drm/i915: First recheck for an empty fence register.

If we wait upon a request and successfully unbind a buffer occupying a
fence register, then that slot will be freed and cause a NULL derefrence
upon rescanning.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>
This commit is contained in:
Chris Wilson 2009-02-11 14:26:44 +00:00 committed by Eric Anholt
parent 040aefa263
commit 9b2412f9ad

View File

@ -1580,6 +1580,7 @@ i915_gem_object_get_fence_reg(struct drm_gem_object *obj, bool write)
}
/* First try to find a free reg */
try_again:
for (i = dev_priv->fence_reg_start; i < dev_priv->num_fence_regs; i++) {
reg = &dev_priv->fence_regs[i];
if (!reg->obj)
@ -1591,7 +1592,6 @@ i915_gem_object_get_fence_reg(struct drm_gem_object *obj, bool write)
struct drm_i915_gem_object *old_obj_priv = NULL;
loff_t offset;
try_again:
/* Could try to use LRU here instead... */
for (i = dev_priv->fence_reg_start;
i < dev_priv->num_fence_regs; i++) {