Rename SRPL_ENTER() to SRPL_FIRST() and SRPL_NEXT() to SRPL_FOLLOW().

This allows us to introduce SRPL_NEXT() that can be used to start
iterating on an arbitrary member of an srp list, hence without calling
SRPL_ENTER().

ok dlg@, jmatthew@

4 files changed, 48 insertions, 33 deletions

diff --git a/share/man/man9/srpl_rc_init.9 b/share/man/man9/srpl_rc_init.9
index 3c5a385751a..87f992aa5c8 100644
--- a/share/man/man9/srpl_rc_init.9
+++ b/share/man/man9/srpl_rc_init.9
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: srpl_rc_init.9,v 1.10 2016/05/18 03:46:03 dlg Exp $
+.\"	$OpenBSD: srpl_rc_init.9,v 1.11 2016/11/20 11:40:58 mpi Exp $
 .\"
 .\" Copyright (c) 2015 David Gwynne <dlg@openbsd.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: May 18 2016 $
+.Dd $Mdocdate: November 20 2016 $
 .Dt SRPL_RC_INIT 9
 .Os
 .Sh NAME
@@ -22,8 +22,9 @@
 .Nm SRPL_HEAD ,
 .Nm SRPL_ENTRY ,
 .Nm SRPL_INIT ,
-.Nm SRPL_ENTER ,
+.Nm SRPL_FIRST,
 .Nm SRPL_NEXT ,
+.Nm SRPL_FOLLOW ,
 .Nm SRPL_FOREACH ,
 .Nm SRPL_LEAVE ,
 .Nm SRPL_EMPTY_LOCKED ,
@@ -50,9 +51,11 @@
 .Fn SRPL_ENTRY "TYPE"
 .Fn "SRPL_INIT" "SRPL_HEAD *sl"
 .Ft void *
-.Fn "SRPL_ENTER" "struct srp_ref *sr" "SRPL_HEAD *sl"
+.Fn "SRPL_FIRST" "struct srp_ref *sr" "SRPL_HEAD *sl"
 .Ft void *
 .Fn "SRPL_NEXT" "struct srp_ref *sr" "struct TYPE *listelm" "FIELDNAME"
+.Ft void *
+.Fn "SRPL_FOLLOW" "struct srp_ref *sr" "struct TYPE *listelm" "FIELDNAME"
 .Fo "SRPL_FOREACH"
 .Fa "VARNAME"
 .Fa "struct srp_ref *sr"
@@ -135,20 +138,30 @@ initialises the SRP list
 .Fa sl
 to an empty state.
 .Pp
-.Fn SRPL_ENTER
-begins iterating over elements in the SRP list
-.Fa sl .
-The reference to the list item is held via
+.Fn SRPL_FIRST
+accesses the first element in the SRP list
+.Fa sl
+and holds its reference via
 .Fa sr .
-Every call to
-.Fn SRPL_ENTER
-must have a corresponding call to
-.Fn SRPL_LEAVE
-to release references to the list and its elements.
 .Pp
 .Fn SRPL_NEXT
 accesses the element in the SRP list after
-.Fa listelm .
+.Fa listelm
+and holds its reference via
+.Fa sr .
+.\".Pp
+.\"Every call to
+.\".Fn SRPL_FIRST
+.\"must have a corresponding call to
+.\".Fn SRPL_LEAVE
+.\"to release references to the list and its elements.
+.Pp
+.Fn SRPL_FOLLOW
+accesses the element in the SRP list after
+.Fa listelm
+and swap the previous reference held via
+.Fa sr
+for the reference of the newly accessed item.
 .Pp
 .Fn SRPL_FOREACH
 creates a loop for traversing the list.
@@ -161,8 +174,9 @@ to release references to the list and its elements.
 .Fn SRPL_LEAVE
 releases references to the list and its elements held by previous
 calls to
-.Fn SRPL_ENTER ,
+.Fn SRPL_FIRST,
 .Fn SRPL_NEXT ,
+.Fn SRPL_FOLLOW ,
 or
 .Fn SRPL_FOREACH .
 .Pp
@@ -224,8 +238,9 @@ An srpl_rc declaration can be initialised with the
 macro.
 .Sh CONTEXT
 .Fn SRPL_INIT ,
-.Fn SRPL_ENTER ,
+.Fn SRPL_FIRST,
 .Fn SRPL_NEXT ,
+.Fn SRPL_FOLLOW ,
 .Fn SRPL_FOREACH ,
 and
 .Fn SRPL_LEAVE
@@ -245,8 +260,9 @@ may be called during autoconf or from process context.
 An appropriate lock must be held that prevents concurrent modifications
 to the list.
 .Sh RETURN VALUES
-.Fn SRPL_ENTER ,
+.Fn SRPL_FIRST ,
 .Fn SRPL_NEXT ,
+.Fn SRPL_FOLLOW ,
 .Fn SRPL_FIRST_LOCKED ,
 and
 .Fn SRPL_NEXT_LOCKED
diff --git a/sys/net/rtable.c b/sys/net/rtable.c
index a82ee8452ca..7656b943bf5 100644
--- a/sys/net/rtable.c
+++ b/sys/net/rtable.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtable.c,v 1.54 2016/11/14 10:32:46 mpi Exp $ */
+/*	$OpenBSD: rtable.c,v 1.55 2016/11/20 11:40:58 mpi Exp $ */
 
