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Commit 6716671d authored by Jiri Slaby's avatar Jiri Slaby Committed by Greg Kroah-Hartman
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TTY: introduce deinit helpers for proper ldisc shutdown 



Introduce deinitialize_tty_struct which should be called after
initialize_tty_struct and before successfull tty_ldisc_setup.

It calls tty_ldisc_deinit which is opposite of tty_ldisc_init. It only
puts a reference to ldisc and assigns NULL to tty->ldisc.

It will be used to shut down ldisc when tty_release cannot be called
yet.

Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent c18d77aa

drivers/tty/tty_io.c

+14 −0
Original line number Diff line number Diff line
@@ -2886,6 +2886,20 @@ void initialize_tty_struct(struct tty_struct *tty, 
	tty->dev = tty_get_device(tty);

}



/**

 *	deinitialize_tty_struct

 *	@tty: tty to deinitialize

 *

 *	This subroutine deinitializes a tty structure that has been newly

 *	allocated but tty_release cannot be called on that yet.

 *

 *	Locking: none - tty in question must not be exposed at this point

 */

void deinitialize_tty_struct(struct tty_struct *tty)

{

	tty_ldisc_deinit(tty);

}



/**

 *	tty_put_char	-	write one character to a tty

 *	@tty: tty

drivers/tty/tty_ldisc.c

+13 −0
Original line number Diff line number Diff line
@@ -956,6 +956,19 @@ void tty_ldisc_init(struct tty_struct *tty) 
	tty_ldisc_assign(tty, ld);

}



/**

 *	tty_ldisc_init		-	ldisc cleanup for new tty

 *	@tty: tty that was allocated recently

 *

 *	The tty structure must not becompletely set up (tty_ldisc_setup) when

 *      this call is made.

 */

void tty_ldisc_deinit(struct tty_struct *tty)

{

	put_ldisc(tty->ldisc);

	tty_ldisc_assign(tty, NULL);

}



void tty_ldisc_begin(void)

{

	/* Setup the default TTY line discipline. */

include/linux/tty.h

+2 −0
Original line number Diff line number Diff line
@@ -472,6 +472,7 @@ extern int tty_add_file(struct tty_struct *tty, struct file *file); 
extern void free_tty_struct(struct tty_struct *tty);

extern void initialize_tty_struct(struct tty_struct *tty,

		struct tty_driver *driver, int idx);

extern void deinitialize_tty_struct(struct tty_struct *tty);

extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,

								int first_ok);

extern int tty_release(struct inode *inode, struct file *filp);
@@ -525,6 +526,7 @@ extern int tty_set_ldisc(struct tty_struct *tty, int ldisc); 
extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);

extern void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty);

extern void tty_ldisc_init(struct tty_struct *tty);

extern void tty_ldisc_deinit(struct tty_struct *tty);

extern void tty_ldisc_begin(void);

/* This last one is just for the tty layer internals and shouldn't be used elsewhere */

extern void tty_ldisc_enable(struct tty_struct *tty);