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    SubjectRe: [PATCH 1/5] TTY: serial, use ASYNCB_CLOSING in uart_close
    Date
    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 <jslaby@suse.cz>

    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


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