On Fri, Jun 19, 2020 at 05:23:18PM +0206, John Ogness wrote: > The reverse-order double lock dance in ioc_release_fn() is using a > retry loop. This is a problem on PREEMPT_RT because it could preempt > the task that would release q->queue_lock and thus live lock in the > retry loop. > > RCU is already managing the freeing of the request queue and icq. If > the trylock fails, use RCU to guarantee that the request queue and > icq are not freed and re-acquire the locks in the correct order, > allowing forward progress. > > Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx> Again, after starring on it for while and reading up and down, I'd say, it looks good. Also a quick test run with blktests and lockdep enabled didn't produce any warnings. Reviewed-by: Daniel Wagner <dwagner@xxxxxxx>
