diff options
Diffstat (limited to 'drivers/tty/tty_io.c')
| -rw-r--r-- | drivers/tty/tty_io.c | 912 |
1 files changed, 447 insertions, 465 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 6616d4a0d41d..a4cfd254fda2 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -158,14 +158,13 @@ static int tty_fasync(int fd, struct file *filp, int on); static void release_tty(struct tty_struct *tty, int idx); /** - * free_tty_struct - free a disused tty - * @tty: tty struct to free + * free_tty_struct - free a disused tty + * @tty: tty struct to free * - * Free the write buffers, tty queue and tty memory itself. + * Free the write buffers, tty queue and tty memory itself. * - * Locking: none. Must be called after tty is definitely unused + * Locking: none. Must be called after tty is definitely unused */ - static void free_tty_struct(struct tty_struct *tty) { tty_ldisc_deinit(tty); @@ -206,8 +205,9 @@ void tty_add_file(struct tty_struct *tty, struct file *file) spin_unlock(&tty->files_lock); } -/* +/** * tty_free_file - free file->private_data + * @file: to free private_data of * * This shall be used only for fail path handling when tty_add_file was not * called yet. @@ -233,15 +233,14 @@ static void tty_del_file(struct file *file) } /** - * tty_name - return tty naming - * @tty: tty structure + * tty_name - return tty naming + * @tty: tty structure * - * Convert a tty structure into a name. The name reflects the kernel - * naming policy and if udev is in use may not reflect user space + * Convert a tty structure into a name. The name reflects the kernel naming + * policy and if udev is in use may not reflect user space * - * Locking: none + * Locking: none */ - const char *tty_name(const struct tty_struct *tty) { if (!tty) /* Hmm. NULL pointer. That's fun. */ @@ -303,16 +302,15 @@ static int check_tty_count(struct tty_struct *tty, const char *routine) } /** - * get_tty_driver - find device of a tty - * @device: device identifier - * @index: returns the index of the tty + * get_tty_driver - find device of a tty + * @device: device identifier + * @index: returns the index of the tty * - * This routine returns a tty driver structure, given a device number - * and also passes back the index number. + * This routine returns a tty driver structure, given a device number and also + * passes back the index number. * - * Locking: caller must hold tty_mutex + * Locking: caller must hold tty_mutex */ - static struct tty_driver *get_tty_driver(dev_t device, int *index) { struct tty_driver *p; @@ -329,17 +327,17 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index) } /** - * tty_dev_name_to_number - return dev_t for device name - * @name: user space name of device under /dev - * @number: pointer to dev_t that this function will populate + * tty_dev_name_to_number - return dev_t for device name + * @name: user space name of device under /dev + * @number: pointer to dev_t that this function will populate * - * This function converts device names like ttyS0 or ttyUSB1 into dev_t - * like (4, 64) or (188, 1). If no corresponding driver is registered then - * the function returns -ENODEV. + * This function converts device names like ttyS0 or ttyUSB1 into dev_t like + * (4, 64) or (188, 1). If no corresponding driver is registered then the + * function returns -%ENODEV. * - * Locking: this acquires tty_mutex to protect the tty_drivers list from - * being modified while we are traversing it, and makes sure to - * release it before exiting. + * Locking: this acquires tty_mutex to protect the tty_drivers list from + * being modified while we are traversing it, and makes sure to + * release it before exiting. */ int tty_dev_name_to_number(const char *name, dev_t *number) { @@ -381,13 +379,12 @@ EXPORT_SYMBOL_GPL(tty_dev_name_to_number); #ifdef CONFIG_CONSOLE_POLL /** - * tty_find_polling_driver - find device of a polled tty - * @name: name string to match - * @line: pointer to resulting tty line nr + * tty_find_polling_driver - find device of a polled tty + * @name: name string to match + * @line: pointer to resulting tty line nr * - * This routine returns a tty driver structure, given a name - * and the condition that the tty driver is capable of polled - * operation. + * This routine returns a tty driver structure, given a name and the condition + * that the tty driver is capable of polled operation. */ struct tty_driver *tty_find_polling_driver(char *name, int *line) { @@ -515,14 +512,13 @@ static