Re: [patch]fix usb serial race due to late shutdown

Am Freitag, 16. März 2007 22:05 schrieb Pete Zaitcev:
> On Fri, 16 Mar 2007 20:43:30 +0100, Oliver Neukum <[email protected]> wrote:
> 
> >  static struct usb_serial *serial_table[SERIAL_TTY_MINORS];	/* initially all NULL */
> > +static u32 deathrow[SERIAL_TTY_MINORS/32];			/* disconnected but open*/
> 
> Can you tell me why do you use a bitmap instead of putting the flag
> into a port? It would only make sense if you wanted to set or clear
> the flag when port is NULL, which you do not. Your accessor functions
> reference port->number. Is there a reason why you don't add a poison
> flag near the new field "busy" which you added?

Originally, I considered freeing more memory at disconnect().
It turned out harder than I thought. I can add it to the port's data
if you like.

> >  static spinlock_t table_lock;
> >  static LIST_HEAD(usb_serial_driver_list);
> > +static DECLARE_WAIT_QUEUE_HEAD(usbserial_henchman);
> 
> Why is this static instead of per-serial?

Overkill. Unnecessary wakeups will be very rare, but the structure would
grow and need initialisation.

	Regards
		Oliver

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