From f751928e0ddf54ea4fe5546f35e99efc5b5d9938 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Fri, 2 Jan 2009 13:49:21 +0000 Subject: [PATCH] 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: Alan Cox Signed-off-by: Linus Torvalds --- drivers/serial/jsm/jsm_tty.c | 2 +- drivers/serial/serial_core.c | 144 +++++++++++++++-------------------- include/linux/serial_core.h | 62 ++++++++------- 3 files changed, 96 insertions(+), 112 deletions(-) diff --git a/drivers/serial/jsm/jsm_tty.c b/drivers/serial/jsm/jsm_tty.c index a697914ae3d..3547558d2ca 100644 --- a/drivers/serial/jsm/jsm_tty.c +++ b/drivers/serial/jsm/jsm_tty.c @@ -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); diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 874786a11fe..daeba1c52c8 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -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. */ diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index feb3b939ec4..2395969faa0 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -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; } -- 2.41.0