DEFINE_SPINLOCK(redirect_lock); static struct file *redirect; /** - * tty_wakeup - request more data - * @tty: terminal + * tty_wakeup - request more data + * @tty: terminal * - * Internal and external helper for wakeups of tty. This function - * informs the line discipline if present that the driver is ready - * to receive more output data. + * Internal and external helper for wakeups of tty. This function informs the + * line discipline if present that the driver is ready to receive more output + * data. */ - void tty_wakeup(struct tty_struct *tty) { struct tty_ldisc *ld; @@ -540,11 +536,11 @@ void tty_wakeup(struct tty_struct *tty) EXPORT_SYMBOL_GPL(tty_wakeup); /** - * tty_release_redirect - Release a redirect on a pty if present - * @tty: tty device + * tty_release_redirect - Release a redirect on a pty if present + * @tty: tty device * - * This is available to the pty code so if the master closes, if the - * slave is a redirect it can release the redirect. + * This is available to the pty code so if the master closes, if the slave is a + * redirect it can release the redirect. */ static struct file *tty_release_redirect(struct tty_struct *tty) { @@ -561,27 +557,29 @@ static struct file *tty_release_redirect(struct tty_struct *tty) } /** - * __tty_hangup - actual handler for hangup events - * @tty: tty device - * @exit_session: if non-zero, signal all foreground group processes + * __tty_hangup - actual handler for hangup events + * @tty: tty device + * @exit_session: if non-zero, signal all foreground group processes + * + * This can be called by a "kworker" kernel thread. That is process synchronous + * but doesn't hold any locks, so we need to make sure we have the appropriate + * locks for what we're doing. + * + * The hangup event clears any pending redirections onto the hung up device. It + * ensures future writes will error and it does the needed line discipline + * hangup and signal delivery. The tty object itself remains intact. + * + * Locking: + * * BTM * - * This can be called by a "kworker" kernel thread. That is process - * synchronous but doesn't hold any locks, so we need to make sure we - * have the appropriate locks for what we're doing. + * * redirect lock for undoing redirection + * * file list lock for manipulating list of ttys + * * tty_ldiscs_lock from called functions + * * termios_rwsem resetting termios data + * * tasklist_lock to walk task list for hangup event * - * The hangup event clears any pending redirections onto the hung up - * device. It ensures future writes will error and it does the needed - * line discipline hangup and signal delivery. The tty object itself - * remains intact. + * * ->siglock to protect ->signal/->sighand * - * Locking: - * BTM - * redirect lock for undoing redirection - * file list lock for manipulating list of ttys - * tty_ldiscs_lock from called functions - * termios_rwsem resetting termios data - * tasklist_lock to walk task list for hangup event - * ->siglock to protect ->signal/->sighand */ static void __tty_hangup(struct tty_struct *tty, int exit_session) { @@ -682,13 +680,12 @@ static void do_tty_hangup(struct work_struct *work) } /** - * tty_hangup - trigger a hangup event - * @tty: tty to hangup + * tty_hangup - trigger a hangup event + * @tty: tty to hangup * - * A carrier loss (virtual or otherwise) has occurred on this like - * schedule a hangup sequence to run after this event. + * A carrier loss (virtual or otherwise) has occurred on @tty. Schedule a + * hangup sequence to run after this event. */ - void tty_hangup(struct tty_struct *tty) { tty_debug_hangup(tty, "hangup\n"); @@ -697,14 +694,13 @@ void tty_hangup(struct tty_struct *tty) EXPORT_SYMBOL(tty_hangup); /** - * tty_vhangup - process vhangup - * @tty: tty to hangup + * tty_vhangup - process vhangup + * @tty: tty to hangup * - * The user has asked via system call for the terminal to be hung up. - * We do this synchronously so that when the syscall returns the process - * is complete. That guarantee is necessary for security reasons. + * The user has asked via system call for the terminal to be hung up. We do + * this synchronously so that when the syscall returns the process is complete. + * That guarantee is necessary for security reasons. */ - void tty_vhangup(struct tty_struct *tty) { tty_debug_hangup(tty, "vhangup\n"); @@ -714,11 +710,10 @@ EXPORT_SYMBOL(tty_vhangup); /** - * tty_vhangup_self - process vhangup for own ctty + * tty_vhangup_self - process