s390/3215: fix tty output containing tabs

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@wowway.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files 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);