Module Name: src
Committed By: riastradh
Date: Sun Dec 19 12:39:41 UTC 2021
Modified Files:
src/sys/external/bsd/drm2/linux: linux_dma_fence.c
Log Message:
drm: Use atomic_load_consume/relaxed to simplify code.
To generate a diff of this commit:
cvs rdiff -u -r1.38 -r1.39 src/sys/external/bsd/drm2/linux/linux_dma_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/linux/linux_dma_fence.c
diff -u src/sys/external/bsd/drm2/linux/linux_dma_fence.c:1.38 src/sys/external/bsd/drm2/linux/linux_dma_fence.c:1.39
--- src/sys/external/bsd/drm2/linux/linux_dma_fence.c:1.38 Sun Dec 19 12:39:25 2021
+++ src/sys/external/bsd/drm2/linux/linux_dma_fence.c Sun Dec 19 12:39:40 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_dma_fence.c,v 1.38 2021/12/19 12:39:25 riastradh Exp $ */
+/* $NetBSD: linux_dma_fence.c,v 1.39 2021/12/19 12:39:40 riastradh Exp $ */
/*-
* Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_dma_fence.c,v 1.38 2021/12/19 12:39:25 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_dma_fence.c,v 1.39 2021/12/19 12:39:40 riastradh Exp $");
#include <sys/atomic.h>
#include <sys/condvar.h>
@@ -394,21 +394,16 @@ dma_fence_get_rcu(struct dma_fence *fenc
struct dma_fence *
dma_fence_get_rcu_safe(struct dma_fence *volatile const *fencep)
{
- struct dma_fence *fence, *fence0;
+ struct dma_fence *fence;
retry:
- fence = *fencep;
-
- /* Load fence only once. */
- __insn_barrier();
-
- /* If there's nothing there, give up. */
- if (fence == NULL)
+ /*
+ * Load the fence, ensuring we observe the fully initialized
+ * content.
+ */
+ if ((fence = atomic_load_consume(fencep)) == NULL)
return NULL;
- /* Make sure we don't load stale fence guts. */
- membar_datadep_consumer();
-
/* Try to acquire a reference. If we can't, try again. */
if (!dma_fence_get_rcu(fence))
goto retry;
@@ -417,9 +412,7 @@ retry:
* Confirm that it's still the same fence. If not, release it
* and retry.
*/
- fence0 = *fencep;
- __insn_barrier();
- if (fence != fence0) {
+ if (fence != atomic_load_relaxed(fencep)) {
dma_fence_put(fence);
goto retry;
}
