Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[mv-sheeva.git] / drivers / char / tty_ldisc.c

diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c
index 913aa8d3f1c5d1d211934791d0a0a44ccc4e7feb..acd76b767d4c10aac5b540e31a1cd2dddf3c8436 100644 (file)
--- a/drivers/char/tty_ldisc.c
+++ b/drivers/char/tty_ldisc.c
@@ -21,7 +21,6 @@
 #include <linux/proc_fs.h>
 #include <linux/init.h>
 #include <linux/module.h>
-#include <linux/smp_lock.h>
 #include <linux/device.h>
 #include <linux/wait.h>
 #include <linux/bitops.h>
@@ -791,17 +790,20 @@ void tty_ldisc_hangup(struct tty_struct *tty)
         * N_TTY.
         */
        if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
-               /* Avoid racing set_ldisc */
+               /* Avoid racing set_ldisc or tty_ldisc_release */
                mutex_lock(&tty->ldisc_mutex);
-               /* Switch back to N_TTY */
-               tty_ldisc_halt(tty);
-               tty_ldisc_wait_idle(tty);
-               tty_ldisc_reinit(tty);
-               /* At this point we have a closed ldisc and we want to
-                  reopen it. We could defer this to the next open but
-                  it means auditing a lot of other paths so this is a FIXME */
-               WARN_ON(tty_ldisc_open(tty, tty->ldisc));
-               tty_ldisc_enable(tty);
+               if (tty->ldisc) {       /* Not yet closed */
+                       /* Switch back to N_TTY */
+                       tty_ldisc_halt(tty);
+                       tty_ldisc_wait_idle(tty);
+                       tty_ldisc_reinit(tty);
+                       /* At this point we have a closed ldisc and we want to
+                          reopen it. We could defer this to the next open but
+                          it means auditing a lot of other paths so this is
+                          a FIXME */
+                       WARN_ON(tty_ldisc_open(tty, tty->ldisc));
+                       tty_ldisc_enable(tty);
+               }
                mutex_unlock(&tty->ldisc_mutex);
                tty_reset_termios(tty);
        }
@@ -866,6 +868,7 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty)
 
        tty_ldisc_wait_idle(tty);
 
+       mutex_lock(&tty->ldisc_mutex);
        /*
         * Now kill off the ldisc
         */
@@ -876,6 +879,7 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty)
 
        /* Ensure the next open requests the N_TTY ldisc */
        tty_set_termios_ldisc(tty, N_TTY);
+       mutex_unlock(&tty->ldisc_mutex);
 
        /* This will need doing differently if we need to lock */
        if (o_tty)