From: Sven Eckelmann <sven@narfation.org>
To: antonio@meshcoding.com
Cc: netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org,
ruben@freifunk-nrw.de, ruben@vfn-nrw.de,
mareklindner@neomailbox.ch, David Miller <davem@davemloft.net>
Subject: Re: [PATCH 1/2] batman-adv: Avoid u32 overflow during gateway select
Date: Sun, 21 Jun 2015 20:27:45 +0200 [thread overview]
Message-ID: <1534492.Qn5WYoJSum@sven-edge> (raw)
In-Reply-To: <20150621.093713.572451264516042062.davem@davemloft.net>
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On Sunday 21 June 2015 09:37:13 David Miller wrote:
> From: Antonio Quartulli <antonio@meshcoding.com>
> Date: Tue, 16 Jun 2015 21:06:23 +0200
>
> > @@ -133,7 +133,7 @@ batadv_gw_get_best_gw_node(struct batadv_priv
> > *bat_priv)>
> > struct batadv_neigh_node *router;
> > struct batadv_neigh_ifinfo *router_ifinfo;
> > struct batadv_gw_node *gw_node, *curr_gw = NULL;
> >
> > - uint32_t max_gw_factor = 0, tmp_gw_factor = 0;
> > + uint64_t max_gw_factor = 0, tmp_gw_factor = 0;
> >
> > uint32_t gw_divisor;
>
> Divides are performed using these variables, so if you make
> them 64-bit the build will fail. You have to use one of the
> routines in include/linux/math64.h in this situation, but
> realize that this operation is now going to be quite expensive.
Just a minor comment: The division is currently "max_gw_factor >> 18" which
the compiler also outputs as such (shrd + shr on i586). This is the reason why
it currently also works on architectures without a native 64 bit div.
Kind regards,
Sven
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next prev parent reply other threads:[~2015-06-21 18:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-16 19:06 pull request [net]: batman-adv 20150616 Antonio Quartulli
2015-06-16 19:06 ` [PATCH 1/2] batman-adv: Avoid u32 overflow during gateway select Antonio Quartulli
2015-06-21 16:37 ` David Miller
2015-06-21 18:27 ` Sven Eckelmann [this message]
2015-06-22 12:53 ` Antonio Quartulli
2015-06-16 19:06 ` [PATCH 2/2] batman-adv: avoid DAT to mess up LAN state Antonio Quartulli
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