Re: when to return -EOPNOTSUPP in _ioctl in a driver

On Tue, Oct 2, 2012 at 8:26 AM, devendra.aaru <devendra.aaru@gmail.com> 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