vhangup for own ctty * - * Perform a vhangup on the current controlling tty + * Perform a vhangup on the current controlling tty */ - void tty_vhangup_self(void) { struct tty_struct *tty; @@ -731,16 +726,15 @@ void tty_vhangup_self(void) } /** - * tty_vhangup_session - hangup session leader exit - * @tty: tty to hangup + * tty_vhangup_session - hangup session leader exit + * @tty: tty to hangup * - * The session leader is exiting and hanging up its controlling terminal. - * Every process in the foreground process group is signalled SIGHUP. + * The session leader is exiting and hanging up its controlling terminal. + * Every process in the foreground process group is signalled %SIGHUP. * - * We do this synchronously so that when the syscall returns the process - * is complete. That guarantee is necessary for security reasons. + * We do this synchronously so that when the syscall returns the process is + * complete. That guarantee is necessary for security reasons. */ - void tty_vhangup_session(struct tty_struct *tty) { tty_debug_hangup(tty, "session hangup\n"); @@ -748,13 +742,11 @@ void tty_vhangup_session(struct tty_struct *tty) } /** - * tty_hung_up_p - was tty hung up - * @filp: file pointer of tty + * tty_hung_up_p - was tty hung up + * @filp: file pointer of tty * - * Return true if the tty has been subject to a vhangup or a carrier - * loss + * Return: true if the tty has been subject to a vhangup or a carrier loss */ - int tty_hung_up_p(struct file *filp) { return (filp && filp->f_op == &hung_up_tty_fops); @@ -771,20 +763,18 @@ void __stop_tty(struct tty_struct *tty) } /** - * stop_tty - propagate flow control - * @tty: tty to stop + * stop_tty - propagate flow control + * @tty: tty to stop * - * Perform flow control to the driver. May be called - * on an already stopped device and will not re-call the driver - * method. + * Perform flow control to the driver. May be called on an already stopped + * device and will not re-call the &tty_driver->stop() method. * - * This functionality is used by both the line disciplines for - * halting incoming flow and by the driver. It may therefore be - * called from any context, may be under the tty atomic_write_lock - * but not always. + * This functionality is used by both the line disciplines for halting incoming + * flow and by the driver. It may therefore be called from any context, may be + * under the tty %atomic_write_lock but not always. * - * Locking: - * flow.lock + * Locking: + * flow.lock */ void stop_tty(struct tty_struct *tty) { @@ -807,15 +797,15 @@ void __start_tty(struct tty_struct *tty) } /** - * start_tty - propagate flow control - * @tty: tty to start + * start_tty - propagate flow control + * @tty: tty to start * - * Start a tty that has been stopped if at all possible. If this - * tty was previous stopped and is now being started, the driver - * start method is invoked and the line discipline woken. + * Start a tty that has been stopped if at all possible. If @tty was previously + * stopped and is now being started, the &tty_driver->start() method is invoked + * and the line discipline woken. * - * Locking: - * flow.lock + * Locking: + * flow.lock */ void start_tty(struct tty_struct *tty) { @@ -908,18 +898,17 @@ static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, /** - * tty_read - read method for tty device files - * @iocb: kernel I/O control block - * @to: destination for the data read + * tty_read - read method for tty device files + * @iocb: kernel I/O control block + * @to: destination for the data read * - * Perform the read system call function on this terminal device. Checks - * for hung up devices before calling the line discipline method. + * Perform the read system call function on this terminal device. Checks + * for hung up devices before calling the line discipline method. * - * Locking: - * Locks the line discipline internally while needed. Multiple - * read calls may be outstanding in parallel. + * Locking: + * Locks the line discipline internally while needed. Multiple read calls + * may be outstanding in parallel. */ - static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to) { int i; @@ -1069,13 +1058,12 @@ out: * @tty: the destination tty_struct * @msg: the message to write * - * This is used for messages that need to be redirected to a specific tty. - * We don't put it into the syslog queue right now maybe in the future if - * really needed. + * This is used for messages that need