[PATCH] drm/ttm: fix two regressions since move_notify changes

[Dave Airlie]

On Wed, Jan 25, 2012 at 5:34 AM, Ben Skeggs <skeggsb at gmail.com> wrote:
> From: Ben Skeggs <bskeggs at redhat.com>
>
> Both changes in dc97b3409a790d2a21aac6e5cdb99558b5944119 cause serious
> regressions in the nouveau driver.
>
> move_notify() was originally able to presume that bo->mem is the old node,
> and new_mem is the new node.  The above commit moves the call to
> move_notify() to after move() has been done, which means that now, sometimes,
> new_mem isn't the new node at all, bo->mem is, and new_mem points at a
> stale, possibly-just-been-killed-by-move node.
>
> This is clearly not a good situation.  This patch reverts this change, and
> replaces it with a cleanup in the move() failure path instead.
>
> The second issue is that the call to move_notify() from cleanup_memtype_use()
> causes the TTM ghost objects to get passed into the driver.  This is clearly
> bad as the driver knows nothing about these "fake" TTM BOs, and ends up
> accessing uninitialised memory.

btw we've had this check in radeon for a long time.
radeon_ttm_bo_is_radeon_bo

not sure how you haven't gotten a ghost object in there up until now.

Dave.