Commit 36c621d8 authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
Browse files

tty: Introduce a tty_port generic block_til_ready



Start sucking more commonality out of the drivers into a single piece of
core code.
Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3b6826b2
......@@ -838,82 +838,6 @@ static int isicom_carrier_raised(struct tty_port *port)
return (ip->status & ISI_DCD)?1 : 0;
}
static int block_til_ready(struct tty_struct *tty, struct file *filp,
struct isi_port *ip)
{
struct tty_port *port = &ip->port;
int do_clocal = 0, retval;
unsigned long flags;
DECLARE_WAITQUEUE(wait, current);
int cd;
/* block if port is in the process of being closed */
if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
pr_dbg("block_til_ready: close in progress.\n");
interruptible_sleep_on(&port->close_wait);
if (port->flags & ASYNC_HUP_NOTIFY)
return -EAGAIN;
else
return -ERESTARTSYS;
}
/* if non-blocking mode is set ... */
if ((filp->f_flags & O_NONBLOCK) ||
(tty->flags & (1 << TTY_IO_ERROR))) {
pr_dbg("block_til_ready: non-block mode.\n");
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}
if (C_CLOCAL(tty))
do_clocal = 1;
/* block waiting for DCD to be asserted, and while
callout dev is busy */
retval = 0;
add_wait_queue(&port->open_wait, &wait);
spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp))
port->count--;
port->blocked_open++;
spin_unlock_irqrestore(&port->lock, flags);
while (1) {
tty_port_raise_dtr_rts(port);
set_current_state(TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
break;
}
cd = tty_port_carrier_raised(port);
if (!(port->flags & ASYNC_CLOSING) &&
(do_clocal || cd))
break;
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
schedule();
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&port->open_wait, &wait);
spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp))
port->count++;
port->blocked_open--;
if (retval == 0)
port->flags |= ASYNC_NORMAL_ACTIVE;
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
static int isicom_open(struct tty_struct *tty, struct file *filp)
{
struct isi_port *port;
......@@ -940,12 +864,13 @@ static int isicom_open(struct tty_struct *tty, struct file *filp)
isicom_setup_board(card);
/* FIXME: locking on port.count etc */
port->port.count++;
tty->driver_data = port;
tty_port_tty_set(&port->port, tty);
error = isicom_setup_port(tty);
if (error == 0)
error = block_til_ready(tty, filp, port);
error = tty_port_block_til_ready(&port->port, tty, filp);
return error;
}
......
......@@ -558,75 +558,6 @@ static void mxser_raise_dtr_rts(struct tty_port *port)
spin_unlock_irqrestore(&mp->slock, flags);
}
static int mxser_block_til_ready(struct tty_struct *tty, struct file *filp,
struct mxser_port *mp)
{
DECLARE_WAITQUEUE(wait, current);
int retval;
int do_clocal = 0;
unsigned long flags;
int cd;
struct tty_port *port = &mp->port;
/*
* If non-blocking mode is set, or the port is not enabled,
* then make the check up front and then exit.
*/
if ((filp->f_flags & O_NONBLOCK) ||
test_bit(TTY_IO_ERROR, &tty->flags)) {
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}
if (tty->termios->c_cflag & CLOCAL)
do_clocal = 1;
/*
* Block waiting for the carrier detect and the line to become
* free (i.e., not in use by the callout). While we are in
* this loop, port->count is dropped by one, so that
* mxser_close() knows when to free things. We restore it upon
* exit, either normal or abnormal.
*/
retval = 0;
add_wait_queue(&port->open_wait, &wait);
spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp))
port->count--;
port->blocked_open++;
spin_unlock_irqrestore(&port->lock, flags);
while (1) {
tty_port_raise_dtr_rts(port);
set_current_state(TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
break;
}
cd = tty_port_carrier_raised(port);
if (!(port->flags & ASYNC_CLOSING) && (do_clocal || cd))
break;
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
schedule();
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&port->open_wait, &wait);
spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp))
port->count++;
port->blocked_open--;
if (retval == 0)
port->flags |= ASYNC_NORMAL_ACTIVE;
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
static int mxser_set_baud(struct tty_struct *tty, long newspd)
{
struct mxser_port *info = tty->driver_data;
......@@ -1110,7 +1041,7 @@ static int mxser_open(struct tty_struct *tty, struct file *filp)
if (retval)
return retval;
retval = mxser_block_til_ready(tty, filp, info);
retval = tty_port_block_til_ready(&info->port, tty, filp);
if (retval)
return retval;
......
......@@ -874,90 +874,6 @@ static int carrier_raised(struct tty_port *port)
return CD;
}
static int block_til_ready(struct tty_struct *tty, struct file *filp,
struct riscom_port *rp)
{
DECLARE_WAITQUEUE(wait, current);
int retval;
int do_clocal = 0;
int CD;
unsigned long flags;
struct tty_port *port = &rp->port;
/*
* If the device is in the middle of being closed, then block
* until it's done, and then try again.
*/
if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
interruptible_sleep_on(&port->close_wait);
if (port->flags & ASYNC_HUP_NOTIFY)
return -EAGAIN;
else
return -ERESTARTSYS;
}
/*
* If non-blocking mode is set, or the port is not enabled,
* then make the check up front and then exit.
*/
if ((filp->f_flags & O_NONBLOCK) ||
(tty->flags & (1 << TTY_IO_ERROR))) {
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}
if (C_CLOCAL(tty))
do_clocal = 1;
/*
* Block waiting for the carrier detect and the line to become
* free (i.e., not in use by the callout). While we are in
* this loop, info->count is dropped by one, so that
* rs_close() knows when to free things. We restore it upon
* exit, either normal or abnormal.
