Re: PATCH 2.4.0.9.2: export ethtool interface

[Andrew Morton <andrewm@xxxxxxxxxx>]

Donald Becker wrote:
> 
> ...
> >   Not a thing you'd want
> > to poll very frequently, particularly as some drivers are racy in this
> > area, and the consequences of hitting the race could be quite bad.
> > spin_lock_bh() is the correct solution for mdio protection, BTW.
> 
> Or having the timer based media monitor just skip the check until the next
> tick if the lock is set.  Imagine taking timer interrupt during the
> user-level ioctl()...  (There are a few other dangerous cases to consider as
> well.)

Yes.  On 2.4 (at least) there is nothing to prevent the driver's ioctl()
function from running on two or more CPUs simultaneously.