drm/i915: Refactor get_fence() to use the common fence writing routine

We can also take advantage of the new 'no retire' mode for seqno waiting
to avoid having to take a reference on the old fence object whilst
flushing an existing fence.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e09ac3a..7bc4a40 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2361,7 +2361,7 @@ i915_gem_object_flush_fence(struct drm_i915_gem_object *obj)
        if (obj->last_fenced_seqno) {
                ret = i915_wait_request(obj->ring,
                                        obj->last_fenced_seqno,
-                                       true);
+                                       false);
                if (ret)
                        return ret;
 
@@ -2449,63 +2449,47 @@ i915_gem_object_get_fence(struct drm_i915_gem_object *obj)
 {
        struct drm_device *dev = obj->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
+       bool enable = obj->tiling_mode != I915_TILING_NONE;
        struct drm_i915_fence_reg *reg;
        int ret;
 
-       if (obj->tiling_mode == I915_TILING_NONE)
-               return i915_gem_object_put_fence(obj);
+       /* Have we updated the tiling parameters upon the object and so
+        * will need to serialise the write to the associated fence register?
+        */
+       if (obj->tiling_changed) {
+               ret = i915_gem_object_flush_fence(obj);
+               if (ret)
+                       return ret;
+       }
 
        /* Just update our place in the LRU if our fence is getting reused. */
        if (obj->fence_reg != I915_FENCE_REG_NONE) {
                reg = &dev_priv->fence_regs[obj->fence_reg];
-               list_move_tail(&reg->lru_list, &dev_priv->mm.fence_list);
+               if (!obj->tiling_changed) {
+                       list_move_tail(&reg->lru_list,
+                                      &dev_priv->mm.fence_list);
+                       return 0;
+               }
+       } else if (enable) {
+               reg = i915_find_fence_reg(dev);
+               if (reg == NULL)
+                       return -EDEADLK;
+
+               if (reg->obj) {
+                       struct drm_i915_gem_object *old = reg->obj;
 
-               if (obj->tiling_changed) {
-                       ret = i915_gem_object_flush_fence(obj);
+                       ret = i915_gem_object_flush_fence(old);
                        if (ret)
                                return ret;
 
-                       goto update;
+                       i915_gem_object_fence_lost(old);
                }
-
+       } else
                return 0;
-       }
-
-       reg = i915_find_fence_reg(dev);
-       if (reg == NULL)
-               return -EDEADLK;
-
-       ret = i915_gem_object_flush_fence(obj);
-       if (ret)
-               return ret;
-
-       if (reg->obj) {
-               struct drm_i915_gem_object *old = reg->obj;
 
-               drm_gem_object_reference(&old->base);
-
-               if (old->tiling_mode)
-                       i915_gem_release_mmap(old);
-
-               ret = i915_gem_object_flush_fence(old);
-               if (ret) {
-                       drm_gem_object_unreference(&old->base);
-                       return ret;
-               }
-
-               old->fence_reg = I915_FENCE_REG_NONE;
-               old->last_fenced_seqno = 0;
-
-               drm_gem_object_unreference(&old->base);
-       }
-
-       reg->obj = obj;
-       list_move_tail(&reg->lru_list, &dev_priv->mm.fence_list);
-       obj->fence_reg = reg - dev_priv->fence_regs;
-
-update:
+       i915_gem_object_update_fence(obj, reg, enable);
        obj->tiling_changed = false;
-       i915_gem_write_fence(dev, reg - dev_priv->fence_regs, obj);
+
        return 0;
 }