[18/26] drm/i915: use new iterator in i915_gem_object_last_write_engine v2

Commit Message

Christian König Sept. 17, 2021, 12:35 p.m. UTC

This is maybe even a fix since the RCU usage here looks incorrect.

v2: add missing rcu_read_lock()/unlock()

Signed-off-by: Christian König <[e-mail]>
---
 drivers/gpu/drm/i915/gem/i915_gem_object.h | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

Patch

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index 48112b9d76df..487329a96e92 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -507,16 +507,18 @@  static inline struct intel_engine_cs *
 i915_gem_object_last_write_engine(struct drm_i915_gem_object *obj)
 {
 	struct intel_engine_cs *engine = NULL;
+	struct dma_resv_iter cursor;
 	struct dma_fence *fence;
 
 	rcu_read_lock();
-	fence = dma_resv_get_excl_unlocked(obj->base.resv);
+	dma_resv_iter_begin(&cursor, obj->base.resv, false);
+	dma_resv_for_each_fence_unlocked(&cursor, fence) {
+		if (fence && dma_fence_is_i915(fence) &&
+		    !dma_fence_is_signaled(fence))
+			engine = to_request(fence)->engine;
+	}
+	dma_resv_iter_end(&cursor);
 	rcu_read_unlock();
-
-	if (fence && dma_fence_is_i915(fence) && !dma_fence_is_signaled(fence))
-		engine = to_request(fence)->engine;
-	dma_fence_put(fence);
-
 	return engine;
 }