[PATCH 055/131] drm/i915: Pin the pages whilst operating on them

[Chris Wilson]

As a safety precaution, whilst we operate on the object's pages
(clflushing them, updating the LRU) make sure we hold a pin on those
pages to prevent them disappearing underneath us.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d8bdabff4012..61808c23b047 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3177,6 +3177,7 @@ i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj, bool write)
 	if (ret)
 		return ret;
 
+	i915_gem_object_pin_pages(obj);
 	i915_gem_object_flush_cpu_write_domain(obj);
 
 	/* Serialise direct access to this object with the barriers for
@@ -3206,6 +3207,7 @@ i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj, bool write)
 
 	/* And bump the LRU for this access */
 	i915_gem_object_bump_inactive_ggtt(obj);
+	i915_gem_object_unpin_pages(obj);
 
 	return 0;
 }
-- 
2.8.1