uml: handle errors on opening host side of consoles

If the host side of a console can't be opened, this will now produce visible
error messages.

enable_chan now returns a status and this is passed up to con_open and
ssl_open, which will complain if anything went wrong.

The default host device for the serial line driver is now a pts device rather
than a pty device since lots of hosts have LEGACY_PTYS disabled.  This had
always been failing on such hosts, but silently.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index 4bd40bb43ec2..1fb3e51108b9 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -454,7 +454,10 @@ int line_open(struct line *lines, struct tty_struct *tty)
         tty->driver_data = line;
         line->tty = tty;
 
-        enable_chan(line);
+        err = enable_chan(line);
+        if (err)
+                return err;
+
         INIT_DELAYED_WORK(&line->task, line_timer_cb);
 
         if(!line->sigio){