[PATCH V2 RESEND] tty/n_gsm.c: use gsm->num to remove mux itself from gsm_mux[]

[xinhui]

From: Pan Xinhui <xinhui.pan@xxxxxxxxxxxxxxxxxx>

There is one filed gsm->num to store mux's index of gsm_mux[]. So use
gsm->num to remove itself from gsm_mux[] instead of the for-loop
traverse in gsm_cleanup_mux().

Signed-off-by: Pan Xinhui <xinhui.pan@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
---
change from V1:
	lock is also held for the if()
---
 drivers/tty/n_gsm.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 9aff371..697b31e 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2038,16 +2038,13 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm)
 	gsm->dead = 1;
 
 	spin_lock(&gsm_mux_lock);
-	for (i = 0; i < MAX_MUX; i++) {
-		if (gsm_mux[i] == gsm) {
-			gsm_mux[i] = NULL;
-			break;
-		}
-	}
-	spin_unlock(&gsm_mux_lock);
 	/* open failed before registering => nothing to do */
-	if (i == MAX_MUX)
+	if (gsm_mux[gsm->num] != gsm) {
+		spin_unlock(&gsm_mux_lock);
 		return;
+	}
+	gsm_mux[gsm->num] = NULL;
+	spin_unlock(&gsm_mux_lock);
 
 	/* In theory disconnecting DLCI 0 is sufficient but for some
 	   modems this is apparently not the case. */
--
1.9.1