From b3868e20f4ce21bb83c7a81bc50664d6a63596a8 Mon Sep 17 00:00:00 2001
From: Peter Hurley <peter@hurleysoftware.com>
Date: Wed, 14 Oct 2015 07:52:27 -0400
Subject: [PATCH] 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>
---
drivers/tty/n_tty.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index b09023b071696..ff728d32cb530 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -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