drm/sched: Add helper to check job dependencies

Lets isolate scheduler internals from drivers such as pvr which currently
walks the dependency array to look for fences.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Danilo Krummrich <dakr@redhat.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Philipp Stanner <pstanner@redhat.com>
Reviewed-by: Matt Coster <matt.coster@imgtec.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Philipp Stanner <phasta@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250113103341.43914-1-tvrtko.ursulin@igalia.com

drivers/gpu/drm/scheduler/sched_main.c

@@ -984,6 +984,29 @@ int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
 }
 EXPORT_SYMBOL(drm_sched_job_add_implicit_dependencies);
 
+/**
+ * drm_sched_job_has_dependency - check whether fence is the job's dependency
+ * @job: scheduler job to check
+ * @fence: fence to look for
+ *
+ * Returns:
+ * True if @fence is found within the job's dependencies, or otherwise false.
+ */
+bool drm_sched_job_has_dependency(struct drm_sched_job *job,
+				  struct dma_fence *fence)
+{
+	struct dma_fence *f;
+	unsigned long index;
+
+	xa_for_each(&job->dependencies, index, f) {
+		if (f == fence)
+			return true;
+	}
+
+	return false;
+}
+EXPORT_SYMBOL(drm_sched_job_has_dependency);
+
 /**
  * drm_sched_job_cleanup - clean up scheduler job resources
  * @job: scheduler job to clean up

include/drm/gpu_scheduler.h

@@ -562,7 +562,8 @@ int drm_sched_job_add_resv_dependencies(struct drm_sched_job *job,
 int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
 					    struct drm_gem_object *obj,
 					    bool write);
-
+bool drm_sched_job_has_dependency(struct drm_sched_job *job,
+				  struct dma_fence *fence);
 
 void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
 				    struct drm_gpu_scheduler **sched_list,