[PATCH] drm/scheduler: Unwrap job dependencies

[Rob Clark <robdclark@gmail.com>]

From: Rob Clark <robdclark@chromium.org>

Container fences have burner contexts, which makes the trick to store at
most one fence per context somewhat useless if we don't unwrap array or
chain fences.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/scheduler/sched_main.c | 47 ++++++++++++++++++--------
 1 file changed, 32 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 9762464e3f99..16b550949c57 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -52,6 +52,7 @@
 #include <linux/wait.h>
 #include <linux/sched.h>
 #include <linux/completion.h>
+#include <linux/dma-fence-unwrap.h>
 #include <linux/dma-resv.h>
 #include <uapi/linux/sched/types.h>
 
@@ -684,27 +685,14 @@ void drm_sched_job_arm(struct drm_sched_job *job)
 }
 EXPORT_SYMBOL(drm_sched_job_arm);
 
-/**
- * drm_sched_job_add_dependency - adds the fence as a job dependency
- * @job: scheduler job to add the dependencies to
- * @fence: the dma_fence to add to the list of dependencies.
- *
- * Note that @fence is consumed in both the success and error cases.
- *
- * Returns:
- * 0 on success, or an error on failing to expand the array.
- */
-int drm_sched_job_add_dependency(struct drm_sched_job *job,
-				 struct dma_fence *fence)
+static int drm_sched_job_add_single_dependency(struct drm_sched_job *job,
+					       struct dma_fence *fence)
 {
 	struct dma_fence *entry;
 	unsigned long index;
 	u32 id = 0;
 	int ret;
 
-	if (!fence)
-		return 0;
-
 	/* Deduplicate if we already depend on a fence from the same context.
 	 * This lets the size of the array of deps scale with the number of
 	 * engines involved, rather than the number of BOs.
@@ -728,6 +716,35 @@ int drm_sched_job_add_dependency(struct drm_sched_job *job,
 
 	return ret;
 }
+
+/**
+ * drm_sched_job_add_dependency - adds the fence as a job dependency
+ * @job: scheduler job to add the dependencies to
+ * @fence: the dma_fence to add to the list of dependencies.
+ *
+ * Note that @fence is consumed in both the success and error cases.
+ *
+ * Returns:
+ * 0 on success, or an error on failing to expand the array.
+ */
+int drm_sched_job_add_dependency(struct drm_sched_job *job,
+				 struct dma_fence *fence)
+{
+	struct dma_fence_unwrap iter;
+	struct dma_fence *f;
+	int ret = 0;
+
+	dma_fence_unwrap_for_each (f, &iter, fence) {
+		dma_fence_get(f);
+		ret = drm_sched_job_add_single_dependency(job, f);
+		if (ret)
+			break;
+	}
+
+	dma_fence_put(fence);
+
+	return ret;
+}
 EXPORT_SYMBOL(drm_sched_job_add_dependency);
 
 /**
-- 
2.42.0