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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Qing Wang <wangqing@vivo.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 132/284] serial: 8250_mid: Balance reference count for PCI DMA device
Date:   Mon, 18 Apr 2022 14:11:53 +0200
Message-Id: <20220418121215.075807968@linuxfoundation.org>
In-Reply-To: <20220418121210.689577360@linuxfoundation.org>
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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 ec957cce8c9a..83446e7ceec7 100644
--- a/drivers/tty/serial/8250/8250_mid.c
+++ b/drivers/tty/serial/8250/8250_mid.c
@@ -75,6 +75,11 @@ 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;
@@ -126,6 +131,11 @@ 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;
@@ -332,9 +342,9 @@ 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;
 }
 
@@ -344,8 +354,7 @@ 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 = {
@@ -353,6 +362,7 @@ 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 = {
@@ -360,6 +370,7 @@ 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