diff options
Diffstat (limited to 'drivers/tty/tty_port.c')
| -rw-r--r-- | drivers/tty/tty_port.c | 528 |
1 files changed, 289 insertions, 239 deletions
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c index 6b137194069f..fe67c5cb0a3f 100644 --- a/drivers/tty/tty_port.c +++ b/drivers/tty/tty_port.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * Tty port functions */ @@ -17,45 +18,71 @@ #include <linux/delay.h> #include <linux/module.h> #include <linux/serdev.h> +#include "tty.h" -static int tty_port_default_receive_buf(struct tty_port *port, - const unsigned char *p, - const unsigned char *f, size_t count) +static size_t tty_port_default_receive_buf(struct tty_port *port, const u8 *p, + const u8 *f, size_t count) { - int ret; struct tty_struct *tty; - struct tty_ldisc *disc; + struct tty_ldisc *ld; tty = READ_ONCE(port->itty); if (!tty) return 0; - disc = tty_ldisc_ref(tty); - if (!disc) + ld = tty_ldisc_ref(tty); + if (!ld) return 0; - ret = tty_ldisc_receive_buf(disc, p, (char *)f, count); + count = tty_ldisc_receive_buf(ld, p, f, count); - tty_ldisc_deref(disc); + tty_ldisc_deref(ld); - return ret; + return count; } -static void tty_port_default_wakeup(struct tty_port *port) +static void tty_port_default_lookahead_buf(struct tty_port *port, const u8 *p, + const u8 *f, size_t count) { - struct tty_struct *tty = tty_port_tty_get(port); + struct tty_struct *tty; + struct tty_ldisc *ld; - if (tty) { - tty_wakeup(tty); - tty_kref_put(tty); - } + tty = READ_ONCE(port->itty); + if (!tty) + return; + + ld = tty_ldisc_ref(tty); + if (!ld) + return; + + if (ld->ops->lookahead_buf) + ld->ops->lookahead_buf(ld->tty, p, f, count); + + tty_ldisc_deref(ld); +} + +static void tty_port_default_wakeup(struct tty_port *port) +{ + scoped_guard(tty_port_tty, port) + tty_wakeup(scoped_tty()); } -static const struct tty_port_client_operations default_client_ops = { +const struct tty_port_client_operations tty_port_default_client_ops = { .receive_buf = tty_port_default_receive_buf, + .lookahead_buf = tty_port_default_lookahead_buf, .write_wakeup = tty_port_default_wakeup, }; +EXPORT_SYMBOL_GPL(tty_port_default_client_ops); +/** + * tty_port_init - initialize tty_port + * @port: tty_port to initialize + * + * Initializes the state of struct tty_port. When a port was initialized using + * this function, one has to destroy the port by tty_port_destroy(). Either + * indirectly by using &tty_port refcounting (tty_port_put()) or directly if + * refcounting is not used. + */ void tty_port_init(struct tty_port *port) { memset(port, 0, sizeof(*port)); @@ -67,7 +94,7 @@ void tty_port_init(struct tty_port *port) spin_lock_init(&port->lock); port->close_delay = (50 * HZ) / 100; port->closing_wait = (3000 * HZ) / 100; - port->client_ops = &default_client_ops; + port->client_ops = &tty_port_default_client_ops; kref_init(&port->kref); } EXPORT_SYMBOL(tty_port_init); @@ -78,10 +105,10 @@ EXPORT_SYMBOL(tty_port_init); * @driver: tty_driver for this device * @index: index of the tty * - * Provide the tty layer wit ha link from a tty (specified by @index) to a - * tty_port (@port). Use this only if neither tty_port_register_device nor - * tty_port_install is used in the driver. If used, this has to be called before - * tty_register_driver. + * Provide the tty layer with a link from a tty (specified by @index) to a + * tty_port (@port). Use this only if neither tty_port_register_device() nor + * tty_port_install() is used in the driver. If used, this has to be called + * before tty_register_driver(). */ void tty_port_link_device(struct tty_port *port, struct tty_driver *driver, unsigned index) @@ -99,9 +126,9 @@ EXPORT_SYMBOL_GPL(tty_port_link_device); * @index: index of the tty * @device: parent if exists, otherwise NULL * - * It is the same as tty_register_device except the provided @port is linked to - * a concrete tty specified by @index. Use this or tty_port_install (or both). - * Call tty_port_link_device as a last resort. + * It is the same as tty_register_device() except the provided @port is linked + * to a concrete tty specified by @index. Use this or tty_port_install() (or + * both). Call tty_port_link_device() as a last resort. */ struct device *tty_port_register_device(struct tty_port *port, struct tty_driver *driver, unsigned index, @@ -120,9 +147,9 @@ EXPORT_SYMBOL_GPL(tty_port_register_device); * @drvdata: Driver data to be set to device. * @attr_grp: Attribute group to be set on device. * - * It is the same as tty_register_device_attr except the provided @port is - * linked to a concrete tty specified by @index. Use this or tty_port_install - * (or both). Call tty_port_link_device as a last resort. + * It is the same as tty_register_device_attr() except the provided @port is + * linked to a concrete tty specified by @index. Use this or tty_port_install() + * (or both). Call tty_port_link_device() as a last resort. */ struct device *tty_port_register_device_attr(struct tty_port *port, struct tty_driver *driver, unsigned index, @@ -140,7 +167,8 @@ EXPORT_SYMBOL_GPL(tty_port_register_device_attr); * @port: tty_port of the device * @driver: tty_driver for this device * @index: index of the tty - * @device: parent if exists, otherwise NULL + * @host: serial port hardware device + * @parent: parent if exists, otherwise NULL * @drvdata: driver data for the device * @attr_grp: attribute group for the device * @@ -149,44 +177,25 @@ EXPORT_SYMBOL_GPL(tty_port_register_device_attr); */ struct device *tty_port_register_device_attr_serdev(struct tty_port *port, struct tty_driver *driver, unsigned index, - struct device *device, void *drvdata, + struct device *host, struct device *parent, void *drvdata, const struct attribute_group **attr_grp) { struct device *dev; tty_port_link_device(port, driver, index); - dev = serdev_tty_port_register(port, device, driver, index); + dev = serdev_tty_port_register(port, host, parent, driver, index); if (PTR_ERR(dev) != -ENODEV) { /* Skip creating cdev if we registered a serdev device */ return dev; } - return tty_register_device_attr(driver, index, device, drvdata, + return tty_register_device_attr(driver, index, parent, drvdata, attr_grp); } EXPORT_SYMBOL_GPL(tty_port_register_device_attr_serdev); /** - * tty_port_register_device_serdev - register tty or serdev device - * @port: tty_port of the device - * @driver: tty_driver for this device - * @index: index of the tty - * @device: parent if exists, otherwise NULL - * - * Register a serdev or tty device depending on if the parent device has any - * defined serdev clients or not. - */ -struct device *tty_port_register_device_serdev(struct tty_port *port, - struct tty_driver *driver, unsigned index, - struct device *device) -{ - return tty_port_register_device_attr_serdev(port, driver, index, - device, NULL, NULL); -} -EXPORT_SYMBOL_GPL(tty_port_register_device_serdev); - -/** * tty_port_unregister_device - deregister a tty or serdev device * @port: tty_port of the device * @driver: tty_driver for this device @@ -212,34 +221,37 @@ EXPORT_SYMBOL_GPL(tty_port_unregister_device); int tty_port_alloc_xmit_buf(struct tty_port *port) { /* We may sleep in get_zeroed_page() */ - mutex_lock(&port->buf_mutex); - if (port->xmit_buf == NULL) - port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL); - mutex_unlock(&port->buf_mutex); + guard(mutex)(&port->buf_mutex); + + if (port->xmit_buf) + return 0; + + port->xmit_buf = (u8 *)get_zeroed_page(GFP_KERNEL); if (port->xmit_buf == NULL) return -ENOMEM; + + kfifo_init(&port->xmit_fifo, port->xmit_buf, PAGE_SIZE); + return 0; } EXPORT_SYMBOL(tty_port_alloc_xmit_buf); void tty_port_free_xmit_buf(struct tty_port *port) { - mutex_lock(&port->buf_mutex); - if (port->xmit_buf != NULL) { - free_page((unsigned long)port->xmit_buf); - port->xmit_buf = NULL; - } - mutex_unlock(&port->buf_mutex); + guard(mutex)(&port->buf_mutex); + free_page((unsigned long)port->xmit_buf); + port->xmit_buf = NULL; + INIT_KFIFO(port->xmit_fifo); } EXPORT_SYMBOL(tty_port_free_xmit_buf); /** - * tty_port_destroy -- destroy inited port - * @port: tty port to be doestroyed + * tty_port_destroy - destroy inited port + * @port: tty port to be destroyed * - * When a port was initialized using tty_port_init, one has to destroy the - * port by this function. Either indirectly by using tty_port refcounting - * (tty_port_put) or directly if refcounting is not