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Date: Wed, 11 Oct 2006 20:50:41 +0200
From: Jiri Slaby <jirislaby@gmail.com>
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To: Linux kernel mailing list <linux-kernel@vger.kernel.org>
CC: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: tty_driver->ttys association
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Hi,

I found this construction in the kernel:
static struct tty_driver *my_ttydriver;
static struct tty_struct *my_tty[PORTS + 1];
static struct termios *my_termios[PORTS + 1];
static struct termios *my_termios_locked[PORTS + 1];

...(alloc+set_op+...)
my_ttydriver->flags = TTY_DRIVER_REAL_RAW|TTY_DRIVER_DYNAMIC_DEV;
my_ttydriver->ttys = my_tty;
my_ttydriver->termios = my_termios;
my_ttydriver->termios_locked = my_termios_locked;
tty_register_driver(my_ttydriver);

The association is completely useless due to
if (p) {
     driver->ttys = (struct tty_struct **)p;
     driver->termios = (struct termios **)(p + driver->num);
     driver->termios_locked = (struct termios **)(p + driver->num * 2);
} else {
     driver->ttys = NULL;
     driver->termios = NULL;
     driver->termios_locked = NULL;
}

in tty_register_driver, isn't it? Can we save some memory?

thanks,
-- 
http://www.fi.muni.cz/~xslaby/            Jiri Slaby
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
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