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linux-next/include/linux/tty.h
Linus Torvalds f23eb2b2b2 tty: stop using "delayed_work" in the tty layer 
Using delayed-work for tty flip buffers ends up causing us to wait for
the next tick to complete some actions.  That's usually not all that
noticeable, but for certain latency-critical workloads it ends up being
totally unacceptable.

As an extreme case of this, passing a token back-and-forth over a pty
will take two ticks per iteration, so even just a thousand iterations
will take 8 seconds assuming a common 250Hz configuration.

Avoiding the whole delayed work issue brings that ping-pong test-case
down to 0.009s on my machine.

In more practical terms, this latency has been a performance problem for
things like dive computer simulators (simulating the serial interface
using the ptys) and for other environments (Alan mentions a CP/M emulator).

Reported-by: Jef Driesen <jefdriesen@telenet.be>
Acked-by: Greg KH <gregkh@suse.de>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 16:17:32 -07:00

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#ifndef _LINUX_TTY_H
#define _LINUX_TTY_H
/*
* 'tty.h' defines some structures used by tty_io.c and some defines.
*/
#ifdef __KERNEL__
#include <linux/fs.h>
#include <linux/major.h>
#include <linux/termios.h>
#include <linux/workqueue.h>
#include <linux/tty_driver.h>
#include <linux/tty_ldisc.h>
#include <linux/mutex.h>
#include <asm/system.h>
/*
* (Note: the *_driver.minor_start values 1, 64, 128, 192 are
* hardcoded at present.)
*/
#define NR_UNIX98_PTY_DEFAULT 4096 /* Default maximum for Unix98 ptys */
#define NR_UNIX98_PTY_MAX (1 << MINORBITS) /* Absolute limit */
#define NR_LDISCS 30
/* line disciplines */
#define N_TTY 0
#define N_SLIP 1
#define N_MOUSE 2
#define N_PPP 3
#define N_STRIP 4
#define N_AX25 5
#define N_X25 6 /* X.25 async */
#define N_6PACK 7
#define N_MASC 8 /* Reserved for Mobitex module <kaz@cafe.net> */
#define N_R3964 9 /* Reserved for Simatic R3964 module */
#define N_PROFIBUS_FDL 10 /* Reserved for Profibus */
#define N_IRDA 11 /* Linux IrDa - http://irda.sourceforge.net/ */
#define N_SMSBLOCK 12 /* SMS block mode - for talking to GSM data */
/* cards about SMS messages */
#define N_HDLC 13 /* synchronous HDLC */
#define N_SYNC_PPP 14 /* synchronous PPP */
#define N_HCI 15 /* Bluetooth HCI UART */
#define N_GIGASET_M101 16 /* Siemens Gigaset M101 serial DECT adapter */
#define N_SLCAN 17 /* Serial / USB serial CAN Adaptors */
#define N_PPS 18 /* Pulse per Second */
#define N_V253 19 /* Codec control over voice modem */
#define N_CAIF 20 /* CAIF protocol for talking to modems */
#define N_GSM0710 21 /* GSM 0710 Mux */
#define N_TI_WL 22 /* for TI's WL BT, FM, GPS combo chips */
/*
* This character is the same as _POSIX_VDISABLE: it cannot be used as
* a c_cc[] character, but indicates that a particular special character
* isn't in use (eg VINTR has no character etc)
*/
#define __DISABLED_CHAR '\0'
struct tty_buffer {
struct tty_buffer *next;
char *char_buf_ptr;
unsigned char *flag_buf_ptr;
int used;
int size;
int commit;
int read;
/* Data points here */
unsigned long data[0];
};
/*
* We default to dicing tty buffer allocations to this many characters
* in order to avoid multiple page allocations. We know the size of
* tty_buffer itself but it must also be taken into account that the
* the buffer is 256 byte aligned. See tty_buffer_find for the allocation
* logic this must match
*/
#define TTY_BUFFER_PAGE (((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF)
struct tty_bufhead {
struct work_struct work;
spinlock_t lock;
struct tty_buffer *head; /* Queue head */
struct tty_buffer *tail; /* Active buffer */
struct tty_buffer *free; /* Free queue head */
int memory_used; /* Buffer space used excluding
free queue */
};
/*
* When a break, frame error, or parity error happens, these codes are
* stuffed into the flags buffer.