to be redirected to a specific tty. We + * don't put it into the syslog queue right now maybe in the future if really + * needed. * * We must still hold the BTM and test the CLOSING flag for the moment. */ - void tty_write_message(struct tty_struct *tty, char *msg) { if (tty) { @@ -1113,18 +1101,18 @@ static ssize_t file_tty_write(struct file *file, struct kiocb *iocb, struct iov_ } /** - * tty_write - write method for tty device file - * @iocb: kernel I/O control block - * @from: iov_iter with data to write + * tty_write - write method for tty device file + * @iocb: kernel I/O control block + * @from: iov_iter with data to write * - * Write data to a tty device via the line discipline. + * Write data to a tty device via the line discipline. * - * Locking: - * Locks the line discipline as required - * Writes to the tty driver are serialized by the atomic_write_lock - * and are then processed in chunks to the device. The line - * discipline write method will not be invoked in parallel for - * each device. + * Locking: + * Locks the line discipline as required + * Writes to the tty driver are serialized by the atomic_write_lock + * and are then processed in chunks to the device. The line + * discipline write method will not be invoked in parallel for + * each device. */ static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from) { @@ -1154,14 +1142,15 @@ ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter) return tty_write(iocb, iter); } -/* - * tty_send_xchar - send priority character +/** + * tty_send_xchar - send priority character + * @tty: the tty to send to + * @ch: xchar to send * - * Send a high priority character to the tty even if stopped + * Send a high priority character to the tty even if stopped. * - * Locking: none for xchar method, write ordering for write method. + * Locking: none for xchar method, write ordering for write method. */ - int tty_send_xchar(struct tty_struct *tty, char ch) { bool was_stopped = tty->flow.stopped; @@ -1188,15 +1177,15 @@ int tty_send_xchar(struct tty_struct *tty, char ch) } /** - * pty_line_name - generate name for a pty - * @driver: the tty driver in use - * @index: the minor number - * @p: output buffer of at least 6 bytes + * pty_line_name - generate name for a pty + * @driver: the tty driver in use + * @index: the minor number + * @p: output buffer of at least 6 bytes * - * Generate a name from a driver reference and write it to the output - * buffer. + * Generate a name from a @driver reference and write it to the output buffer + * @p. * - * Locking: None + * Locking: None */ static void pty_line_name(struct tty_driver *driver, int index, char *p) { @@ -1209,15 +1198,15 @@ static void pty_line_name(struct tty_driver *driver, int index, char *p) } /** - * tty_line_name - generate name for a tty - * @driver: the tty driver in use - * @index: the minor number - * @p: output buffer of at least 7 bytes + * tty_line_name - generate name for a tty + * @driver: the tty driver in use + * @index: the minor number + * @p: output buffer of at least 7 bytes * - * Generate a name from a driver reference and write it to the output - * buffer. + * Generate a name from a @driver reference and write it to the output buffer + * @p. * - * Locking: None + * Locking: None */ static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p) { @@ -1229,15 +1218,15 @@ static ssize_t tty_line_name(struct tty_driver *driver, int index, char *p) } /** - * tty_driver_lookup_tty() - find an existing tty, if any - * @driver: the driver for the tty - * @file: file object - * @idx: the minor number + * tty_driver_lookup_tty() - find an existing tty, if any + * @driver: the driver for the tty + * @file: file object + * @idx: the minor number * - * Return the tty, if found. If not found, return NULL or ERR_PTR() if the - * driver lookup() method returns an error. + * Return: the tty, if found. If not found, return %NULL or ERR_PTR() if the + * driver lookup() method returns an error. * - * Locking: tty_mutex must be held. If the tty is found, bump the tty kref. + * Locking: tty_mutex must be held. If the tty is found, bump the tty kref. */ static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, struct file *file, int idx) @@ -1258,13 +1247,12 @@ static struct tty_struct *tty_driver_lookup_tty(struct tty_driver *driver, } /** - * tty_init_termios - helper for termios setup - * @tty: the tty to set up + * tty_init_termios - helper for termios setup + * @tty: