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tty: Replace ASYNC_INITIALIZED bit and update atomically

Bladeren bron 
Replace ASYNC_INITIALIZED bit in the tty_port::flags field with
TTY_PORT_INITIALIZED bit in the tty_port::iflags field. Introduce helpers
tty_port_set_initialized() and tty_port_initialized() to abstract
atomic bit ops.

Note: the transforms for test_and_set_bit() and test_and_clear_bit()
are unnecessary as the state transitions are already mutually exclusive;
the tty lock prevents concurrent open/close/hangup.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley
2016-04-09 17:53:25 -07:00
gecommit door Greg Kroah-Hartman
bovenliggende 80f02d5424
commit d41861ca19
27 gewijzigde bestanden met toevoegingen van 157 en 150 verwijderingen
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13
drivers/tty/tty_port.c
Bestand weergeven

@@ -204,7 +204,8 @@ static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty)
if (port->console)
goto out;
if (test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) {
if (tty_port_initialized(port)) {
tty_port_set_initialized(port, 0);
/*
* Drop DTR/RTS if HUPCL is set. This causes any attached
* modem to hang up the line.
@@ -393,13 +394,13 @@ int tty_port_block_til_ready(struct tty_port *port,
while (1) {
/* Indicate we are open */
if (C_BAUD(tty) && test_bit(ASYNCB_INITIALIZED, &port->flags))
if (C_BAUD(tty) && tty_port_initialized(port))
tty_port_raise_dtr_rts(port);
prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);
/* Check for a hangup or uninitialised port.
Return accordingly */
if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
if (tty_hung_up_p(filp) || !tty_port_initialized(port)) {
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
@@ -480,7 +481,7 @@ int tty_port_close_start(struct tty_port *port,
tty->closing = 1;
if (test_bit(ASYNCB_INITIALIZED, &port->flags)) {
if (tty_port_initialized(port)) {
/* Don't block on a stalled port, just pull the chain */
if (tty->flow_stopped)
tty_driver_flush_buffer(tty);
@@ -578,7 +579,7 @@ int tty_port_open(struct tty_port *port, struct tty_struct *tty,
mutex_lock(&port->mutex);
if (!test_bit(ASYNCB_INITIALIZED, &port->flags)) {
if (!tty_port_initialized(port)) {
clear_bit(TTY_IO_ERROR, &tty->flags);
if (port->ops->activate) {
int retval = port->ops->activate(port, tty);
@@ -587,7 +588,7 @@ int tty_port_open(struct tty_port *port, struct tty_struct *tty,
return retval;
}
}
set_bit(ASYNCB_INITIALIZED, &port->flags);
tty_port_set_initialized(port, 1);
}
mutex_unlock(&port->mutex);
return tty_port_block_til_ready(port, tty, filp);