linux-kernel - Re: [PATCH] e100: expose broadcast

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Date:	Fri, 23 Apr 2010 13:58:16 -0700
From:	Stephen Hemminger <shemminger@...tta.com>
To:	Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Cc:	Erwan Velu <erwanaliasr1@...il.com>,
	netdev <netdev@...r.kernel.org>,
	David Miller <davem@...emloft.net>,
	linux-kernel@...r.kernel.org, jesse.brandeburg@...el.com,
	bruce.w.allan@...el.com, alexander.h.duyck@...el.com,
	peter.p.waskiewicz.jr@...el.com, john.ronciak@...el.com
Subject: Re: [PATCH] e100: expose broadcast_disabled as a module option

On Fri, 23 Apr 2010 13:22:22 -0700
Jeff Kirsher <jeffrey.t.kirsher@...el.com> wrote:

> On Fri, Apr 23, 2010 at 13:14, Erwan Velu <erwanaliasr1@...il.com> wrote:
> > Hi folks,
> >
> > I've been facing a very noisy network where hundreds broadcast packets
> > were generated every second.
> > When this traffic can't be controlled at the source, there is a side
> > effect on some systems.
> > I was having some idle systems that will never be targeted by this
> > broadcast traffic that got loaded just by receiving that "flood".
> > I mean by loaded that this light hardware was generating 300
> > context/switches per second.
> >
> > I was looking for many options to avoid this traffic to disturb this
> > hosts and I discovered that the e100 driver was featuring a
> > "broadcast_disabled" configure option.
> > I realize that this option is not controllable, so I wrote this simple
> > patch that expose this option as a module option.
> > This allow me to tell this hosts not to listen anymore this traffic.
> >
> > The result is clearly good as my systems are now running at 21
> > context/switches while being idle.
> > Hope this patch isn't too bad and could help others that faces the same problem.
> >
> > Patch can be downloaded here :
> > http://konilope.linuxeries.org/e100_broadcast_disabled.patch
> >
> > Even if gmail is eating the inlined, patch, at least that make it
> > easier to read it for humans.
> > If the patch is acked, the downloaded one will be more clean ;)
> >
> > This patch was generated on top of the latest 2.6 torvald's git.
> > Cheers,
> > Erwan
> >
> > Signed-off-by: Erwan Velu <erwanaliasr1@...il.com>
> >
> > diff --git a/drivers/net/e100.c b/drivers/net/e100.c
> > index b997e57..2ba582f 100644
> > --- a/drivers/net/e100.c
> > +++ b/drivers/net/e100.c
> > @@ -194,12 +194,15 @@ MODULE_FIRMWARE(FIRMWARE_D102E);
> >  static int debug = 3;
> >  static int eeprom_bad_csum_allow = 0;
> >  static int use_io = 0;
> > +static int broadcast_disabled = 0;
> >  module_param(debug, int, 0);
> >  module_param(eeprom_bad_csum_allow, int, 0);
> >  module_param(use_io, int, 0);
> > +module_param(broadcast_disabled, int, 0);
> >  MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");
> >  MODULE_PARM_DESC(eeprom_bad_csum_allow, "Allow bad eeprom checksums");
> >  MODULE_PARM_DESC(use_io, "Force use of i/o access mode");
> > +MODULE_PARM_DESC(broadcast_disabled, "Filter broadcast packets
> > (0=disabled (default), 1=enabled)");
> >  #define DPRINTK(nlevel, klevel, fmt, args...) \
> >        (void)((NETIF_MSG_##nlevel & nic->msg_enable) && \
> >        printk(KERN_##klevel PFX "%s: %s: " fmt, nic->netdev->name, \
> > @@ -1131,6 +1134,8 @@ static void e100_configure(struct nic *nic,
> > struct cb *cb, struct sk_buff *skb)
> >                config->promiscuous_mode = 0x1;         /* 1=on, 0=off */
> >        }
> >
> > +       config->broadcast_disabled = broadcast_disabled; /* Broadcast filtering */
> > +
> >        if (nic->flags & multicast_all)
> >                config->multicast_all = 0x1;            /* 1=accept, 0=no */
> > --
> 
> Adding Netdev...
> 

What is wrong with using existing IFF_BROADCAST flag?


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