Re: [patch 36/61] lock validator: special locking: serial

[Ingo Molnar]

* Andrew Morton <akpm@xxxxxxxx> wrote:

> > +/*
> > + * lockdep: port->lock is initialized in two places, but we
> > + *          want only one lock-type:
> > + */
> > +static struct lockdep_type_key port_lock_key;
> > +
> >  /**
> >   *	uart_set_options - setup the serial console parameters
> >   *	@port: pointer to the serial ports uart_port structure
> > @@ -1869,7 +1875,7 @@ uart_set_options(struct uart_port *port,
> >  	 * Ensure that the serial console lock is initialised
> >  	 * early.
> >  	 */
> > -	spin_lock_init(&port->lock);
> > +	spin_lock_init_key(&port->lock, &port_lock_key);
> >  
> >  	memset(&termios, 0, sizeof(struct termios));
> >  
> > @@ -2255,7 +2261,7 @@ int uart_add_one_port(struct uart_driver
> >  	 * initialised.
> >  	 */
> >  	if (!(uart_console(port) && (port->cons->flags & CON_ENABLED)))
> > -		spin_lock_init(&port->lock);
> > +		spin_lock_init_key(&port->lock, &port_lock_key);
> >  
> >  	uart_configure_port(drv, state, port);
> >  
> 
> Is there a cleaner way of doing this?
> 
> Perhaps write a new helper function which initialises the spinlock, 
> call that?  Rather than open-coding lockdep stuff?

yes, we can do that too - but that would have an effect to non-lockdep 
kernels too.

Also, the initialization of the 'port' seems a bit twisted here, already 
initialized and not-yet-initialized ports can be passed in to 
uard_add_one_port(). So i did not want to touch the structure of the 
code - hence the open-coded solution.

	Ingo
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