d24e80b2ae
Doorbells in SMT need to coordinate msgsnd/msgclr and DPDES access from multiple threads that affect the same state. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Cédric Le Goater <clg@kaod.org>