n_gsm.c: add tx_lock in gsm_send

From: xiaojin <[email protected]>
Date: Wed, 19 Dec 2012 11:53:43 +0800
Subject: [PATCH] n_gsm.c: add tx_lock in gsm_send

All the call to gsm->output should be in the tx_lock, that could avoid potential race from MUX level. But we have no tx_lock in gsm_send.

This patch is to add tx_lock in gsm_send.

---
 drivers/tty/n_gsm.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

index dcc0430..4572117 100644
@@ -573,6 +573,7 @@ static void gsm_send(struct gsm_mux *gsm, int addr,

int cr, int control)
int len;
u8 cbuf[10];
u8 ibuf[3];
+ unsigned long flags;

switch (gsm->encoding) {
case 0:
@@ -602,7 +603,9 @@ static void gsm_send(struct gsm_mux *gsm, int addr, int cr, int control)
WARN_ON(1);
return;
}
+ spin_lock_irqsave(&gsm->tx_lock, flags);
gsm->output(gsm, cbuf, len);
+ spin_unlock_irqrestore(&gsm->tx_lock, flags);
gsm_print_packet("-->", addr, cr, control, NULL, 0);
}

1.7.1