On Fri, Sep 11, 2020 at 1:36 PM Viresh Kumar <viresh.ku...@linaro.org> wrote: > > On 11-09-20, 12:11, pet...@infradead.org wrote: > > On Wed, Sep 02, 2020 at 12:54:41PM +0530, Viresh Kumar wrote: > > > + atomic_t reset_pending; > > > > > + atomic_set(&stats->reset_pending, 0); > > > + if (atomic_read(&stats->reset_pending)) > > > + bool pending = atomic_read(&stats->reset_pending); > > > + atomic_set(&stats->reset_pending, 1); > > > + bool pending = atomic_read(&stats->reset_pending); > > > + if (atomic_read(&stats->reset_pending)) > > > > What do you think atomic_t is doing for you? > > I was trying to avoid races while two writes are going in parallel, > but obviously as this isn't a RMW operation, it won't result in > anything for me. > > Maybe what I should be doing is just READ_ONCE()/WRITE_ONCE()? So the > other side doesn't see any intermediate value that was never meant to > be set/read ?
If the value in question is a pointer or an int (or equivalent), READ_ONCE()/WRITE_ONCE() should be sufficient, and should be used at least as a matter of annotation of the sensitive code IMO. IIRC, atomic_set() and atomic_read() are pretty much the same as WRITE_ONCE() and READ_ONCE(), respectively, anyway. Cheers!
