TTY: pdc_cons, fix regression in close

The test in pdc_console_tty_close '!tty->count' was always wrong
because tty->count is decremented after tty->ops->close is called and
thus can never be zero. Hence the 'then' branch was never executed and
the timer never deleted.

This did not matter until commit 5dd5bc40f3b6 ("TTY: pdc_cons, use
tty_port").  There we needed to set TTY in tty_port to NULL, but this
never happened due to the bug above.

So change the test to really trigger at the last close by changing the
condition to 'tty->count == 1'.

Well, the driver should not touch tty->count at all.  It should use
tty_port->count and count open count there itself.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-and-tested-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/parisc/kernel/pdc_cons.c b/arch/parisc/kernel/pdc_cons.c
index 4f004596a6e7ad920674fb14780c668fe015b965..0b3393381a81261209d8b0fac80d20b6db7654c2 100644 (file)
--- a/arch/parisc/kernel/pdc_cons.c
+++ b/arch/parisc/kernel/pdc_cons.c
@@ -104,7 +104,7 @@ static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
 
 static void pdc_console_tty_close(struct tty_struct *tty, struct file *filp)
 {
-       if (!tty->count) {
+       if (tty->count == 1) {
                del_timer_sync(&pdc_console_timer);
                tty_port_tty_set(&tty_port, NULL);
        }