12 files changed, 29 insertions, 41 deletions

diff --git a/Documentation/serial/driver b/Documentation/serial/driver
index e9c0178cd202..ac7eabbf662a 100644
--- a/Documentation/serial/driver
+++ b/Documentation/serial/driver
@@ -107,8 +107,8 @@ hardware.
         indicate that the signal is permanently active.  If RI is
         not available, the signal should not be indicated as active.
 
-        Locking: none.
-        Interrupts: caller dependent.
+        Locking: port->lock taken.
+        Interrupts: locally disabled.
         This call must not sleep
 
   stop_tx(port,tty_stop)
diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 34e75bc8f4cc..b53b53bb1475 100644
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -1376,13 +1376,10 @@ static unsigned int serial8250_tx_empty(struct uart_port *port)
 static unsigned int serial8250_get_mctrl(struct uart_port *port)
 {
         struct uart_8250_port *up = (struct uart_8250_port *)port;
-        unsigned long flags;
         unsigned char status;
         unsigned int ret;
 
-        spin_lock_irqsave(&up->port.lock, flags);
         status = serial_in(up, UART_MSR);
-        spin_unlock_irqrestore(&up->port.lock, flags);
 
         ret = 0;
         if (status & UART_MSR_DCD)
diff --git a/drivers/serial/au1x00_uart.c b/drivers/serial/au1x00_uart.c
index 5400dc2c087e..6104aeef1243 100644
--- a/drivers/serial/au1x00_uart.c
+++ b/drivers/serial/au1x00_uart.c
@@ -556,13 +556,10 @@ static unsigned int serial8250_tx_empty(struct uart_port *port)
 static unsigned int serial8250_get_mctrl(struct uart_port *port)
 {
         struct uart_8250_port *up = (struct uart_8250_port *)port;
-        unsigned long flags;
         unsigned char status;
         unsigned int ret;
 
-        spin_lock_irqsave(&up->port.lock, flags);
         status = serial_in(up, UART_MSR);
-        spin_unlock_irqrestore(&up->port.lock, flags);
 
         ret = 0;
         if (status & UART_MSR_DCD)
diff --git a/drivers/serial/ip22zilog.c b/drivers/serial/ip22zilog.c
index 3ea46c069f6f..ea5bf4d4daa3 100644
--- a/drivers/serial/ip22zilog.c
+++ b/drivers/serial/ip22zilog.c
@@ -518,27 +518,28 @@ static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id, struct pt_regs *re
 static __inline__ unsigned char ip22zilog_read_channel_status(struct uart_port *port)
 {
         struct zilog_channel *channel;
-        unsigned long flags;
         unsigned char status;
 
-        spin_lock_irqsave(&port->lock, flags);
-
         channel = ZILOG_CHANNEL_FROM_PORT(port);
         status = readb(&channel->control);
         ZSDELAY();
 
-        spin_unlock_irqrestore(&port->lock, flags);
-
         return status;
 }
 
 /* The port lock is not held.  */
 static unsigned int ip22zilog_tx_empty(struct uart_port *port)
 {
+        unsigned long flags;
         unsigned char status;
         unsigned int ret;
 
+        spin_lock_irqsave(&port->lock, flags);
+
         status = ip22zilog_read_channel_status(port);
+
+        spin_unlock_irqrestore(&port->lock, flags);
+
         if (status & Tx_BUF_EMP)
                 ret = TIOCSER_TEMT;
         else
@@ -547,7 +548,7 @@ static unsigned int ip22zilog_tx_empty(struct uart_port *port)
         return ret;
 }
 
-/* The port lock is not held.  */
+/* The port lock is held and interrupts are disabled.  */
 static unsigned int ip22zilog_get_mctrl(struct uart_port *port)
 {
         unsigned char status;
diff --git a/drivers/serial/mpsc.c b/drivers/serial/mpsc.c
index a2a643318002..e43276c6a954 100644
--- a/drivers/serial/mpsc.c
+++ b/drivers/serial/mpsc.c
@@ -1058,12 +1058,9 @@ mpsc_get_mctrl(struct uart_port *port)
 {
         struct mpsc_port_info *pi = (struct mpsc_port_info *)port;
         u32 mflags, status;
-        ulong iflags;
 
