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Commit d03702a2 authored by Jiri Slaby's avatar Jiri Slaby Committed by Greg Kroah-Hartman
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PTY: add tty_port 



This has *no* function in the PTY driver yet. However as the tty
buffers will move to the tty_port structure, we will need tty_port for
all TTYs in the system, PTY inclusive.

For PTYs this is ensured by allocating 2 tty_port's in pty_install,
i.e. where the tty->link is allocated. Both tty_port's are properly
assigned to each end of the tty.

Freeing is done at the same place where tty is freed, i.e. in
tty->ops->cleanup.

This means BTW that tty_port does not outlive TTY in PTY. This might
be a subject to change in the future if we see some problems.

Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5d249bc6

drivers/tty/pty.c

+21 −4
Original line number Diff line number Diff line
@@ -286,12 +286,15 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, 
		bool legacy)

{

	struct tty_struct *o_tty;

	struct tty_port *ports[2];

	int idx = tty->index;

	int retval = -ENOMEM;



	o_tty = alloc_tty_struct();

	if (!o_tty)

		goto err;

	ports[0] = kmalloc(sizeof **ports, GFP_KERNEL);

	ports[1] = kmalloc(sizeof **ports, GFP_KERNEL);

	if (!o_tty || !ports[0] || !ports[1])

		goto err_free_tty;

	if (!try_module_get(driver->other->owner)) {

		/* This cannot in fact currently happen */

		goto err_free_tty;
@@ -335,6 +338,10 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, 
	/* Establish the links in both directions */

	tty->link   = o_tty;

	o_tty->link = tty;

	tty_port_init(ports[0]);

	tty_port_init(ports[1]);

	o_tty->port = ports[0];

	tty->port = ports[1];



	tty_driver_kref_get(driver);

	tty->count++;
@@ -348,11 +355,17 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty, 
	deinitialize_tty_struct(o_tty);

	module_put(o_tty->driver->owner);

err_free_tty:

	kfree(ports[0]);

	kfree(ports[1]);

	free_tty_struct(o_tty);

err:

	return retval;

}



static void pty_cleanup(struct tty_struct *tty)

{

	kfree(tty->port);

}



/* Traditional BSD devices */

#ifdef CONFIG_LEGACY_PTYS
@@ -391,6 +404,7 @@ static const struct tty_operations master_pty_ops_bsd = { 
	.unthrottle = pty_unthrottle,

	.set_termios = pty_set_termios,

	.ioctl = pty_bsd_ioctl,

	.cleanup = pty_cleanup,

	.resize = pty_resize

};
@@ -404,6 +418,7 @@ static const struct tty_operations slave_pty_ops_bsd = { 
	.chars_in_buffer = pty_chars_in_buffer,

	.unthrottle = pty_unthrottle,

	.set_termios = pty_set_termios,

	.cleanup = pty_cleanup,

	.resize = pty_resize

};
@@ -555,6 +570,7 @@ static const struct tty_operations ptm_unix98_ops = { 
	.set_termios = pty_set_termios,

	.ioctl = pty_unix98_ioctl,

	.shutdown = pty_unix98_shutdown,

	.cleanup = pty_cleanup,

	.resize = pty_resize

};
@@ -570,7 +586,8 @@ static const struct tty_operations pty_unix98_ops = { 
	.chars_in_buffer = pty_chars_in_buffer,

	.unthrottle = pty_unthrottle,

	.set_termios = pty_set_termios,

	.shutdown = pty_unix98_shutdown

	.shutdown = pty_unix98_shutdown,

	.cleanup = pty_cleanup,

};



/**