On 25/11/2025 10:44, Philipp Stanner wrote:
Almost all users of dma_fence_signal() ignore the return code which
would indicate that the fence was already signaled. The same return code
by dma_fence_add_callback() cannot be ignored, however, because it's
needed to detect races.
For an already signaled fence, dma_fence_signal() returns -EINVAL,
whereas dma_fence_add_callback() returns -ENOENT.
Unify the error codes by having dma_fence_signal() return -ENOENT, too.
Signed-off-by: Philipp Stanner <[email protected]>
---
drivers/dma-buf/dma-fence.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index 3a48896ded62..09d97624e647 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -373,7 +373,7 @@ int dma_fence_signal_timestamp_locked(struct dma_fence
*fence,
lockdep_assert_held(fence->lock);
if (unlikely(__dma_fence_is_signaled(fence)))
- return -EINVAL;
+ return -ENOENT;
/* Stash the cb_list before replacing it with the timestamp */
list_replace(&fence->cb_list, &cb_list);
Story checks out AFAICT - only two callers fetch the error, xe and kfd,
and neither does anything with it. So I'd say it makes sense to unify
the errno.
Reviewed-by: Tvrtko Ursulin <[email protected]>
Regards,
Tvrtko
P.S. Just not sure of the 1/2 on which this one ends depending on. I
*think* I suggested the helper in the context of some discussion long
long time ago but what it was? And what about all the drivers which look
at the signaled bit directly?