*/
#define TTY_NORMAL 0
#define TTY_BREAK 1
#define TTY_FRAME 2
#define TTY_PARITY 3
#define TTY_OVERRUN 4
#define INTR_CHAR(tty) ((tty)->termios->c_cc[VINTR])
#define QUIT_CHAR(tty) ((tty)->termios->c_cc[VQUIT])
#define ERASE_CHAR(tty) ((tty)->termios->c_cc[VERASE])
#define KILL_CHAR(tty) ((tty)->termios->c_cc[VKILL])
#define EOF_CHAR(tty) ((tty)->termios->c_cc[VEOF])
#define TIME_CHAR(tty) ((tty)->termios->c_cc[VTIME])
#define MIN_CHAR(tty) ((tty)->termios->c_cc[VMIN])
#define SWTC_CHAR(tty) ((tty)->termios->c_cc[VSWTC])
#define START_CHAR(tty) ((tty)->termios->c_cc[VSTART])
#define STOP_CHAR(tty) ((tty)->termios->c_cc[VSTOP])
#define SUSP_CHAR(tty) ((tty)->termios->c_cc[VSUSP])
#define EOL_CHAR(tty) ((tty)->termios->c_cc[VEOL])
#define REPRINT_CHAR(tty) ((tty)->termios->c_cc[VREPRINT])
#define DISCARD_CHAR(tty) ((tty)->termios->c_cc[VDISCARD])
#define WERASE_CHAR(tty) ((tty)->termios->c_cc[VWERASE])
#define LNEXT_CHAR(tty) ((tty)->termios->c_cc[VLNEXT])
#define EOL2_CHAR(tty) ((tty)->termios->c_cc[VEOL2])
#define _I_FLAG(tty, f) ((tty)->termios->c_iflag & (f))
#define _O_FLAG(tty, f) ((tty)->termios->c_oflag & (f))
#define _C_FLAG(tty, f) ((tty)->termios->c_cflag & (f))
#define _L_FLAG(tty, f) ((tty)->termios->c_lflag & (f))
#define I_IGNBRK(tty) _I_FLAG((tty), IGNBRK)
#define I_BRKINT(tty) _I_FLAG((tty), BRKINT)
#define I_IGNPAR(tty) _I_FLAG((tty), IGNPAR)
#define I_PARMRK(tty) _I_FLAG((tty), PARMRK)
#define I_INPCK(tty) _I_FLAG((tty), INPCK)
#define I_ISTRIP(tty) _I_FLAG((tty), ISTRIP)
#define I_INLCR(tty) _I_FLAG((tty), INLCR)
#define I_IGNCR(tty) _I_FLAG((tty), IGNCR)
#define I_ICRNL(tty) _I_FLAG((tty), ICRNL)
#define I_IUCLC(tty) _I_FLAG((tty), IUCLC)
#define I_IXON(tty) _I_FLAG((tty), IXON)
#define I_IXANY(tty) _I_FLAG((tty), IXANY)
#define I_IXOFF(tty) _I_FLAG((tty), IXOFF)
#define I_IMAXBEL(tty) _I_FLAG((tty), IMAXBEL)
#define I_IUTF8(tty) _I_FLAG((tty), IUTF8)
#define O_OPOST(tty) _O_FLAG((tty), OPOST)
#define O_OLCUC(tty) _O_FLAG((tty), OLCUC)
#define O_ONLCR(tty) _O_FLAG((tty), ONLCR)
#define O_OCRNL(tty) _O_FLAG((tty), OCRNL)
