Module Name:    src
Committed By:   riastradh
Date:           Mon Aug 27 13:36:53 UTC 2018

Modified Files:
        src/sys/external/bsd/drm2/include/linux: fence.h
        src/sys/external/bsd/drm2/linux: linux_fence.c

Log Message:
Use atomics to manage fence->flags.

Outside users use this field too, and expect it to be managed with
atomics.


To generate a diff of this commit:
cvs rdiff -u -r1.11 -r1.12 src/sys/external/bsd/drm2/include/linux/fence.h
cvs rdiff -u -r1.1 -r1.2 src/sys/external/bsd/drm2/linux/linux_fence.c

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/fence.h
diff -u src/sys/external/bsd/drm2/include/linux/fence.h:1.11 src/sys/external/bsd/drm2/include/linux/fence.h:1.12
--- src/sys/external/bsd/drm2/include/linux/fence.h:1.11	Mon Aug 27 13:33:59 2018
+++ src/sys/external/bsd/drm2/include/linux/fence.h	Mon Aug 27 13:36:53 2018
@@ -1,4 +1,4 @@
-/*	$NetBSD: fence.h,v 1.11 2018/08/27 13:33:59 riastradh Exp $	*/
+/*	$NetBSD: fence.h,v 1.12 2018/08/27 13:36:53 riastradh Exp $	*/
 
 /*-
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -46,7 +46,7 @@ struct fence_cb;
 struct fence {
 	struct kref		refcount;
 	spinlock_t		*lock;
-	unsigned long		flags;
+	volatile unsigned long	flags;
 	unsigned		context;
 	unsigned		seqno;
 	const struct fence_ops	*ops;

Index: src/sys/external/bsd/drm2/linux/linux_fence.c
diff -u src/sys/external/bsd/drm2/linux/linux_fence.c:1.1 src/sys/external/bsd/drm2/linux/linux_fence.c:1.2
--- src/sys/external/bsd/drm2/linux/linux_fence.c:1.1	Mon Aug 27 13:33:59 2018
+++ src/sys/external/bsd/drm2/linux/linux_fence.c	Mon Aug 27 13:36:53 2018
@@ -1,4 +1,4 @@
-/*	$NetBSD: linux_fence.c,v 1.1 2018/08/27 13:33:59 riastradh Exp $	*/
+/*	$NetBSD: linux_fence.c,v 1.2 2018/08/27 13:36:53 riastradh Exp $	*/
 
 /*-
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,12 +30,13 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_fence.c,v 1.1 2018/08/27 13:33:59 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_fence.c,v 1.2 2018/08/27 13:36:53 riastradh Exp $");
 
 #include <sys/atomic.h>
 #include <sys/condvar.h>
 #include <sys/queue.h>
 
+#include <linux/atomic.h>
 #include <linux/errno.h>
 #include <linux/kref.h>
 #include <linux/fence.h>
@@ -191,12 +192,14 @@ fence_ensure_signal_enabled(struct fence
 	if (fence->flags & (1u << FENCE_FLAG_SIGNALED_BIT))
 		return -ENOENT;
 
-	/* If the enable signalling callback has been called, success.  */
-	if (fence->flags & (1u << FENCE_FLAG_ENABLE_SIGNAL_BIT))
+	/*
+	 * If the enable signaling callback has been called, success.
+	 * Otherwise, set the bit indicating it.
+	 */
+	if (test_and_set_bit(FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags))
 		return 0;
 
 	/* Otherwise, note that we've called it and call it.  */
-	fence->flags |= 1u << FENCE_FLAG_ENABLE_SIGNAL_BIT;
 	if (!(*fence->ops->enable_signaling)(fence)) {
 		/* If it failed, signal and return -ENOENT.  */
 		fence_signal_locked(fence);
@@ -377,9 +380,8 @@ fence_signal_locked(struct fence *fence)
 	KASSERT(spin_is_locked(fence->lock));
 
 	/* If it's been signalled, fail; otherwise set the signalled bit.  */
-	if (fence->flags & (1u << FENCE_FLAG_SIGNALED_BIT))
+	if (test_and_set_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags))
 		return -EINVAL;
-	fence->flags |= 1u << FENCE_FLAG_SIGNALED_BIT;
 
 	/* Wake waiters.  */
 	cv_broadcast(&fence->f_cv);

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