Re: [PATCH 1/1] UIO: Add a write() function to enable/disable interrupts

Tom Spink
2008-05-23T12:00:30Z

2008/5/23 Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>:
> Hello Tom,
>
>> > Tom Spink wrote:
>> >> The added benefit is that the code becomes less complex, as you don't
>> >> have to check buffer sizes and copy the integer from userspace.
>> > AFAIK this is wrong. You need to copy the integer from userspace in
>> > uio_ioctl. Actually it's a value coming from user space, so you need to
>> > do it somewhere.
>>
>> Not really in this case. It's not a *pointer* to a value in
>> userspace, so you don't need to copy anything. If it was being used
>> to point to a memory location holding a value, then yes, it would need
>> to be copied across. But in this case, it's just being used to pass
>> across 1 or 0.
> ah, OK, you're right. Thanks for correcting my correction :-)

Heh, no problem. My initial idea was just a thought anyway, just to
maintain a bit of extensibility if .write is ever needed for something
else. :-)

> Uwe

--
Tom Spink