tty_lock: undo the old tty_lock use on the ctty
get_current_tty has its own consistent locking. That means a pile of the
tty lock cases are not needed. As get_current_tty also keeps a reference the
tty object lifetime means we can propogate the lock removal out.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index d939bd7..b425c79 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -855,10 +855,11 @@
*/
void no_tty(void)
{
+ /* FIXME: Review locking here. The tty_lock never covered any race
+ between a new association and proc_clear_tty but possible we need
+ to protect against this anyway */
struct task_struct *tsk = current;
- tty_lock();
disassociate_ctty(0);
- tty_unlock();
proc_clear_tty(tsk);
}
@@ -1800,6 +1801,9 @@
*
* We cannot return driver and index like for the other nodes because
* devpts will not work then. It expects inodes to be from devpts FS.
+ *
+ * We need to move to returning a refcounted object from all the lookup
+ * paths including this one.
*/
static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp)
{
@@ -1816,6 +1820,7 @@
/* noctty = 1; */
tty_kref_put(tty);
/* FIXME: we put a reference and return a TTY! */
+ /* This is only safe because the caller holds tty_mutex */
return tty;
}