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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