#define O_ONOCR(tty) _O_FLAG((tty), ONOCR)
#define O_ONLRET(tty) _O_FLAG((tty), ONLRET)
#define O_OFILL(tty) _O_FLAG((tty), OFILL)
#define O_OFDEL(tty) _O_FLAG((tty), OFDEL)
#define O_NLDLY(tty) _O_FLAG((tty), NLDLY)
#define O_CRDLY(tty) _O_FLAG((tty), CRDLY)
#define O_TABDLY(tty) _O_FLAG((tty), TABDLY)
#define O_BSDLY(tty) _O_FLAG((tty), BSDLY)
#define O_VTDLY(tty) _O_FLAG((tty), VTDLY)
#define O_FFDLY(tty) _O_FLAG((tty), FFDLY)
#define C_BAUD(tty) _C_FLAG((tty), CBAUD)
#define C_CSIZE(tty) _C_FLAG((tty), CSIZE)
#define C_CSTOPB(tty) _C_FLAG((tty), CSTOPB)
#define C_CREAD(tty) _C_FLAG((tty), CREAD)
#define C_PARENB(tty) _C_FLAG((tty), PARENB)
#define C_PARODD(tty) _C_FLAG((tty), PARODD)
#define C_HUPCL(tty) _C_FLAG((tty), HUPCL)
#define C_CLOCAL(tty) _C_FLAG((tty), CLOCAL)
#define C_CIBAUD(tty) _C_FLAG((tty), CIBAUD)
#define C_CRTSCTS(tty) _C_FLAG((tty), CRTSCTS)
#define L_ISIG(tty) _L_FLAG((tty), ISIG)
#define L_ICANON(tty) _L_FLAG((tty), ICANON)
#define L_XCASE(tty) _L_FLAG((tty), XCASE)
#define L_ECHO(tty) _L_FLAG((tty), ECHO)
#define L_ECHOE(tty) _L_FLAG((tty), ECHOE)
#define L_ECHOK(tty) _L_FLAG((tty), ECHOK)
#define L_ECHONL(tty) _L_FLAG((tty), ECHONL)
#define L_NOFLSH(tty) _L_FLAG((tty), NOFLSH)
#define L_TOSTOP(tty) _L_FLAG((tty), TOSTOP)
#define L_ECHOCTL(tty) _L_FLAG((tty), ECHOCTL)
#define L_ECHOPRT(tty) _L_FLAG((tty), ECHOPRT)
#define L_ECHOKE(tty) _L_FLAG((tty), ECHOKE)
#define L_FLUSHO(tty) _L_FLAG((tty), FLUSHO)
#define L_PENDIN(tty) _L_FLAG((tty), PENDIN)
#define L_IEXTEN(tty) _L_FLAG((tty), IEXTEN)
#define L_EXTPROC(tty) _L_FLAG((tty), EXTPROC)
struct device;
struct signal_struct;
/*
* Port level information. Each device keeps its own port level information
* so provide a common structure for those ports wanting to use common support
* routines.
*
* The tty port has a different lifetime to the tty so must be kept apart.
* In addition be careful as tty -> port mappings are valid for the life
* of the tty object but in many cases port -> tty mappings are valid only
* until a hangup so don't use the wrong path.
