Hello,
res of copy_to_user = 4
Any idea?
John
On 12/20/05, Bernd Petrovitsch <bernd@xxxxxxxxx> wrote:
> On Tue, 2005-12-20 at 14:02 +0200, John Que wrote:
> [...]
> > I had written a very simple ioctl() method in a module;
> > this ioctl calls copy_to_user();
> >
> > I am getting EFAULT when trying to call this ioctl from
> > use space.
> >
> > Any idea what can be the reason ?
>
> Yes.
>
> > Here is the code:
> >
> > static unsigned long my_ioctl(struct inode* inode,
> > struct file* file,
> > unsigned int cmd,
> > unsigned long data)
> >
> > {
> > ...
> > ...
> > case MY_IOCTL:
> > {
> > unsigned int result = 99;
> >
> > if (copy_to_user((unsigned int *)data,
> > &result,
> > sizeof(unsigned int)))
> > {
> > printk("copy_to_user failed\n");
> > return -EFAULT;
> > }
> >
> > }
>
> What value is returned by copy_to_user()?
>
> Bernd
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