drm/i915/gt: Remove local entries from GGTT on suspend

Across suspend/resume, we clear the entire GGTT and rebuild from
scratch. In particular, we want to only preserve the global entries for
use by the HW, and delay reinstating the local binds until required by
the user. This means that we can evict any local binds in the global GTT,
saving any time in preserving their state, as they will be rebound on
demand.

References: https://gitlab.freedesktop.org/drm/intel/-/issues/1947
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200528082427.21402-2-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 22198b7..9b30ddc 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -1229,31 +1229,9 @@ int i915_vma_move_to_active(struct i915_vma *vma,
 	return 0;
 }
 
-int __i915_vma_unbind(struct i915_vma *vma)
+void __i915_vma_evict(struct i915_vma *vma)
 {
-	int ret;
-
-	lockdep_assert_held(&vma->vm->mutex);
-
-	if (i915_vma_is_pinned(vma)) {
-		vma_print_allocator(vma, "is pinned");
-		return -EAGAIN;
-	}
-
-	/*
-	 * After confirming that no one else is pinning this vma, wait for
-	 * any laggards who may have crept in during the wait (through
-	 * a residual pin skipping the vm->mutex) to complete.
-	 */
-	ret = i915_vma_sync(vma);
-	if (ret)
-		return ret;
-
-	if (!drm_mm_node_allocated(&vma->node))
-		return 0;
-
 	GEM_BUG_ON(i915_vma_is_pinned(vma));
-	GEM_BUG_ON(i915_vma_is_active(vma));
 
 	if (i915_vma_is_map_and_fenceable(vma)) {
 		/* Force a pagefault for domain tracking on next user access */
@@ -1292,6 +1270,33 @@ int __i915_vma_unbind(struct i915_vma *vma)
 
 	i915_vma_detach(vma);
 	vma_unbind_pages(vma);
+}
+
+int __i915_vma_unbind(struct i915_vma *vma)
+{
+	int ret;
+
+	lockdep_assert_held(&vma->vm->mutex);
+
+	if (!drm_mm_node_allocated(&vma->node))
+		return 0;
+
+	if (i915_vma_is_pinned(vma)) {
+		vma_print_allocator(vma, "is pinned");
+		return -EAGAIN;
+	}
+
+	/*
+	 * After confirming that no one else is pinning this vma, wait for
+	 * any laggards who may have crept in during the wait (through
+	 * a residual pin skipping the vm->mutex) to complete.
+	 */
+	ret = i915_vma_sync(vma);
+	if (ret)
+		return ret;
+
+	GEM_BUG_ON(i915_vma_is_active(vma));
+	__i915_vma_evict(vma);
 
 	drm_mm_remove_node(&vma->node); /* pairs with i915_vma_release() */
 	return 0;
@@ -1303,13 +1308,13 @@ int i915_vma_unbind(struct i915_vma *vma)
 	intel_wakeref_t wakeref = 0;
 	int err;
 
-	if (!drm_mm_node_allocated(&vma->node))
-		return 0;
-
 	/* Optimistic wait before taking the mutex */
 	err = i915_vma_sync(vma);
 	if (err)
-		goto out_rpm;
+		return err;
+
+	if (!drm_mm_node_allocated(&vma->node))
+		return 0;
 
 	if (i915_vma_is_pinned(vma)) {
 		vma_print_allocator(vma, "is pinned");