*/
struct tty_port;
struct tty_port_operations {
/* Return 1 if the carrier is raised */
int (*carrier_raised)(struct tty_port *port);
/* Control the DTR line */
void (*dtr_rts)(struct tty_port *port, int raise);
/* Called when the last close completes or a hangup finishes
IFF the port was initialized. Do not use to free resources. Called
under the port mutex to serialize against activate/shutdowns */
void (*shutdown)(struct tty_port *port);
void (*drop)(struct tty_port *port);
/* Called under the port mutex from tty_port_open, serialized using
the port mutex */
/* FIXME: long term getting the tty argument *out* of this would be
good for consoles */
int (*activate)(struct tty_port *port, struct tty_struct *tty);
/* Called on the final put of a port */
void (*destruct)(struct tty_port *port);
};
struct tty_port {
struct tty_struct *tty; /* Back pointer */
const struct tty_port_operations *ops; /* Port operations */
spinlock_t lock; /* Lock protecting tty field */
int blocked_open; /* Waiting to open */
int count; /* Usage count */
wait_queue_head_t open_wait; /* Open waiters */
wait_queue_head_t close_wait; /* Close waiters */
wait_queue_head_t delta_msr_wait; /* Modem status change */
unsigned long flags; /* TTY flags ASY_*/
unsigned char console:1; /* port is a console */
struct mutex mutex; /* Locking */
struct mutex buf_mutex; /* Buffer alloc lock */
unsigned char *xmit_buf; /* Optional buffer */
unsigned int close_delay; /* Close port delay */
unsigned int closing_wait; /* Delay for output */
int drain_delay; /* Set to zero if no pure time
based drain is needed else
set to size of fifo */
struct kref kref; /* Ref counter */
};
/*
* Where all of the state associated with a tty is kept while the tty
* is open. Since the termios state should be kept even if the tty
* has been closed --- for things like the baud rate, etc --- it is
* not stored here, but rather a pointer to the real state is stored
* here. Possible the winsize structure should have the same
* treatment, but (1) the default 80x24 is usually right and (2) it's
* most often used by a windowing system, which will set the correct
* size each time the window is created or resized anyway.
* - TYT, 9/14/92
*/
struct tty_operations;
struct tty_struct {
int magic;
struct kref kref;
struct device *dev;
struct tty_driver *driver;
const struct tty_operations *ops;
int index;
/* Protects ldisc changes: Lock tty not pty */
struct mutex ldisc_mutex;
struct tty_ldisc *ldisc;
struct mutex termios_mutex;
spinlock_t ctrl_lock;
/* Termios values are protected by the termios mutex */
struct ktermios *termios, *termios_locked;
struct termiox *termiox; /* May be NULL for unsupported */
char name[64];
struct pid *pgrp; /* Protected by ctrl lock */
struct pid *session;
unsigned long flags;
int count;
struct winsize winsize; /* termios mutex */
unsigned char stopped:1, hw_stopped:1, flow_stopped:1, packet:1;
unsigned char low_latency:1, warned:1;
unsigned char ctrl_status; /* ctrl_lock */
unsigned int receive_room; /* Bytes free for queue */
struct tty_struct *link;
struct fasync_struct *fasync;
struct tty_bufhead buf; /* Locked internally */
int alt_speed; /* For magic substitution of 38400 bps */
wait_queue_head_t write_wait;
wait_queue_head_t read_wait;
struct work_struct hangup_work;
void *disc_data;
void *driver_data;
struct list_head tty_files;
#define N_TTY_BUF_SIZE 4096
/*
* The following is data for the N_TTY line discipline. For
* historical reasons, this is included in the tty structure.
* Mostly locked by the BKL.
*/
unsigned int column;
unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
unsigned char closing:1;
unsigned char echo_overrun:1;
unsigned short minimum_to_wake;
unsigned long overrun_time;
int num_overrun;
unsigned long process_char_map[256/(8*sizeof(unsigned long))];
char *read_buf;
int read_head;
int read_tail;
int read_cnt;
unsigned long read_flags[N_TTY_BUF_SIZE/(8*sizeof(unsigned long))];
unsigned char *echo_buf;
unsigned int echo_pos;
unsigned int echo_cnt;
int canon_data;
unsigned long canon_head;
unsigned int canon_column;
struct mutex atomic_read_lock;
struct mutex atomic_write_lock;
struct mutex output_lock;
struct mutex echo_lock;
unsigned char *write_buf;
int write_cnt;
spinlock_t read_lock;
/* If the tty has a pending do_SAK, queue it here - akpm */
struct work_struct SAK_work;
struct tty_port *port;
};
/* Each of a tty's open files has private_data pointing to tty_file_private */
struct tty_file_private {
struct tty_struct *tty;
struct file *file;
struct list_head list;
};
/* tty magic number */
#define TTY_MAGIC 0x5401
/*
* These bits are used in the flags field of the tty structure.
