[PATCH v3 1/8] tracing, dma-buf: add a trace_dma_fence_sync_to event

[Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>]

This new event can be used to trace where a given dma_fence is added
as a dependency of some other work.

I plan to use it in amdgpu.

Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
---
 drivers/dma-buf/dma-fence.c      |  1 +
 include/trace/events/dma_fence.h | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index 0393a9bba3a8..e7276c043984 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -23,6 +23,7 @@
 EXPORT_TRACEPOINT_SYMBOL(dma_fence_emit);
 EXPORT_TRACEPOINT_SYMBOL(dma_fence_enable_signal);
 EXPORT_TRACEPOINT_SYMBOL(dma_fence_signaled);
+EXPORT_TRACEPOINT_SYMBOL(dma_fence_used_as_dependency);
 
 static DEFINE_SPINLOCK(dma_fence_stub_lock);
 static struct dma_fence dma_fence_stub;
diff --git a/include/trace/events/dma_fence.h b/include/trace/events/dma_fence.h
index 3963e79ca7b4..5a5d272031ce 100644
--- a/include/trace/events/dma_fence.h
+++ b/include/trace/events/dma_fence.h
@@ -83,6 +83,33 @@ DEFINE_EVENT(dma_fence, dma_fence_wait_end,
 	TP_ARGS(fence)
 );
 
+TRACE_EVENT(dma_fence_used_as_dependency,
+
+	TP_PROTO(struct dma_fence *fence, const char *reason),
+
+	TP_ARGS(fence, reason),
+
+	TP_STRUCT__entry(
+		__string(driver, fence->ops->get_driver_name(fence))
+		__string(timeline, fence->ops->get_timeline_name(fence))
+		__field(unsigned int, context)
+		__field(unsigned int, seqno)
+		__string(reason, reason)
+	),
+
+	TP_fast_assign(
+		__assign_str(driver, fence->ops->get_driver_name(fence));
+		__assign_str(timeline, fence->ops->get_timeline_name(fence));
+		__entry->context = fence->context;
+		__entry->seqno = fence->seqno;
+		__assign_str(reason, reason);
+	),
+
+	TP_printk("driver=%s timeline=%s context=%u seqno=%u reason=%s",
+		  __get_str(driver), __get_str(timeline), __entry->context,
+		  __entry->seqno, __get_str(reason))
+);
+
 #endif /*  _TRACE_DMA_FENCE_H */
 
 /* This part must be outside protection */
-- 
2.40.1