Re: Serial-Core: USB-Serial port current issues.

["Luiz Fernando N. Capitulino" <lcapitulino@mandriva.com.br>]

On Wed, 14 Jun 2006 17:53:08 -0700
Pete Zaitcev <zaitcev@redhat.com> wrote:

| On Wed, 14 Jun 2006 17:38:24 -0300, "Luiz Fernando N. Capitulino" <lcapitulino@mandriva.com.br> wrote:
| 
| >  I think BUG_ON(in_interrupt()) does the job. I'll try it here, and
| > if it doesn't trigger I'll submit a patch to Andrew only for
| > testing porpuses (ie, not for mainline).
| 
| Luiz, you can't be serious! You have to do a review and write call paths
| on a piece of paper or however you prefer to do it. Your testing is
| extremely limited as we know, you don't even have a null-modem cable.
| So if the patch does not trip in your testing it tells you absolutely
| nothing. But even in context of AKPM's tree you can't rely on run-time
| checks to pick this sort of things.

 Hey, take it easy. :)

 I won't test it in my patches. I'll hack the Serial Core code and add
debug code just before every call to those functions we want to know
whether they run in interrupt context or not.

 Yeah, I know, it's still limited because the driver itself can call its
methods directly in interrupt context. But I think it's a good start.

| And putting a BUG in there is irresponsible too. It's such a critical
| subsystem. Drop bytes or return zero modem lines, but do not bug out.

 Well, I want the easier, fastest and non-questionable way to know whether
they are called from an interrupt context or not. The first thing that
came to my mind was: blow up everything if it has been called in
interrupt context.

 But I'm open for suggestions, of course.

-- 
Luiz Fernando N. Capitulino