From: Peter Hurley <peter@hurleysoftware.com>
Date: Sat, 15 Jun 2013 13:14:29 +0000 (-0400)
Subject: n_tty: Don't wait for buffer work in read() loop
X-Git-Tag: v3.12-rc1~182^2~205
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f95499c3030fe1bfad57745f2db1959c5b43dca8;p=platform%2Fkernel%2Flinux-exynos.git

n_tty: Don't wait for buffer work in read() loop

User-space read() can run concurrently with receiving from device;
waiting for receive_buf() to complete is not required.

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

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index fe1c399..a6eea30d0 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1724,7 +1724,6 @@ static inline int input_available_p(struct tty_struct *tty, int amt)
 {
 	struct n_tty_data *ldata = tty->disc_data;
 
-	tty_flush_to_ldisc(tty);
 	if (ldata->icanon && !L_EXTPROC(tty)) {
 		if (ldata->canon_head != ldata->read_tail)
 			return 1;