serial: uartps: Fix uartps_major handling

There are two parts which should be fixed. The first one is to assigned
uartps_major at the end of probe() to avoid complicated logic when
something fails.
The second part is initialized uartps_major number to 0 when last device is
removed. This will ensure that on next probe driver will ask for new
dynamic major number.

Fixes: ab262666018d ("serial: uartps: Use the same dynamic major number for all ports")
Reported-by: Paul Thomas <pthomas8589@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/d2652cda992833315c4f96f06953eb547f928918.1570194248.git.michal.simek@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index da4563a..4e55bc3 100644 (file)
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1550,7 +1550,6 @@ static int cdns_uart_probe(struct platform_device *pdev)
                goto err_out_id;
        }
 
-       uartps_major = cdns_uart_uart_driver->tty_driver->major;
        cdns_uart_data->cdns_uart_driver = cdns_uart_uart_driver;
 
        /*
@@ -1680,6 +1679,7 @@ static int cdns_uart_probe(struct platform_device *pdev)
                console_port = NULL;
 #endif
 
+       uartps_major = cdns_uart_uart_driver->tty_driver->major;
        cdns_uart_data->cts_override = of_property_read_bool(pdev->dev.of_node,
                                                             "cts-override");
        return 0;
@@ -1741,6 +1741,12 @@ static int cdns_uart_remove(struct platform_device *pdev)
                console_port = NULL;
 #endif
 
+       /* If this is last instance major number should be initialized */
+       mutex_lock(&bitmap_lock);
+       if (bitmap_empty(bitmap, MAX_UART_INSTANCES))
+               uartps_major = 0;
+       mutex_unlock(&bitmap_lock);
+
        uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
        return rc;
 }