[Bridge] BRCTL is displaying only 32 bridge interfaces even /proc/net/dev is showing more then that

Stephen Hemminger shemminger at vyatta.com
Tue Mar 31 13:50:38 PDT 2009

On Mon, 30 Mar 2009 18:03:31 -0700
Stephen Hemminger <shemminger at vyatta.com> wrote:

> On Fri, 20 Mar 2009 15:15:50 +0530 (IST)
> rahul bhardwaj <rahul_bhardwaj36in at yahoo.co.in> wrote:
> > Hi All,
> > I am using Linux 2.6.15 kernel. I want to create 4094 bridge interface but I am able to see only 32 bridge interfaces with the help of "brctl show". I am able see other interfaces into /proc/net/dev but brctl is not showing more then 32. It is also not allowing any operations (add/del) over those interfaces. Is it correct behaviour or I have do some changes in some settings. 
> > Could anybody please help me in this? 
> > 
> 2.6.15 is old, so I could well be wrong, but as I remember:
> The old interface (via ioctl) only had room for 32 bridges, so probably that
> was it. When interface changed to sysfs that was addressed.
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Did you try updating the bridge utils. The older versions had MAX_BRIDGES
defined as 32, and the code was written such that it read the whole configuration
multiple times.

Current code has MAX_BRIDGES=1024, but that is only used on older kernels
that don't support sysfs.  With sysfs the interface just walks the contents
of /sys/class/net and that can handle as many interfaces as you have memory for.

No kernel change should be needed.

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