[Spice-devel] [PATCH 09/11] Move main reference counter to GEM object instead of TTM ones

[Dave Airlie]

On 27 May 2015 at 20:04, Frediano Ziglio <fziglio at redhat.com> wrote:
> qxl_bo structure has two reference counters, one in the GEM object and
> another in the TTM object. The GEM object keep a counter to the TTM object
> so when GEM counter reached zero the TTM counter (using qxl_bo_unref) was
> decremented. The qxl object is fully freed (both GEM and TTM part are cleaned)
> when the TTM counter reach zero.
> One issue was that surface idr structure has no owning on qxl_bo objects however
> it contains a pointer to qxl_bo object. This caused some nasty race condition
> for instance qxl_bo object was reaped even after counter was already zero.
> This patch fix these races moving main counter (the one used by qxl_bo_(un)ref)
> to GEM object which cleanup routine (qxl_gem_object_free) remove the idr pointer
> (using qxl_surface_evict) when the counters are still valid.

Uggh, but yes, not sure I like this fix for the problem, but if it works,

Reviewed-by: Dave Airlie <airlied at redhat.com>