-        spin_lock_irqsave(&pi->port.lock, iflags);
         status = (pi->mirror_regs) ? pi->MPSC_CHR_10_m :
                 readl(pi->mpsc_base + MPSC_CHR_10);
-        spin_unlock_irqrestore(&pi->port.lock, iflags);
 
         mflags = 0;
         if (status & 0x1)
diff --git a/drivers/serial/pmac_zilog.c b/drivers/serial/pmac_zilog.c
index 85abd8a045e0..1c9f71617123 100644
--- a/drivers/serial/pmac_zilog.c
+++ b/drivers/serial/pmac_zilog.c
@@ -604,7 +604,7 @@ static void pmz_set_mctrl(struct uart_port *port, unsigned int mctrl)
 /* 
  * Get Modem Control bits (only the input ones, the core will
  * or that with a cached value of the control ones)
- * The port lock is not held.
+ * The port lock is held and interrupts are disabled.
  */
 static unsigned int pmz_get_mctrl(struct uart_port *port)
 {
@@ -615,7 +615,7 @@ static unsigned int pmz_get_mctrl(struct uart_port *port)
         if (ZS_IS_ASLEEP(uap) || uap->node == NULL)
                 return 0;
 
-        status = pmz_peek_status(to_pmz(port));
+        status = read_zsreg(uap, R0);
 
         ret = 0;
         if (status & DCD)
diff --git a/drivers/serial/pxa.c b/drivers/serial/pxa.c
index 08b08d6ae904..461c81c93207 100644
--- a/drivers/serial/pxa.c
+++ b/drivers/serial/pxa.c
@@ -274,14 +274,11 @@ static unsigned int serial_pxa_tx_empty(struct uart_port *port)
 static unsigned int serial_pxa_get_mctrl(struct uart_port *port)
 {
         struct uart_pxa_port *up = (struct uart_pxa_port *)port;
-        unsigned long flags;
         unsigned char status;
         unsigned int ret;
 
 return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
-        spin_lock_irqsave(&up->port.lock, flags);
         status = serial_in(up, UART_MSR);
-        spin_unlock_irqrestore(&up->port.lock, flags);
 
         ret = 0;
         if (status & UART_MSR_DCD)
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 36b1ae083fb7..f5ce58d0514d 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -828,7 +828,10 @@ static int uart_tiocmget(struct tty_struct *tty, struct file *file)
         if ((!file || !tty_hung_up_p(file)) &&
             !(tty->flags & (1 << TTY_IO_ERROR))) {
                 result = port->mctrl;
+
+                spin_lock_irq(&port->lock);
                 result |= port->ops->get_mctrl(port);
+                spin_unlock_irq(&port->lock);
         }
         up(&state->sem);
 
@@ -1369,6 +1372,7 @@ uart_block_til_ready(struct file *filp, struct uart_state *state)
         DECLARE_WAITQUEUE(wait, current);
         struct uart_info *info = state->info;
         struct uart_port *port = state->port;
+        unsigned int mctrl;
 
         info->blocked_open++;
         state->count--;
@@ -1416,7 +1420,10 @@ uart_block_til_ready(struct file *filp, struct uart_state *state)
                  * and wait for the carrier to indicate that the
                  * modem is ready for us.
                  */
-                if (port->ops->get_mctrl(port) & TIOCM_CAR)
+                spin_lock_irq(&port->lock);
+                mctrl = port->ops->get_mctrl(port);
+                spin_unlock_irq(&port->lock);
+                if (mctrl & TIOCM_CAR)
                         break;
 
                 up(&state->sem);
@@ -1618,7 +1625,9 @@ static int uart_line_info(char *buf, struct uart_driver *drv, int i)
 
         if(capable(CAP_SYS_ADMIN))
         {
+                spin_lock_irq(&port->lock);
                 status = port->ops->get_mctrl(port);
+                spin_unlock_irq(&port->lock);
 
                 ret += sprintf(buf + ret, " tx:%d rx:%d",
                                 port->icount.tx, port->icount.rx);
diff --git a/drivers/serial/serial_txx9.c b/drivers/serial/serial_txx9.c
index 3f1051a4a13f..d085030df70b 100644
--- a/drivers/serial/serial_txx9.c
+++ b/drivers/serial/serial_txx9.c
@@ -442,13 +442,10 @@ static unsigned int serial_txx9_tx_empty(struct uart_port *port)
 static unsigned int serial_txx9_get_mctrl(struct uart_port *port)
 {
         struct uart_txx9_port *up = (struct uart_txx9_port *)port;
-        unsigned long flags;
         unsigned int ret;
 
