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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: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
wifi-calibration
Chen Gang 2012-12-27 15:51:31 +08:00 committed by Greg Kroah-Hartman
parent 074d35cebe
commit b342dd512f
1 changed files with 8 additions and 1 deletions
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9
drivers/tty/serial/serial_core.c
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@ -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;
}
/*