MFC r268634:

Manage struct sigacts refcnt with atomics instead of a mutex.

1 files changed, 7 insertions, 10 deletions

diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 17a0e61..1d21f06 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -59,6 +59,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/lock.h>
 #include <sys/malloc.h>
 #include <sys/mutex.h>
+#include <sys/refcount.h>
 #include <sys/namei.h>
 #include <sys/proc.h>
 #include <sys/procdesc.h>
@@ -3432,21 +3433,17 @@ void
 sigacts_free(struct sigacts *ps)
 {
 
-	mtx_lock(&ps->ps_mtx);
-	ps->ps_refcnt--;
-	if (ps->ps_refcnt == 0) {
-		mtx_destroy(&ps->ps_mtx);
-		free(ps, M_SUBPROC);
-	} else
-		mtx_unlock(&ps->ps_mtx);
+	if (refcount_release(&ps->ps_refcnt) == 0)
+		return;
+	mtx_destroy(&ps->ps_mtx);
+	free(ps, M_SUBPROC);
 }
 
 struct sigacts *
 sigacts_hold(struct sigacts *ps)
 {
-	mtx_lock(&ps->ps_mtx);
-	ps->ps_refcnt++;
-	mtx_unlock(&ps->ps_mtx);
+
+	refcount_acquire(&ps->ps_refcnt);
 	return (ps);
 }