On Tue, Oct 2, 2012 at 8:26 AM, devendra.aaru [off-list ref] wrote:

Hi all,

While going through some code, i have found a place in which we do return,
-EOPNOTSUPP in an ioctl and the code of ioctl does just this one.


static int drv_ioctl(.. *fops, ...)
{
          return -EOPNOTSUPP;
}


do we actually need to specify a pointer to the ioctl callback, if the
driver doesn't support ioctl?

What type of driver? For networking if you do not have
ops->ndo_do_ioctl then -EOPNOTSUPP is returned. See dev_ifsioc() and
prior to that dev_ioctl() on net/core/dev.c.

  Luis