[3.16.y-ckt stable] Patch "s390/3215: fix tty output containing tabs" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    s390/3215: fix tty output containing tabs

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt4.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From fbf62d837f1c278f8e367c92d740f3d51bc98166 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <schwidefsky at de.ibm.com>
Date: Wed, 13 Aug 2014 12:01:30 +0200
Subject: s390/3215: fix tty output containing tabs

commit e512d56c799517f33b301d81e9a5e0ebf30c2d1e upstream.

git commit 37f81fa1f63ad38e16125526bb2769ae0ea8d332
"n_tty: do O_ONLCR translation as a single write"
surfaced a bug in the 3215 device driver. In combination this
broke tab expansion for tty ouput.

The cause is an asymmetry in the behaviour of tty3215_ops->write
vs tty3215_ops->put_char. The put_char function scans for '\t'
but the write function does not.

As the driver has logic for the '\t' expansion remove XTABS
from c_oflag of the initial termios as well.

Reported-by: Stephen Powell <zlinuxman at wowway.com>
Signed-off-by: Martin Schwidefsky <schwidefsky at de.ibm.com>
Cc: Ben Hutchings <ben at decadent.org.uk>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/s390/char/con3215.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index a6d47e5eee9e..c43aca69fb30 100644
--- a/drivers/s390/char/con3215.c
+++ b/drivers/s390/char/con3215.c
@@ -1035,12 +1035,26 @@ static int tty3215_write(struct tty_struct * tty,
 			 const unsigned char *buf, int count)
 {
 	struct raw3215_info *raw;
+	int i, written;

 	if (!tty)
 		return 0;
 	raw = (struct raw3215_info *) tty->driver_data;
-	raw3215_write(raw, buf, count);
-	return count;
+	written = count;
+	while (count > 0) {
+		for (i = 0; i < count; i++)
+			if (buf[i] == '\t' || buf[i] == '\n')
+				break;
+		raw3215_write(raw, buf, i);
+		count -= i;
+		buf += i;
+		if (count > 0) {
+			raw3215_putchar(raw, *buf);
+			count--;
+			buf++;
+		}
+	}
+	return written;
 }

 /*
@@ -1188,7 +1202,7 @@ static int __init tty3215_init(void)
 	driver->subtype = SYSTEM_TYPE_TTY;
 	driver->init_termios = tty_std_termios;
 	driver->init_termios.c_iflag = IGNBRK | IGNPAR;
-	driver->init_termios.c_oflag = ONLCR | XTABS;
+	driver->init_termios.c_oflag = ONLCR;
 	driver->init_termios.c_lflag = ISIG;
 	driver->flags = TTY_DRIVER_REAL_RAW;
 	tty_set_operations(driver, &tty3215_ops);
--
2.1.4