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-rw-r--r--include/linux/dma-fence.h31
1 files changed, 16 insertions, 15 deletions
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index 6b788467b2e3..05d29dbc7e62 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Fence mechanism for dma-buf to allow for asynchronous dma access
*
@@ -7,15 +8,6 @@
* Authors:
* Rob Clark <robdclark@gmail.com>
* Maarten Lankhorst <maarten.lankhorst@canonical.com>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
*/
#ifndef __LINUX_DMA_FENCE_H
@@ -112,6 +104,14 @@ struct dma_fence_cb {
*/
struct dma_fence_ops {
/**
+ * @use_64bit_seqno:
+ *
+ * True if this dma_fence implementation uses 64bit seqno, false
+ * otherwise.
+ */
+ bool use_64bit_seqno;
+
+ /**
* @get_driver_name:
*
* Returns the driver name. This is a callback to allow drivers to
@@ -410,18 +410,19 @@ dma_fence_is_signaled(struct dma_fence *fence)
* __dma_fence_is_later - return if f1 is chronologically later than f2
* @f1: the first fence's seqno
* @f2: the second fence's seqno from the same context
+ * @ops: dma_fence_ops associated with the seqno
*
* Returns true if f1 is chronologically later than f2. Both fences must be
* from the same context, since a seqno is not common across contexts.
*/
-static inline bool __dma_fence_is_later(u64 f1, u64 f2)
+static inline bool __dma_fence_is_later(u64 f1, u64 f2,
+ const struct dma_fence_ops *ops)
{
/* This is for backward compatibility with drivers which can only handle
- * 32bit sequence numbers. Use a 64bit compare when any of the higher
- * bits are none zero, otherwise use a 32bit compare with wrap around
- * handling.
+ * 32bit sequence numbers. Use a 64bit compare when the driver says to
+ * do so.
*/
- if (upper_32_bits(f1) || upper_32_bits(f2))
+ if (ops->use_64bit_seqno)
return f1 > f2;
return (int)(lower_32_bits(f1) - lower_32_bits(f2)) > 0;
@@ -441,7 +442,7 @@ static inline bool dma_fence_is_later(struct dma_fence *f1,
if (WARN_ON(f1->context != f2->context))
return false;
- return __dma_fence_is_later(f1->seqno, f2->seqno);
+ return __dma_fence_is_later(f1->seqno, f2->seqno, f1->ops);
}
/**