Re: [PATCH 1/2] BKL: Remove BKL from default_llseek()

Jan Blunck
2009-11-18T17:55:38Z

On Wed, Nov 18, Oliver Neukum wrote:

> Am Mittwoch, 18. November 2009 18:27:30 schrieb Jamie Lokier:
> > > No. Your logic is flawed
> > >
> > > The BKL is protected something here - it protects the change of offset
> > > with respect to other BKL users within drivers. The question is what if
> > > anything in any other driver code depends upon the BKL and uses it to
> > > protect f_pos. Probably very little if anything but a grep for f_pos
> > > through the drivers might not be a bad idea before assuming this. Very
> > > few touch f_pos except in their own llseek method.
> >
> > Of course, drivers shouldn't be using f_pos outside their llseek
> > method, as they should all behave the same with pread/pwrite as with
> > llseek+read/write.
>
> Might not a driver update f_pos after read/write?

Actually the VFS is doing that for you in read/write syscall. So anything you
change in your driver gets corrected (or overwritten anyway).

Regards,
Jan

--
Jan Blunck <jblunck@suse.de>