the tty to set up * - * Initialise the termios structure for this tty. This runs under - * the tty_mutex currently so we can be relaxed about ordering. + * Initialise the termios structure for this tty. This runs under the + * %tty_mutex currently so we can be relaxed about ordering. */ - void tty_init_termios(struct tty_struct *tty) { struct ktermios *tp; @@ -1287,6 +1275,14 @@ void tty_init_termios(struct tty_struct *tty) } EXPORT_SYMBOL_GPL(tty_init_termios); +/** + * tty_standard_install - usual tty->ops->install + * @driver: the driver for the tty + * @tty: the tty + * + * If the @driver overrides @tty->ops->install, it still can call this function + * to perform the standard install operations. + */ int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty) { tty_init_termios(tty); @@ -1298,16 +1294,15 @@ int tty_standard_install(struct tty_driver *driver, struct tty_struct *tty) EXPORT_SYMBOL_GPL(tty_standard_install); /** - * tty_driver_install_tty() - install a tty entry in the driver - * @driver: the driver for the tty - * @tty: the tty + * tty_driver_install_tty() - install a tty entry in the driver + * @driver: the driver for the tty + * @tty: the tty * - * Install a tty object into the driver tables. The tty->index field - * will be set by the time this is called. This method is responsible - * for ensuring any need additional structures are allocated and - * configured. + * Install a tty object into the driver tables. The @tty->index field will be + * set by the time this is called. This method is responsible for ensuring any + * need additional structures are allocated and configured. * - * Locking: tty_mutex for now + * Locking: tty_mutex for now */ static int tty_driver_install_tty(struct tty_driver *driver, struct tty_struct *tty) @@ -1317,14 +1312,14 @@ static int tty_driver_install_tty(struct tty_driver *driver, } /** - * tty_driver_remove_tty() - remove a tty from the driver tables - * @driver: the driver for the tty - * @tty: tty to remove + * tty_driver_remove_tty() - remove a tty from the driver tables + * @driver: the driver for the tty + * @tty: tty to remove * - * Remvoe a tty object from the driver tables. The tty->index field - * will be set by the time this is called. + * Remove a tty object from the driver tables. The tty->index field will be set + * by the time this is called. * - * Locking: tty_mutex for now + * Locking: tty_mutex for now */ static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct *tty) { @@ -1335,13 +1330,13 @@ static void tty_driver_remove_tty(struct tty_driver *driver, struct tty_struct * } /** - * tty_reopen() - fast re-open of an open tty - * @tty: the tty to open + * tty_reopen() - fast re-open of an open tty + * @tty: the tty to open * - * Return 0 on success, -errno on error. - * Re-opens on master ptys are not allowed and return -EIO. + * Re-opens on master ptys are not allowed and return -%EIO. * - * Locking: Caller must hold tty_lock + * Locking: Caller must hold tty_lock + * Return: 0 on success, -errno on error. */ static int tty_reopen(struct tty_struct *tty) { @@ -1379,30 +1374,28 @@ static int tty_reopen(struct tty_struct *tty) } /** - * tty_init_dev - initialise a tty device - * @driver: tty driver we are opening a device on - * @idx: device index + * tty_init_dev - initialise a tty device + * @driver: tty driver we are opening a device on + * @idx: device index * - * Prepare a tty device. This may not be a "new" clean device but - * could also be an active device. The pty drivers require special - * handling because of this. + * Prepare a tty device. This may not be a "new" clean device but could also be + * an active device. The pty drivers require special handling because of this. * - * Locking: - * The function is called under the tty_mutex, which - * protects us from the tty struct or driver itself going away. + * Locking: + * The function is called under the tty_mutex, which protects us from the + * tty struct or driver itself going away. * - * On exit the tty device has the line discipline attached and - * a reference count of 1. If a pair was created for pty/tty use - * and the other was a pty master then it too has a reference count of 1. + * On exit the tty device has the line discipline attached and a reference + * count of 1. If a pair was created for pty/tty use and the other was a pty + * master then it too has a reference count of 1. * - * WSH 06/09/97: Rewritten to remove races and properly clean