Index: sys/kern/kern_intr.c
===================================================================
--- sys/kern/kern_intr.c
+++ sys/kern/kern_intr.c
@@ -160,12 +160,13 @@
 
 	ie = ithd->it_event;
 	td = ithd->it_thread;
+	mtx_assert(&ie->ie_lock, MA_OWNED);
 
 	/* Determine the overall priority of this event. */
-	if (TAILQ_EMPTY(&ie->ie_handlers))
+	if (SLIST_EMPTY(&ie->ie_handlers))
 		pri = PRI_MAX_ITHD;
 	else
-		pri = TAILQ_FIRST(&ie->ie_handlers)->ih_pri;
+		pri = SLIST_FIRST(&ie->ie_handlers)->ih_pri;
 
 	/* Update name and priority. */
 	strlcpy(td->td_name, ie->ie_fullname, sizeof(td->td_name));
@@ -195,7 +196,7 @@
 	space = 1;
 
 	/* Run through all the handlers updating values. */
-	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
+	SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
 		if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 1 <
 		    sizeof(ie->ie_fullname)) {
 			strcat(ie->ie_fullname, " ");
@@ -257,7 +258,7 @@
 	ie->ie_flags = flags;
 	ie->ie_irq = irq;
 	ie->ie_cpu = NOCPU;
-	TAILQ_INIT(&ie->ie_handlers);
+	SLIST_INIT(&ie->ie_handlers);
 	mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF);
 
 	va_start(ap, fmt);
@@ -378,7 +379,7 @@
 	TAILQ_FOREACH(ie, &event_list, ie_list)
 		if (ie->ie_irq == irq &&
 		    (ie->ie_flags & IE_SOFT) == 0 &&
-		    TAILQ_FIRST(&ie->ie_handlers) != NULL)
+		    SLIST_FIRST(&ie->ie_handlers) != NULL)
 			break;
 	mtx_unlock(&event_lock);
 	return (ie);
@@ -474,7 +475,7 @@
 
 	mtx_lock(&event_lock);
 	mtx_lock(&ie->ie_lock);
-	if (!TAILQ_EMPTY(&ie->ie_handlers)) {
+	if (!SLIST_EMPTY(&ie->ie_handlers)) {
 		mtx_unlock(&ie->ie_lock);
 		mtx_unlock(&event_lock);
 		return (EBUSY);
@@ -504,7 +505,7 @@
 
 	error = kproc_kthread_add(ithread_loop, ithd, &intrproc,
 		    &td, RFSTOPPED | RFHIGHPID,
-	    	    0, "intr", "%s", name);
+		    0, "intr", "%s", name);
 	if (error)
 		panic("kproc_create() failed with %d", error);
 	thread_lock(td);
@@ -539,6 +540,7 @@
     enum intr_type flags, void **cookiep)
 {
 	struct intr_handler *ih, *temp_ih;
+	struct intr_handler **prevptr;
 	struct intr_thread *it;
 
 	if (ie == NULL || name == NULL || (handler == NULL && filter == NULL))
@@ -561,9 +563,9 @@
 
 	/* We can only have one exclusive handler in a event. */
 	mtx_lock(&ie->ie_lock);
-	if (!TAILQ_EMPTY(&ie->ie_handlers)) {
+	if (!SLIST_EMPTY(&ie->ie_handlers)) {
 		if ((flags & INTR_EXCL) ||
-		    (TAILQ_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
+		    (SLIST_FIRST(&ie->ie_handlers)->ih_flags & IH_EXCLUSIVE)) {
 			mtx_unlock(&ie->ie_lock);
 			free(ih, M_ITHREAD);
 			return (EINVAL);
@@ -588,14 +590,15 @@
 	}
 
 	/* Add the new handler to the event in priority order. */
-	TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) {
+	SLIST_FOREACH_PREVPTR(temp_ih, prevptr, &ie->ie_handlers, ih_next) {
 		if (temp_ih->ih_pri > ih->ih_pri)
 			break;
 	}
-	if (temp_ih == NULL)
-		TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next);
-	else
-		TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next);
+
+	/* "SLIST_INSERT_PREVPTR". */
+	SLIST_NEXT(ih, ih_next) = temp_ih;
+	*prevptr = ih;
+
 	intr_event_update(ie);
 
