Commit b3868e20 authored Oct 14, 2015 by Peter Hurley Committed by Greg Kroah-Hartman Oct 17, 2015

n_tty: Remove reader wakeups for TTY_BREAK/TTY_PARITY chars



Waking the reader immediately upon receipt of TTY_BREAK or TTY_PARITY
chars has no effect on the outcome of read():
1. Only non-canonical/EXTPROC mode applies since canonical mode
   will not return data until a line termination is received anyway
2. EXTPROC mode - the reader will always be woken by the input worker
3. Non-canonical modes
   a. MIN == 0, TIME == 0
   b. MIN == 0, TIME > 0
   c. MIN > 0, TIME > 0
      minimum_to_wake is always 1 in these modes so the reader will always
      be woken by the input worker
   d. MIN > 0, TIME == 0
      although the reader will not be woken by the input worker unless the
      minimum data is received, the reader would not otherwise have
      returned the received data

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 4bd01622

drivers/tty/n_tty.c

+0 −4

Original line number	Diff line number	Diff line
		@@ -1179,8 +1179,6 @@ static void n_tty_receive_break(struct tty_struct *tty)
		put_tty_queue('\0', ldata);
		}
		put_tty_queue('\0', ldata);
		if (waitqueue_active(&tty->read_wait))
		wake_up_interruptible_poll(&tty->read_wait, POLLIN);
		}

		/**
		@@ -1237,8 +1235,6 @@ static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
		put_tty_queue('\0', ldata);
		} else
		put_tty_queue(c, ldata);
		if (waitqueue_active(&tty->read_wait))
		wake_up_interruptible_poll(&tty->read_wait, POLLIN);
		}

		static void