Introduce a reader version of the NET_LOCK().

This will be used to first allow read-only ioctl(2) to be executed while
the softnet taskq is running.  Then it will allows us to execute multiple
softnet taskq in parallel.

Tested by Hrvoje Popovski, ok kettenis@, sashan@, visa@, tb@

4 files changed, 32 insertions, 22 deletions

diff --git a/sys/net/if.c b/sys/net/if.c
index 626a7922a12..3bdd998fc7b 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if.c,v 1.524 2017/11/09 09:07:01 tb Exp $	*/
+/*	$OpenBSD: if.c,v 1.525 2017/11/10 08:55:49 mpi Exp $	*/
 /*	$NetBSD: if.c,v 1.35 1996/05/07 05:26:04 thorpej Exp $	*/
 
 /*
@@ -906,7 +906,7 @@ if_input_process(void *xifidx)
 	 * to PF globals, pipex globals, unicast and multicast addresses
 	 * lists.
 	 */
-	NET_LOCK();
+	NET_RLOCK();
 	s = splnet();
 	while ((m = ml_dequeue(&ml)) != NULL) {
 		/*
@@ -923,7 +923,7 @@ if_input_process(void *xifidx)
 			m_freem(m);
 	}
 	splx(s);
-	NET_UNLOCK();
+	NET_RUNLOCK();
 out:
 	if_put(ifp);
 }
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index bb6940a7a07..238ab79df32 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_input.c,v 1.330 2017/11/08 16:29:20 visa Exp $	*/
+/*	$OpenBSD: ip_input.c,v 1.331 2017/11/10 08:55:49 mpi Exp $	*/
 /*	$NetBSD: ip_input.c,v 1.30 1996/03/16 23:53:58 christos Exp $	*/
 
 /*
@@ -1818,11 +1818,11 @@ ip_send_dispatch(void *xmq)
 	if (ml_empty(&ml))
 		return;
 
-	NET_LOCK();
+	NET_RLOCK();
 	while ((m = ml_dequeue(&ml)) != NULL) {
 		ip_output(m, NULL, NULL, 0, NULL, NULL, 0);
 	}
-	NET_UNLOCK();
+	NET_RUNLOCK();
 }
 
 void
diff --git a/sys/netinet6/ip6_input.c b/sys/netinet6/ip6_input.c
index f106d0a3250..caf6dfeb23b 100644
--- a/sys/netinet6/ip6_input.c
+++ b/sys/netinet6/ip6_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip6_input.c,v 1.207 2017/11/01 06:35:38 mpi Exp $	*/
+/*	$OpenBSD: ip6_input.c,v 1.208 2017/11/10 08:55:49 mpi Exp $	*/
 /*	$KAME: ip6_input.c,v 1.188 2001/03/29 05:34:31 itojun Exp $	*/
 
 /*
@@ -1459,7 +1459,7 @@ ip6_send_dispatch(void *xmq)
 	if (ml_empty(&ml))
 		return;
 
-	NET_LOCK();
+	NET_RLOCK();
 	while ((m = ml_dequeue(&ml)) != NULL) {
 		/*
 		 * To avoid a "too big" situation at an intermediate router and
@@ -1470,7 +1470,7 @@ ip6_send_dispatch(void *xmq)
 		 */
 		ip6_output(m, NULL, NULL, IPV6_MINMTU, NULL, NULL);
 	}
-	NET_UNLOCK();
+	NET_RUNLOCK();
 }
 
 void
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index 7a4c2fa2ed4..ba836006091 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: systm.h,v 1.133 2017/08/11 21:24:20 mpi Exp $	*/
+/*	$OpenBSD: systm.h,v 1.134 2017/11/10 08:55:49 mpi Exp $	*/
 /*	$NetBSD: systm.h,v 1.50 1996/06/09 04:55:09 briggs Exp $	*/
 
 /*-
@@ -296,26 +296,36 @@ int	uiomove(void *, size_t, struct uio *);
 
 extern struct rwlock netlock;
 
-#define	NET_LOCK()							\
-do {									\
-	rw_enter_write(&netlock);					\
-} while (0)
+#define	NET_LOCK()		NET_WLOCK()
+#define	NET_UNLOCK()		NET_WUNLOCK()
+#define	NET_ASSERT_UNLOCKED()	NET_ASSERT_WUNLOCKED()
+
+
+#define	NET_WLOCK()	do { rw_enter_write(&netlock); } while (0)
+#define	NET_WUNLOCK()	do { rw_exit_write(&netlock); } while (0)
 
-#define	NET_UNLOCK()							\
+#define	NET_ASSERT_WLOCKED()						\
 do {									\
-	rw_exit_write(&netlock);					\
+	int _s = rw_status(&netlock);					\
+	if (_s != RW_WRITE)						\
+		splassert_fail(RW_WRITE, _s, __func__);			\
 } while (0)
 
-#define	NET_ASSERT_LOCKED()						\
+#define	NET_ASSERT_WUNLOCKED()						\
 do {									\
-	if (rw_status(&netlock) != RW_WRITE)				\
-		splassert_fail(RW_WRITE, rw_status(&netlock), __func__);\
+	int _s = rw_status(&netlock);					\
+	if (_s == RW_WRITE)						\
+		splassert_fail(0, RW_WRITE, __func__);			\
 } while (0)
 
-#define	NET_ASSERT_UNLOCKED()						\
+#define	NET_RLOCK()	do { rw_enter_read(&netlock); } while (0)
+#define	NET_RUNLOCK()	do { rw_exit_read(&netlock); } while (0)
+
+#define	NET_ASSERT_LOCKED()						\
 do {									\
-	if (rw_status(&netlock) == RW_WRITE)				\
-		splassert_fail(0, rw_status(&netlock), __func__);	\
+	int _s = rw_status(&netlock);					\
+	if (_s != RW_WRITE && _s != RW_READ)				\
+		splassert_fail(RW_READ, _s, __func__);			\
 } while (0)
 
 __returns_twice int	setjmp(label_t *);