up after a - * failed open. The new code protects the open with a mutex, so it's - * really quite straightforward. The mutex locking can probably be - * relaxed for the (most common) case of reopening a tty. + * WSH 06/09/97: Rewritten to remove races and properly clean up after a failed + * open. The new code protects the open with a mutex, so it's really quite + * straightforward. The mutex locking can probably be relaxed for the (most + * common) case of reopening a tty. * - * Return: returned tty structure + * Return: new tty structure */ - struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx) { struct tty_struct *tty; @@ -1503,10 +1496,10 @@ void tty_save_termios(struct tty_struct *tty) EXPORT_SYMBOL_GPL(tty_save_termios); /** - * tty_flush_works - flush all works of a tty/pty pair - * @tty: tty device to flush works for (or either end of a pty pair) + * tty_flush_works - flush all works of a tty/pty pair + * @tty: tty device to flush works for (or either end of a pty pair) * - * Sync flush all works belonging to @tty (and the 'other' tty). + * Sync flush all works belonging to @tty (and the 'other' tty). */ static void tty_flush_works(struct tty_struct *tty) { @@ -1519,19 +1512,19 @@ static void tty_flush_works(struct tty_struct *tty) } /** - * release_one_tty - release tty structure memory - * @work: work of tty we are obliterating + * release_one_tty - release tty structure memory + * @work: work of tty we are obliterating * - * Releases memory associated with a tty structure, and clears out the - * driver table slots. This function is called when a device is no longer - * in use. It also gets called when setup of a device fails. + * Releases memory associated with a tty structure, and clears out the + * driver table slots. This function is called when a device is no longer + * in use. It also gets called when setup of a device fails. * - * Locking: - * takes the file list lock internally when working on the list - * of ttys that the driver keeps. + * Locking: + * takes the file list lock internally when working on the list of ttys + * that the driver keeps. * - * This method gets called from a work queue so that the driver private - * cleanup ops can sleep (needed for USB at least) + * This method gets called from a work queue so that the driver private + * cleanup ops can sleep (needed for USB at least) */ static void release_one_tty(struct work_struct *work) { @@ -1568,13 +1561,12 @@ static void queue_release_one_tty(struct kref *kref) } /** - * tty_kref_put - release a tty kref - * @tty: tty device + * tty_kref_put - release a tty kref + * @tty: tty device * - * Release a reference to a tty device and if need be let the kref - * layer destruct the object for us + * Release a reference to the @tty device and if need be let the kref layer + * destruct the object for us. */ - void tty_kref_put(struct tty_struct *tty) { if (tty) @@ -1583,18 +1575,17 @@ void tty_kref_put(struct tty_struct *tty) EXPORT_SYMBOL(tty_kref_put); /** - * release_tty - release tty structure memory - * @tty: tty device release - * @idx: index of the tty device release - * - * Release both @tty and a possible linked partner (think pty pair), - * and decrement the refcount of the backing module. + * release_tty - release tty structure memory + * @tty: tty device release + * @idx: index of the tty device release * - * Locking: - * tty_mutex - * takes the file list lock internally when working on the list - * of ttys that the driver keeps. + * Release both @tty and a possible linked partner (think pty pair), + * and decrement the refcount of the backing module. * + * Locking: + * tty_mutex + * takes the file list lock internally when working on the list of ttys + * that the driver keeps. */ static void release_tty(struct tty_struct *tty, int idx) { @@ -1619,12 +1610,12 @@ static void release_tty(struct tty_struct *tty, int idx) } /** - * tty_release_checks - check a tty before real release - * @tty: tty to check - * @idx: index of the tty + * tty_release_checks - check a tty before real release + * @tty: tty to check + * @idx: index of the tty * - * Performs some paranoid checking before true release of the @tty. - * This is a no-op unless TTY_PARANOIA_CHECK is defined. + * Performs some paranoid checking before true release of the @tty. This is a + * no-op unless %TTY_PARANOIA_CHECK is defined. */ static int tty_release_checks(struct tty_struct *tty, int idx) { @@ -1661,12 +1652,12 @@ static int