Index: sys/amd64/include/atomic.h
===================================================================
--- sys/amd64/include/atomic.h
+++ sys/amd64/include/atomic.h
@@ -679,4 +679,6 @@
 
 #endif /* !WANT_FUNCTIONS */
 
+#include <sys/atomic_common2.h>
+
 #endif /* !_MACHINE_ATOMIC_H_ */
Index: sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c
===================================================================
--- sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c
+++ sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c
@@ -86,7 +86,7 @@
 vn_rele_async(vnode_t *vp, taskq_t *taskq)
 {
 	VERIFY(vp->v_count > 0);
-	if (refcount_release_if_not_last(&vp->v_usecount)) {
+	if (atomic_dec_int_if_not_last(&vp->v_usecount)) {
 		return;
 	}
 	VERIFY(taskq_dispatch((taskq_t *)taskq,
Index: sys/kern/vfs_subr.c
===================================================================
--- sys/kern/vfs_subr.c
+++ sys/kern/vfs_subr.c
@@ -72,7 +72,6 @@
 #include <sys/pctrie.h>
 #include <sys/priv.h>
 #include <sys/reboot.h>
-#include <sys/refcount.h>
 #include <sys/rwlock.h>
 #include <sys/sched.h>
 #include <sys/sleepqueue.h>
@@ -1161,7 +1160,7 @@
 		freevnodes--;
 		vp->v_iflag &= ~VI_FREE;
 		VNODE_REFCOUNT_FENCE_REL();
-		refcount_acquire(&vp->v_holdcnt);
+		atomic_add_int(&vp->v_holdcnt, 1);
 
 		mtx_unlock(&vnode_free_list_mtx);
 		VI_UNLOCK(vp);
@@ -2656,8 +2655,8 @@
 	    vp, ("%s called for an initialized vnode", __FUNCTION__));
 	ASSERT_VI_UNLOCKED(vp, __FUNCTION__);
 
-	refcount_init(&vp->v_holdcnt, 1);
-	refcount_init(&vp->v_usecount, 1);
+	atomic_store_int(&vp->v_holdcnt, 1);
+	atomic_store_int(&vp->v_usecount, 1);
 }
 
 /*
@@ -2711,7 +2710,7 @@
 	enum vgetstate vs;
 
