# Re: \[PATCH\] Video : Amba: Use in\_interrupt() in clcdfb\_sleep().

- From: santosh prasad nayak \<hidden\>
- Date: 2012-03-11 14:17:32 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2012/03/3833831
- Thread: https://ratatoskr.run/linux-fbdev/2012/03/3833822/t.md

```text
Not to use in_atomic()  in driver code.

 Following article  inspired me to do the change.
http://lwn.net/Articles/274695/

"in_atomic() is for core kernel use only. Because in special
circumstances (ie: kmap_atomic()) we run inc_preempt_count() even on
non-preemptible kernels to tell the per-arch fault handler that it was
invoked by copy_*_user() inside kmap_atomic(), and it must fail.
In other words, in_atomic() works in a specific low-level situation,
but it was never meant to be used in a wider context. Its placement in
hardirq.h next to macros which can be used elsewhere was, thus, almost
certainly a mistake. As Alan Stern pointed out, the fact that Linux
Device Drivers recommends the use of in_atomic() will not have helped
the situation. Your editor recommends that the authors of that book be
immediately sacked. "

In the present case, we just check whether its an IRQ context or user
context. So for that
we can use "in_interrupt()".

Greg also mentions the same in the following mail.
http://www.spinics.net/lists/newbies/msg43402.html

Regards
Santosh

On Sun, Mar 11, 2012 at 6:57 PM, Russell King - ARM Linux
[ref] wrote:
> On Sun, Mar 11, 2012 at 06:44:25PM +0530, santosh nayak wrote:
>> From: Santosh Nayak <redacted>
>>
>> Instead of "in_atomic()", we can use in_interrupt() to check whether
>> its an interrupt context.
>
> What are you trying to fix?
>
> Your description is an example of a bad commit comment.  It merely
> describes the change, which anyone can see by looking at the diff.
> What it totally and utterly fails to do is to describe _why_ the
> change is necessary or what the problem is.
>
> So, until it does, this patch gets a definite NAK.
```