[PATCH] Serial: Adjust serial locking
This patch changes the way serial ports are locked when getting modem
status. This change is necessary because we will need to atomically
read the modem status and take action depending on the CTS status.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/serial/sunsab.c b/drivers/serial/sunsab.c
index 10e2990..8d19888 100644
--- a/drivers/serial/sunsab.c
+++ b/drivers/serial/sunsab.c
@@ -426,18 +426,15 @@
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 @@
val = readb(&up->regs->r.star);
result |= (val & SAB82532_STAR_CTS) ? TIOCM_CTS : 0;
- spin_unlock_irqrestore(&up->port.lock, flags);
-
return result;
}