On Thursday 25 August 2011, Jiri Slaby wrote:

We need to move port->mutex locking after wait_until_sent in
uart_close (for rationale see next patches). But if we did it now, we
would introduce a race between close and open. This is exactly why
port->mutex is locked at the top of uart_close.

To avoid the race, we add ASYNCB_CLOSING to uart_close. Like every
other sane TTY driver. Thanks to tty_port_block_til_ready used in
uart_open we will have this for free. Then we can move the port->mutex
lock.

Also note that this will make the conversion to tty_port helpers
easier. They are currently handling ASYNC_CLOSING flag correctly.

Signed-off-by: Jiri Slaby <redacted>

The series looks good to me,

Acked-by: Arnd Bergmann <arnd@arndb.de>

The only thing left to note is probably that there are a bunch
of drivers that implement their own *_wait_until_sent function
and call that from their *_close function instead of calling
tty_wait_until_sent. These drivers continue to suffer from the
same stalls that you are fixing the other ones.

	Arnd