drm/i915: Pin backing pages whilst exporting through a dmabuf vmap
We need to refcount our pages in order to prevent reaping them at
inopportune times, such as when they currently vmapped or exported to
another driver. However, we also wish to keep the lazy deallocation of
our pages so we need to take a pin/unpinned approach rather than a
simple refcount.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index ada8ea1..12a0757 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1008,6 +1008,7 @@
unsigned int has_global_gtt_mapping:1;
struct page **pages;
+ int pages_pin_count;
/**
* DMAR support
@@ -1341,6 +1342,17 @@
void i915_gem_lastclose(struct drm_device *dev);
int __must_check i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
+static inline void i915_gem_object_pin_pages(struct drm_i915_gem_object *obj)
+{
+ BUG_ON(obj->pages == NULL);
+ obj->pages_pin_count++;
+}
+static inline void i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj)
+{
+ BUG_ON(obj->pages_pin_count == 0);
+ obj->pages_pin_count--;
+}
+
int __must_check i915_mutex_lock_interruptible(struct drm_device *dev);
int i915_gem_object_sync(struct drm_i915_gem_object *obj,
struct intel_ring_buffer *to);