[PATCH 08/18] drm/i915: Allow objects to be created with no backing pages, but stolen space

Chris Wilson
2012-10-19T17:05:02Z

In order to accommodate objects that are not backed by struct pages, but
instead point into a contiguous region of stolen space, we need to make
various changes to avoid dereferencing obj->pages or obj->base.filp.

First introduce a marker for the stolen object, that specifies its
offset into the stolen region and implies that it has no backing pages.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_debugfs.c | 2 ++
drivers/gpu/drm/i915/i915_drv.h | 2 ++
2 files changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 3c5710f..c0d1029 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -125,6 +125,8 @@ describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
if (obj->gtt_space != NULL)
seq_printf(m, " (gtt offset: %08x, size: %08x)",
obj->gtt_offset, (unsigned int)obj->gtt_space->size);
+ if (obj->stolen)
+ seq_printf(m, " (stolen: %08lx)", obj->stolen->start);
if (obj->pin_mappable || obj->fault_mappable) {
char s[3], *t = s;
if (obj->pin_mappable)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 997abb3..055bd08 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -935,6 +935,8 @@ struct drm_i915_gem_object {

/** Current space allocated to this object in the GTT, if any. */
struct drm_mm_node *gtt_space;
+ /** Stolen memory for this object, instead of being backed by shmem. */
+ struct drm_mm_node *stolen;
struct list_head gtt_list;

/** This object's place on the active/inactive lists */
--
1.7.10.4