used. + * When a port was initialized using tty_port_init(), one has to destroy the + * port by this function. Either indirectly by using &tty_port refcounting + * (tty_port_put()) or directly if refcounting is not used. */ void tty_port_destroy(struct tty_port *port) { @@ -255,8 +267,7 @@ static void tty_port_destructor(struct kref *kref) /* check if last port ref was dropped before tty release */ if (WARN_ON(port->itty)) return; - if (port->xmit_buf) - free_page((unsigned long)port->xmit_buf); + free_page((unsigned long)port->xmit_buf); tty_port_destroy(port); if (port->ops && port->ops->destruct) port->ops->destruct(port); @@ -264,6 +275,13 @@ static void tty_port_destructor(struct kref *kref) kfree(port); } +/** + * tty_port_put - drop a reference to tty_port + * @port: port to drop a reference of (can be NULL) + * + * The final put will destroy and free up the @port using + * @port->ops->destruct() hook, or using kfree() if not provided. + */ void tty_port_put(struct tty_port *port) { if (port) @@ -272,90 +290,89 @@ void tty_port_put(struct tty_port *port) EXPORT_SYMBOL(tty_port_put); /** - * tty_port_tty_get - get a tty reference - * @port: tty port + * tty_port_tty_get - get a tty reference + * @port: tty port * - * Return a refcount protected tty instance or NULL if the port is not - * associated with a tty (eg due to close or hangup) + * Return a refcount protected tty instance or %NULL if the port is not + * associated with a tty (eg due to close or hangup). */ - struct tty_struct *tty_port_tty_get(struct tty_port *port) { - unsigned long flags; - struct tty_struct *tty; - - spin_lock_irqsave(&port->lock, flags); - tty = tty_kref_get(port->tty); - spin_unlock_irqrestore(&port->lock, flags); - return tty; + guard(spinlock_irqsave)(&port->lock); + return tty_kref_get(port->tty); } EXPORT_SYMBOL(tty_port_tty_get); /** - * tty_port_tty_set - set the tty of a port - * @port: tty port - * @tty: the tty + * tty_port_tty_set - set the tty of a port + * @port: tty port + * @tty: the tty * - * Associate the port and tty pair. Manages any internal refcounts. - * Pass NULL to deassociate a port + * Associate the port and tty pair. Manages any internal refcounts. Pass %NULL + * to deassociate a port. */ - void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty) { - unsigned long flags; - - spin_lock_irqsave(&port->lock, flags); + guard(spinlock_irqsave)(&port->lock); tty_kref_put(port->tty); port->tty = tty_kref_get(tty); - spin_unlock_irqrestore(&port->lock, flags); } EXPORT_SYMBOL(tty_port_tty_set); +/** + * tty_port_shutdown - internal helper to shutdown the device + * @port: tty port to be shut down + * @tty: the associated tty + * + * It is used by tty_port_hangup() and tty_port_close(). Its task is to + * shutdown the device if it was initialized (note consoles remain + * functioning). It lowers DTR/RTS (if @tty has HUPCL set) and invokes + * @port->ops->shutdown(). + */ static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty) { - mutex_lock(&port->mutex); + guard(mutex)(&port->mutex); + if (port->console) - goto out; + return; - 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. - */ - if (tty && C_HUPCL(tty)) - tty_port_lower_dtr_rts(port); + if (!tty_port_initialized(port)) + return; - if (port->ops->shutdown) - port->ops->shutdown(port); - } -out: - mutex_unlock(&port->mutex); + tty_port_set_initialized(port, false); + /* + * Drop DTR/RTS if HUPCL is set. This causes any attached + * modem to hang up the line. + */ + if (tty && C_HUPCL(tty)) + tty_port_lower_dtr_rts(port); + + if (port->ops->shutdown) + port->ops->shutdown(port); } /** - * tty_port_hangup - hangup helper - * @port: tty port + * tty_port_hangup - hangup helper + * @port: tty port * - * Perform port level tty hangup flag and count changes. Drop the tty - * reference. + * Perform port level tty hangup flag and count changes. Drop the tty + * reference. * - * Caller holds tty lock. + * Caller holds tty lock. */ - void tty_port_hangup(struct tty_port *port) { struct tty_struct *tty; - unsigned long flags; - spin_lock_irqsave(&port->lock, flags); - port->count = 0; - tty = port->tty; - if (tty) - set_bit(TTY_IO_ERROR, &tty->flags); - port->tty = NULL; - spin_unlock_irqrestore(&port->lock, flags); - tty_port_set_active(port, 0); + scoped_guard(spinlock_irqsave, &port->lock) { + port->count = 0; + tty = port->tty; + if (tty) + set_bit(TTY_IO_ERROR, &tty->flags); + port->tty = NULL; + } + + tty_port_set_active(port, false); tty_port_shutdown(port, tty); tty_kref_put(tty); wake_up_interruptible(&port->open_wait); @@ -363,25 +380,23 @@ void tty_port_hangup(struct tty_port *port) } EXPORT_SYMBOL(tty_port_hangup); -/** - * tty_port_tty_hangup - helper to hang up a tty - * - * @port: tty port - * @check_clocal: hang only ttys with CLOCAL unset? - */ -void tty_port_tty_hangup(struct tty_port *port, bool check_clocal) +void __tty_port_tty_hangup(struct tty_port *port, bool check_clocal, bool async) { - struct tty_struct *tty = tty_port_tty_get(port); + scoped_guard(tty_port_tty, port) { + struct tty_struct *tty = scoped_tty(); - if (tty && (!check_clocal || !C_CLOCAL(tty))) - tty_hangup(tty); - tty_kref_put(tty); + if (!check_clocal || !C_CLOCAL(tty)) { + if (async) + tty_hangup(tty); + else + tty_vhangup(tty); + } + } } -EXPORT_SYMBOL_GPL(tty_port_tty_hangup); +EXPORT_SYMBOL_GPL(__tty_port_tty_hangup); /** * tty_port_tty_wakeup - helper to wake up a tty - * * @port: tty port */ void tty_port_tty_wakeup(struct tty_port *port) @@ -391,97 +406,94 @@ void tty_port_tty_wakeup(struct tty_port *port) EXPORT_SYMBOL_GPL(tty_port_tty_wakeup); /** - * tty_port_carrier_raised - carrier raised check - * @port: tty port + * tty_port_carrier_raised - carrier raised check + * @port: tty port * - * Wrapper for the carrier detect logic. For the moment this is used - * to hide some internal details. This will eventually become entirely - * internal to the tty port. + * Wrapper for the carrier detect logic. For the moment this is used + * to hide some internal details. This will eventually become entirely + * internal to the tty port. */ - -int tty_port_carrier_raised(struct tty_port *port) +bool tty_port_carrier_raised(struct tty_port *port) { if (port->ops->carrier_raised == NULL) - return 1; + return true; return port->ops->carrier_raised(port); } EXPORT_SYMBOL(tty_port_carrier_raised); /** - * tty_port_raise_dtr_rts - Raise DTR/RTS - * @port: tty port + * tty_port_raise_dtr_rts - Raise DTR/RTS + * @port: tty port * - * Wrapper for the DTR/RTS raise logic. For the moment this is used - * to hide some internal details. This will eventually become entirely - * internal to the tty port. + * Wrapper for the DTR/RTS raise logic. For the moment this is used to hide + * some internal details. This will eventually become entirely internal to the + * tty port. */ - void tty_port_raise_dtr_rts(struct tty_port *port) { if (port->ops->dtr_rts) - port->ops->dtr_rts(port, 1); + port->ops->dtr_rts(port, true); } EXPORT_SYMBOL(tty_port_raise_dtr_rts); /** - * tty_port_lower_dtr_rts - Lower DTR/RTS - * @port: tty port + * tty_port_lower_dtr_rts - Lower DTR/RTS + * @port: tty port * - * Wrapper for the DTR/RTS raise logic. For the moment this is used - * to hide some internal details. This will eventually become entirely - * internal to the tty port. + * Wrapper for the DTR/RTS raise logic. For the moment this is used to hide + * some internal details. This will eventually become entirely internal to the + * tty port. */ - void tty_port_lower_dtr_rts(struct tty_port *port) { if (port->ops->dtr_rts) - port->ops->dtr_rts(port, 0); + port->ops->dtr_rts(port, false); } EXPORT_SYMBOL(tty_port_lower_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 or NULL - * - * 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 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. - * - * Caller holds tty lock. - * - * NB: May drop and reacquire tty lock when blocking, so tty and tty_port - * may have changed state (eg., may have been hung up). + * 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 or %NULL + * + * 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 @port must implement the @port->ops->carrier_raised method if it + * can do carrier detect and the @port->ops->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. + * + * Caller holds tty lock. + * + * Note: May drop and reacquire