[PATCH 2/6] drm/i915/userptr: Only flush the workqueue if required

[Chris Wilson]

To avoid waiting for work from other invalidate-range threads where
not required, only wait on the userptr cancel workqueue if we have added
some work to it.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski at intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_userptr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index 6ef05d5b884d..dc9bf5282071 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -145,7 +145,8 @@ static void i915_gem_userptr_mn_invalidate_range_start(struct mmu_notifier *_mn,
 		del_object(mo);
 	spin_unlock(&mn->lock);
 
-	flush_workqueue(mn->wq);
+	if (!list_empty(&cancelled))
+		flush_workqueue(mn->wq);
 }
 
 static const struct mmu_notifier_ops i915_gem_userptr_notifier = {
-- 
2.11.0