 /*
  * Copyright (c) 2014-2016 Martin Pieuchot
@@ -536,7 +536,7 @@ rtable_lookup(unsigned int rtableid, struct sockaddr *dst,
 	}
 
 #ifdef SMALL_KERNEL
-	rt = SRPL_ENTER(&sr, &an->an_rtlist);
+	rt = SRPL_FIRST(&sr, &an->an_rtlist);
 #else
 	SRPL_FOREACH(rt, &sr, &an->an_rtlist, rt_next) {
 		if (prio != RTP_ANY &&
@@ -583,7 +583,7 @@ rtable_match(unsigned int rtableid, struct sockaddr *dst, uint32_t *src)
 	if (an == NULL)
 		goto out;
 
-	rt = SRPL_ENTER(&sr, &an->an_rtlist);
+	rt = SRPL_FIRST(&sr, &an->an_rtlist);
 	rtref(rt);
 	SRPL_LEAVE(&sr);
 
@@ -614,11 +614,11 @@ rtable_match(unsigned int rtableid, struct sockaddr *dst, uint32_t *src)
 		 * the end of the list and then pick the first route.
 		 */
 
-		mrt = SRPL_ENTER(&sr, &an->an_rtlist);
+		mrt = SRPL_FIRST(&sr, &an->an_rtlist);
 		while (hash > threshold && mrt != NULL) {
 			if (mrt->rt_priority == rt->rt_priority)
 				hash -= threshold;
-			mrt = SRPL_NEXT(&sr, mrt, rt_next);
+			mrt = SRPL_FOLLOW(&sr, mrt, rt_next);
 		}
 
 		if (mrt != NULL) {
diff --git a/sys/netinet/ip_carp.c b/sys/netinet/ip_carp.c
index ff3ae78600d..73d959eac26 100644
--- a/sys/netinet/ip_carp.c
+++ b/sys/netinet/ip_carp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_carp.c,v 1.295 2016/10/25 07:21:02 yasuoka Exp $	*/
+/*	$OpenBSD: ip_carp.c,v 1.296 2016/11/20 11:40:58 mpi Exp $	*/
 
 /*
  * Copyright (c) 2002 Michael Shalayeff. All rights reserved.
@@ -1329,7 +1329,7 @@ carp_iamatch(struct ifnet *ifp)
 	struct srp_ref sr;
 	int match = 0;
 
-	vhe = SRPL_ENTER(&sr, &sc->carp_vhosts); /* head */
+	vhe = SRPL_FIRST(&sr, &sc->carp_vhosts);
 	if (vhe->state == MASTER)
 		match = 1;
 	SRPL_LEAVE(&sr);
@@ -1381,7 +1381,7 @@ carp_vhe_match(struct carp_softc *sc, uint8_t *ena)
 	struct srp_ref sr;
 	int match = 0;
 
-	vhe = SRPL_ENTER(&sr, &sc->carp_vhosts); /* head */
+	vhe = SRPL_FIRST(&sr, &sc->carp_vhosts);
 	match = (vhe->state == MASTER || sc->sc_balancing >= CARP_BAL_IP) &&
 	    !memcmp(ena, sc->sc_ac.ac_enaddr, ETHER_ADDR_LEN);
 	SRPL_LEAVE(&sr);
@@ -2312,7 +2312,7 @@ carp_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *sa,
 	KASSERT(sc->sc_carpdev != NULL);
 
 	if (sc->cur_vhe == NULL) {
-		vhe = SRPL_ENTER(&sr, &sc->carp_vhosts); /* head */
+		vhe = SRPL_FIRST(&sr, &sc->carp_vhosts);
 		ismaster = (vhe->state == MASTER);
 		SRPL_LEAVE(&sr);
 	} else {
diff --git a/sys/sys/srp.h b/sys/sys/srp.h
index cedbd20bd87..383135432af 100644
--- a/sys/sys/srp.h
+++ b/sys/sys/srp.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: srp.h,v 1.12 2016/10/21 06:27:50 dlg Exp $ */
+/*	$OpenBSD: srp.h,v 1.13 2016/11/20 11:40:58 mpi Exp $ */
 
 /*
  * Copyright (c) 2014 Jonathan Matthew <jmatthew@openbsd.org>
@@ -110,15 +110,14 @@ struct {								\
 	struct srp		se_next;				\
 }
 
-#define SRPL_ENTER(_sr, _sl)		srp_enter((_sr), &(_sl)->sl_head)
-
-#define SRPL_NEXT(_sr, _e, _ENTRY)	\
-	srp_follow((_sr), &(_e)->_ENTRY.se_next)
+#define SRPL_FIRST(_sr, _sl)		srp_enter((_sr), &(_sl)->sl_head)
+#define SRPL_NEXT(_sr, _e, _ENTRY)	srp_enter((_sr), &(_e)->_ENTRY.se_next)
+#define SRPL_FOLLOW(_sr, _e, _ENTRY)	srp_follow((_sr), &(_e)->_ENTRY.se_next)
 
 #define SRPL_FOREACH(_c, _sr, _sl, _ENTRY)				\
-	for ((_c) = SRPL_ENTER(_sr, _sl);				\
+	for ((_c) = SRPL_FIRST(_sr, _sl);				\
 	    (_c) != NULL; 						\
-	    (_c) = SRPL_NEXT(_sr, _c, _ENTRY))
+	    (_c) = SRPL_FOLLOW(_sr, _c, _ENTRY))
 
 #define SRPL_LEAVE(_sr)			srp_leave((_sr))