tty lock when blocking, so @tty and @port may + * have changed state (eg., may have been hung up). */ - 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; DEFINE_WAIT(wait); /* 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 */ + * the port has just hung up or is in another error state. + */ if (tty_io_error(tty)) { - tty_port_set_active(port, 1); + tty_port_set_active(port, true); return 0; } if (filp == NULL || (filp->f_flags & O_NONBLOCK)) { /* Indicate we are open */ if (C_BAUD(tty)) tty_port_raise_dtr_rts(port); - tty_port_set_active(port, 1); + tty_port_set_active(port, true); return 0; } @@ -489,16 +501,17 @@ int tty_port_block_til_ready(struct tty_port *port, 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 */ + * carrier, but we must also wait for any close that is in progress + * before the next open may complete. + */ retval = 0; /* The port lock protects the port counts */ - spin_lock_irqsave(&port->lock, flags); - port->count--; - port->blocked_open++; - spin_unlock_irqrestore(&port->lock, flags); + scoped_guard(spinlock_irqsave, &port->lock) { + port->count--; + port->blocked_open++; + } while (1) { /* Indicate we are open */ @@ -507,7 +520,8 @@ int tty_port_block_til_ready(struct tty_port *port, prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE); /* Check for a hangup or uninitialised port. - Return accordingly */ + * Return accordingly. + */ if (tty_hung_up_p(filp) || !tty_port_initialized(port)) { if (port->flags & ASYNC_HUP_NOTIFY) retval = -EAGAIN; @@ -534,14 +548,15 @@ int tty_port_block_til_ready(struct tty_port *port, finish_wait(&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--; - spin_unlock_irqrestore(&port->lock, flags); + * we must not mess that up further. + */ + scoped_guard(spinlock_irqsave, &port->lock) { + if (!tty_hung_up_p(filp)) + port->count++; + port->blocked_open--; + } if (retval == 0) - tty_port_set_active(port, 1); + tty_port_set_active(port, true); return retval; } EXPORT_SYMBOL(tty_port_block_til_ready); @@ -560,38 +575,48 @@ static void tty_port_drain_delay(struct tty_port *port, struct tty_struct *tty) schedule_timeout_interruptible(timeout); } -/* Caller holds tty lock. */ +/** + * tty_port_close_start - helper for tty->ops->close, part 1/2 + * @port: tty_port of the device + * @tty: tty being closed + * @filp: passed file pointer + * + * Decrements and checks open count. Flushes the port if this is the last + * close. That means, dropping the data from the outpu buffer on the device and + * waiting for sending logic to finish. The rest of close handling is performed + * in tty_port_close_end(). + * + * Locking: Caller holds tty lock. + * + * Return: 1 if this is the last close, otherwise 0 + */ int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, struct file *filp) { - unsigned long flags; - if (tty_hung_up_p(filp)) return 0; - spin_lock_irqsave(&port->lock, flags); - if (tty->count == 1 && port->count != 1) { - tty_warn(tty, "%s: tty->count = 1 port count = %d\n", __func__, - port->count); - port->count = 1; - } - if (--port->count < 0) { - tty_warn(tty, "%s: bad port count (%d)\n", __func__, - port->count); - port->count = 0; - } + scoped_guard(spinlock_irqsave, &port->lock) { + if (tty->count == 1 && port->count != 1) { + tty_warn(tty, "%s: tty->count = 1 port count = %d\n", __func__, + port->count); + port->count = 1; + } + if (--port->count < 0) { + tty_warn(tty, "%s: bad port count (%d)\n", __func__, + port->count); + port->count = 0; + } - if (port->count) { - spin_unlock_irqrestore(&port->lock, flags); - return 0; + if (port->count) + return 0; } - spin_unlock_irqrestore(&port->lock, flags); tty->closing = 1; if (tty_port_initialized(port)) { /* Don't block on a stalled port, just pull the chain */ - if (tty->flow_stopped) + if (tty->flow.tco_stopped) tty_driver_flush_buffer(tty); if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE) tty_wait_until_sent(tty, port->closing_wait); @@ -606,7 +631,17 @@ int tty_port_close_start(struct tty_port *port, } EXPORT_SYMBOL(tty_port_close_start); -/* Caller holds tty lock */ +/** + * tty_port_close_end - helper for tty->ops->close, part 2/2 + * @port: tty_port of the device + * @tty: tty being closed + * + * This is a continuation of the first part: tty_port_close_start(). This + * should be called after turning off the device. It flushes the data from the + * line discipline and delays the close by @port->close_delay. + * + * Locking: Caller holds tty lock. + */ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty) { unsigned long flags; @@ -624,14 +659,22 @@ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty) wake_up_interruptible(&port->open_wait); } spin_unlock_irqrestore(&port->lock, flags); - tty_port_set_active(port, 0); + tty_port_set_active(port, false); } EXPORT_SYMBOL(tty_port_close_end); /** - * tty_port_close + * tty_port_close - generic tty->ops->close handler + * @port: tty_port of the device + * @tty: tty being closed + * @filp: passed file pointer * - * Caller holds tty lock + * It is a generic helper to be used in driver's @tty->ops->close. It wraps a + * sequence of tty_port_close_start(), tty_port_shutdown(), and + * tty_port_close_end(). The latter two are called only if this is the last + * close. See the respective functions for the details. + * + * Locking: Caller holds tty lock */ void tty_port_close(struct tty_port *port, struct tty_struct *tty, struct file *filp) @@ -639,7 +682,8 @@ void tty_port_close(struct tty_port *port, struct tty_struct *tty, if (tty_port_close_start(port, tty, filp) == 0) return; tty_port_shutdown(port, tty); - set_bit(TTY_IO_ERROR, &tty->flags); + if (!port->console) + set_bit(TTY_IO_ERROR, &tty->flags); tty_port_close_end(port, tty); tty_port_tty_set(port, NULL); } @@ -651,9 +695,9 @@ EXPORT_SYMBOL(tty_port_close); * @driver: tty_driver for this device * @tty: tty to be installed * - * It is the same as tty_standard_install except the provided @port is linked - * to a concrete tty specified by @tty. Use this or tty_port_register_device - * (or both). Call tty_port_link_device as a last resort. + * It is the same as tty_standard_install() except the provided @port is linked + * to a concrete tty specified by @tty. Use this or tty_port_register_device() + * (or both). Call tty_port_link_device() as a last resort. */ int tty_port_install(struct tty_port *port, struct tty_driver *driver, struct tty_struct *tty) @@ -664,19 +708,29 @@ int tty_port_install(struct tty_port *port, struct tty_driver *driver, EXPORT_SYMBOL_GPL(tty_port_install); /** - * tty_port_open + * tty_port_open - generic tty->ops->open handler + * @port: tty_port of the device + * @tty: tty to be opened + * @filp: passed file pointer * - * Caller holds tty lock. + * It is a generic helper to be used in driver's @tty->ops->open. It activates + * the devices using @port->ops->activate if not active already. And waits for + * the device to be ready using tty_port_block_til_ready() (e.g. raises + * DTR/CTS and waits for carrier). + * + * Note that @port->ops->shutdown is not called when @port->ops->activate + * returns an error (on the contrary, @tty->ops->close is). * - * NB: may drop and reacquire tty lock (in tty_port_block_til_ready()) so - * tty and tty_port may have changed state (eg., may be hung up now) + * Locking: Caller holds tty lock. + * + * Note: may drop and reacquire tty lock (in tty_port_block_til_ready()) so + * @tty and @port may have changed state (eg., may be hung up now). */ int tty_port_open(struct tty_port *port, struct tty_struct *tty, struct file *filp) { - spin_lock_irq(&port->lock); - ++port->count; - spin_unlock_irq(&port->lock); + scoped_guard(spinlock_irq, &port->lock) + ++port->count; tty_port_tty_set(port, tty); /* @@ -685,21 +739,17 @@ int tty_port_open(struct tty_port *port, struct tty_struct *tty, * port mutex. */ - mutex_lock(&port->mutex); - - if (!tty_port_initialized(port)) { + scoped_guard(mutex, &port->mutex) { + if (tty_port_initialized(port)) + break; clear_bit(TTY_IO_ERROR, &tty->flags); if (port->ops->activate) { int retval = port->ops->activate(port, tty); - if (retval) { - mutex_unlock(&port->mutex); + if (retval) return retval; - } } - tty_port_set_initialized(port, 1); + tty_port_set_initialized(port, true); } - mutex_unlock(&port->mutex); return tty_port_block_til_ready(port, tty, filp); } - EXPORT_SYMBOL(tty_port_open); |