 	if (__predict_true(vp->v_type != VCHR)) {
-		if (refcount_acquire_if_not_zero(&vp->v_usecount)) {
+		if (atomic_inc_int_if_not_zero(&vp->v_usecount)) {
 			vs = VGET_USECOUNT;
 		} else {
 			_vhold(vp, interlock);
@@ -2725,7 +2724,7 @@
 			vs = VGET_HOLDCNT;
 		} else {
 			v_incr_devcount(vp);
-			refcount_acquire(&vp->v_usecount);
+			atomic_add_int(&vp->v_usecount, 1);
 			vs = VGET_USECOUNT;
 		}
 		if (!interlock)
@@ -2793,12 +2792,12 @@
 	 * we have to drop ours.
 	 */
 	if (vp->v_type != VCHR &&
-	    refcount_acquire_if_not_zero(&vp->v_usecount)) {
+	    atomic_inc_int_if_not_zero(&vp->v_usecount)) {
 #ifdef INVARIANTS
 		int old = atomic_fetchadd_int(&vp->v_holdcnt, -1) - 1;
 		VNASSERT(old > 0, vp, ("%s: wrong hold count", __func__));
 #else
-		refcount_release(&vp->v_holdcnt);
+		atomic_subtract_int(&vp->v_holdcnt, 1);
 #endif
 		VNODE_REFCOUNT_FENCE_ACQ();
 		VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp,
@@ -2820,12 +2819,12 @@
 	 * ourselves in the same spot.
 	 */
 	if (vp->v_type != VCHR) {
-		if (refcount_acquire_if_not_zero(&vp->v_usecount)) {
+		if (atomic_inc_int_if_not_zero(&vp->v_usecount)) {
 #ifdef INVARIANTS
 			int old = atomic_fetchadd_int(&vp->v_holdcnt, -1) - 1;
 			VNASSERT(old > 0, vp, ("%s: wrong hold count", __func__));
 #else
-			refcount_release(&vp->v_holdcnt);
+			atomic_subtract_int(&vp->v_holdcnt, 1);
 #endif
 			VNODE_REFCOUNT_FENCE_ACQ();
 			VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp,
@@ -2836,7 +2835,7 @@
 		}
 	} else {
 		if (vp->v_usecount > 0)
-			refcount_release(&vp->v_holdcnt);
+			atomic_subtract_int(&vp->v_holdcnt, 1);
 	}
 	if ((vp->v_iflag & VI_OWEINACT) == 0) {
 		oweinact = 0;
@@ -2846,7 +2845,7 @@
 		VNODE_REFCOUNT_FENCE_REL();
 	}
 	v_incr_devcount(vp);
-	refcount_acquire(&vp->v_usecount);
+	atomic_add_int(&vp->v_usecount, 1);
 	if (oweinact && VOP_ISLOCKED(vp) == LK_EXCLUSIVE &&
 	    (flags & LK_NOWAIT) == 0)
 		vinactive(vp, curthread);
@@ -2865,7 +2864,7 @@
 	ASSERT_VI_UNLOCKED(vp, __func__);
 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 	if (vp->v_type != VCHR &&
-	    refcount_acquire_if_not_zero(&vp->v_usecount)) {
+	    atomic_inc_int_if_not_zero(&vp->v_usecount)) {
 		VNODE_REFCOUNT_FENCE_ACQ();
 		VNASSERT(vp->v_holdcnt > 0, vp,
 		    ("%s: active vnode not held", __func__));
@@ -2885,7 +2884,7 @@
 	ASSERT_VI_LOCKED(vp, __func__);
 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 	if (vp->v_type != VCHR &&
-	    refcount_acquire_if_not_zero(&vp->v_usecount)) {
+	    atomic_inc_int_if_not_zero(&vp->v_usecount)) {
 		VNODE_REFCOUNT_FENCE_ACQ();
 		VNASSERT(vp->v_holdcnt > 0, vp,
 		    ("%s: active vnode not held", __func__));
@@ -2900,7 +2899,7 @@
 		VNODE_REFCOUNT_FENCE_REL();
 	}
 	v_incr_devcount(vp);
-	refcount_acquire(&vp->v_usecount);
+	atomic_add_int(&vp->v_usecount, 1);
 }
 
 void
@@ -2918,7 +2917,7 @@
 	int old = atomic_fetchadd_int(&vp->v_usecount, 1);
 	VNASSERT(old > 0, vp, ("%s: wrong use count", __func__));
 #else
-	refcount_acquire(&vp->v_usecount);
+	atomic_add_int(&vp->v_usecount, 1);
 #endif
 }
 