*
* So that interrupts won't be able to mess up the queues,
* copy_to_cooked must be atomic with respect to itself, as must
* tty->write. Thus, you must use the inline functions set_bit() and
* clear_bit() to make things atomic.
*/
#define TTY_THROTTLED 0 /* Call unthrottle() at threshold min */
#define TTY_IO_ERROR 1 /* Cause an I/O error (may be no ldisc too) */
#define TTY_OTHER_CLOSED 2 /* Other side (if any) has closed */
#define TTY_EXCLUSIVE 3 /* Exclusive open mode */
#define TTY_DEBUG 4 /* Debugging */
#define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */
#define TTY_PUSH 6 /* n_tty private */
#define TTY_CLOSING 7 /* ->close() in progress */
#define TTY_LDISC 9 /* Line discipline attached */
#define TTY_LDISC_CHANGING 10 /* Line discipline changing */
#define TTY_LDISC_OPEN 11 /* Line discipline is open */
#define TTY_HW_COOK_OUT 14 /* Hardware can do output cooking */
#define TTY_HW_COOK_IN 15 /* Hardware can do input cooking */
#define TTY_PTY_LOCK 16 /* pty private */
#define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */
#define TTY_HUPPED 18 /* Post driver->hangup() */
#define TTY_FLUSHING 19 /* Flushing to ldisc in progress */
#define TTY_FLUSHPENDING 20 /* Queued buffer flush pending */
#define TTY_HUPPING 21 /* ->hangup() in progress */
#define TTY_WRITE_FLUSH(tty) tty_write_flush((tty))
extern void tty_write_flush(struct tty_struct *);
extern struct ktermios tty_std_termios;
extern void console_init(void);
extern int vcs_init(void);
extern struct class *tty_class;
/**
* tty_kref_get - get a tty reference
* @tty: tty device
*
* Return a new reference to a tty object. The caller must hold
* sufficient locks/counts to ensure that their existing reference cannot
* go away
*/
static inline struct tty_struct *tty_kref_get(struct tty_struct *tty)
{
if (tty)
kref_get(&tty->kref);
return tty;
}
extern void tty_kref_put(struct tty_struct *tty);
extern int tty_paranoia_check(struct tty_struct *tty, struct inode *inode,
const char *routine);
extern char *tty_name(struct tty_struct *tty, char *buf);
extern void tty_wait_until_sent(struct tty_struct *tty, long timeout);
extern int tty_check_change(struct tty_struct *tty);
extern void stop_tty(struct tty_struct *tty);
extern void start_tty(struct tty_struct *tty);
extern int tty_register_driver(struct tty_driver *driver);
extern int tty_unregister_driver(struct tty_driver *driver);
extern struct device *tty_register_device(struct tty_driver *driver,
unsigned index, struct device *dev);
extern void tty_unregister_device(struct tty_driver *driver, unsigned index);
extern int tty_read_raw_data(struct tty_struct *tty, unsigned char *bufp,
int buflen);
extern void tty_write_message(struct tty_struct *tty, char *msg);
extern int tty_put_char(struct tty_struct *tty, unsigned char c);
extern int tty_chars_in_buffer(struct tty_struct *tty);
extern int tty_write_room(struct tty_struct *tty);
extern void tty_driver_flush_buffer(struct tty_struct *tty);
extern void tty_throttle(struct tty_struct *tty);
extern void tty_unthrottle(struct tty_struct *tty);
extern int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
extern void tty_shutdown(struct tty_struct *tty);
extern void tty_free_termios(struct tty_struct *tty);
extern int is_current_pgrp_orphaned(void);
extern struct pid *tty_get_pgrp(struct tty_struct *tty);
extern int is_ignored(int sig);
extern int tty_signal(int sig, struct tty_struct *tty);
extern void tty_hangup(struct tty_struct *tty);
extern void tty_vhangup(struct tty_struct *tty);
extern void tty_vhangup_locked(struct tty_struct *tty);
extern void tty_vhangup_self(void);
