4 files changed, 5 insertions, 18 deletions

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index b5f57d0b30ee..f40298e9873a 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -739,13 +739,11 @@ void tty_vhangup_self(void)
 {
         struct tty_struct *tty;
 
-        mutex_lock(&tty_mutex);
         tty = get_current_tty();
         if (tty) {
                 tty_vhangup(tty);
                 tty_kref_put(tty);
         }
-        mutex_unlock(&tty_mutex);
 }
 
 /**
@@ -801,11 +799,9 @@ void disassociate_ctty(int on_exit)
         struct pid *tty_pgrp = NULL;
 
 
-        mutex_lock(&tty_mutex);
         tty = get_current_tty();
         if (tty) {
                 tty_pgrp = get_pid(tty->pgrp);
-                mutex_unlock(&tty_mutex);
                 lock_kernel();
                 if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
                         tty_vhangup(tty);
@@ -822,7 +818,6 @@ void disassociate_ctty(int on_exit)
                         kill_pgrp(old_pgrp, SIGCONT, on_exit);
                         put_pid(old_pgrp);
                 }
-                mutex_unlock(&tty_mutex);
                 return;
         }
         if (tty_pgrp) {
@@ -837,7 +832,6 @@ void disassociate_ctty(int on_exit)
         current->signal->tty_old_pgrp = NULL;
         spin_unlock_irq(&current->sighand->siglock);
 
-        mutex_lock(&tty_mutex);
         tty = get_current_tty();
         if (tty) {
                 unsigned long flags;
@@ -854,7 +848,6 @@ void disassociate_ctty(int on_exit)
                        " = NULL", tty);
 #endif
         }
-        mutex_unlock(&tty_mutex);
 
         /* Now clear signal->tty under the lock */
         read_lock(&tasklist_lock);
@@ -3180,14 +3173,11 @@ static void proc_set_tty(struct task_struct *tsk, struct tty_struct *tty)
 struct tty_struct *get_current_tty(void)
 {
         struct tty_struct *tty;
-        WARN_ON_ONCE(!mutex_is_locked(&tty_mutex));
+        unsigned long flags;
+
+        spin_lock_irqsave(&current->sighand->siglock, flags);
         tty = tty_kref_get(current->signal->tty);
-        /*
-         * session->tty can be changed/cleared from under us, make sure we
-         * issue the load. The obtained pointer, when not NULL, is valid as
-         * long as we hold tty_mutex.
-         */
-        barrier();
+        spin_unlock_irqrestore(&current->sighand->siglock, flags);
         return tty;
 }
 EXPORT_SYMBOL_GPL(get_current_tty);
diff --git a/drivers/s390/char/fs3270.c b/drivers/s390/char/fs3270.c
index 3ef5425d0eb8..84fbc90480dc 100644
--- a/drivers/s390/char/fs3270.c
+++ b/drivers/s390/char/fs3270.c
@@ -431,6 +431,7 @@ fs3270_open(struct inode *inode, struct file *filp)
                 tty = get_current_tty();
                 if (!tty || tty->driver->major != IBM_TTY3270_MAJOR) {
                         tty_kref_put(tty);
+                        mutex_unlock(&tty_mutex);
                         rc = -ENODEV;
                         goto out;
                 }
diff --git a/fs/dquot.c b/fs/dquot.c
index 7417a6ca3129..ad7e59003e04 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -895,9 +895,7 @@ static void print_warning(struct dquot *dquot, const int warntype)
             warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(dquot))
                 return;
 
-        mutex_lock(&tty_mutex);
         tty = get_current_tty();
-        mutex_unlock(&tty_mutex);
         if (!tty)
                 return;
         tty_write_message(tty, dquot->dq_sb->s_id);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 089d61a23952..48881394fbd4 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2121,9 +2121,7 @@ static inline void flush_unauthorized_files(struct files_struct *files)
         long j = -1;
         int drop_tty = 0;
 
-        mutex_lock(&tty_mutex);
         tty = get_current_tty();
-        mutex_unlock(&tty_mutex);
         if (tty) {
                 file_list_lock();
                 file = list_entry(tty->tty_files.next, typeof(*file), f_u.fu_list);