Module Name: src
Committed By: riastradh
Date: Sun Dec 19 11:20:49 UTC 2021
Modified Files:
src/sys/external/bsd/drm2/linux: linux_dma_fence.c
Log Message:
drm/dma-fence: Fix zero timeout semantics in dma_fence_default_wait.
To generate a diff of this commit:
cvs rdiff -u -r1.15 -r1.16 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:1.15 src/sys/external/bsd/drm2/linux/linux_dma_fence.c:1.16
--- src/sys/external/bsd/drm2/linux/linux_dma_fence.c:1.15 Sun Dec 19 11:09:17 2021
+++ src/sys/external/bsd/drm2/linux/linux_dma_fence.c Sun Dec 19 11:20:49 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_dma_fence.c,v 1.15 2021/12/19 11:09:17 riastradh Exp $ */
+/* $NetBSD: linux_dma_fence.c,v 1.16 2021/12/19 11:20:49 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 1.15 2021/12/19 11:09:17 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_dma_fence.c,v 1.16 2021/12/19 11:20:49 riastradh Exp $");
#include <sys/atomic.h>
#include <sys/condvar.h>
@@ -782,10 +782,11 @@ dma_fence_wait(struct dma_fence *fence,
*
* Default implementation of fence wait callback using a condition
* variable. If the fence is already signalled, return timeout,
- * or 1 if no timeout. If the enable signalling callback hasn't
- * been called, call it, and if it fails, act as if the fence had
- * been signalled. Otherwise, wait on the internal condvar. If
- * timeout is MAX_SCHEDULE_TIMEOUT, treat it as no timeout.
+ * or 1 if timeout is zero meaning poll. If the enable signalling
+ * callback hasn't been called, call it, and if it fails, act as
+ * if the fence had been signalled. Otherwise, wait on the
+ * internal condvar. If timeout is MAX_SCHEDULE_TIMEOUT, wait
+ * indefinitely.
*/
long
dma_fence_default_wait(struct dma_fence *fence, bool intr, long timeout)
@@ -800,15 +801,20 @@ dma_fence_default_wait(struct dma_fence
/* Optimistically try to skip the lock if it's already signalled. */
if (fence->flags & (1u << DMA_FENCE_FLAG_SIGNALED_BIT))
- return (timeout < MAX_SCHEDULE_TIMEOUT ? timeout : 1);
+ return (timeout ? timeout : 1);
/* Acquire the lock. */
spin_lock(fence->lock);
- /* Ensure signalling is enabled, or fail if we can't. */
- ret = dma_fence_ensure_signal_enabled(fence);
- if (ret)
- goto out;
+ /* Ensure signalling is enabled, or stop if already completed. */
+ if (dma_fence_ensure_signal_enabled(fence) != 0)
+ return (timeout ? timeout : 1);
+
+ /* If merely polling, stop here. */
+ if (timeout == 0) {
+ spin_unlock(fence->lock);
+ return 0;
+ }
/* Find out what our deadline is so we can handle spurious wakeup. */
if (timeout < MAX_SCHEDULE_TIMEOUT) {
@@ -854,7 +860,6 @@ dma_fence_default_wait(struct dma_fence
}
}
-out:
/* All done. Release the lock. */
spin_unlock(fence->lock);