*/
retval = 0;
add_wait_queue(&port->open_wait, &wait);
spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp))
port->count--;
port->blocked_open++;
spin_unlock_irqrestore(&port->lock, flags);
while (1) {
CD = tty_port_carrier_raised(port);
set_current_state(TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp) ||
!(port->flags & ASYNC_INITIALIZED)) {
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
break;
}
if (!(port->flags & ASYNC_CLOSING) &&
(do_clocal || CD))
break;
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
schedule();
}
__set_current_state(TASK_RUNNING);
remove_wait_queue(&port->open_wait, &wait);
spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp))
port->count++;
port->blocked_open--;
if (retval == 0)
port->flags |= ASYNC_NORMAL_ACTIVE;
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
static int rc_open(struct tty_struct *tty, struct file *filp)
{
int board;
......@@ -984,7 +900,7 @@ static int rc_open(struct tty_struct *tty, struct file *filp)
error = rc_setup_port(bp, port);
if (error == 0)
error = block_til_ready(tty, filp, port);
error = tty_port_block_til_ready(&port->port, tty, filp);
return error;
}
......
......@@ -3401,6 +3401,7 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
set_current_state(TASK_RUNNING);
remove_wait_queue(&port->open_wait, &wait);
/* FIXME: Racy on hangup during close wait */
if (extra_count)
port->count++;
port->blocked_open--;
......
......@@ -151,3 +151,108 @@ void tty_port_raise_dtr_rts(struct tty_port *port)
port->ops->raise_dtr_rts(port);
}
EXPORT_SYMBOL(tty_port_raise_dtr_rts);
/**
* tty_port_block_til_ready - Waiting logic for tty open
* @port: the tty port being opened
* @tty: the tty device being bound
* @filp: the file pointer of the opener
*
* Implement the core POSIX/SuS tty behaviour when opening a tty device.
* Handles:
* - hangup (both before and during)
* - non blocking open
* - rts/dtr/dcd
* - signals
* - port flags and counts
*
* The passed tty_port must implement the carrier_raised method if it can
* do carrier detect and the raise_dtr_rts method if it supports software
* management of these lines. Note that the dtr/rts raise is done each
* iteration as a hangup may have previously dropped them while we wait.
*/
int tty_port_block_til_ready(struct tty_port *port,
struct tty_struct *tty, struct file *filp)
{
int do_clocal = 0, retval;
unsigned long flags;
DECLARE_WAITQUEUE(wait, current);
int cd;
/* block if port is in the process of being closed */
if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
interruptible_sleep_on(&port->close_wait);
if (port->flags & ASYNC_HUP_NOTIFY)
return -EAGAIN;
else
return -ERESTARTSYS;
}
/* if non-blocking mode is set we can pass directly to open unless
the port has just hung up or is in another error state */
if ((filp->f_flags & O_NONBLOCK) ||
(tty->flags & (1 << TTY_IO_ERROR))) {
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}
if (C_CLOCAL(tty))
do_clocal = 1;
/* Block waiting until we can proceed. We may need to wait for the
carrier, but we must also wait for any close that is in progress
before the next open may complete */
retval = 0;
add_wait_queue(&port->open_wait, &wait);
/* The port lock protects the port counts */
spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp))
port->count--;
port->blocked_open++;
spin_unlock_irqrestore(&port->lock, flags);
while (1) {
/* Indicate we are open */
tty_port_raise_dtr_rts(port);
set_current_state(TASK_INTERRUPTIBLE);
/* Check for a hangup or uninitialised port. Return accordingly */
if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
break;
}
/* Probe the carrier. For devices with no carrier detect this
will always return true */
cd = tty_port_carrier_raised(port);
if (!(port->flags & ASYNC_CLOSING) &&
(do_clocal || cd))
break;
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
schedule();
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&port->open_wait, &wait);
/* Update counts. A parallel hangup will have set count to zero and
we must not mess that up further */
spin_lock_irqsave(&port->lock, flags);
if (!tty_hung_up_p(filp))
port->count++;
port->blocked_open--;
if (retval == 0)
port->flags |= ASYNC_NORMAL_ACTIVE;
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
EXPORT_SYMBOL(tty_port_block_til_ready);
......@@ -631,8 +631,8 @@ static void scc_enable_rx_interrupts(void *ptr)
static int scc_carrier_raised(struct tty_port *port)
{
struct scc_port *scc = container_of(port, struct scc_port, gs.port);
unsigned channel = port->channel;
struct scc_port *sc = container_of(port, struct scc_port, gs.port);
unsigned channel = sc->channel;
return !!(scc_last_status_reg[channel] & SR_DCD);
}
......@@ -643,7 +643,7 @@ static void scc_shutdown_port(void *ptr)
struct scc_port *port = ptr;
port->gs.port.flags &= ~ GS_ACTIVE;
if (port->gs.port.tty && port->gs.port.tty->termios->c_cflag & HUPCL) {
if (port->gs.port.tty && (port->gs.port.tty->termios->c_cflag & HUPCL)) {
scc_setsignals (port, 0, 0);
}
}
......
......@@ -439,6 +439,8 @@ extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
extern int tty_port_carrier_raised(struct tty_port *port);
extern void tty_port_raise_dtr_rts(struct tty_port *port);
extern void tty_port_hangup(struct tty_port *port);
extern int tty_port_block_til_ready(struct tty_port *port,
struct tty_struct *tty, struct file *filp);
extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
extern int tty_unregister_ldisc(int disc);
......
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