Module Name: src
Committed By: riastradh
Date: Wed Jul 24 02:28:36 UTC 2013
Modified Files:
src/sys/external/bsd/drm2/include/linux [riastradh-drm2]: atomic.h
Log Message:
Add Linux SMP atomic inc/dec memory barriers to <linux/atomic.h>.
To generate a diff of this commit:
cvs rdiff -u -r1.1.2.7 -r1.1.2.8 \
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:1.1.2.7 src/sys/external/bsd/drm2/include/linux/atomic.h:1.1.2.8
--- src/sys/external/bsd/drm2/include/linux/atomic.h:1.1.2.7 Wed Jul 24 02:27:52 2013
+++ src/sys/external/bsd/drm2/include/linux/atomic.h Wed Jul 24 02:28:36 2013
@@ -1,4 +1,4 @@
-/* $NetBSD: atomic.h,v 1.1.2.7 2013/07/24 02:27:52 riastradh Exp $ */
+/* $NetBSD: atomic.h,v 1.1.2.8 2013/07/24 02:28:36 riastradh Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -135,4 +135,23 @@ test_and_change_bit(unsigned long bit, v
return (v & (1 << bit));
}
+#if defined(MULTIPROCESSOR) && !defined(__HAVE_ATOMIC_AS_MEMBAR)
+/*
+ * XXX These memory barriers are doubtless overkill, but I am having
+ * trouble understanding the intent and use of the Linux atomic membar
+ * API. I think that for reference counting purposes, the sequences
+ * should be insn/inc/enter and exit/dec/insn, but the use of the
+ * before/after memory barriers is not consistent throughout Linux.
+ */
+# define smp_mb__before_atomic_inc() membar_sync()
+# define smp_mb__after_atomic_inc() membar_sync()
+# define smp_mb__before_atomic_dec() membar_sync()
+# define smp_mb__after_atomic_dec() membar_sync()
+#else
+# define smp_mb__before_atomic_inc() __insn_barrier()
+# define smp_mb__after_atomic_inc() __insn_barrier()
+# define smp_mb__before_atomic_dec() __insn_barrier()
+# define smp_mb__after_atomic_dec() __insn_barrier()
+#endif
+
#endif /* _LINUX_ATOMIC_H_ */