-        spin_lock_irqsave(&up->port.lock, flags);
         ret =  ((sio_in(up, TXX9_SIFLCR) & TXX9_SIFLCR_RTSSC) ? 0 : TIOCM_RTS)
                 | ((sio_in(up, TXX9_SICISR) & TXX9_SICISR_CTSS) ? 0 : TIOCM_CTS);
-        spin_unlock_irqrestore(&up->port.lock, flags);
 
         return ret;
 }
diff --git a/drivers/serial/sunsab.c b/drivers/serial/sunsab.c
index 10e2990a40d4..8d198880756a 100644
--- a/drivers/serial/sunsab.c
+++ b/drivers/serial/sunsab.c
@@ -426,18 +426,15 @@ static void sunsab_set_mctrl(struct uart_port *port, unsigned int mctrl)
                 sunsab_tx_idle(up);
 }
 
-/* port->lock is not held.  */
+/* port->lock is held by caller and interrupts are disabled.  */
 static unsigned int sunsab_get_mctrl(struct uart_port *port)
 {
         struct uart_sunsab_port *up = (struct uart_sunsab_port *) port;
-        unsigned long flags;
         unsigned char val;
         unsigned int result;
 
         result = 0;
 
-        spin_lock_irqsave(&up->port.lock, flags);
-
         val = readb(&up->regs->r.pvr);
         result |= (val & up->pvr_dsr_bit) ? 0 : TIOCM_DSR;
 
@@ -447,8 +444,6 @@ static unsigned int sunsab_get_mctrl(struct uart_port *port)
         val = readb(&up->regs->r.star);
         result |= (val & SAB82532_STAR_CTS) ? TIOCM_CTS : 0;
 
-        spin_unlock_irqrestore(&up->port.lock, flags);
-
         return result;
 }
 
diff --git a/drivers/serial/sunsu.c b/drivers/serial/sunsu.c
index ddc97c905e14..d57a3553aea3 100644
--- a/drivers/serial/sunsu.c
+++ b/drivers/serial/sunsu.c
@@ -572,13 +572,10 @@ static unsigned int sunsu_tx_empty(struct uart_port *port)
 static unsigned int sunsu_get_mctrl(struct uart_port *port)
 {
         struct uart_sunsu_port *up = (struct uart_sunsu_port *) port;
-        unsigned long flags;
         unsigned char status;
         unsigned int ret;
 
-        spin_lock_irqsave(&up->port.lock, flags);
         status = serial_in(up, UART_MSR);
-        spin_unlock_irqrestore(&up->port.lock, flags);
 
         ret = 0;
         if (status & UART_MSR_DCD)
diff --git a/drivers/serial/sunzilog.c b/drivers/serial/sunzilog.c
index 8e65206d3d76..bff42a7b89d0 100644
--- a/drivers/serial/sunzilog.c
+++ b/drivers/serial/sunzilog.c
@@ -610,27 +610,28 @@ static irqreturn_t sunzilog_interrupt(int irq, void *dev_id, struct pt_regs *reg
 static __inline__ unsigned char sunzilog_read_channel_status(struct uart_port *port)
 {
         struct zilog_channel __iomem *channel;
-        unsigned long flags;
         unsigned char status;
 
-        spin_lock_irqsave(&port->lock, flags);
-
         channel = ZILOG_CHANNEL_FROM_PORT(port);
         status = sbus_readb(&channel->control);
         ZSDELAY();
 
-        spin_unlock_irqrestore(&port->lock, flags);
-
         return status;
 }
 
 /* The port lock is not held.  */
 static unsigned int sunzilog_tx_empty(struct uart_port *port)
 {
+        unsigned long flags;
         unsigned char status;
         unsigned int ret;
 
+        spin_lock_irqsave(&port->lock, flags);
+
         status = sunzilog_read_channel_status(port);
+
+        spin_unlock_irqrestore(&port->lock, flags);
+
         if (status & Tx_BUF_EMP)
                 ret = TIOCSER_TEMT;
         else
@@ -639,7 +640,7 @@ static unsigned int sunzilog_tx_empty(struct uart_port *port)
         return ret;
 }
 
-/* The port lock is not held.  */
+/* The port lock is held and interrupts are disabled.  */
 static unsigned int sunzilog_get_mctrl(struct uart_port *port)
 {
         unsigned char status;