[ARM] 4417/1: Serial: Fix AMBA drivers locking

The -rt patch triggered a lockdep warning in the amba serial drivers, which never shows up on UP kernels. On SMP systems this would trigger as well. Release the port lock before calling tty_flip_buffer_push() and reacquire it after the call. This matches the code in the 8250 serial driver. Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Russell King <[email protected]>
koalo · May 30, 2007 · 2389b27 · 2389b27
1 parent 2ccdd1e
commit 2389b27
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/drivers/serial/amba-pl010.c b/drivers/serial/amba-pl010.c
@@ -167,8 +167,9 @@ static void pl010_rx_chars(struct uart_amba_port *uap)
 	ignore_char:
 		status = readb(uap->port.membase + UART01x_FR);
 	}
+	spin_unlock(&port->lock);
 	tty_flip_buffer_push(tty);
-	return;
+	spin_lock(&port->lock);
 }
 
 static void pl010_tx_chars(struct uart_amba_port *uap)

diff --git a/drivers/serial/amba-pl011.c b/drivers/serial/amba-pl011.c
@@ -153,8 +153,9 @@ static void pl011_rx_chars(struct uart_amba_port *uap)
 	ignore_char:
 		status = readw(uap->port.membase + UART01x_FR);
 	}
+	spin_unlock(&uap->port.lock);
 	tty_flip_buffer_push(tty);
-	return;
+	spin_lock(&uap->port.lock);
 }
 
 static void pl011_tx_chars(struct uart_amba_port *uap)