Index: head/sys/compat/linuxkpi/common/include/linux/hrtimer.h
===================================================================
--- head/sys/compat/linuxkpi/common/include/linux/hrtimer.h
+++ head/sys/compat/linuxkpi/common/include/linux/hrtimer.h
@@ -48,7 +48,6 @@
 	enum hrtimer_restart (*function)(struct hrtimer *);
 	struct mtx mtx;
 	struct callout callout;
-	uint32_t flags;
 };
 
 #define	hrtimer_active(hrtimer)	linux_hrtimer_active(hrtimer)
Index: head/sys/compat/linuxkpi/common/src/linux_hrtimer.c
===================================================================
--- head/sys/compat/linuxkpi/common/src/linux_hrtimer.c
+++ head/sys/compat/linuxkpi/common/src/linux_hrtimer.c
@@ -37,9 +37,6 @@
 
 #include <linux/hrtimer.h>
 
-/* hrtimer flags */
-#define	HRTIMER_ACTIVE		0x01
-
 static void
 hrtimer_call_handler(void *arg)
 {
@@ -49,7 +46,7 @@
 	hrtimer = arg;
 	ret = hrtimer->function(hrtimer);
 	MPASS(ret == HRTIMER_NORESTART);
-	hrtimer->flags &= ~HRTIMER_ACTIVE;
+	callout_deactivate(&hrtimer->callout);
 }
 
 bool
@@ -58,19 +55,20 @@
 	bool ret;
 
 	mtx_lock(&hrtimer->mtx);
-	ret = (hrtimer->flags & HRTIMER_ACTIVE) != 0;
+	ret = callout_active(&hrtimer->callout);
 	mtx_unlock(&hrtimer->mtx);
 	return (ret);
 }
 
+/*
+ * Cancel active hrtimer.
+ * Return 1 if timer was active and cancellation succeeded, or 0 otherwise.
+ */
 int
 linux_hrtimer_cancel(struct hrtimer *hrtimer)
 {
 
-	if (!hrtimer_active(hrtimer))
-		return (0);
-	(void)callout_drain(&hrtimer->callout);
-	return (1);
+	return (callout_drain(&hrtimer->callout) > 0);
 }
 
 void
@@ -78,7 +76,6 @@
 {
 
 	hrtimer->function = NULL;
-	hrtimer->flags = 0;
 	mtx_init(&hrtimer->mtx, "hrtimer", NULL, MTX_DEF | MTX_RECURSE);
 	callout_init_mtx(&hrtimer->callout, &hrtimer->mtx, 0);
 }
@@ -103,6 +100,5 @@
 	mtx_lock(&hrtimer->mtx);
 	callout_reset_sbt(&hrtimer->callout, nstosbt(time.tv64), nstosbt(nsec),
 	    hrtimer_call_handler, hrtimer, 0);
-	hrtimer->flags |= HRTIMER_ACTIVE;
 	mtx_unlock(&hrtimer->mtx);
 }