RE: [PATCH] net/sched/sch_tbf.c: fix linking error

From: Qais Yousef
Date: Thu Dec 12 2013 - 09:29:45 EST


> -----Original Message-----
> From: Eric Dumazet [mailto:eric.dumazet@xxxxxxxxx]
> Sent: 12 December 2013 14:18
> To: Qais Yousef
> Cc: Yang Yingliang; Eric Dumazet; Jamal Hadi Salim; David S. Miller;
> netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> next@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] net/sched/sch_tbf.c: fix linking error
>
> On Thu, 2013-12-12 at 12:38 +0000, Qais Yousef wrote:
> > ERROR: "__udivdi3" [net/sched/sch_tbf.ko] undefined!
> >
> > introduced by: cc106e441a63 (net: sched: tbf: fix the calculation of
> > max_size)
> >
> > which adds a 64 by 32 bit division without using do_div().
> > Fix it by using do_div(len/ 53) instead of len/53.
> >
> > Signed-off-by: Qais Yousef <qais.yousef@xxxxxxxxxx>
> > Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> > Cc: Jamal Hadi Salim <jhs@xxxxxxxxxxxx>
> > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> > Cc: netdev@xxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Cc: linux-next@xxxxxxxxxxxxxxx
> > ---
> > We caught this error on linux-next today. This is my quick attemp of a fix.
> > If it's not appropriate or doesn't make sense my apologies and feel
> > free to resend a better fix :)
> >
> > net/sched/sch_tbf.c | 6 ++++--
> > 1 files changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c index
> > a44928c..771cbec 100644
> > --- a/net/sched/sch_tbf.c
> > +++ b/net/sched/sch_tbf.c
> > @@ -131,8 +131,10 @@ static u64 psched_ns_t2l(const struct
> > psched_ratecfg *r,
> >
> > do_div(len, NSEC_PER_SEC);
> >
> > - if (unlikely(r->linklayer == TC_LINKLAYER_ATM))
> > - len = (len / 53) * 48;
> > + if (unlikely(r->linklayer == TC_LINKLAYER_ATM)) {
> > + do_div(len, 53);
> > + len *= 48;
> > + }
> >
> > if (len > r->overhead)
> > len -= r->overhead;
>
> This looks like this was already fixed yesterday in David net tree :
>
> http://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=d55d282e6
> af88120ad90e93a88f70e3116dc0e3d
>

Ah, ok. Thanks for checking this and sorry about the noise.

Qais

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