extern void tty_unhangup(struct file *filp);
extern int tty_hung_up_p(struct file *filp);
extern void do_SAK(struct tty_struct *tty);
extern void __do_SAK(struct tty_struct *tty);
extern void disassociate_ctty(int priv);
extern void no_tty(void);
extern void tty_flip_buffer_push(struct tty_struct *tty);
extern void tty_flush_to_ldisc(struct tty_struct *tty);
extern void tty_buffer_free_all(struct tty_struct *tty);
extern void tty_buffer_flush(struct tty_struct *tty);
extern void tty_buffer_init(struct tty_struct *tty);
extern speed_t tty_get_baud_rate(struct tty_struct *tty);
extern speed_t tty_termios_baud_rate(struct ktermios *termios);
extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
extern void tty_termios_encode_baud_rate(struct ktermios *termios,
speed_t ibaud, speed_t obaud);
extern void tty_encode_baud_rate(struct tty_struct *tty,
speed_t ibaud, speed_t obaud);
extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
extern int tty_termios_hw_change(struct ktermios *a, struct ktermios *b);
extern int tty_set_termios(struct tty_struct *tty, struct ktermios *kt);
extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
extern void tty_ldisc_deref(struct tty_ldisc *);
extern struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *);
extern void tty_ldisc_hangup(struct tty_struct *tty);
extern const struct file_operations tty_ldiscs_proc_fops;
extern void tty_wakeup(struct tty_struct *tty);
extern void tty_ldisc_flush(struct tty_struct *tty);
extern long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
extern int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg);
extern int tty_perform_flush(struct tty_struct *tty, unsigned long arg);
extern dev_t tty_devnum(struct tty_struct *tty);
extern void proc_clear_tty(struct task_struct *p);
extern struct tty_struct *get_current_tty(void);
extern void tty_default_fops(struct file_operations *fops);
extern struct tty_struct *alloc_tty_struct(void);
extern int tty_add_file(struct tty_struct *tty, struct file *file);
extern void free_tty_struct(struct tty_struct *tty);
extern void initialize_tty_struct(struct tty_struct *tty,
struct tty_driver *driver, int idx);
extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx,
int first_ok);
extern int tty_release(struct inode *inode, struct file *filp);
extern int tty_init_termios(struct tty_struct *tty);
extern struct tty_struct *tty_pair_get_tty(struct tty_struct *tty);
extern struct tty_struct *tty_pair_get_pty(struct tty_struct *tty);
extern struct mutex tty_mutex;
extern spinlock_t tty_files_lock;
extern void tty_write_unlock(struct tty_struct *tty);
extern int tty_write_lock(struct tty_struct *tty, int ndelay);
#define tty_is_writelocked(tty) (mutex_is_locked(&tty->atomic_write_lock))
extern void tty_port_init(struct tty_port *port);
extern int tty_port_alloc_xmit_buf(struct tty_port *port);
extern void tty_port_free_xmit_buf(struct tty_port *port);
extern void tty_port_put(struct tty_port *port);
static inline struct tty_port *tty_port_get(struct tty_port *port)
{
if (port)
kref_get(&port->kref);
return port;
}
extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
extern int tty_port_carrier_raised(struct tty_port *port);
extern void tty_port_raise_dtr_rts(struct tty_port *port);
extern void tty_port_lower_dtr_rts(struct tty_port *port);
extern void tty_port_hangup(struct tty_port *port);
extern int tty_port_block_til_ready(struct tty_port *port,
struct tty_struct *tty, struct file *filp);
extern int tty_port_close_start(struct tty_port *port,
struct tty_struct *tty, struct file *filp);
extern void tty_port_close_end(struct tty_port *port, struct tty_struct *tty);
