[PATCH 5.16 0665/1017] serial: 8250_mid: Balance reference count for PCI DMA device

Greg Kroah-Hartman
2022-04-05T10:04:37Z

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit 67ec6dd0b257bd81b4e9fcac89b29da72f6265e5 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/serial/8250/8250_mid.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mid.c b/drivers/tty/serial/8250/8250_mid.c
index efa0515139f8..e6c1791609dd 100644
--- 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;
@@ -330,9 +340,9 @@ 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;
}

@@ -342,8 +352,7 @@ 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 = {
@@ -351,6 +360,7 @@ 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 = {
@@ -358,6 +368,7 @@ 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 = {
--
2.34.1