 1.23 1996/05/07 02:40:27 thorpej Exp $	*/
 
 /*
@@ -255,7 +255,7 @@ struct ifaddr {
 struct ifmaddr {
 	struct sockaddr		*ifma_addr;	/* Protocol address */
 	unsigned int		 ifma_ifidx;	/* Index of the interface */
-	unsigned int		 ifma_refcnt;	/* Count of references */
+	struct refcnt		 ifma_refcnt;	/* Count of references */
 	TAILQ_ENTRY(ifmaddr)	 ifma_list;	/* Per-interface list */
 };
 
diff --git a/sys/netinet/in.c b/sys/netinet/in.c
index 624c67db34f..d2207b3e124 100644
--- a/sys/netinet/in.c
+++ b/sys/netinet/in.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in.c,v 1.184 2023/04/24 12:11:56 kn Exp $	*/
+/*	$OpenBSD: in.c,v 1.185 2023/06/28 11:49:49 kn Exp $	*/
 /*	$NetBSD: in.c,v 1.26 1996/02/13 23:41:39 christos Exp $	*/
 
 /*
@@ -839,7 +839,7 @@ in_addmulti(struct in_addr *ap, struct ifnet *ifp)
 		/*
 		 * Found it; just increment the reference count.
 		 */
-		++inm->inm_refcnt;
+		refcnt_take(&inm->inm_refcnt);
 	} else {
 		/*
 		 * New address; allocate a new multicast record
@@ -849,7 +849,7 @@ in_addmulti(struct in_addr *ap, struct ifnet *ifp)
 		inm->inm_sin.sin_len = sizeof(struct sockaddr_in);
 		inm->inm_sin.sin_family = AF_INET;
 		inm->inm_sin.sin_addr = *ap;
-		inm->inm_refcnt = 1;
+		refcnt_init_trace(&inm->inm_refcnt, DT_REFCNT_IDX_IFMADDR);
 		inm->inm_ifidx = ifp->if_index;
 		inm->inm_ifma.ifma_addr = sintosa(&inm->inm_sin);
 
@@ -890,7 +890,7 @@ in_delmulti(struct in_multi *inm)
 
 	NET_ASSERT_LOCKED();
 
-	if (--inm->inm_refcnt != 0)
+	if (refcnt_rele(&inm->inm_refcnt) == 0)
 		return;
 
 	ifp = if_get(inm->inm_ifidx);
diff --git a/sys/netinet6/in6.c b/sys/netinet6/in6.c
index 3651a5f23f6..1266354e202 100644
--- a/sys/netinet6/in6.c
+++ b/sys/netinet6/in6.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6.c,v 1.261 2023/04/21 00:41:13 kn Exp $	*/
+/*	$OpenBSD: in6.c,v 1.262 2023/06/28 11:49:49 kn Exp $	*/
 /*	$KAME: in6.c,v 1.372 2004/06/14 08:14:21 itojun Exp $	*/
 
 /*
@@ -1032,7 +1032,7 @@ in6_addmulti(struct in6_addr *maddr6, struct ifnet *ifp, int *errorp)
 		/*
 		 * Found it; just increment the reference count.
 		 */
-		in6m->in6m_refcnt++;
+		refcnt_take(&in6m->in6m_refcnt);
 	} else {
 		/*
 		 * New address; allocate a new multicast record
@@ -1047,7 +1047,7 @@ in6_addmulti(struct in6_addr *maddr6, struct ifnet *ifp, int *errorp)
 		in6m->in6m_sin.sin6_len = sizeof(struct sockaddr_in6);
 		in6m->in6m_sin.sin6_family = AF_INET6;
 		in6m->in6m_sin.sin6_addr = *maddr6;
-		in6m->in6m_refcnt = 1;
+		refcnt_init_trace(&in6m->in6m_refcnt, DT_REFCNT_IDX_IFMADDR);
 		in6m->in6m_ifidx = ifp->if_index;
 		in6m->in6m_ifma.ifma_addr = sin6tosa(&in6m->in6m_sin);
 
@@ -1088,7 +1088,7 @@ in6_delmulti(struct in6_multi *in6m)
 
 	NET_ASSERT_LOCKED();
 
-	if (--in6m->in6m_refcnt == 0) {
+	if (refcnt_rele(&in6m->in6m_refcnt) != 0) {
 		/*
 		 * No remaining claims to this record; let MLD6 know
 		 * that we are leaving the multicast group.
diff --git a/sys/sys/refcnt.h b/sys/sys/refcnt.h
index 447973817f4..47a40f61bef 100644
--- a/sys/sys/refcnt.h
+++ b/sys/sys/refcnt.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: refcnt.h,v 1.9 2023/04/28 20:03:14 mvs Exp $ */
+/*	$OpenBSD: refcnt.h,v 1.10 2023/06/28 11:49:49 kn Exp $ */
 
 /*
  * Copyright (c) 2015 David Gwynne <dlg@openbsd.org>
@@ -45,9 +45,10 @@ unsigned int	refcnt_read(struct refcnt *);
 
 /* sorted alphabetically, keep in sync with dev/dt/dt_prov_static.c */
 #define DT_REFCNT_IDX_IFADDR	1
-#define DT_REFCNT_IDX_INPCB	2
-#define DT_REFCNT_IDX_RTENTRY	3
-#define DT_REFCNT_IDX_TDB	4
+#define DT_REFCNT_IDX_IFMADDR	2
+#define DT_REFCNT_IDX_INPCB	3
+#define DT_REFCNT_IDX_RTENTRY	4
+#define DT_REFCNT_IDX_TDB	5
 
 #endif /* _KERNEL */