extern void tty_port_close(struct tty_port *port,
struct tty_struct *tty, struct file *filp);
extern int tty_port_open(struct tty_port *port,
struct tty_struct *tty, struct file *filp);
static inline int tty_port_users(struct tty_port *port)
{
return port->count + port->blocked_open;
}
extern int tty_register_ldisc(int disc, struct tty_ldisc_ops *new_ldisc);
extern int tty_unregister_ldisc(int disc);
extern int tty_set_ldisc(struct tty_struct *tty, int ldisc);
extern int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty);
extern void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty);
extern void tty_ldisc_init(struct tty_struct *tty);
extern void tty_ldisc_begin(void);
/* This last one is just for the tty layer internals and shouldn't be used elsewhere */
extern void tty_ldisc_enable(struct tty_struct *tty);
/* n_tty.c */
extern struct tty_ldisc_ops tty_ldisc_N_TTY;
extern void n_tty_inherit_ops(struct tty_ldisc_ops *ops);
/* tty_audit.c */
#ifdef CONFIG_AUDIT
extern void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
size_t size);
extern void tty_audit_exit(void);
extern void tty_audit_fork(struct signal_struct *sig);
extern void tty_audit_tiocsti(struct tty_struct *tty, char ch);
extern void tty_audit_push(struct tty_struct *tty);
extern int tty_audit_push_task(struct task_struct *tsk,
uid_t loginuid, u32 sessionid);
#else
static inline void tty_audit_add_data(struct tty_struct *tty,
unsigned char *data, size_t size)
{
}
static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
{
}
static inline void tty_audit_exit(void)
{
}
static inline void tty_audit_fork(struct signal_struct *sig)
{
}
static inline void tty_audit_push(struct tty_struct *tty)
{
}
static inline int tty_audit_push_task(struct task_struct *tsk,
uid_t loginuid, u32 sessionid)
{
return 0;
}
#endif
/* tty_io.c */
extern int __init tty_init(void);
/* tty_ioctl.c */
extern int n_tty_ioctl_helper(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg);
/* serial.c */
extern void serial_console_init(void);
/* pcxx.c */
extern int pcxe_open(struct tty_struct *tty, struct file *filp);
/* vt.c */
extern int vt_ioctl(struct tty_struct *tty,
unsigned int cmd, unsigned long arg);
extern long vt_compat_ioctl(struct tty_struct *tty,
unsigned int cmd, unsigned long arg);
/* tty_mutex.c */
/* functions for preparation of BKL removal */
extern void __lockfunc tty_lock(void) __acquires(tty_lock);
extern void __lockfunc tty_unlock(void) __releases(tty_lock);
extern struct task_struct *__big_tty_mutex_owner;
#define tty_locked() (current == __big_tty_mutex_owner)
/*
* wait_event_interruptible_tty -- wait for a condition with the tty lock held
*
* The condition we are waiting for might take a long time to
* become true, or might depend on another thread taking the
* BTM. In either case, we need to drop the BTM to guarantee
* forward progress. This is a leftover from the conversion
* from the BKL and should eventually get removed as the BTM
* falls out of use.
*
* Do not use in new code.
*/
#define wait_event_interruptible_tty(wq, condition) \
({ \
int __ret = 0; \
if (!(condition)) { \
__wait_event_interruptible_tty(wq, condition, __ret); \
} \
__ret; \
})
#define __wait_event_interruptible_tty(wq, condition, ret) \
do { \
DEFINE_WAIT(__wait); \
\
for (;;) { \
prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
if (condition) \
break; \
if (!signal_pending(current)) { \
tty_unlock(); \
schedule(); \
tty_lock(); \
continue; \
} \
ret = -ERESTARTSYS; \
break; \
} \
finish_wait(&wq, &__wait); \
} while (0)
#endif /* __KERNEL__ */
#endif
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