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Commit f751928e authored by Alan Cox's avatar Alan Cox Committed by Linus Torvalds
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tty: We want the port object to be persistent 



Move the tty_port and uart_info bits around a little. By embedding the uart_info
into the uart_port we get rid of lots of corner case testing and also get the
ability to go port<->state<->info which is a bit more elegant than the current
data structures.

Downsides - we allocate a tiny bit more memory for unused ports, upside we've
removed as much code as it saved for most users..

Signed-off-by: default avatarAlan Cox <alan@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6ef53066

drivers/serial/jsm/jsm_tty.c

+1 −1
Original line number Diff line number Diff line
@@ -272,7 +272,7 @@ static void jsm_tty_close(struct uart_port *port) 
	jsm_printk(CLOSE, INFO, &channel->ch_bd->pci_dev, "start\n");



	bd = channel->ch_bd;

	ts = channel->uart_port.info->port.tty->termios;

	ts = port->info->port.tty->termios;



	channel->ch_flags &= ~(CH_STOPI);

drivers/serial/serial_core.c

+61 −83
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ static struct lock_class_key port_lock_key; 


#define HIGH_BITS_OFFSET	((sizeof(long)-sizeof(int))*8)



#define uart_users(state)	((state)->count + ((state)->info ? (state)->info->port.blocked_open : 0))

#define uart_users(state)	((state)->count + (state)->info.port.blocked_open)



#ifdef CONFIG_SERIAL_CORE_CONSOLE

#define uart_console(port)	((port)->cons && (port)->cons->index == (port)->line)
@@ -94,7 +94,7 @@ static void __uart_start(struct tty_struct *tty) 
	struct uart_state *state = tty->driver_data;

	struct uart_port *port = state->port;



	if (!uart_circ_empty(&state->info->xmit) && state->info->xmit.buf &&

	if (!uart_circ_empty(&state->info.xmit) && state->info.xmit.buf &&

	    !tty->stopped && !tty->hw_stopped)

		port->ops->start_tx(port);

}
@@ -113,7 +113,7 @@ static void uart_start(struct tty_struct *tty) 
static void uart_tasklet_action(unsigned long data)

{

	struct uart_state *state = (struct uart_state *)data;

	tty_wakeup(state->info->port.tty);

	tty_wakeup(state->info.port.tty);

}



static inline void
@@ -139,7 +139,7 @@ uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear) 
 */

static int uart_startup(struct uart_state *state, int init_hw)

{

	struct uart_info *info = state->info;

	struct uart_info *info = &state->info;

	struct uart_port *port = state->port;

	unsigned long page;

	int retval = 0;
@@ -212,14 +212,15 @@ static int uart_startup(struct uart_state *state, int init_hw) 
 */

static void uart_shutdown(struct uart_state *state)

{

	struct uart_info *info = state->info;

	struct uart_info *info = &state->info;

	struct uart_port *port = state->port;

	struct tty_struct *tty = info->port.tty;



	/*

	 * Set the TTY IO error marker

	 */

	if (info->port.tty)

		set_bit(TTY_IO_ERROR, &info->port.tty->flags);

	if (tty)

		set_bit(TTY_IO_ERROR, &tty->flags);



	if (info->flags & UIF_INITIALIZED) {

		info->flags &= ~UIF_INITIALIZED;
@@ -227,7 +228,7 @@ static void uart_shutdown(struct uart_state *state) 
		/*

		 * Turn off DTR and RTS early.

		 */

		if (!info->port.tty || (info->port.tty->termios->c_cflag & HUPCL))

		if (!tty || (tty->termios->c_cflag & HUPCL))

			uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);



		/*
@@ -427,7 +428,7 @@ EXPORT_SYMBOL(uart_get_divisor); 
static void

uart_change_speed(struct uart_state *state, struct ktermios *old_termios)

{

	struct tty_struct *tty = state->info->port.tty;

	struct tty_struct *tty = state->info.port.tty;

	struct uart_port *port = state->port;

	struct ktermios *termios;
@@ -444,14 +445,14 @@ uart_change_speed(struct uart_state *state, struct ktermios *old_termios) 
	 * Set flags based on termios cflag

