Commit 26b23209 authored by Jiri Slaby's avatar Jiri Slaby Committed by Greg Kroah-Hartman

TTY: tty_driver, document tty->ops->shutdown limitation

Note that tty->ops->shutdown is called from whatever context the user
drops the last tty reference from. E.g. if one takes a reference in
an ISR, tty close happens on other CPU and the final tty put is from
the ISR, tty->ops->shutdown will be called from that hard irq context.

We would have a problem in vt if we start using tty refcounting from
other contexts than user there. It is because vt's shutdown uses
mutexes. This is yet to be fixed.
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Reported-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 91cedcde
......@@ -50,6 +50,8 @@
* Note that tty_shutdown() is not called if ops->shutdown is defined.
* This means one is responsible to take care of calling ops->remove (e.g.
* via tty_driver_remove_tty) and releasing tty->termios.
* Note that this hook may be called from *all* the contexts where one
* uses tty refcounting (e.g. tty_port_tty_get).
*
*
* void (*cleanup)(struct tty_struct * tty);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment