[PATCH] drm/i915: extract object unplug code from busy/wait_timeout ioctl

[daniel.vetter at ffwll.ch (Daniel Vetter)]

Both need to do the same dance (or at least should). Some slight
changes:
- busy_ioctl now unconditionally checks for olr. Before emitting a
  require flush would have prevent the olr check and hence required a
  second call to the busy ioctl to really emit the request.
- the timeout wait now also retires request. Not really required for
  abi-reasons, but makes a notch more sense imo.

I've tested this by pimping the i-g-t test some more and also checking
the polling behviour of the wait_rendering_timeout ioctl versus what
busy_ioctl returns.

Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem.c |   61 ++++++++++++++++++--------------------
 1 files changed, 29 insertions(+), 32 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d2eaa00..521e294 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2000,6 +2000,31 @@ i915_gem_object_wait_rendering(struct drm_i915_gem_object *obj)
 }
 
 /**
+ * Ensures that an object will eventually get non-busy by flushing any required
+ * write domains, emitting any outstanding lazy request and retiring and
+ * completed requests. The unplug moniker is stolen from the linux block layer.
+ */
+static int
+i915_gem_unplug_object(struct drm_i915_gem_object *obj)
+{
+	int ret;
+
+	if (obj->active) {
+		ret = i915_gem_object_flush_gpu_write_domain(obj);
+		if (ret)
+			return ret;
+
+		ret = i915_gem_check_olr(obj->ring,
+					 obj->last_rendering_seqno);
+		if (ret)
+			return ret;
+		i915_gem_retire_requests_ring(obj->ring);
+	}
+
+	return 0;
+}
+
+/**
  * i915_gem_wait_ioctl - implements DRM_IOCTL_I915_GEM_WAIT
  * @DRM_IOCTL_ARGS: standard ioctl arguments
  *
@@ -2043,11 +2068,8 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 		return -ENOENT;
 	}
 
-	/* Need to make sure the object is flushed first. This non-obvious
-	 * flush is required to enforce that (active && !olr) == no wait
-	 * necessary.
-	 */
-	ret = i915_gem_object_flush_gpu_write_domain(obj);
+	/* Need to make sure the object gets un-active eventually. */
+	ret = i915_gem_unplug_object(obj);
 	if (ret)
 		goto out;
 
@@ -2059,10 +2081,6 @@ i915_gem_wait_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 	if (seqno == 0)
 		 goto out;
 
-	ret = i915_gem_check_olr(ring, seqno);
-	if (ret)
-		goto out;
-
 	/* Do this after OLR check to make sure we make forward progress polling
 	 * on this IOCTL with a 0 timeout (like busy ioctl)
 	 */
@@ -3302,30 +3320,9 @@ i915_gem_busy_ioctl(struct drm_device *dev, void *data,
 	 * become non-busy without any further actions, therefore emit any
 	 * necessary flushes here.
 	 */
-	args->busy = obj->active;
-	if (args->busy) {
-		/* Unconditionally flush objects, even when the gpu still uses this
-		 * object. Userspace calling this function indicates that it wants to
-		 * use this buffer rather sooner than later, so issuing the required
-		 * flush earlier is beneficial.
-		 */
-		if (obj->base.write_domain & I915_GEM_GPU_DOMAINS) {
-			ret = i915_gem_flush_ring(obj->ring,
-						  0, obj->base.write_domain);
-		} else {
-			ret = i915_gem_check_olr(obj->ring,
-						 obj->last_rendering_seqno);
-		}
+	ret = i915_gem_unplug_object(obj);
 
-		/* Update the active list for the hardware's current position.
-		 * Otherwise this only updates on a delayed timer or when irqs
-		 * are actually unmasked, and our working set ends up being
-		 * larger than required.
-		 */
-		i915_gem_retire_requests_ring(obj->ring);
-
-		args->busy = obj->active;
-	}
+	args->busy = obj->active;
 
 	drm_gem_object_unreference(&obj->base);
 unlock:
-- 
1.7.7.6