 	CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name,
@@ -621,7 +624,7 @@
 
 	mtx_lock(&ie->ie_lock);
 #ifdef INVARIANTS
-	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
+	SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
 		if (ih == cookie)
 			break;
 	}
@@ -721,15 +724,13 @@
 	return;
 }
 
-
 int
 intr_event_remove_handler(void *cookie)
 {
 	struct intr_handler *handler = (struct intr_handler *)cookie;
 	struct intr_event *ie;
-#ifdef INVARIANTS
 	struct intr_handler *ih;
-#endif
+	struct intr_handler **prevptr;
 #ifdef notyet
 	int dead;
 #endif
@@ -740,25 +741,26 @@
 	KASSERT(ie != NULL,
 	    ("interrupt handler \"%s\" has a NULL interrupt event",
 	    handler->ih_name));
+
 	mtx_lock(&ie->ie_lock);
 	CTR3(KTR_INTR, "%s: removing %s from %s", __func__, handler->ih_name,
 	    ie->ie_name);
-#ifdef INVARIANTS
-	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next)
+	SLIST_FOREACH_PREVPTR(ih, prevptr, &ie->ie_handlers, ih_next) {
 		if (ih == handler)
-			goto ok;
-	mtx_unlock(&ie->ie_lock);
-	panic("interrupt handler \"%s\" not found in interrupt event \"%s\"",
-	    ih->ih_name, ie->ie_name);
-ok:
-#endif
+			break;
+	}
+	if (ih == NULL) {
+		panic("interrupt handler \"%s\" not found in "
+		    "interrupt event \"%s\"", handler->ih_name, ie->ie_name);
+	}
+
 	/*
 	 * If there is no ithread, then just remove the handler and return.
 	 * XXX: Note that an INTR_FAST handler might be running on another
 	 * CPU!
 	 */
 	if (ie->ie_thread == NULL) {
-		TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
+		SLIST_REMOVE_PREVPTR(prevptr, ih, ih_next);
 		mtx_unlock(&ie->ie_lock);
 		free(handler, M_ITHREAD);
 		return (0);
@@ -789,11 +791,12 @@
 		 */
 		atomic_store_rel_int(&ie->ie_thread->it_need, 1);
 	} else
-		TAILQ_REMOVE(&ie->ie_handlers, handler, ih_next);
+		SLIST_REMOVE_PREVPTR(prevptr, ih, ih_next);
 	thread_unlock(ie->ie_thread->it_thread);
 	while (handler->ih_flags & IH_DEAD)
 		msleep(handler, &ie->ie_lock, 0, "iev_rmh", 0);
 	intr_event_update(ie);
+
 #ifdef notyet
 	/*
 	 * XXX: This could be bad in the case of ppbus(8).  Also, I think
@@ -801,8 +804,8 @@
 	 * interrupt.
 	 */
 	dead = 1;
-	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
-		if (!(ih->ih_flags & IH_FAST)) {
+	SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
+		if (ih->ih_handler != NULL) {
 			dead = 0;
 			break;
 		}
@@ -828,7 +831,7 @@
 	/*
 	 * If no ithread or no handlers, then we have a stray interrupt.
 	 */
-	if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers) ||
+	if (ie == NULL || SLIST_EMPTY(&ie->ie_handlers) ||
 	    ie->ie_thread == NULL)
 		return (EINVAL);
 
@@ -962,24 +965,23 @@
 	return (intr_event_remove_handler(cookie));
 }
 
-
 /*
  * This is a public function for use by drivers that mux interrupt
  * handlers for child devices from their interrupt handler.
  */
-void
+static void
 intr_event_execute_handlers(struct proc *p, struct intr_event *ie)
 {
-	struct intr_handler *ih, *ihn;
+	struct intr_handler *ih, **ihp;
 
-	TAILQ_FOREACH_SAFE(ih, &ie->ie_handlers, ih_next, ihn) {
+	SLIST_FOREACH_PREVPTR_SAFE(ih, ihp, &ie->ie_handlers, ih_next) {
 		/*
 		 * If this handler is marked for death, remove it from
 		 * the list of handlers and wake up the sleeper.
 		 */
 		if (ih->ih_flags & IH_DEAD) {
 			mtx_lock(&ie->ie_lock);
-			TAILQ_REMOVE(&ie->ie_handlers, ih, ih_next);
+			SLIST_REMOVE_PREVPTR(ihp, ih, ih_next);
 			ih->ih_flags &= ~IH_DEAD;
 			wakeup(ih);
 			mtx_unlock(&ie->ie_lock);
@@ -1157,7 +1159,7 @@
 #endif
 
