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);
Kernel test robot reports lockdep_assert_held(fence->lock) inside here.
Probably just copy and paste error, at least I don't see a reason why
dma_fence_signal couldn't be called.
Regards,
Tvrtko
+ 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.
*/
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);
