X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Ftty%2Ftty_ldisc.c;h=9bee25cfa0be5e5a39cd00a2aa8e2fd57ac69096;hb=HEAD;hp=3737f55272d2c1184463edc3714f89fb2724730e;hpb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;p=kvmfornfv.git

diff --git a/kernel/drivers/tty/tty_ldisc.c b/kernel/drivers/tty/tty_ldisc.c
index 3737f5527..9bee25cfa 100644
--- a/kernel/drivers/tty/tty_ldisc.c
+++ b/kernel/drivers/tty/tty_ldisc.c
@@ -22,10 +22,7 @@
 #undef LDISC_DEBUG_HANGUP
 
 #ifdef LDISC_DEBUG_HANGUP
-#define tty_ldisc_debug(tty, f, args...) ({				       \
-	char __b[64];							       \
-	printk(KERN_DEBUG "%s: %s: " f, __func__, tty_name(tty, __b), ##args); \
-})
+#define tty_ldisc_debug(tty, f, args...)	tty_debug(tty, f, ##args)
 #else
 #define tty_ldisc_debug(tty, f, args...)
 #endif
@@ -322,7 +319,7 @@ __tty_ldisc_lock_nested(struct tty_struct *tty, unsigned long timeout)
 
 static inline void __tty_ldisc_unlock(struct tty_struct *tty)
 {
-	return ldsem_up_write(&tty->ldisc_sem);
+	ldsem_up_write(&tty->ldisc_sem);
 }
 
 static int __lockfunc
@@ -420,6 +417,10 @@ EXPORT_SYMBOL_GPL(tty_ldisc_flush);
  *	they are not on hot paths so a little discipline won't do
  *	any harm.
  *
+ *	The line discipline-related tty_struct fields are reset to
+ *	prevent the ldisc driver from re-using stale information for
+ *	the new ldisc instance.
+ *
  *	Locking: takes termios_rwsem
  */
 
@@ -428,6 +429,9 @@ static void tty_set_termios_ldisc(struct tty_struct *tty, int num)
 	down_write(&tty->termios_rwsem);
 	tty->termios.c_line = num;
 	up_write(&tty->termios_rwsem);
+
+	tty->disc_data = NULL;
+	tty->receive_room = 0;
 }
 
 /**
@@ -450,6 +454,8 @@ static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
 		ret = ld->ops->open(tty);
 		if (ret)
 			clear_bit(TTY_LDISC_OPEN, &tty->flags);
+
+		tty_ldisc_debug(tty, "%p: opened\n", tty->ldisc);
 		return ret;
 	}
 	return 0;
@@ -470,6 +476,7 @@ static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld)
 	clear_bit(TTY_LDISC_OPEN, &tty->flags);
 	if (ld->ops->close)
 		ld->ops->close(tty);
+	tty_ldisc_debug(tty, "%p: closed\n", tty->ldisc);
 }
 
 /**
@@ -483,7 +490,6 @@ static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld)
 
 static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)
 {
-	char buf[64];
 	struct tty_ldisc *new_ldisc;
 	int r;
 
@@ -504,7 +510,7 @@ static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)
 		if (r < 0)
 			panic("Couldn't open N_TTY ldisc for "
 			      "%s --- error %d.",
-			      tty_name(tty, buf), r);
+			      tty_name(tty), r);
 	}
 }
 
@@ -593,7 +599,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
 
 	/* Restart the work queue in case no characters kick it off. Safe if
 	   already running */
-	schedule_work(&tty->port->buf.work);
+	tty_buffer_restart_work(tty->port);
 
 	tty_unlock(tty);
 	return retval;
@@ -664,7 +670,7 @@ void tty_ldisc_hangup(struct tty_struct *tty)
 	int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS;
 	int err = 0;
 
-	tty_ldisc_debug(tty, "closing ldisc: %p\n", tty->ldisc);
+	tty_ldisc_debug(tty, "%p: closing\n", tty->ldisc);
 
 	ld = tty_ldisc_ref(tty);
 	if (ld != NULL) {
@@ -714,7 +720,7 @@ void tty_ldisc_hangup(struct tty_struct *tty)
 	if (reset)
 		tty_reset_termios(tty);
 
-	tty_ldisc_debug(tty, "re-opened ldisc: %p\n", tty->ldisc);
+	tty_ldisc_debug(tty, "%p: re-opened\n", tty->ldisc);
 }
 
 /**
@@ -778,8 +784,6 @@ void tty_ldisc_release(struct tty_struct *tty)
 	 * it does not race with the set_ldisc code path.
 	 */
 
-	tty_ldisc_debug(tty, "closing ldisc: %p\n", tty->ldisc);
-
 	tty_ldisc_lock_pair(tty, o_tty);
 	tty_ldisc_kill(tty);
 	if (o_tty)
@@ -789,7 +793,7 @@ void tty_ldisc_release(struct tty_struct *tty)
 	/* And the memory resources remaining (buffers, termios) will be
 	   disposed of when the kref hits zero */
 
-	tty_ldisc_debug(tty, "ldisc closed\n");
+	tty_ldisc_debug(tty, "released\n");
 }
 
 /**