[PATCH] tty/n_gsm.c: fix a memory leak in gsmld_open

["xinhui.pan" <xinhuix.pan@intel.com>]

If gsmld_attach_gsm fails, the gsm is not used anymore.
tty core will not call gsmld_close to do the cleanup work.
tty core just restore to the tty old ldisc.
That always causes memory leak.

Signed-off-by: xinhui.pan <xinhuiX.pan@intel.com>
Reported-by: Peter Hurley <peter@hurleysoftware.com>
---
 drivers/tty/n_gsm.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 81e7ccb..6cb1a6d 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2368,6 +2368,7 @@ static void gsmld_close(struct tty_struct *tty)
 static int gsmld_open(struct tty_struct *tty)
 {
 	struct gsm_mux *gsm;
+	int ret;
 
 	if (tty->ops->write == NULL)
 		return -EINVAL;
@@ -2382,7 +2383,13 @@ static int gsmld_open(struct tty_struct *tty)
 
 	/* Attach the initial passive connection */
 	gsm->encoding = 1;
-	return gsmld_attach_gsm(tty, gsm);
+
+	ret = gsmld_attach_gsm(tty, gsm);
+	if (ret != 0) {
+		gsm_cleanup_mux(gsm);
+		mux_put(gsm);
+	}
+	return ret;
 }
 
 /**
-- 
1.7.9.5