On Wed, Apr 27, 2016 at 11:49:35AM -0700, Linus Torvalds wrote: > On Wed, Apr 27, 2016 at 9:11 AM, Tejun Heo <[email protected]> wrote: > > > > Unfortunately, we were missing a smp_rmb() after clearing PENDING for > > execution, so nothing guaranteed visibility of the changes that a > > queueing loser has made, which manifested as a reproducible blk-mq > > stall. > > That explanation makes no sense. A smp_rmb() after a store makes no > sense what-so-ever. > > Happily, the code itself does and has a big comment. It's not a > "smp_rmb()", it's a full memory barrier. Which *does* make sense as > serializing a store wrt a following load.
Heh, yeah, brainfart. smp_mb(), obviously. Thanks. -- tejun
