[ofa-general] Re: locking requirements when calling dev_set_mtu()

[Ben Hutchings <bhutchings@solarflare.com>]

Eli Cohen wrote:
> Hi,
> 
> I have the need to change the MTU of IP over IB from the driver code
> and not from the shell. Looking for the right way to do it I came
> across the dev_set_mtu() which seems appropriate as it handles all
> notifications too. However, it is not clear to me whether I have to
> wrap the call to dev_set_mtu() with any locks. Specifically, I was
> referred to a mail thread that suggests that I have to use
> rtnl_lock()/rtnl_unlock():
> http://marc.info/?l=linux-netdev&m=121201324611292&w=2
[...]

Essentially any function that changes net device configuration requires
the caller to hold the RTNL lock.  This probably ought to be consistently
documented through kernel-doc and/or ASSERT_RTNL() though.

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.