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PTY: add tty_port

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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: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby 2012-06-04 13:35:30 +02:00 committed by Greg Kroah-Hartman
parent 5d249bc6a6
commit d03702a27d
1 changed files with 21 additions and 4 deletions
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25
drivers/tty/pty.c
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@ -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 @@ err_deinit_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,
};
/**