[src/trunk]: src/sys/external/bsd/drm2 Use Linux atomic64 for ww mutex class.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/594d7a32db35
branches:  trunk
changeset: 835468:594d7a32db35
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Mon Aug 27 15:11:32 2018 +0000

description:
Use Linux atomic64 for ww mutex class.

This way we can take advantage of the hash-locked atomic64 on
platforms that lack native atomic_inc_64_nv.

diffstat:

 sys/external/bsd/drm2/include/linux/ww_mutex.h |  7 ++++---
 sys/external/bsd/drm2/linux/linux_ww_mutex.c   |  6 +++---
 2 files changed, 7 insertions(+), 6 deletions(-)

diffs (55 lines):

diff -r a9f0d5586a27 -r 594d7a32db35 sys/external/bsd/drm2/include/linux/ww_mutex.h
--- a/sys/external/bsd/drm2/include/linux/ww_mutex.h    Mon Aug 27 15:11:17 2018 +0000
+++ b/sys/external/bsd/drm2/include/linux/ww_mutex.h    Mon Aug 27 15:11:32 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ww_mutex.h,v 1.12 2018/08/27 06:06:41 riastradh Exp $  */
+/*     $NetBSD: ww_mutex.h,v 1.13 2018/08/27 15:11:32 riastradh Exp $  */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -37,15 +37,16 @@
 #include <sys/mutex.h>
 #include <sys/rbtree.h>
 
+#include <linux/atomic.h>
 #include <linux/mutex.h>
 
 struct ww_class {
-       volatile uint64_t       wwc_ticket;
+       atomic64_t      wwc_ticket;
 };
 
 #define        DEFINE_WW_CLASS(CLASS)                                                \
        struct ww_class CLASS = {                                             \
-               .wwc_ticket = 0,                                              \
+               .wwc_ticket = ATOMIC64_INIT(0),                               \
        }
 
 struct ww_acquire_ctx {
diff -r a9f0d5586a27 -r 594d7a32db35 sys/external/bsd/drm2/linux/linux_ww_mutex.c
--- a/sys/external/bsd/drm2/linux/linux_ww_mutex.c      Mon Aug 27 15:11:17 2018 +0000
+++ b/sys/external/bsd/drm2/linux/linux_ww_mutex.c      Mon Aug 27 15:11:32 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: linux_ww_mutex.c,v 1.4 2017/09/16 23:56:42 christos Exp $      */
+/*     $NetBSD: linux_ww_mutex.c,v 1.5 2018/08/27 15:11:32 riastradh Exp $     */
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_ww_mutex.c,v 1.4 2017/09/16 23:56:42 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_ww_mutex.c,v 1.5 2018/08/27 15:11:32 riastradh Exp $");
 
 #include <sys/types.h>
 #include <sys/atomic.h>
@@ -92,7 +92,7 @@
 
        ctx->wwx_class = class;
        ctx->wwx_owner = curlwp;
-       ctx->wwx_ticket = atomic_inc_64_nv(&class->wwc_ticket);
+       ctx->wwx_ticket = atomic64_inc_return(&class->wwc_ticket);
        ctx->wwx_acquired = 0;
        ctx->wwx_acquire_done = false;
 }