Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / drivers / tty / pty.c

diff --git a/kernel/drivers/tty/pty.c b/kernel/drivers/tty/pty.c
index 78e9836..807d801 100644 (file)
--- a/kernel/drivers/tty/pty.c
+++ b/kernel/drivers/tty/pty.c
@@ -59,7 +59,7 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
        if (!tty->link)
                return;
        set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
-       tty_flip_buffer_push(tty->link->port);
+       wake_up_interruptible(&tty->link->read_wait);
        wake_up_interruptible(&tty->link->write_wait);
        if (tty->driver->subtype == PTY_TYPE_MASTER) {
                set_bit(TTY_OTHER_CLOSED, &tty->flags);
@@ -247,9 +247,7 @@ static int pty_open(struct tty_struct *tty, struct file *filp)
                goto out;
 
        clear_bit(TTY_IO_ERROR, &tty->flags);
-       /* TTY_OTHER_CLOSED must be cleared before TTY_OTHER_DONE */
        clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
-       clear_bit(TTY_OTHER_DONE, &tty->link->flags);
        set_bit(TTY_THROTTLED, &tty->flags);
        return 0;
 
@@ -681,14 +679,14 @@ static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
 /* this is called once with whichever end is closed last */
 static void pty_unix98_shutdown(struct tty_struct *tty)
 {
-       struct inode *ptmx_inode;
+       struct pts_fs_info *fsi;
 
        if (tty->driver->subtype == PTY_TYPE_MASTER)
-               ptmx_inode = tty->driver_data;
+               fsi = tty->driver_data;
        else
-               ptmx_inode = tty->link->driver_data;
-       devpts_kill_index(ptmx_inode, tty->index);
-       devpts_del_ref(ptmx_inode);
+               fsi = tty->link->driver_data;
+       devpts_kill_index(fsi, tty->index);
+       devpts_put_ref(fsi);
 }
 
 static const struct tty_operations ptm_unix98_ops = {
@@ -740,6 +738,7 @@ static const struct tty_operations pty_unix98_ops = {
 
 static int ptmx_open(struct inode *inode, struct file *filp)
 {
+       struct pts_fs_info *fsi;
        struct tty_struct *tty;
        struct inode *slave_inode;
        int retval;
@@ -754,47 +753,41 @@ static int ptmx_open(struct inode *inode, struct file *filp)
        if (retval)
                return retval;
 
+       fsi = devpts_get_ref(inode, filp);
+       retval = -ENODEV;
+       if (!fsi)
+               goto out_free_file;
+
        /* find a device that is not in use. */
        mutex_lock(&devpts_mutex);
-       index = devpts_new_index(inode);
-       if (index < 0) {
-               retval = index;
-               mutex_unlock(&devpts_mutex);
-               goto err_file;
-       }
-
+       index = devpts_new_index(fsi);
        mutex_unlock(&devpts_mutex);
 
-       mutex_lock(&tty_mutex);
-       tty = tty_init_dev(ptm_driver, index);
+       retval = index;
+       if (index < 0)
+               goto out_put_ref;
 
-       if (IS_ERR(tty)) {
-               retval = PTR_ERR(tty);
-               goto out;
-       }
 
+       mutex_lock(&tty_mutex);
+       tty = tty_init_dev(ptm_driver, index);
        /* The tty returned here is locked so we can safely
           drop the mutex */
        mutex_unlock(&tty_mutex);
 
-       set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
-       tty->driver_data = inode;
+       retval = PTR_ERR(tty);
+       if (IS_ERR(tty))
+               goto out;
 
        /*
-        * In the case where all references to ptmx inode are dropped and we
-        * still have /dev/tty opened pointing to the master/slave pair (ptmx
-        * is closed/released before /dev/tty), we must make sure that the inode
-        * is still valid when we call the final pty_unix98_shutdown, thus we
-        * hold an additional reference to the ptmx inode. For the same /dev/tty
-        * last close case, we also need to make sure the super_block isn't
-        * destroyed (devpts instance unmounted), before /dev/tty is closed and
-        * on its release devpts_kill_index is called.
+        * From here on out, the tty is "live", and the index and
+        * fsi will be killed/put by the tty_release()
         */
-       devpts_add_ref(inode);
+       set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
+       tty->driver_data = fsi;
 
        tty_add_file(tty, filp);
 
-       slave_inode = devpts_pty_new(inode,
+       slave_inode = devpts_pty_new(fsi,
                        MKDEV(UNIX98_PTY_SLAVE_MAJOR, index), index,
                        tty->link);
        if (IS_ERR(slave_inode)) {
@@ -813,12 +806,14 @@ static int ptmx_open(struct inode *inode, struct file *filp)
        return 0;
 err_release:
        tty_unlock(tty);
+       // This will also put-ref the fsi
        tty_release(inode, filp);
        return retval;
 out:
-       mutex_unlock(&tty_mutex);
-       devpts_kill_index(inode, index);
-err_file:
+       devpts_kill_index(fsi, index);
+out_put_ref:
+       devpts_put_ref(fsi);
+out_free_file:
        tty_free_file(filp);
        return retval;
 }