On 13/10/2025 14:48, Christian König wrote:
Instead of doing this on the first call of the function just initialize
the stub fence during kernel load.
This has the clear advantage of lower overhead and also doesn't rely on
the ops to not be NULL any more.
Signed-off-by: Christian König <[email protected]>
---
drivers/dma-buf/dma-fence.c | 32 +++++++++++++++-----------------
1 file changed, 15 insertions(+), 17 deletions(-)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index f0539c73ed57..51ee13d005bc 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -121,29 +121,27 @@ static const struct dma_fence_ops dma_fence_stub_ops = {
.get_timeline_name = dma_fence_stub_get_name,
};
+static int __init dma_fence_init_stub(void)
+{
+ dma_fence_init(&dma_fence_stub, &dma_fence_stub_ops,
+ &dma_fence_stub_lock, 0, 0);
+
+ set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
+ &dma_fence_stub.flags);
+
+ dma_fence_signal_locked(&dma_fence_stub);
+ return 0;
+}
+subsys_initcall(dma_fence_init_stub);
+
/**
* dma_fence_get_stub - return a signaled fence
*
- * Return a stub fence which is already signaled. The fence's
- * timestamp corresponds to the first time after boot this
- * function is called.
+ * Return a stub fence which is already signaled. The fence's timestamp
+ * corresponds to the initialisation time of the linux kernel.
We sure hope it's Linux kernel and not some imposter! :D (Ie. you can
drop linux if you want.)
*/
struct dma_fence *dma_fence_get_stub(void)
{
- spin_lock(&dma_fence_stub_lock);
- if (!dma_fence_stub.ops) {
- dma_fence_init(&dma_fence_stub,
- &dma_fence_stub_ops,
- &dma_fence_stub_lock,
- 0, 0);
-
- set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
- &dma_fence_stub.flags);
-
- dma_fence_signal_locked(&dma_fence_stub);
- }
- spin_unlock(&dma_fence_stub_lock);
-
return dma_fence_get(&dma_fence_stub);
}
EXPORT_SYMBOL(dma_fence_get_stub);
Reviewed-by: Tvrtko Ursulin <[email protected]>
Regards,
Tvrtko
