drivers/tty/serial: extern function which for release resource, need check pointer, before free it

PATCH New Chen Gang 1 participant 1 message Dec 27, 2012 TTY layer and serial drivers

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Chen Gang

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2012-12-27 07:50 UTC #0 lore raw

PATCH 1/1 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 <[email protected]>

---
 drivers/tty/serial/serial_core.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

drivers/tty/serial/serial_core.c +8 -1

index 2c7230a..bd65549 100644
@@ -2642,6 +2642,7 @@ 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());

@@ -2656,6 +2657,11 @@ 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);

@@ -2679,9 +2685,10 @@ 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;
 }
 
 /*

Signature · 1 line

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