On Wed, Dec 12, 2018 at 12:42:52PM +0900, Sergey Senozhatsky wrote:
> Something like this (not tested):
>
> ---
>
> drivers/tty/serial/serial_core.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/tty/serial/serial_core.c
> b/drivers/tty/serial/serial_core.c
> index c439a5a1e6c0..64050f506348 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -268,6 +268,7 @@ static void uart_shutdown(struct tty_struct *tty, struct
> uart_state *state)
> struct uart_port *uport = uart_port_check(state);
> struct tty_port *port = &state->port;
> unsigned long flags = 0;
> + char *xmit_buf = NULL;
>
> /*
> * Set the TTY IO error marker
> @@ -297,15 +298,16 @@ static void uart_shutdown(struct tty_struct *tty,
> struct uart_state *state)
> */
> tty_port_set_suspended(port, 0);
>
> + uart_port_lock(state, flags);
> + xmit_buf = state->xmit.buf;
> + state->xmit.buf = NULL;
> + uart_port_unlock(uport, flags);
> +
> /*
> * Free the transmit buffer page.
> */
> - uart_port_lock(state, flags);
> - if (state->xmit.buf) {
> - free_page((unsigned long)state->xmit.buf);
> - state->xmit.buf = NULL;
> - }
> - uart_port_unlock(uport, flags);
> + if (xmit_buf)
> + free_page((unsigned long)xmit_buf);
> }
That looks sensible anyhow. One should strive to not do alloc or free
under locks as much as possible anyway.