	 */

	if (termios->c_cflag & CRTSCTS)

		state->info->flags |= UIF_CTS_FLOW;

		state->info.flags |= UIF_CTS_FLOW;

	else

		state->info->flags &= ~UIF_CTS_FLOW;

		state->info.flags &= ~UIF_CTS_FLOW;



	if (termios->c_cflag & CLOCAL)

		state->info->flags &= ~UIF_CHECK_CD;

		state->info.flags &= ~UIF_CHECK_CD;

	else

		state->info->flags |= UIF_CHECK_CD;

		state->info.flags |= UIF_CHECK_CD;



	port->ops->set_termios(port, termios, old_termios);

}
@@ -479,7 +480,7 @@ static int uart_put_char(struct tty_struct *tty, unsigned char ch) 
{

	struct uart_state *state = tty->driver_data;



	return __uart_put_char(state->port, &state->info->xmit, ch);

	return __uart_put_char(state->port, &state->info.xmit, ch);

}



static void uart_flush_chars(struct tty_struct *tty)
@@ -500,13 +501,13 @@ uart_write(struct tty_struct *tty, const unsigned char *buf, int count) 
	 * This means you called this function _after_ the port was

	 * closed.  No cookie for you.

	 */

	if (!state || !state->info) {

	if (!state) {

		WARN_ON(1);

		return -EL3HLT;

	}



	port = state->port;

	circ = &state->info->xmit;

	circ = &state->info.xmit;



	if (!circ->buf)

		return 0;
@@ -537,7 +538,7 @@ static int uart_write_room(struct tty_struct *tty) 
	int ret;



	spin_lock_irqsave(&state->port->lock, flags);

	ret = uart_circ_chars_free(&state->info->xmit);

	ret = uart_circ_chars_free(&state->info.xmit);

	spin_unlock_irqrestore(&state->port->lock, flags);

	return ret;

}
@@ -549,7 +550,7 @@ static int uart_chars_in_buffer(struct tty_struct *tty) 
	int ret;



	spin_lock_irqsave(&state->port->lock, flags);

	ret = uart_circ_chars_pending(&state->info->xmit);

	ret = uart_circ_chars_pending(&state->info.xmit);

	spin_unlock_irqrestore(&state->port->lock, flags);

	return ret;

}
@@ -564,7 +565,7 @@ static void uart_flush_buffer(struct tty_struct *tty) 
	 * This means you called this function _after_ the port was

	 * closed.  No cookie for you.

	 */

	if (!state || !state->info) {

	if (!state) {

		WARN_ON(1);

		return;

	}
@@ -573,7 +574,7 @@ static void uart_flush_buffer(struct tty_struct *tty) 
	pr_debug("uart_flush_buffer(%d) called\n", tty->index);



	spin_lock_irqsave(&port->lock, flags);

	uart_circ_clear(&state->info->xmit);

	uart_circ_clear(&state->info.xmit);

	if (port->ops->flush_buffer)

		port->ops->flush_buffer(port);

	spin_unlock_irqrestore(&port->lock, flags);
@@ -837,15 +838,15 @@ static int uart_set_info(struct uart_state *state, 
	state->closing_wait    = closing_wait;

	if (new_serial.xmit_fifo_size)

		port->fifosize = new_serial.xmit_fifo_size;

	if (state->info->port.tty)

		state->info->port.tty->low_latency =

	if (state->info.port.tty)

		state->info.port.tty->low_latency =

			(port->flags & UPF_LOW_LATENCY) ? 1 : 0;



 check_and_exit:

	retval = 0;

	if (port->type == PORT_UNKNOWN)

		goto exit;

	if (state->info->flags & UIF_INITIALIZED) {

	if (state->info.flags & UIF_INITIALIZED) {

		if (((old_flags ^ port->flags) & UPF_SPD_MASK) ||

		    old_custom_divisor != port->custom_divisor) {

			/*
@@ -858,7 +859,7 @@ static int uart_set_info(struct uart_state *state, 
				printk(KERN_NOTICE

				       "%s sets custom speed on %s. This "

				       "is deprecated.\n", current->comm,

				       tty_name(state->info->port.tty, buf));

				       tty_name(state->info.port.tty, buf));

			}

			uart_change_speed(state, NULL);

		}
@@ -889,8 +890,8 @@ static int uart_get_lsr_info(struct uart_state *state, 
	 * interrupt happens).

