tty: revert incorrectly applied lock patch

I sent GregKH this after the pre-requisites. He dropped the pre-requesites
for good reason and unfortunately then applied this patch. Without this
reverted you get random kernel memory corruption which will make bisecting
anything between it and the properly applied patches a complete sod.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 9 insertions, 14 deletions

diff --git a/include/linux/tty.h b/include/linux/tty.h
index 7f9d7df9b131..40b18d7ad929 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -268,7 +268,6 @@ struct tty_struct {
         struct mutex ldisc_mutex;
         struct tty_ldisc *ldisc;
 
-        struct mutex legacy_mutex;
         struct mutex termios_mutex;
         spinlock_t ctrl_lock;
         /* Termios values are protected by the termios mutex */
@@ -611,12 +610,8 @@ extern long vt_compat_ioctl(struct tty_struct *tty,
 
 /* tty_mutex.c */
 /* functions for preparation of BKL removal */
-extern void __lockfunc tty_lock(struct tty_struct *tty);
-extern void __lockfunc tty_unlock(struct tty_struct *tty);
-extern void __lockfunc tty_lock_pair(struct tty_struct *tty,
-                                struct tty_struct *tty2);
-extern void __lockfunc tty_unlock_pair(struct tty_struct *tty,
-                                struct tty_struct *tty2);
+extern void __lockfunc tty_lock(void) __acquires(tty_lock);
+extern void __lockfunc tty_unlock(void) __releases(tty_lock);
 
 /*
  * this shall be called only from where BTM is held (like close)
@@ -631,9 +626,9 @@ extern void __lockfunc tty_unlock_pair(struct tty_struct *tty,
 static inline void tty_wait_until_sent_from_close(struct tty_struct *tty,
                 long timeout)
 {
-        tty_unlock(tty); /* tty->ops->close holds the BTM, drop it while waiting */
+        tty_unlock(); /* tty->ops->close holds the BTM, drop it while waiting */
         tty_wait_until_sent(tty, timeout);
-        tty_lock(tty);
+        tty_lock();
 }
 
 /*
@@ -648,16 +643,16 @@ static inline void tty_wait_until_sent_from_close(struct tty_struct *tty,
  *
  * Do not use in new code.
  */
-#define wait_event_interruptible_tty(tty, wq, condition)                \
+#define wait_event_interruptible_tty(wq, condition)                     \
 ({                                                                      \
         int __ret = 0;                                                  \
         if (!(condition)) {                                             \
-                __wait_event_interruptible_tty(tty, wq, condition, __ret);      \
+                __wait_event_interruptible_tty(wq, condition, __ret);   \
         }                                                               \
         __ret;                                                          \
 })
 
-#define __wait_event_interruptible_tty(tty, wq, condition, ret)         \
+#define __wait_event_interruptible_tty(wq, condition, ret)              \
 do {                                                                    \
         DEFINE_WAIT(__wait);                                            \
                                                                         \
@@ -666,9 +661,9 @@ do {									\
                 if (condition)                                          \
                         break;                                          \
                 if (!signal_pending(current)) {                         \
-                        tty_unlock(tty);                                        \
+                        tty_unlock();                                   \
                         schedule();                                     \
-                        tty_lock(tty);                                  \
+                        tty_lock();                                     \
                         continue;                                       \
                 }                                                       \
                 ret = -ERESTARTSYS;                                     \