FreeBSD: add knlist_init_sx() for exclusive locks

This will be used to implement kqfilter support for zvol cdevs.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Rob Wing <rew@FreeBSD.org>
Closes openzfs#13773

include/os/freebsd/zfs/sys/freebsd_event.h

@@ -0,0 +1,37 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2022 Rob Wing
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef	_ZFS_FREEBSD_EVENT_H
+#define	_ZFS_FREEBSD_EVENT_H
+
+#ifdef _KERNEL
+
+void   knlist_init_sx(struct knlist *knl, struct sx *lock);
+
+#endif /* !_KERNEL */
+
+#endif /* !_ZFS_FREEBSD_EVENT_H */

module/Makefile.bsd

@@ -172,6 +172,7 @@ SRCS+=	abd_os.c \
 	arc_os.c \
 	crypto_os.c \
 	dmu_os.c \
+	event_os.c \
 	hkdf.c \
 	kmod_core.c \
 	spa_os.c \

module/os/freebsd/zfs/event_os.c

@@ -0,0 +1,65 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2022 Rob Wing
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/lock.h>
+#include <sys/sx.h>
+#include <sys/event.h>
+
+#include <sys/freebsd_event.h>
+
+static void
+knlist_sx_xlock(void *arg)
+{
+
+	sx_xlock((struct sx *)arg);
+}
+
+static void
+knlist_sx_xunlock(void *arg)
+{
+
+	sx_xunlock((struct sx *)arg);
+}
+
+static void
+knlist_sx_assert_lock(void *arg, int what)
+{
+
+	if (what == LA_LOCKED)
+		sx_assert((struct sx *)arg, SX_LOCKED);
+	else
+		sx_assert((struct sx *)arg, SX_UNLOCKED);
+}
+
+void
+knlist_init_sx(struct knlist *knl, struct sx *lock)
+{
+
+	knlist_init(knl, lock, knlist_sx_xlock, knlist_sx_xunlock,
+	    knlist_sx_assert_lock);
+}