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Commit b342dd51 authored by Chen Gang's avatar Chen Gang Committed by Greg Kroah-Hartman
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drivers/tty/serial: extern function which for release resource, need check pointer, before free it 



  for extern function uart_remove_one_port:
    need check pointer whether be NULL, before the main work.
    just like what the other extern function uart_add_one_port has done.
    uart_add_one_port and uart_remove_one_port are pair

  information:
    for the callers (such as drivers/tty/serial/jsm: jsm_tty.c, jsm_driver.c)
    they realy assume that:
      they still can call uart_remove_one_port, after uart_add_one_port failed
    we (as an extern function), have to understand it (just like kfree).

Signed-off-by: default avatarChen Gang <gang.chen@asianux.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 074d35ce

drivers/tty/serial/serial_core.c

+8 −1
Original line number Diff line number Diff line
@@ -2643,6 +2643,7 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport) 
{

	struct uart_state *state = drv->state + uport->line;

	struct tty_port *port = &state->port;

	int ret = 0;



	BUG_ON(in_interrupt());
@@ -2657,6 +2658,11 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport) 
	 * succeeding while we shut down the port.

	 */

	mutex_lock(&port->mutex);

	if (!state->uart_port) {

		mutex_unlock(&port->mutex);

		ret = -EINVAL;

		goto out;

	}

	uport->flags |= UPF_DEAD;

	mutex_unlock(&port->mutex);
@@ -2680,9 +2686,10 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport) 
	uport->type = PORT_UNKNOWN;



	state->uart_port = NULL;

out:

	mutex_unlock(&port_mutex);



	return 0;

	return ret;

}



/*