tty: Minor tidyups and document fixes for n_tty (17b82060) · Commits · e / devices / android_kernel_fairphone_FP3

drivers/char/n_tty.c

+37 −11

Original line number	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)
		{
		/* tty->read_cnt is not read locked ? */
		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)
		{
		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
		* @tty; tty device
		*
		* Check whether to call the driver.unthrottle function.
		* 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.
		* Check whether to call the driver unthrottle functions
		*
		* Can sleep, may be called under the atomic_read_lock mutex but
		* this is not guaranteed.
		*/

		static void check_unthrottle(struct tty_struct *tty)
		{
		if (tty->count)
		@@ -158,6 +166,8 @@ static void check_unthrottle(struct tty_struct *tty)
		* Reset the read buffer counters, clear the flags,
		* and make sure the driver is unthrottled. Called
		* 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)
		{
		@@ -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
		* 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)
		@@ -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
		* at this instant in time.
		*
		* Locking: read_lock
		*/

		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
		* 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)
		@@ -422,6 +436,12 @@ static void echo_char(unsigned char c, struct tty_struct *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)
		{
		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
		* present in the stream from the driver layer. Handles the complexities
		* 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)
		@@ -447,6 +469,7 @@ static void eraser(unsigned char c, struct tty_struct *tty)
		int head, seen_alnums, cnt;
		unsigned long flags;

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

		seen_alnums = 0;
		/* FIXME: Locking ?? */
		while (tty->read_head != tty->canon_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
		* settings and character used. Called from the driver receive_buf
		* path so serialized.
		*
		* Locking: ctrl_lock, read_lock (both via flush buffer)
		*/

		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
		* guaranteed that this function will not be re-entered or in progress
		* when the ldisc is closed.
		*
		* Locking: Caller holds tty->termios_mutex
		*/

		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:

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

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

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