> On Tue, Mar 09, 2010 at 09:12:13PM +0100, Arnd Bergmann wrote:
> > On Tuesday 09 March 2010, Thadeu Lima de Souza Cascardo wrote:
> > > MODULE_AUTHOR("Vojtech Pavlik <vojtech@suse.cz>");
> > > @@ -1881,7 +1880,7 @@ static int input_open_file(struct inode *inode, struct file *file)
> > > const struct file_operations *old_fops, *new_fops = NULL;
> > > int err;
> > >
> > > - lock_kernel();
> > > + mutex_lock(&input_mutex);
> > > /* No load-on-demand here? */
> > > handler = input_table[iminor(inode) >> 5];
> > > if (!handler || !(new_fops = fops_get(handler->fops))) {
> > > @@ -1909,7 +1908,7 @@ static int input_open_file(struct inode *inode, struct file *file)
> > > }
> > > fops_put(old_fops);
> > > out:
> > > - unlock_kernel();
> > > + mutex_unlock(&input_mutex);
> > > return err;
> > > }
> > >
> > > --
> >
> > Well, actually please have a look at
> >
http://git.kernel.org/?p=linux/kernel/git/arnd/playground.git;a=commitdiff;h=c06fd0234...
> >
> > * use mutex_lock_interruptible() where possible
> > * you probably don't want to hold input_mutex when calling into the lower
> > device's open function
> >
> > Arnd
>
> Yeah. I was just looking at your appointed branch. And I've noticed your
> change was better.
>
> I was willing to let the open call go unprotected. But ended up checking
> that the three callees were fine (they do not call any of the other
> functions that take the mutex).
>
> Since the fops_put/fops_get do protect that section from the handler
> removal and I can't think of any other race right now, I think your
> version is really better.
>
> Acked-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
>
