On Sun, Oct 25, 2020 at 12:51 AM Arnd Bergmann <[email protected]> wrote: > > On Sat, Oct 24, 2020 at 5:54 PM harshal chaudhari > <[email protected]> wrote: > > On Tue, Oct 13, 2020 at 4:42 PM David Laight <[email protected]> > > wrote: > > > So I am a little bit confused about this check whether it's required or not > > Please could you point me in the right direction? > > > > In any case, thanks for your help ... > > > > Here is a driver source located in: linux/drivers/misc/xilinx_sdfec.c > > > > static long xsdfec_dev_ioctl(struct file *fptr, unsigned int cmd, > > unsigned long data) > > { > > struct xsdfec_dev *xsdfec; > > void __user *arg = NULL; > > int rval = -EINVAL; > > > > if (_IOC_TYPE(cmd) != XSDFEC_MAGIC) > > return -ENOTTY; > > > > /* check if ioctl argument is present and valid */ > > if (_IOC_DIR(cmd) != _IOC_NONE) > > { > > arg = (void __user *)data; > > if (!arg) > > return rval; > > } > > > > All of this can be removed, and replaced with unconditional > > void __user *arg = (void __user *)data; > int rval; > > with an "rval = -ENOTTY" added in the 'default' case. This will > make it behave more like other drivers, returning -ENOTTY for > any unknown ioctl command, and returning -EFAULT for all > invalid pointers, including NULL. > > xsdfec_dev_compat_ioctl() can removed as well, with the file operations > changed to an unconditional (removing the #ifdef) > > .compat_ioctl = compat_ptr_ioctl(), > > This will not affect behavior, it's just another simplification.
Thanks a lot Arnd. Got the point. and i will make the change and i will send it to relevant maintainers of that driver file. Once again thanks! > Arnd
