On Wed, Apr 24, 2019 at 06:19:30PM +0800, Yuyang Du wrote: > In mark_lock_irq(), the following checks are performed: > > ---------------------------------- > | -> | unsafe | read unsafe | > |----------------------------------| > | safe | F B | F* B* | > |----------------------------------| > | read safe | F? B* | - | > ---------------------------------- > > Where: > F: check_usage_forwards > B: check_usage_backwards > *: check enabled by STRICT_READ_CHECKS > ?: check enabled by the !dir condition > > From checking point of view, the special F? case does not make sense, > whereas it perhaps is made for peroformance concern. As later patch will > address this issue, remove this exception, which makes the checks > consistent later. > > With STRICT_READ_CHECKS = 1 which is default, there is no functional > change.
Oh man.. thinking required and it is way late.. anyway this whole read stuff made me remember we had a patch set on readlocks last year. https://lkml.kernel.org/r/[email protected] I remember reviewing that a few times and then it dropped on the floor, probably because Spectre crap or something sucked up all my time again :/ Sorry Boqun!