@@ -2989,7 +2988,7 @@
 		 * count which provides liveness of the vnode, in which case we
 		 * have to vdrop.
 		 */
-		if (!refcount_release(&vp->v_usecount))
+		if (atomic_fetchadd_int(&vp->v_usecount, -1) - 1 > 0)
 			return;
 		VI_LOCK(vp);
 		/*
@@ -3003,7 +3002,7 @@
 	} else {
 		VI_LOCK(vp);
 		v_decr_devcount(vp);
-		if (!refcount_release(&vp->v_usecount)) {
+		if (atomic_fetchadd_int(&vp->v_usecount, -1) - 1 > 0) {
 			VI_UNLOCK(vp);
 			return;
 		}
@@ -3114,7 +3113,7 @@
 		ASSERT_VI_UNLOCKED(vp, __func__);
 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
 	if (!locked) {
-		if (refcount_acquire_if_not_zero(&vp->v_holdcnt)) {
+		if (atomic_inc_int_if_not_zero(&vp->v_holdcnt)) {
 			VNODE_REFCOUNT_FENCE_ACQ();
 			VNASSERT((vp->v_iflag & VI_FREE) == 0, vp,
 			    ("_vhold: vnode with holdcnt is free"));
@@ -3123,7 +3122,7 @@
 		VI_LOCK(vp);
 	}
 	if ((vp->v_iflag & VI_FREE) == 0) {
-		refcount_acquire(&vp->v_holdcnt);
+		atomic_add_int(&vp->v_holdcnt, 1);
 		if (!locked)
 			VI_UNLOCK(vp);
 		return;
@@ -3157,7 +3156,7 @@
 	TAILQ_INSERT_HEAD(&mp->mnt_activevnodelist, vp, v_actfreelist);
 	mp->mnt_activevnodelistsize++;
 	mtx_unlock(&mp->mnt_listmtx);
-	refcount_acquire(&vp->v_holdcnt);
+	atomic_add_int(&vp->v_holdcnt, 1);
 	if (!locked)
 		VI_UNLOCK(vp);
 }
@@ -3201,11 +3200,11 @@
 		panic("vdrop: wrong holdcnt");
 	}
 	if (!locked) {
-		if (refcount_release_if_not_last(&vp->v_holdcnt))
+		if (atomic_dec_int_if_not_last(&vp->v_holdcnt))
 			return;
 		VI_LOCK(vp);
 	}
-	if (refcount_release(&vp->v_holdcnt) == 0) {
+	if (atomic_fetchadd_int(&vp->v_holdcnt, -1) - 1 > 0) {
 		VI_UNLOCK(vp);
 		return;
 	}
@@ -5846,12 +5845,12 @@
 	 * acquired with vhold(), but that might try to acquire the vnode
 	 * interlock, which would be a LOR with the mount vnode list lock.
 	 */
-	held = refcount_acquire_if_not_zero(&vp->v_holdcnt);
+	held = atomic_inc_int_if_not_zero(&vp->v_holdcnt);
 	mtx_unlock(&mp->mnt_listmtx);
 	if (!held)
 		goto abort;
 	VI_LOCK(vp);
-	if (!refcount_release_if_not_last(&vp->v_holdcnt)) {
+	if (!atomic_dec_int_if_not_last(&vp->v_holdcnt)) {
 		vdropl(vp);
 		goto abort;
 	}
Index: sys/sys/atomic_common2.h
===================================================================
--- /dev/null
+++ sys/sys/atomic_common2.h
@@ -0,0 +1,41 @@
+#ifndef _SYS_ATOMIC_COMMON2_H_
+#define	_SYS_ATOMIC_COMMON2_H_
+
+#ifndef _MACHINE_ATOMIC_H_
+#error do not include this header, use machine/atomic.h
+#endif
+
+#define ATOMIC_MODIFY_UNLESS(TYPE)				\
+static __inline __result_use_check bool				\
+atomic_inc_##TYPE##_if_not_zero(volatile u_##TYPE *var)		\
+{								\
+	u_##TYPE old;						\
+								\
+	old = *var;						\
+	for (;;) {						\
+		if (__predict_false(old == 0))			\
+			return (false);				\
+		if (atomic_fcmpset_##TYPE(var, &old, old + 1))	\
+			return (true);				\
+	}							\
+}								\
+static __inline __result_use_check bool				\
+atomic_dec_##TYPE##_if_not_last(volatile u_##TYPE *var)		\
+{								\
+	u_##TYPE old;						\
+								\
+	atomic_thread_fence_rel();				\
+	old = atomic_load_##TYPE(var);				\
+	for (;;) {						\
+		if (__predict_false(old == 1))			\
+			return (false);				\
+		if (atomic_fcmpset_##TYPE(var, &old, old - 1))	\
+			return (true);				\
+	}							\
+}
+
+ATOMIC_MODIFY_UNLESS(short);
+ATOMIC_MODIFY_UNLESS(int);
+ATOMIC_MODIFY_UNLESS(long);
+
+#endif