	 */

	if (port->x_char ||

	    ((uart_circ_chars_pending(&state->info->xmit) > 0) &&

	     !state->info->port.tty->stopped && !state->info->port.tty->hw_stopped))

	    ((uart_circ_chars_pending(&state->info.xmit) > 0) &&

	     !state->info.port.tty->stopped && !state->info.port.tty->hw_stopped))

		result &= ~TIOCSER_TEMT;



	return put_user(result, value);
@@ -1017,7 +1018,7 @@ uart_wait_modem_status(struct uart_state *state, unsigned long arg) 
	port->ops->enable_ms(port);

	spin_unlock_irq(&port->lock);



	add_wait_queue(&state->info->delta_msr_wait, &wait);

	add_wait_queue(&state->info.delta_msr_wait, &wait);

	for (;;) {

		spin_lock_irq(&port->lock);

		memcpy(&cnow, &port->icount, sizeof(struct uart_icount));
@@ -1045,7 +1046,7 @@ uart_wait_modem_status(struct uart_state *state, unsigned long arg) 
	}



	current->state = TASK_RUNNING;

	remove_wait_queue(&state->info->delta_msr_wait, &wait);

	remove_wait_queue(&state->info.delta_msr_wait, &wait);



	return ret;

}
@@ -1241,7 +1242,7 @@ static void uart_set_termios(struct tty_struct *tty, 
	 */

	if (!(old_termios->c_cflag & CLOCAL) &&

	    (tty->termios->c_cflag & CLOCAL))

		wake_up_interruptible(&state->info->port.open_wait);

		wake_up_interruptible(&info->port.open_wait);

#endif

}
@@ -1303,7 +1304,7 @@ static void uart_close(struct tty_struct *tty, struct file *filp) 
	 * At this point, we stop accepting input.  To do this, we

	 * disable the receive line status interrupts.

	 */

	if (state->info->flags & UIF_INITIALIZED) {

	if (state->info.flags & UIF_INITIALIZED) {

		unsigned long flags;

		spin_lock_irqsave(&port->lock, flags);

		port->ops->stop_rx(port);
@@ -1322,9 +1323,9 @@ static void uart_close(struct tty_struct *tty, struct file *filp) 
	tty_ldisc_flush(tty);



	tty->closing = 0;

	state->info->port.tty = NULL;

	state->info.port.tty = NULL;



	if (state->info->port.blocked_open) {

	if (state->info.port.blocked_open) {

		if (state->close_delay)

			msleep_interruptible(state->close_delay);

	} else if (!uart_console(port)) {
@@ -1334,8 +1335,8 @@ static void uart_close(struct tty_struct *tty, struct file *filp) 
	/*

	 * Wake up anyone trying to open this port.

	 */

	state->info->flags &= ~UIF_NORMAL_ACTIVE;

	wake_up_interruptible(&state->info->port.open_wait);

	state->info.flags &= ~UIF_NORMAL_ACTIVE;

	wake_up_interruptible(&state->info.port.open_wait);



 done:

	mutex_unlock(&state->mutex);
@@ -1409,19 +1410,20 @@ static void uart_wait_until_sent(struct tty_struct *tty, int timeout) 
static void uart_hangup(struct tty_struct *tty)

{

	struct uart_state *state = tty->driver_data;

	struct uart_info *info = &state->info;



	BUG_ON(!kernel_locked());

	pr_debug("uart_hangup(%d)\n", state->port->line);



	mutex_lock(&state->mutex);

	if (state->info && state->info->flags & UIF_NORMAL_ACTIVE) {

	if (info->flags & UIF_NORMAL_ACTIVE) {

		uart_flush_buffer(tty);

		uart_shutdown(state);

		state->count = 0;

		state->info->flags &= ~UIF_NORMAL_ACTIVE;

		state->info->port.tty = NULL;

		wake_up_interruptible(&state->info->port.open_wait);

		wake_up_interruptible(&state->info->delta_msr_wait);

		info->flags &= ~UIF_NORMAL_ACTIVE;

		info->port.tty = NULL;

		wake_up_interruptible(&info->port.open_wait);

		wake_up_interruptible(&info->delta_msr_wait);

	}

	mutex_unlock(&state->mutex);

