Re: [PATCH 1/1] Char: vt, make sysfs operations atomic

[Jiri Slaby]

On 05/27/2008 09:43 PM, Aristeu Rozanski wrote:
> > Hold console sem while creating/destroying sysfs files. Serialisation is
> > so far done by BKL held in tty release_dev and chrdev_open, but no other
> > locks are held in open path.
> >
> >  				tty->termios->c_iflag |= IUTF8;
> >  			else
> >  				tty->termios->c_iflag &= ~IUTF8;
> > -			release_console_sem();
> >  			vcs_make_sysfs(tty);
> > +			release_console_sem();
> >  			return ret;
> >  		}
> >  	}
> > @@ -2772,8 +2772,8 @@ static void con_close(struct tty_struct *tty, struct file *filp)
> >  		if (vc)
> >  			vc->vc_tty = NULL;
> >  		tty->driver_data = NULL;
> > -		release_console_sem();
> >  		vcs_remove_sysfs(tty);
> > +		release_console_sem();
> >  		mutex_unlock(&tty_mutex);
> >  		/*
> >  		 * tty_mutex is released, but we still hold BKL, so there is
> the reason for the code be the way it is is because vcs_{add,remove}_sysfs()
> may sleep

What's the point? To have races in the code but not sleep inside the semaphore?
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