s390 tty: Prepare for put_char to return success/fail

Put the changes into the drivers first.  This will still compile/work but
produce a warning if bisected so can still be debugged

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c
index ed507594e62b..35707c04e613 100644
--- a/drivers/s390/char/sclp_vt220.c
+++ b/drivers/s390/char/sclp_vt220.c
@@ -524,11 +524,15 @@ sclp_vt220_close(struct tty_struct *tty, struct file *filp)
  * NOTE: include/linux/tty_driver.h specifies that a character should be
  * ignored if there is no room in the queue. This driver implements a different
  * semantic in that it will block when there is no more room left.
+ *
+ * FIXME: putchar can currently be called from BH and other non blocking
+ * handlers so  this semantic isn't a good idea.
  */
-static void
+static int
 sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
 {
         __sclp_vt220_write(&ch, 1, 0, 0, 1);
+        return 1;
 }
 
 /*