}
@@ -1434,7 +1436,7 @@ static void uart_hangup(struct tty_struct *tty) 
 */

static void uart_update_termios(struct uart_state *state)

{

	struct tty_struct *tty = state->info->port.tty;

	struct tty_struct *tty = state->info.port.tty;

	struct uart_port *port = state->port;



	if (uart_console(port) && port->cons->cflag) {
@@ -1469,7 +1471,7 @@ static int 
uart_block_til_ready(struct file *filp, struct uart_state *state)

{

	DECLARE_WAITQUEUE(wait, current);

	struct uart_info *info = state->info;

	struct uart_info *info = &state->info;

	struct uart_port *port = state->port;

	unsigned int mctrl;
@@ -1563,28 +1565,6 @@ static struct uart_state *uart_get(struct uart_driver *drv, int line) 
		ret = -ENXIO;

		goto err_unlock;

	}



	/* BKL: RACE HERE - LEAK */

	/* We should move this into the uart_state structure and kill off

	   this whole complexity */

	if (!state->info) {

		state->info = kzalloc(sizeof(struct uart_info), GFP_KERNEL);

		if (state->info) {

			init_waitqueue_head(&state->info->port.open_wait);

			init_waitqueue_head(&state->info->delta_msr_wait);



			/*

			 * Link the info into the other structures.

			 */

			state->port->info = state->info;



			tasklet_init(&state->info->tlet, uart_tasklet_action,

				     (unsigned long)state);

		} else {

			ret = -ENOMEM;

			goto err_unlock;

		}

	}

	return state;



 err_unlock:
@@ -1641,9 +1621,10 @@ static int uart_open(struct tty_struct *tty, struct file *filp) 
	 * Any failures from here onwards should not touch the count.

	 */

	tty->driver_data = state;

	state->port->info = &state->info;

	tty->low_latency = (state->port->flags & UPF_LOW_LATENCY) ? 1 : 0;

	tty->alt_speed = 0;

	state->info->port.tty = tty;

	state->info.port.tty = tty;



	/*

	 * If the port is in the middle of closing, bail out now.
@@ -1676,8 +1657,8 @@ static int uart_open(struct tty_struct *tty, struct file *filp) 
	/*

	 * If this is the first open to succeed, adjust things to suit.

	 */

	if (retval == 0 && !(state->info->flags & UIF_NORMAL_ACTIVE)) {

		state->info->flags |= UIF_NORMAL_ACTIVE;

	if (retval == 0 && !(state->info.flags & UIF_NORMAL_ACTIVE)) {

		state->info.flags |= UIF_NORMAL_ACTIVE;



		uart_update_termios(state);

	}
@@ -2028,11 +2009,11 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port) 
	}

	port->suspended = 1;



	if (state->info && state->info->flags & UIF_INITIALIZED) {

	if (state->info.flags & UIF_INITIALIZED) {

		const struct uart_ops *ops = port->ops;

		int tries;



		state->info->flags = (state->info->flags & ~UIF_INITIALIZED)

		state->info.flags = (state->info.flags & ~UIF_INITIALIZED)

				     | UIF_SUSPENDED;



		spin_lock_irq(&port->lock);
@@ -2107,15 +2088,15 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port) 
		/*

		 * If that's unset, use the tty termios setting.

		 */

		if (state->info && state->info->port.tty && termios.c_cflag == 0)

			termios = *state->info->port.tty->termios;

		if (state->info.port.tty && termios.c_cflag == 0)

			termios = *state->info.port.tty->termios;



		uart_change_pm(state, 0);

		port->ops->set_termios(port, &termios, NULL);

		console_start(port->cons);

	}



	if (state->info && state->info->flags & UIF_SUSPENDED) {

	if (state->info.flags & UIF_SUSPENDED) {

		const struct uart_ops *ops = port->ops;

		int ret;
@@ -2130,7 +2111,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port) 
			ops->set_mctrl(port, port->mctrl);

			ops->start_tx(port);

			spin_unlock_irq(&port->lock);

			state->info->flags |= UIF_INITIALIZED;

			state->info.flags |= UIF_INITIALIZED;

		} else {

			/*

			 * Failed to resume - maybe hardware went away?
@@ -2140,7 +2121,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port) 
			uart_shutdown(state);

