Re: [PATCH 4/5] ceph: fix improper use of smp_mb__before_atomic()

[Yan, Zheng]

On 5/10/19 4:55 AM, Andrea Parri wrote:
> On Tue, Apr 30, 2019 at 05:08:43PM +0800, Yan, Zheng wrote:
> > On Tue, Apr 30, 2019 at 4:26 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > > On Mon, Apr 29, 2019 at 10:15:00PM +0200, Andrea Parri wrote:
> > > > This barrier only applies to the read-modify-write operations; in
> > > > particular, it does not apply to the atomic64_set() primitive.
> > > >
> > > > Replace the barrier with an smp_mb().
> > >
> > > > @@ -541,7 +541,7 @@ static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
> > > >                                           long long release_count,
> > > >                                           long long ordered_count)
> > > >   {
> > > > -     smp_mb__before_atomic();
> > >
> > > same
> > >          /*
> > >           * XXX: the comment that explain this barrier goes here.
> > >           */
> >
> > makes sure operations that setup readdir cache (update page cache and
> > i_size) are strongly ordered with following atomic64_set.
>
> Thanks for the suggestion, Yan.
>
> To be clear: would you like me to integrate your comment and resend?
> any other suggestions?

Yes, please

Regards
Yan, Zheng

> Thanx,
>    Andrea
>
>
> > > > +     smp_mb();
> > >
> > > >        atomic64_set(&ci->i_complete_seq[0], release_count);
> > > >        atomic64_set(&ci->i_complete_seq[1], ordered_count);
> > > >   }
> > > > --
> > > > 2.7.4