tty: moxa: Fix modem op locking

This is overkill and mostly not needed

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c
index d180aa9..ac06d01 100644 (file)
--- a/drivers/char/moxa.c
+++ b/drivers/char/moxa.c
@@ -139,7 +139,7 @@ struct moxa_port {
        int cflag;
        unsigned long statusflags;
 
-       u8 DCDState;
+       u8 DCDState;            /* Protected by the port lock */
        u8 lineCtrl;
        u8 lowChkFlag;
 };
@@ -1141,9 +1141,9 @@ static int moxa_carrier_raised(struct tty_port *port)
        struct moxa_port *ch = container_of(port, struct moxa_port, port);
        int dcd;
 
-       spin_lock_bh(&moxa_lock);
+       spin_lock_irq(&port->lock);
        dcd = ch->DCDState;
-       spin_unlock_bh(&moxa_lock);
+       spin_unlock_irq(&port->lock);
        return dcd;
 }
 
@@ -1267,16 +1267,9 @@ static int moxa_chars_in_buffer(struct tty_struct *tty)
 
 static int moxa_tiocmget(struct tty_struct *tty, struct file *file)
 {
-       struct moxa_port *ch;
+       struct moxa_port *ch = tty->driver_data;
        int flag = 0, dtr, rts;
 
-       mutex_lock(&moxa_openlock);
-       ch = tty->driver_data;
-       if (!ch) {
-               mutex_unlock(&moxa_openlock);
-               return -EINVAL;
-       }
-
        MoxaPortGetLineOut(ch, &dtr, &rts);
        if (dtr)
                flag |= TIOCM_DTR;
@@ -1289,7 +1282,6 @@ static int moxa_tiocmget(struct tty_struct *tty, struct file *file)
                flag |= TIOCM_DSR;
        if (dtr & 4)
                flag |= TIOCM_CD;
-       mutex_unlock(&moxa_openlock);
        return flag;
 }
 
@@ -1368,15 +1360,20 @@ static void moxa_hangup(struct tty_struct *tty)
 static void moxa_new_dcdstate(struct moxa_port *p, u8 dcd)
 {
        struct tty_struct *tty;
+       unsigned long flags;
        dcd = !!dcd;
 
+       spin_lock_irqsave(&p->port.lock, flags);
        if (dcd != p->DCDState) {
+               p->DCDState = dcd;
+               spin_unlock_irqrestore(&p->port.lock, flags);
                tty = tty_port_tty_get(&p->port);
                if (tty && C_CLOCAL(tty) && !dcd)
                        tty_hangup(tty);
                tty_kref_put(tty);
        }
-       p->DCDState = dcd;
+       else
+               spin_unlock_irqrestore(&p->port.lock, flags);
 }
 
 static int moxa_poll_port(struct moxa_port *p, unsigned int handle,
@@ -1878,9 +1875,7 @@ static int MoxaPortLineStatus(struct moxa_port *port)
        val &= 0x0B;
        if (val & 8)
                val |= 4;
-       spin_lock_bh(&moxa_lock);
        moxa_new_dcdstate(port, val & 8);
-       spin_unlock_bh(&moxa_lock);
        val &= 7;
        return val;
 }