		}



		state->info->flags &= ~UIF_SUSPENDED;

		state->info.flags &= ~UIF_SUSPENDED;

	}



	mutex_unlock(&state->mutex);
@@ -2383,8 +2364,12 @@ int uart_register_driver(struct uart_driver *drv) 


		state->close_delay     = 500;	/* .5 seconds */

		state->closing_wait    = 30000;	/* 30 seconds */



		mutex_init(&state->mutex);



		tty_port_init(&state->info.port);

		init_waitqueue_head(&state->info.delta_msr_wait);

		tasklet_init(&state->info.tlet, uart_tasklet_action,

			     (unsigned long)state);

	}



	retval = tty_register_driver(normal);
@@ -2455,7 +2440,7 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port) 
	state->pm_state = -1;



	port->cons = drv->cons;

	port->info = state->info;

	port->info = &state->info;



	/*

	 * If this port is a console, then the spinlock is already
@@ -2527,17 +2512,10 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port) 
	 */

	tty_unregister_device(drv->tty_driver, port->line);



	info = state->info;

	info = &state->info;

	if (info && info->port.tty)

		tty_vhangup(info->port.tty);



	/*

	 * All users of this port should now be disconnected from

	 * this driver, and the port shut down.  We should be the

	 * only thread fiddling with this port from now on.

	 */

	state->info = NULL;



	/*

	 * Free the port IO and memory resources, if any.

	 */

include/linux/serial_core.h

+34 −28
Original line number Diff line number Diff line
@@ -315,36 +315,14 @@ struct uart_port { 
	void			*private_data;		/* generic platform data pointer */

};



/*

 * This is the state information which is persistent across opens.

 * The low level driver must not to touch any elements contained

 * within.

 */

struct uart_state {

	unsigned int		close_delay;		/* msec */

	unsigned int		closing_wait;		/* msec */



#define USF_CLOSING_WAIT_INF	(0)

#define USF_CLOSING_WAIT_NONE	(~0U)



	int			count;

	int			pm_state;

	struct uart_info	*info;

	struct uart_port	*port;



	struct mutex		mutex;

};



#define UART_XMIT_SIZE	PAGE_SIZE



typedef unsigned int __bitwise__ uif_t;



/*

 * This is the state information which is only valid when the port

 * is open; it may be freed by the core driver once the device has

 * is open; it may be cleared the core driver once the device has

 * been closed.  Either the low level driver or the core can modify

 * stuff here.

 */

typedef unsigned int __bitwise__ uif_t;



struct uart_info {

	struct tty_port		port;

	struct circ_buf		xmit;
@@ -366,6 +344,29 @@ struct uart_info { 
	wait_queue_head_t	delta_msr_wait;

};



/*

 * This is the state information which is persistent across opens.

 * The low level driver must not to touch any elements contained

 * within.

 */

struct uart_state {

	unsigned int		close_delay;		/* msec */

	unsigned int		closing_wait;		/* msec */



#define USF_CLOSING_WAIT_INF	(0)

#define USF_CLOSING_WAIT_NONE	(~0U)



	int			count;

	int			pm_state;

	struct uart_info	info;

	struct uart_port	*port;



	struct mutex		mutex;

};



#define UART_XMIT_SIZE	PAGE_SIZE





/* number of characters left in xmit buffer before we ask for more */

#define WAKEUP_CHARS		256
@@ -439,8 +440,13 @@ int uart_resume_port(struct uart_driver *reg, struct uart_port *port); 
#define uart_circ_chars_free(circ)	\

	(CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))



#define uart_tx_stopped(portp)		\

	((portp)->info->port.tty->stopped || (portp)->info->port.tty->hw_stopped)

static inline int uart_tx_stopped(struct uart_port *port)

{

	struct tty_struct *tty = port->info->port.tty;

	if(tty->stopped || tty->hw_stopped)

		return 1;

	return 0;

}



/*

 * The following are helper functions for the low level drivers.
@@ -451,7 +457,7 @@ uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) 
#ifdef SUPPORT_SYSRQ

	if (port->sysrq) {

		if (ch && time_before(jiffies, port->sysrq)) {

			handle_sysrq(ch, port->info ? port->info->port.tty : NULL);

			handle_sysrq(ch, port->info->port.tty);

			port->sysrq = 0;

			return 1;

		}