Module Name: src
Committed By: riastradh
Date: Sun Dec 19 01:45:53 UTC 2021
Modified Files:
src/sys/external/bsd/drm2/include/linux: atomic.h
Log Message:
atomic_dec_if_positive
To generate a diff of this commit:
cvs rdiff -u -r1.27 -r1.28 src/sys/external/bsd/drm2/include/linux/atomic.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/external/bsd/drm2/include/linux/atomic.h
diff -u src/sys/external/bsd/drm2/include/linux/atomic.h:1.27 src/sys/external/bsd/drm2/include/linux/atomic.h:1.28
--- src/sys/external/bsd/drm2/include/linux/atomic.h:1.27 Sun Dec 19 01:44:19 2021
+++ src/sys/external/bsd/drm2/include/linux/atomic.h Sun Dec 19 01:45:53 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: atomic.h,v 1.27 2021/12/19 01:44:19 riastradh Exp $ */
+/* $NetBSD: atomic.h,v 1.28 2021/12/19 01:45:53 riastradh Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -155,6 +155,23 @@ atomic_dec_and_test(atomic_t *atomic)
return atomic_dec_return(atomic) == 0;
}
+static inline int
+atomic_dec_if_positive(atomic_t *atomic)
+{
+ int v;
+
+ smp_mb__before_atomic();
+ do {
+ v = atomic->a_u.au_uint;
+ __insn_barrier();
+ if (v <= 0)
+ break;
+ } while (atomic_cas_uint(&atomic->a_u.au_uint, v, v - 1) != v);
+ smp_mb__after_atomic();
+
+ return v - 1;
+}
+
static inline void
atomic_or(int value, atomic_t *atomic)
{
