[Intel-gfx] [PATCH 1/3] drm/i915: Handle i915_active_fence_set() with the same fence
Chris Wilson
chris at chris-wilson.co.uk
Wed Nov 6 15:48:08 UTC 2019
If the caller wants to overwrite the currently tracked fence, with
itself, as far as the tracking is concerned it is a no-op, so simply
allow it.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
drivers/gpu/drm/i915/i915_active.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
index 207383dda84d..cde984744f20 100644
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -759,7 +759,9 @@ __i915_active_fence_set(struct i915_active_fence *active,
prev = rcu_dereference_protected(active->fence, active_is_held(active));
if (prev) {
- GEM_BUG_ON(prev == fence);
+ if (unlikely(prev == fence))
+ goto unlock;
+
spin_lock_nested(prev->lock, SINGLE_DEPTH_NESTING);
__list_del_entry(&active->cb.node);
spin_unlock(prev->lock); /* serialise with prev->cb_list */
@@ -781,6 +783,7 @@ __i915_active_fence_set(struct i915_active_fence *active,
rcu_assign_pointer(active->fence, fence);
list_add_tail(&active->cb.node, &fence->cb_list);
+unlock:
spin_unlock_irqrestore(fence->lock, flags);
return prev;
--
2.24.0
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