X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=drivers%2Fchar%2Ftty_ldisc.c;h=acd76b767d4c10aac5b540e31a1cd2dddf3c8436;hb=c57c3743784e08d8ceaaea928a8c84ad8b403aed;hp=913aa8d3f1c5d1d211934791d0a0a44ccc4e7feb;hpb=67fc25ef34a27dc43ce6dfc98a8b249db304d641;p=mv-sheeva.git

diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c
index 913aa8d3f1c..acd76b767d4 100644
--- 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)