 	/* An interrupt with no event or handlers is a stray interrupt. */
-	if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers))
+	if (ie == NULL || SLIST_EMPTY(&ie->ie_handlers))
 		return (EINVAL);
 
 	/*
@@ -1172,7 +1174,8 @@
 	critical_enter();
 	oldframe = td->td_intr_frame;
 	td->td_intr_frame = frame;
-	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
+
+	SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
 		if (ih->ih_filter == NULL) {
 			thread = 1;
 			continue;
@@ -1218,7 +1221,7 @@
 		if (ie->ie_post_filter != NULL)
 			ie->ie_post_filter(ie->ie_source);
 	}
-	
+
 	/* Schedule the ithread if needed. */
 	if (thread) {
 		int error __unused;
@@ -1364,7 +1367,7 @@
 	db_printf("\n");
 
 	if (handlers)
-		TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next)
+		SLIST_FOREACH(ih, &ie->ie_handlers, ih_next)
 		    db_dump_intrhand(ih);
 }
 
@@ -1379,7 +1382,7 @@
 	verbose = strchr(modif, 'v') != NULL;
 	all = strchr(modif, 'a') != NULL;
 	TAILQ_FOREACH(ie, &event_list, ie_list) {
-		if (!all && TAILQ_EMPTY(&ie->ie_handlers))
+		if (!all && SLIST_EMPTY(&ie->ie_handlers))
 			continue;
 		db_dump_intr_event(ie, verbose);
 		if (db_pager_quit)
Index: sys/sys/interrupt.h
===================================================================
--- sys/sys/interrupt.h
+++ sys/sys/interrupt.h
@@ -52,7 +52,7 @@
 	char		 ih_name[MAXCOMLEN + 1]; /* Name of handler. */
 	struct intr_event *ih_event;	/* Event we are connected to. */
 	int		 ih_need;	/* Needs service. */
-	TAILQ_ENTRY(intr_handler) ih_next; /* Next handler for this event. */
+	SLIST_ENTRY(intr_handler) ih_next; /* Next handler for this event. */
 	u_char		 ih_pri;	/* Priority of this handler. */
 	struct intr_thread *ih_thread;	/* Ithread for filtered handler. */
 };
@@ -105,7 +105,7 @@
  */
 struct intr_event {
 	TAILQ_ENTRY(intr_event) ie_list;
-	TAILQ_HEAD(, intr_handler) ie_handlers; /* Interrupt handlers. */
+	SLIST_HEAD(, intr_handler) ie_handlers; /* Interrupt handlers. */
 	char		ie_name[MAXCOMLEN + 1]; /* Individual event name. */
 	char		ie_fullname[MAXCOMLEN + 1];
 	struct mtx	ie_lock;
@@ -174,7 +174,6 @@
 int	intr_event_describe_handler(struct intr_event *ie, void *cookie,
 	    const char *descr);
 int	intr_event_destroy(struct intr_event *ie);
-void	intr_event_execute_handlers(struct proc *p, struct intr_event *ie);
 int	intr_event_handle(struct intr_event *ie, struct trapframe *frame);
 int	intr_event_remove_handler(void *cookie);
 int	intr_getaffinity(int irq, int mode, void *mask);
Index: sys/sys/queue.h
===================================================================
--- sys/sys/queue.h
+++ sys/sys/queue.h
@@ -258,6 +258,11 @@
 	    ((var) = *(varp)) != NULL;					\
 	    (varp) = &SLIST_NEXT((var), field))
 
+#define	SLIST_FOREACH_PREVPTR_SAFE(var, varp, head, field)		\
+	for ((varp) = &SLIST_FIRST((head));				\
+	    ((var) = *(varp)) != NULL;					\
+	    (varp) = *(varp) == (var) ? &SLIST_NEXT((var), field) : varp)
+
 #define	SLIST_INIT(head) do {						\
 	SLIST_FIRST((head)) = NULL;					\
 } while (0)