Index: head/sys/sys/seqc.h
===================================================================
--- head/sys/sys/seqc.h	(revision 358732)
+++ head/sys/sys/seqc.h	(revision 358733)
@@ -1,114 +1,115 @@
 /*-
  * Copyright (c) 2014 Mateusz Guzik <mjg@FreeBSD.org>
  *
  * 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 AUTHOR 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 AUTHOR 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.
  *
  * $FreeBSD$
  */
 
 #ifndef _SYS_SEQC_H_
 #define _SYS_SEQC_H_
 
 #ifdef _KERNEL
 #include <sys/systm.h>
 #endif
 #include <sys/types.h>
 
 /*
  * seqc_t may be included in structs visible to userspace
  */
 typedef uint32_t seqc_t;
 
 #ifdef _KERNEL
 
 /* A hack to get MPASS macro */
 #include <sys/lock.h>
 
 #include <machine/cpu.h>
 
 static __inline bool
 seqc_in_modify(seqc_t seqcp)
 {
 
 	return (seqcp & 1);
 }
 
 static __inline void
 seqc_write_begin(seqc_t *seqcp)
 {
 
 	critical_enter();
 	MPASS(!seqc_in_modify(*seqcp));
 	*seqcp += 1;
 	atomic_thread_fence_rel();
 }
 
 static __inline void
 seqc_write_end(seqc_t *seqcp)
 {
 
-	atomic_store_rel_int(seqcp, *seqcp + 1);
+	atomic_thread_fence_rel();
+	*seqcp += 1;
 	MPASS(!seqc_in_modify(*seqcp));
 	critical_exit();
 }
 
 static __inline seqc_t
 seqc_read_any(const seqc_t *seqcp)
 {
 
 	return (atomic_load_acq_int(__DECONST(seqc_t *, seqcp)));
 }
 
 static __inline seqc_t
 seqc_read(const seqc_t *seqcp)
 {
 	seqc_t ret;
 
 	for (;;) {
-		ret = atomic_load_acq_int(__DECONST(seqc_t *, seqcp));
+		ret = seqc_read_any(seqcp);
 		if (__predict_false(seqc_in_modify(ret))) {
 			cpu_spinwait();
 			continue;
 		}
 		break;
 	}
 
 	return (ret);
 }
 
 static __inline bool
 seqc_consistent_nomb(const seqc_t *seqcp, seqc_t oldseqc)
 {
 
 	return (*seqcp == oldseqc);
 }
 
 static __inline bool
 seqc_consistent(const seqc_t *seqcp, seqc_t oldseqc)
 {
 
 	atomic_thread_fence_acq();
 	return (seqc_consistent_nomb(seqcp, oldseqc));
 }
 
 #endif	/* _KERNEL */
 #endif	/* _SYS_SEQC_H_ */