Re: [PATCH V2] RDMA/rtrs: Call {get,put}_cpu_ptr to silence a debug kernel warning

[Guoqing Jiang <guoqing.jiang@xxxxxxxxx>]

On 11/30/21 7:03 PM, Jinpu Wang wrote:
> On Tue, Nov 30, 2021 at 11:40 AM Christoph Lameter<cl@xxxxxxxxxx>  wrote:
> > On Sun, 28 Nov 2021, Guoqing Jiang wrote:
> >
> > >        int cpu;
> > >
> > >        cpu = raw_smp_processor_id();
> > > -     s = this_cpu_ptr(stats->pcpu_stats);
> > > +     s = get_cpu_ptr(stats->pcpu_stats);
> > >        if (con->cpu != cpu) {
> > >                s->cpu_migr.to++;
> > >
> > > @@ -27,14 +27,16 @@ void rtrs_clt_update_wc_stats(struct rtrs_clt_con *con)
> > >                s = per_cpu_ptr(stats->pcpu_stats, con->cpu);
> > >                atomic_inc(&s->cpu_migr.from);
> > >        }
> > > +     put_cpu_ptr(stats->pcpu_stats);
> > >   }
> > >
> > >   void rtrs_clt_inc_failover_cnt(struct rtrs_clt_stats *stats)
> > >   {
> > >        struct rtrs_clt_stats_pcpu *s;
> > >
> > > -     s = this_cpu_ptr(stats->pcpu_stats);
> > > +     s = get_cpu_ptr(stats->pcpu_stats);
> > >        s->rdma.failover_cnt++;
> > > +     put_cpu_ptr(stats->pcpu_stats);
> > This is equivalent to
> >
> > this_cpu_inc(stats->pcpu_stats.rdma.failover_cnt);
> >
> > Which will also reduce the segment to a single cpu instruction.
> Thanks for your suggestion, Christoph.

Good suggestion!

> As the patch is already applied, I will send a new patch as suggested.

Thanks for it.

Cheers,
Guoqing