diff options
| author | Alan Cox <alan@linux.intel.com> | 2012-05-03 22:21:53 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-05-04 16:47:38 -0700 |
| commit | 3af502b96649ccb7462da73b0cca446c8384b155 (patch) | |
| tree | 8d2f1a77e25354c69d61192e544bedb681cbb80e | |
| parent | 22886ee96895b7a9f9d06da4dc9420b61b4ef1f7 (diff) | |
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>
| -rw-r--r-- | drivers/tty/tty_io.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index d939bd705c7..b425c79675a 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -855,10 +855,11 @@ void disassociate_ctty(int on_exit) */ 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 @@ int tty_release(struct inode *inode, struct file *filp) * * 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 @@ static struct tty_struct *tty_open_current_tty(dev_t device, struct file *filp) /* 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; } |