tty: Minor tidyups and document fixes for n_tty (17b82060) · Commits · jan.koester / Linux

drivers/char/n_tty.c

+37 −11

Original line number	Original line	Diff line number	Diff line
	@@ -99,6 +99,7 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,

	static void n_tty_set_room(struct tty_struct *tty)		static void n_tty_set_room(struct tty_struct *tty)
	{		{
			/* tty->read_cnt is not read locked ? */
	int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;		int left = N_TTY_BUF_SIZE - tty->read_cnt - 1;

	/*		/*
	@@ -121,6 +122,16 @@ static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
	}		}
	}		}

			/**
			* put_tty_queue - add character to tty
			* @c: character
			* @tty: tty device
			*
			* Add a character to the tty read_buf queue. This is done under the
			* read_lock to serialize character addition and also to protect us
			* against parallel reads or flushes
			*/

	static void put_tty_queue(unsigned char c, struct tty_struct *tty)		static void put_tty_queue(unsigned char c, struct tty_struct *tty)
	{		{
	unsigned long flags;		unsigned long flags;
	@@ -137,14 +148,11 @@ static void put_tty_queue(unsigned char c, struct tty_struct *tty)
	* check_unthrottle - allow new receive data		* check_unthrottle - allow new receive data
	* @tty; tty device		* @tty; tty device
	*		*
	* Check whether to call the driver.unthrottle function.		* Check whether to call the driver unthrottle functions
	* We test the TTY_THROTTLED bit first so that it always		*
	* indicates the current state. The decision about whether
	* it is worth allowing more input has been taken by the caller.
	* Can sleep, may be called under the atomic_read_lock mutex but		* Can sleep, may be called under the atomic_read_lock mutex but
	* this is not guaranteed.		* this is not guaranteed.
	*/		*/

	static void check_unthrottle(struct tty_struct *tty)		static void check_unthrottle(struct tty_struct *tty)
	{		{
	if (tty->count)		if (tty->count)
	@@ -158,6 +166,8 @@ static void check_unthrottle(struct tty_struct *tty)
	* Reset the read buffer counters, clear the flags,		* Reset the read buffer counters, clear the flags,
	* and make sure the driver is unthrottled. Called		* and make sure the driver is unthrottled. Called
	* from n_tty_open() and n_tty_flush_buffer().		* from n_tty_open() and n_tty_flush_buffer().
			*
			* Locking: tty_read_lock for read fields.
	*/		*/
	static void reset_buffer_flags(struct tty_struct *tty)		static void reset_buffer_flags(struct tty_struct *tty)
	{		{
	@@ -181,7 +191,7 @@ static void reset_buffer_flags(struct tty_struct *tty)
	* at hangup) or when the N_TTY line discipline internally has to		* at hangup) or when the N_TTY line discipline internally has to
	* clean the pending queue (for example some signals).		* clean the pending queue (for example some signals).
	*		*
	* Locking: ctrl_lock		* Locking: ctrl_lock, read_lock.
	*/		*/

	static void n_tty_flush_buffer(struct tty_struct *tty)		static void n_tty_flush_buffer(struct tty_struct *tty)
	@@ -207,6 +217,8 @@ static void n_tty_flush_buffer(struct tty_struct *tty)
	*		*
	* Report the number of characters buffered to be delivered to user		* Report the number of characters buffered to be delivered to user
	* at this instant in time.		* at this instant in time.
			*
			* Locking: read_lock
	*/		*/

	static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)		static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
	@@ -410,6 +422,8 @@ static ssize_t opost_block(struct tty_struct *tty,
	*		*
	* Echo user input back onto the screen. This must be called only when		* Echo user input back onto the screen. This must be called only when
	* L_ECHO(tty) is true. Called from the driver receive_buf path.		* L_ECHO(tty) is true. Called from the driver receive_buf path.
			*
			* Relies on BKL for tty column locking
	*/		*/

	static void echo_char(unsigned char c, struct tty_struct *tty)		static void echo_char(unsigned char c, struct tty_struct *tty)
	@@ -422,6 +436,12 @@ static void echo_char(unsigned char c, struct tty_struct *tty)
	opost(c, tty);		opost(c, tty);
	}		}

