kern/intr: switch intr_event_handle() to return stray count

Comparable to the current situation.  Minor savings, one caller simply
passes the count directly through.

Differential Revision: https://reviews.freebsd.org/D38449

Author: ehem

sys/kern/kern_intr.c

@@ -1411,9 +1411,9 @@ intr_event_incr(struct intr_event *ie)
  *
  * Return value:
  * o 0:                         everything ok.
- * o EINVAL:                    stray interrupt.
+ * o non-0:                     stray interrupt, current count.
  */
-int
+u_long
 intr_event_handle(struct intr_event *ie, struct trapframe *frame)
 {
 	struct intr_handler *ih;
@@ -1431,16 +1431,14 @@ intr_event_handle(struct intr_event *ie, struct trapframe *frame)
 
 	/* An interrupt with no event is a stray interrupt. */
 	if (ie == NULL)
-		return (EINVAL);
+		return (~0UL);
 
 	/* Increment the interrupt counter. */
 	intr_event_incr(ie);
 
 	/* An interrupt with no handlers is a stray interrupt. */
-	if (CK_SLIST_EMPTY(&ie->ie_handlers)) {
-		++ie->ie_stray;
-		return (EINVAL);
-	}
+	if (CK_SLIST_EMPTY(&ie->ie_handlers))
+		return (++ie->ie_stray);
 
 	/*
 	 * Execute fast interrupt handlers directly.
@@ -1537,7 +1535,7 @@ intr_event_handle(struct intr_event *ie, struct trapframe *frame)
 	/* The interrupt is not aknowledged by any filter and has no ithread. */
 	if (!thread && !filter) {
 		++ie->ie_stray;
-		return (stray ? EINVAL : 0);
+		return (stray ? ie->ie_stray : 0);
 	}
 	return (0);
 }

sys/sys/interrupt.h

@@ -180,7 +180,7 @@ 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_incr(struct intr_event *ie);
-int	intr_event_handle(struct intr_event *ie, struct trapframe *frame);
+u_long	intr_event_handle(struct intr_event *ie, struct trapframe *frame);
 int	intr_event_remove_handler(void *cookie);
 int	intr_event_suspend_handler(void *cookie);
 int	intr_event_resume_handler(void *cookie);

sys/x86/x86/intr_machdep.c

@@ -306,6 +306,7 @@ intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame)
 {
 	struct intr_event *ie;
 	int vector;
+	u_long strays;
 
 	/*
 	 * We count software interrupts when we process them.  The
@@ -329,11 +330,11 @@ intr_execute_handlers(struct intsrc *isrc, struct trapframe *frame)
 	 * For stray interrupts, mask and EOI the source, bump the
 	 * stray count, and log the condition.
 	 */
-	if (intr_event_handle(ie, frame) != 0) {
+	if ((strays = intr_event_handle(ie, frame)) != 0) {
 		isrc->is_pic->pic_disable_source(isrc, PIC_EOI);
-		if (*isrc->is_straycount < INTR_STRAY_LOG_MAX)
+		if (strays < INTR_STRAY_LOG_MAX)
 			log(LOG_ERR, "stray irq%d\n", vector);
-		else if (*isrc->is_straycount == INTR_STRAY_LOG_MAX)
+		else if (strays == INTR_STRAY_LOG_MAX)
 			log(LOG_CRIT,
 			    "too many stray irq %d's: not logging anymore\n",
 			    vector);