[PATCH v3 6/6] dma-buf: Check status of enable-signaling bit on debug

[Arvind Yadav]

Fence signaling must be enabled to make sure that
the dma_fence_is_signaled() function ever returns true.
Since drivers and implementations sometimes mess this up,
this ensures correct behaviour when DEBUG_WW_MUTEX_SLOWPATH
is used during debugging.
This should make any implementation bugs resulting in not
signaled fences much more obvious.

Signed-off-by: Arvind Yadav <Arvind.Yadav@xxxxxxx>
---

Changes in v1,v2 :
1- Addressing Christian's comment to replace
CONFIG_DEBUG_WW_MUTEX_SLOWPATH instead of CONFIG_DEBUG_FS.
2- As per Christian's comment moving this patch at last so
The version of this patch is also changed and previously
it was [PATCH 1/4]

---
 include/linux/dma-fence.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index 775cdc0b4f24..ba1ddc14c5d4 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -428,6 +428,11 @@ dma_fence_is_signaled_locked(struct dma_fence *fence)
 static inline bool
 dma_fence_is_signaled(struct dma_fence *fence)
 {
+#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
+	if (!test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags))
+		return false;
+#endif
+
 	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
 		return true;
 
-- 
2.25.1