[PATCH] mkiss: Fix error handling in mkiss_open()

[Fabio Estevam <fabio.estevam@freescale.com>]

If register_netdev() fails we are not propagating the error and
we return success because ax_open() succeeded previously.

Fix this by checking the return value of ax_open() and 
register_netdev() and propagate the error in case of failure.

Reported-by: RUC_Soft_Sec <zy900702@163.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
 drivers/net/hamradio/mkiss.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
index 2ffbf13..216bfd3 100644
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -728,11 +728,12 @@ static int mkiss_open(struct tty_struct *tty)
 	dev->type = ARPHRD_AX25;
 
 	/* Perform the low-level AX25 initialization. */
-	if ((err = ax_open(ax->dev))) {
+	err = ax_open(ax->dev);
+	if (err)
 		goto out_free_netdev;
-	}
 
-	if (register_netdev(dev))
+	err = register_netdev(dev);
+	if (err)
 		goto out_free_buffers;
 
 	/* after register_netdev() - because else printk smashes the kernel */
-- 
1.9.1