Since a purged buffer is one without any associated pages, attempting to
use it should generate EFAULT rather than EINVAL, as it is not strictly
an invalid parameter.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
 
        if (obj->madv != I915_MADV_WILLNEED) {
                DRM_ERROR("Attempting to mmap a purgeable buffer\n");
-               ret = -EINVAL;
+               ret = -EFAULT;
                goto out;
        }
 
 
        if (obj->madv != I915_MADV_WILLNEED) {
                DRM_ERROR("Attempting to obtain a purgeable object\n");
-               return -EINVAL;
+               return -EFAULT;
        }
 
        BUG_ON(obj->pages_pin_count);
 
        if (obj->madv != I915_MADV_WILLNEED) {
                DRM_ERROR("Attempting to pin a purgeable buffer\n");
-               ret = -EINVAL;
+               ret = -EFAULT;
                goto out;
        }