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Date: Wed, 23 Feb 2022 17:12:40 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jiri Slaby <jirislaby@...nel.org>,
Qing Wang <wangqing@...o.com>
Subject: [PATCH v3 1/1] serial: 8250_lpss: 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: 9a1870ce812e ("serial: 8250: don't use slave_id of dma_slave_config")
Depends-on: a13e19cf3dc1 ("serial: 8250_lpss: split LPSS driver to separate module")
Reported-by: Qing Wang <wangqing@...o.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
v3: split out as independent patch from the series (the rest is under discussion)
drivers/tty/serial/8250/8250_lpss.c | 28 ++++++++++++++++++++++------
1 file changed, 22 insertions(+), 6 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
index d3bafec7619d..0f5af061e0b4 100644
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -117,8 +117,7 @@ static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
{
struct dw_dma_slave *param = &lpss->dma_param;
struct pci_dev *pdev = to_pci_dev(port->dev);
- unsigned int dma_devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0);
- struct pci_dev *dma_dev = pci_get_slot(pdev->bus, dma_devfn);
+ struct pci_dev *dma_dev;
switch (pdev->device) {
case PCI_DEVICE_ID_INTEL_BYT_UART1:
@@ -137,6 +136,8 @@ static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
return -EINVAL;
}
+ dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(PCI_SLOT(pdev->devfn), 0));
+
param->dma_dev = &dma_dev->dev;
param->m_master = 0;
param->p_master = 1;
@@ -152,6 +153,14 @@ static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
return 0;
}
+static void byt_serial_exit(struct lpss8250 *lpss)
+{
+ struct dw_dma_slave *param = &lpss->dma_param;
+
+ /* Paired with pci_get_slot() in the byt_serial_setup() above */
+ put_device(param->dma_dev);
+}
+
static int ehl_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
{
struct uart_8250_dma *dma = &lpss->data.dma;
@@ -170,6 +179,13 @@ static int ehl_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
return 0;
}
+static void ehl_serial_exit(struct lpss8250 *lpss)
+{
+ struct uart_8250_port *up = serial8250_get_port(lpss->data.line);
+
+ up->dma = NULL;
+}
+
#ifdef CONFIG_SERIAL_8250_DMA
static const struct dw_dma_platform_data qrk_serial_dma_pdata = {
.nr_channels = 2,
@@ -344,8 +360,7 @@ static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
return 0;
err_exit:
- if (lpss->board->exit)
- lpss->board->exit(lpss);
+ lpss->board->exit(lpss);
pci_free_irq_vectors(pdev);
return ret;
}
@@ -356,8 +371,7 @@ static void lpss8250_remove(struct pci_dev *pdev)
serial8250_unregister_port(lpss->data.line);
- if (lpss->board->exit)
- lpss->board->exit(lpss);
+ lpss->board->exit(lpss);
pci_free_irq_vectors(pdev);
}
@@ -365,12 +379,14 @@ static const struct lpss8250_board byt_board = {
.freq = 100000000,
.base_baud = 2764800,
.setup = byt_serial_setup,
+ .exit = byt_serial_exit,
};
static const struct lpss8250_board ehl_board = {
.freq = 200000000,
.base_baud = 12500000,
.setup = ehl_serial_setup,
+ .exit = ehl_serial_exit,
};
static const struct lpss8250_board qrk_board = {
--
2.34.1
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