serial: 8250_mid: Balance reference count for PCI DMA device

The pci_get_slot() increases its reference count, the caller
must decrement the reference count by calling pci_dev_put().

Fixes: 90b9aacf912a ("serial: 8250_pci: add Intel Tangier support")
Fixes: f549e94effa1 ("serial: 8250_pci: add Intel Penwell ports")
Reported-by: Qing Wang <wangqing@vivo.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Depends-on: d9eda9bab237 ("serial: 8250_pci: Intel MID UART support to its own driver")
Link: https://lore.kernel.org/r/20220215100920.41984-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_mid.c b/drivers/tty/serial/8250/8250_mid.c
index 83592b51a99662bc46e163fc09359b0f6f7a0ad6..a2a03acb04ad3e28b601257dea88fa5469f2a722 100644 (file)
--- a/drivers/tty/serial/8250/8250_mid.c
+++ b/drivers/tty/serial/8250/8250_mid.c
@@ -73,6 +73,11 @@ static int pnw_setup(struct mid8250 *mid, struct uart_port *p)
        return 0;
 }
 
+static void pnw_exit(struct mid8250 *mid)
+{
+       pci_dev_put(mid->dma_dev);
+}
+
 static int tng_handle_irq(struct uart_port *p)
 {
        struct mid8250 *mid = p->private_data;
@@ -124,6 +129,11 @@ static int tng_setup(struct mid8250 *mid, struct uart_port *p)
        return 0;
 }
 
+static void tng_exit(struct mid8250 *mid)
+{
+       pci_dev_put(mid->dma_dev);
+}
+
 static int dnv_handle_irq(struct uart_port *p)
 {
        struct mid8250 *mid = p->private_data;
@@ -328,9 +338,9 @@ static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
        pci_set_drvdata(pdev, mid);
        return 0;
+
 err:
-       if (mid->board->exit)
-               mid->board->exit(mid);
+       mid->board->exit(mid);
        return ret;
 }
 
@@ -340,8 +350,7 @@ static void mid8250_remove(struct pci_dev *pdev)
 
        serial8250_unregister_port(mid->line);
 
-       if (mid->board->exit)
-               mid->board->exit(mid);
+       mid->board->exit(mid);
 }
 
 static const struct mid8250_board pnw_board = {
@@ -349,6 +358,7 @@ static const struct mid8250_board pnw_board = {
        .freq = 50000000,
        .base_baud = 115200,
        .setup = pnw_setup,
+       .exit = pnw_exit,
 };
 
 static const struct mid8250_board tng_board = {
@@ -356,6 +366,7 @@ static const struct mid8250_board tng_board = {
        .freq = 38400000,
        .base_baud = 1843200,
        .setup = tng_setup,
+       .exit = tng_exit,
 };
 
 static const struct mid8250_board dnv_board = {