drm/i915: un-inline i915_gem_drain_workqueue()

i915_gem_drain_workqueue() is not used on any hot paths. Un-unline it.

Replace the do-while with a for loop while at it.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/2c89e7e0a3528caf7ba9ffa29b2bb9f13f2357d1.1662390010.git.jani.nikula@intel.com

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c2d6172ba4bb..4c89b33ada95 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1085,6 +1085,28 @@ out:
 	return err;
 }
 
+/*
+ * Similar to objects above (see i915_gem_drain_freed-objects), in general we
+ * have workers that are armed by RCU and then rearm themselves in their
+ * callbacks. To be paranoid, we need to drain the workqueue a second time after
+ * waiting for the RCU grace period so that we catch work queued via RCU from
+ * the first pass. As neither drain_workqueue() nor flush_workqueue() report a
+ * result, we make an assumption that we only don't require more than 3 passes
+ * to catch all _recursive_ RCU delayed work.
+ */
+void i915_gem_drain_workqueue(struct drm_i915_private *i915)
+{
+	int i;
+
+	for (i = 0; i < 3; i++) {
+		flush_workqueue(i915->wq);
+		rcu_barrier();
+		i915_gem_drain_freed_objects(i915);
+	}
+
+	drain_workqueue(i915->wq);
+}
+
 int i915_gem_init(struct drm_i915_private *dev_priv)
 {
 	int ret;