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

drivers/gpu/drm/i915/i915_drv.h

@@ -995,27 +995,7 @@ static inline void i915_gem_drain_freed_objects(struct drm_i915_private *i915)
 	}
 }
 
-static inline void i915_gem_drain_workqueue(struct drm_i915_private *i915)
-{
-	/*
-	 * 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.
-	 *
-	 */
-	int pass = 3;
-	do {
-		flush_workqueue(i915->wq);
-		rcu_barrier();
-		i915_gem_drain_freed_objects(i915);
-	} while (--pass);
-	drain_workqueue(i915->wq);
-}
+void i915_gem_drain_workqueue(struct drm_i915_private *i915);
 
 struct i915_vma * __must_check
 i915_gem_object_ggtt_pin_ww(struct drm_i915_gem_object *obj,

drivers/gpu/drm/i915/i915_gem.c

@@ -1085,6 +1085,28 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
 	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;