			/**
			* finsh_erasing - complete erase
			* @tty: tty doing the erase
			*
			* Relies on BKL for tty column locking
			*/
	static inline void finish_erasing(struct tty_struct *tty)		static inline void finish_erasing(struct tty_struct *tty)
	{		{
	if (tty->erasing) {		if (tty->erasing) {
	@@ -439,6 +459,8 @@ static inline void finish_erasing(struct tty_struct *tty)
	* Perform erase and necessary output when an erase character is		* Perform erase and necessary output when an erase character is
	* present in the stream from the driver layer. Handles the complexities		* present in the stream from the driver layer. Handles the complexities
	* of UTF-8 multibyte symbols.		* of UTF-8 multibyte symbols.
			*
			* Locking: read_lock for tty buffers, BKL for column/erasing state
	*/		*/

	static void eraser(unsigned char c, struct tty_struct *tty)		static void eraser(unsigned char c, struct tty_struct *tty)
	@@ -447,6 +469,7 @@ static void eraser(unsigned char c, struct tty_struct *tty)
	int head, seen_alnums, cnt;		int head, seen_alnums, cnt;
	unsigned long flags;		unsigned long flags;

			/* FIXME: locking needed ? */
	if (tty->read_head == tty->canon_head) {		if (tty->read_head == tty->canon_head) {
	/* opost('\a', tty); / / what do you think? */		/* opost('\a', tty); / / what do you think? */
	return;		return;
	@@ -481,6 +504,7 @@ static void eraser(unsigned char c, struct tty_struct *tty)
	}		}

	seen_alnums = 0;		seen_alnums = 0;
			/* FIXME: Locking ?? */
	while (tty->read_head != tty->canon_head) {		while (tty->read_head != tty->canon_head) {
	head = tty->read_head;		head = tty->read_head;

	@@ -583,6 +607,8 @@ static void eraser(unsigned char c, struct tty_struct *tty)
	* may caus terminal flushing to take place according to the termios		* may caus terminal flushing to take place according to the termios
	* settings and character used. Called from the driver receive_buf		* settings and character used. Called from the driver receive_buf
	* path so serialized.		* path so serialized.
			*
			* Locking: ctrl_lock, read_lock (both via flush buffer)
	*/		*/

	static inline void isig(int sig, struct tty_struct *tty, int flush)		static inline void isig(int sig, struct tty_struct *tty, int flush)
	@@ -1007,6 +1033,8 @@ int is_ignored(int sig)
	* and is protected from re-entry by the tty layer. The user is		* and is protected from re-entry by the tty layer. The user is
	* guaranteed that this function will not be re-entered or in progress		* guaranteed that this function will not be re-entered or in progress
	* when the ldisc is closed.		* when the ldisc is closed.
			*
			* Locking: Caller holds tty->termios_mutex
	*/		*/

	static void n_tty_set_termios(struct tty_struct tty, struct ktermios old)		static void n_tty_set_termios(struct tty_struct tty, struct ktermios old)
	@@ -1266,10 +1294,7 @@ static ssize_t read_chan(struct tty_struct tty, struct file file,

	do_it_again:		do_it_again:

	if (!tty->read_buf) {		BUG_ON(!tty->read_buf);
	printk(KERN_ERR "n_tty_read_chan: read_buf == NULL?!?\n");
	return -EIO;
	}

	c = job_control(tty, file);		c = job_control(tty, file);
	if (c < 0)		if (c < 0)
	@@ -1589,7 +1614,7 @@ static unsigned long inq_canon(struct tty_struct *tty)
	{		{
	int nr, head, tail;		int nr, head, tail;

	if (!tty->canon_data \|\| !tty->read_buf)		if (!tty->canon_data)
	return 0;		return 0;
	head = tty->canon_head;		head = tty->canon_head;
	tail = tty->read_tail;		tail = tty->read_tail;
	@@ -1613,6 +1638,7 @@ static int n_tty_ioctl(struct tty_struct tty, struct file file,
	case TIOCOUTQ:		case TIOCOUTQ:
	return put_user(tty_chars_in_buffer(tty), (int __user *) arg);		return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
	case TIOCINQ:		case TIOCINQ:
			/* FIXME: Locking */
	retval = tty->read_cnt;		retval = tty->read_cnt;
	if (L_ICANON(tty))		if (L_ICANON(tty))
	retval = inq_canon(tty);		retval = inq_canon(tty);