Re: [PATCH net-next v3 1/2] ipvs: add READ_ONCE barrier for ipvs->sysctl_amemthresh

[Aleksandr Mikhalitsyn]

On Sun, Apr 21, 2024 at 1:06 PM Julian Anastasov <ja@xxxxxx> wrote:
>
>
>         Hello,

Dear Julian,

Thanks a lot for the fast review and suggestions!

Kind regards,
Alex

>
> On Thu, 18 Apr 2024, Alexander Mikhalitsyn wrote:
>
> > Cc: Julian Anastasov <ja@xxxxxx>
> > Cc: Simon Horman <horms@xxxxxxxxxxxx>
> > Cc: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
> > Cc: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxx>
> > Cc: Florian Westphal <fw@xxxxxxxxx>
> > Suggested-by: Julian Anastasov <ja@xxxxxx>
> > Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
>
>         Looks good to me, thanks!
>
> Acked-by: Julian Anastasov <ja@xxxxxx>
>
> > ---
> >  net/netfilter/ipvs/ip_vs_ctl.c | 14 +++++++-------
> >  1 file changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> > index 143a341bbc0a..32be24f0d4e4 100644
> > --- a/net/netfilter/ipvs/ip_vs_ctl.c
> > +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> > @@ -94,6 +94,7 @@ static void update_defense_level(struct netns_ipvs *ipvs)
> >  {
> >       struct sysinfo i;
> >       int availmem;
> > +     int amemthresh;
> >       int nomem;
> >       int to_change = -1;
> >
> > @@ -105,7 +106,8 @@ static void update_defense_level(struct netns_ipvs *ipvs)
> >       /* si_swapinfo(&i); */
> >       /* availmem = availmem - (i.totalswap - i.freeswap); */
> >
> > -     nomem = (availmem < ipvs->sysctl_amemthresh);
> > +     amemthresh = max(READ_ONCE(ipvs->sysctl_amemthresh), 0);
> > +     nomem = (availmem < amemthresh);
> >
> >       local_bh_disable();
> >
> > @@ -145,9 +147,8 @@ static void update_defense_level(struct netns_ipvs *ipvs)
> >               break;
> >       case 1:
> >               if (nomem) {
> > -                     ipvs->drop_rate = ipvs->drop_counter
> > -                             = ipvs->sysctl_amemthresh /
> > -                             (ipvs->sysctl_amemthresh-availmem);
> > +                     ipvs->drop_counter = amemthresh / (amemthresh - availmem);
> > +                     ipvs->drop_rate = ipvs->drop_counter;
> >                       ipvs->sysctl_drop_packet = 2;
> >               } else {
> >                       ipvs->drop_rate = 0;
> > @@ -155,9 +156,8 @@ static void update_defense_level(struct netns_ipvs *ipvs)
> >               break;
> >       case 2:
> >               if (nomem) {
> > -                     ipvs->drop_rate = ipvs->drop_counter
> > -                             = ipvs->sysctl_amemthresh /
> > -                             (ipvs->sysctl_amemthresh-availmem);
> > +                     ipvs->drop_counter = amemthresh / (amemthresh - availmem);
> > +                     ipvs->drop_rate = ipvs->drop_counter;
> >               } else {
> >                       ipvs->drop_rate = 0;
> >                       ipvs->sysctl_drop_packet = 1;
> > --
> > 2.34.1
>
> Regards
>
> --
> Julian Anastasov <ja@xxxxxx>
>