[PATCH 3/3] drm/nouveau: Add helper to check base fence

Philipp Stanner
2025-04-10T09:25:01Z

Nouveau, unfortunately, checks whether a dma_fence is already siganled
at various different places with, at times, different methods. In
nouveau_fence_update() it generally signals all fences the hardware is
done with by evaluating the sequence number. That mechanism then has no
way to tell the caller nouveau_fence_done() whether a particular fence
is actually signaled, which is why the internal bits of the dma_fence
get checked.

This can be made more readable by providing a new wrapper, which can
then later be helpful to solve an unrelated bug.

Add nouveau_fence_base_is_signaled().

Signed-off-by: Philipp Stanner <phasta@kernel.org>
---
drivers/gpu/drm/nouveau/nouveau_fence.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c
index db6f4494405c..0d58a81b3402 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
@@ -256,6 +256,12 @@ nouveau_fence_emit(struct nouveau_fence *fence)
return ret;
}

+static inline bool
+nouveau_fence_base_is_signaled(struct nouveau_fence *fence)
+{
+ return test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->base.flags);
+}
+
bool
nouveau_fence_done(struct nouveau_fence *fence)
{
@@ -263,7 +269,7 @@ nouveau_fence_done(struct nouveau_fence *fence)
struct nouveau_channel *chan;
unsigned long flags;

- if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->base.flags))
+ if (nouveau_fence_base_is_signaled(fence))
return true;

spin_lock_irqsave(&fctx->lock, flags);
@@ -272,7 +278,7 @@ nouveau_fence_done(struct nouveau_fence *fence)
nvif_event_block(&fctx->event);
spin_unlock_irqrestore(&fctx->lock, flags);

- return test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->base.flags);
+ return nouveau_fence_base_is_signaled(fence);
}

static long
--
2.48.1