tty_release_checks(struct tty_struct *tty, int idx) } /** - * tty_kclose - closes tty opened by tty_kopen - * @tty: tty device + * tty_kclose - closes tty opened by tty_kopen + * @tty: tty device * - * Performs the final steps to release and free a tty device. It is the - * same as tty_release_struct except that it also resets TTY_PORT_KOPENED - * flag on tty->port. + * Performs the final steps to release and free a tty device. It is the same as + * tty_release_struct() except that it also resets %TTY_PORT_KOPENED flag on + * @tty->port. */ void tty_kclose(struct tty_struct *tty) { @@ -1691,12 +1682,12 @@ void tty_kclose(struct tty_struct *tty) EXPORT_SYMBOL_GPL(tty_kclose); /** - * tty_release_struct - release a tty struct - * @tty: tty device - * @idx: index of the tty + * tty_release_struct - release a tty struct + * @tty: tty device + * @idx: index of the tty * - * Performs the final steps to release and free a tty device. It is - * roughly the reverse of tty_init_dev. + * Performs the final steps to release and free a tty device. It is roughly the + * reverse of tty_init_dev(). */ void tty_release_struct(struct tty_struct *tty, int idx) { @@ -1720,24 +1711,23 @@ void tty_release_struct(struct tty_struct *tty, int idx) EXPORT_SYMBOL_GPL(tty_release_struct); /** - * tty_release - vfs callback for close - * @inode: inode of tty - * @filp: file pointer for handle to tty + * tty_release - vfs callback for close + * @inode: inode of tty + * @filp: file pointer for handle to tty * - * Called the last time each file handle is closed that references - * this tty. There may however be several such references. + * Called the last time each file handle is closed that references this tty. + * There may however be several such references. * - * Locking: - * Takes bkl. See tty_release_dev + * Locking: + * Takes BKL. See tty_release_dev(). * - * Even releasing the tty structures is a tricky business.. We have - * to be very careful that the structures are all released at the - * same time, as interrupts might otherwise get the wrong pointers. + * Even releasing the tty structures is a tricky business. We have to be very + * careful that the structures are all released at the same time, as interrupts + * might otherwise get the wrong pointers. * * WSH 09/09/97: rewritten to avoid some nasty race conditions that could * lead to double frees or releasing memory still in use. */ - int tty_release(struct inode *inode, struct file *filp) { struct tty_struct *tty = file_tty(filp); @@ -1880,15 +1870,15 @@ int tty_release(struct inode *inode, struct file *filp) } /** - * tty_open_current_tty - get locked tty of current task - * @device: device number - * @filp: file pointer to tty - * @return: locked tty of the current task iff @device is /dev/tty + * tty_open_current_tty - get locked tty of current task + * @device: device number + * @filp: file pointer to tty + * @return: locked tty of the current task iff @device is /dev/tty * - * Performs a re-open of the current task's controlling tty. + * Performs a re-open of the current task's controlling tty. * - * We cannot return driver and index like for the other nodes because - * devpts will not work then. It expects inodes to be from devpts FS. + * We cannot return driver and index like for the other nodes because devpts + * will not work then. It expects inodes to be from devpts FS. */ static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp) { @@ -1916,16 +1906,17 @@ static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp) } /** - * tty_lookup_driver - lookup a tty driver for a given device file - * @device: device number - * @filp: file pointer to tty - * @index: index for the device in the @return driver - * @return: driver for this inode (with increased refcount) + * tty_lookup_driver - lookup a tty driver for a given device file + * @device: device number + * @filp: file pointer to tty + * @index: index for the device in the @return driver * - * If @return is not erroneous, the caller is responsible to decrement the - * refcount by tty_driver_kref_put. + * If returned value is not erroneous, the caller is responsible to decrement + * the refcount by tty_driver_kref_put(). * - * Locking: tty_mutex protects get_tty_driver + * Locking: %tty_mutex protects get_tty_driver() + * + * Return: driver for this inode (with increased refcount) */ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp, int *index) @@ -2001,19 +1992,18 @@ out: } /** - * tty_kopen_exclusive - open a tty device for kernel - * @device: dev_t of device to open + * tty_kopen_exclusive - open a tty device for kernel + * @device: dev_t of device to open * - * Opens tty exclusively for kernel. Performs the driver lookup, - * makes sure it's not already opened and performs the first-time - * tty initialization. + * Opens tty exclusively for kernel. Performs the driver lookup, makes sure + * it's not already opened and performs the first-time tty initialization. * - * Returns the locked initialized &tty_struct + * Claims the global %tty_mutex to serialize: + * * concurrent first-time tty initialization + * * concurrent tty driver removal w/ lookup + * * concurrent tty removal from driver table * - * Claims the global tty_mutex to serialize: - * - concurrent first-time tty initialization - * - concurrent tty driver removal w/ lookup - * - concurrent tty removal from driver table + * Return: the locked initialized &tty_struct */ struct tty_struct *tty_kopen_exclusive(dev_t device) { @@ -2022,13 +2012,13 @@ struct tty_struct *tty_kopen_exclusive(dev_t device) EXPORT_SYMBOL_GPL(tty_kopen_exclusive); /** - * tty_kopen_shared - open a tty device for shared in-kernel use - * @device: dev_t of device to open + * tty_kopen_shared - open a tty device for shared in-kernel use + * @device: dev_t of device to open * - * Opens an already existing tty for in-kernel use. Compared to - * tty_kopen_exclusive() above it doesn't ensure to be the only user. + * Opens an already existing tty for in-kernel use. Compared to + * tty_kopen_exclusive() above it doesn't ensure to be the only user. * - * Locking is identical to tty_kopen() above. + * Locking: identical to tty_kopen() above. */ struct tty_struct *tty_kopen_shared(dev_t device) { @@ -2037,19 +2027,20 @@ struct tty_struct *tty_kopen_shared(dev_t device) EXPORT_SYMBOL_GPL(tty_kopen_shared); /** - * tty_open_by_driver - open a tty device - * @device: dev_t of device to open - * @filp: file pointer to tty + * tty_open_by_driver - open a tty device + * @device: dev_t of device to open + * @filp: file pointer to tty + * + * Performs the driver lookup, checks for a reopen, or otherwise performs the + * first-time tty initialization. * - * Performs the driver lookup, checks for a reopen, or otherwise - * performs the first-time tty initialization. * - * Returns the locked initialized or re-opened &tty_struct + * Claims the global tty_mutex to serialize: + * * concurrent first-time tty initialization + * * concurrent tty driver removal w/ lookup + * * concurrent tty removal from driver table * - * Claims the global tty_mutex to serialize: - * - concurrent first-time tty initialization - * - concurrent tty driver removal w/ lookup - * - concurrent tty removal from driver table + * Return: the locked initialized or re-opened &tty_struct */ static struct tty_struct *tty_open_by_driver(dev_t device, struct file *filp) @@ -2104,29 +2095,28 @@ out: } /** - * tty_open - open a tty device - * @inode: inode of device file - * @filp: file pointer to tty + * tty_open - open a tty device + * @inode: inode of device file + * @filp: file pointer to tty * - * tty_open and tty_release keep up the tty count that contains the - * number of opens done on a tty. We cannot use the inode-count, as - * different inodes might point to the same tty. + * tty_open() and tty_release() keep up the tty count that contains the number + * of opens done on a tty. We cannot use the inode-count, as different inodes + * might point to the same tty. * - * Open-counting is needed for pty masters, as well as for keeping - * track of serial lines: DTR is dropped when the last close happens. - * (This is not done solely through tty->count, now. - Ted 1/27/92) + * Open-counting is needed for pty masters, as well as for keeping track of + * serial lines: DTR is dropped when the last close happens. + * (This is not done solely through tty->count, now. - Ted 1/27/92) * - * The termios state of a pty is reset on first open so that - * settings don't persist across reuse. + * The termios state of a pty is reset on the first open so that settings don't + * persist across reuse. * - * Locking: tty_mutex protects tty, tty_lookup_driver and tty_init_dev. - * tty->count should protect the rest. - * ->siglock protects ->signal/->sighand + * Locking: + * * %tty_mutex protects tty, tty_lookup_driver() and tty_init_dev(). + * * @tty->count should protect the rest. + * * ->siglock protect |