Re: [PATCH] cyber2000fb: New framebuffer_alloc API and class_dev changes

[Kronos <kronos@kronoz.cjb.net>]

Il Tue, Sep 16, 2003 at 02:44:59PM +0100, Russell King ha scritto: 
> On Tue, Sep 16, 2003 at 03:40:09PM +0200, Kronos wrote:
> > Il Mon, Sep 15, 2003 at 11:58:32PM +0100, Russell King ha scritto: 
> > > On Tue, Sep 16, 2003 at 12:17:42AM +0200, Kronos wrote:
> > > > Il Mon, Sep 15, 2003 at 10:40:42PM +0100, Russell King ha scritto: 
> > > > > There is another reason why the above is fundamentally flawed - who says
> > > > > that "release_cfb_info" will still be in module space by the time you
> > > > > need to call it?
> > > > > 
> > > > > Eg, you unload your framebuffer driver module immediately after the device
> > > > > has gone away, but someone is keeping the sysfs files associated with
> > > > > the fb_info open.
> > > > 
> > > > I'm quite sure that this can't happen. If someone is keeping a sysfs
> > > > file open module use count won't be zero. Right?
> > > 
> > > Where are you handling the module use count of the framebuffer driver?
> > 
> > Every   attribute   (ie.  sysfs   file)   has   a  .owner   field   (see
> > include/linux/sysfs.h), the module  use count is handled  by sysfs. If a
> > sysfs file is open the module can't be unloaded.
> 
> The .owner field is set to the module which defined the sysfs attribute.
> This wouldn't be the driver, but would be some other part of the framebuffer
> layer.

Good point. I  was thinking  at files  created by  the driver  itself, I
forgot about  dev attribute. I  can overwrite  .owner of  dev attribute,
fbmem can't be built as module. Sounds good?

> > > Is there somewhere I can view the core changes?
> > 
> > They are on fbdev for review, I put a copy here:
> > http://web.tiscali.it/kronoz/linux/fbdev-class_dev-fbmem.c.diff
> 
> When I tried to get at the fbdev site, it seemed to be down.  Maybe
> some of the kernel documentation needs to be updated?

Try here: http://linux-fbdev.sf.net
Mailing lists are here: http://linux-fbdev.sourceforge.net/mlist.html

Luca
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