lkml.org 
[lkml]   [2008]   [Feb]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
DateSat, 9 Feb 2008 12:41:45 +0100 (CET)
FromGuennadi Liakhovetski <>
SubjectRe: [PATCH 1/2] prevent gpio chip drivers from unloading while used
On Fri, 8 Feb 2008, David Brownell wrote:

> > Yes, that's what I'm saying. I had a GPIO in use and rmmod-ed pca953x. It
> > did produce an error message
> >
> > pca953x 0-0041: gpiochip_remove() failed, -16
> >
> > , but rmmod completed.
>
> Doesn't that seem buglike to you?
>
> Oh, right -- the module exit code will ignore that status, it doesn't
> even have a way to report failures any more. Crap.
>
> So it looks like we have no choice but to do this. Can you make sure
> all the rmmod-capable gpio_chip drivers support this? Ignore the SOC
> support, that never supports rmmod -- just the stuff in drivers/gpio.

As long as you find these two patches acceptable, I'll cook up an
incremental patch to fix those.

> > AFAIU, the only 2 ways currently to prevent rmmod
> > from completing, are: increment module use-count, then the respective
> > module_exit() function is not called at all and rmmod fails with -EBUSY.
> > Or block in rmmod until the resource becomes free. None of these has
> > happened. BTW, I think, there's the same problem with i2c adapter drivers.
>
> Right. In fact, every time you'd expect driver removal errors to
> cause module removal to fail. Maybe this is part of that whole
> "should we even *support* rmmod" discussion, which I tuned out.

We don't want to start another one here, do we?:-)

Thanks
Guennadi
---
Guennadi Liakhovetski

\
 
 \ /
  Last update: 2008-02-09 12:43    [from the cache]
©2003-2010