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>

1 files changed, 10 insertions, 15 deletions

diff --git a/drivers/char/moxa.c b/drivers/char/moxa.c
index d180aa965a5a..ac06d0131db5 100644
--- 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;
 }