2022-02-15 05:24:59

by 王擎

Subject: [PATCH] tty: serial: 8250: add missing pci_dev_put() before return

From: Wang Qing <[email protected]>

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

Signed-off-by: Wang Qing <[email protected]>
---
drivers/tty/serial/8250/8250_lpss.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
index d3bafec..57e462f
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -149,6 +149,8 @@ static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
/* Disable TX counter interrupts */
writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT);

+ pci_dev_put(dma_dev);
+
return 0;
}

--
2.7.4

2022-02-15 06:33:52

by Jiri Slaby

Subject: Re: [PATCH] tty: serial: 8250: add missing pci_dev_put() before return

On 15. 02. 22, 6:55, Jiri Slaby wrote:
> On 15. 02. 22, 3:00, Qing Wang wrote:
>> From: Wang Qing <[email protected]>
>>
>> pci_get_slot() increases its reference count, the caller must
>> decrement the reference count by calling pci_dev_put()
>>
>> Signed-off-by: Wang Qing <[email protected]>
>> ---
>>   drivers/tty/serial/8250/8250_lpss.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/tty/serial/8250/8250_lpss.c
>> b/drivers/tty/serial/8250/8250_lpss.c
>> index d3bafec..57e462f
>> --- a/drivers/tty/serial/8250/8250_lpss.c
>> +++ b/drivers/tty/serial/8250/8250_lpss.c
>> @@ -149,6 +149,8 @@ static int byt_serial_setup(struct lpss8250 *lpss,
>> struct uart_port *port)
>>       /* Disable TX counter interrupts */
>>       writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT);
>> +    pci_dev_put(dma_dev);
>
>
> What about the "return -ENODEV" few lines above?

On the top of that, the code stores the pointer to the dev:
param->dma_dev = &dma_dev->dev;

So we should likely put the device in ->exit(), not ->setup().

thanks,
--
js
suse labs

2022-02-15 08:05:25

by Jiri Slaby

Subject: Re: [PATCH] tty: serial: 8250: add missing pci_dev_put() before return

On 15. 02. 22, 3:00, Qing Wang wrote:
> From: Wang Qing <[email protected]>
>
> pci_get_slot() increases its reference count, the caller must
> decrement the reference count by calling pci_dev_put()
>
> Signed-off-by: Wang Qing <[email protected]>
> ---
> drivers/tty/serial/8250/8250_lpss.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
> index d3bafec..57e462f
> --- a/drivers/tty/serial/8250/8250_lpss.c
> +++ b/drivers/tty/serial/8250/8250_lpss.c
> @@ -149,6 +149,8 @@ static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
> /* Disable TX counter interrupts */
> writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT);
>
> + pci_dev_put(dma_dev);


What about the "return -ENODEV" few lines above?

> return 0;
> }
>


--
js
suse labs

2022-02-15 16:01:43

by Andy Shevchenko

Subject: Re: [PATCH] tty: serial: 8250: add missing pci_dev_put() before return

On Tue, Feb 15, 2022 at 07:02:57AM +0100, Jiri Slaby wrote:
> On 15. 02. 22, 6:55, Jiri Slaby wrote:
> > On 15. 02. 22, 3:00, Qing Wang wrote:
> > > From: Wang Qing <[email protected]>
> > >
> > > pci_get_slot() increases its reference count, the caller must
> > > decrement the reference count by calling pci_dev_put()

Wang, thank you for the report!

...

> > What about the "return -ENODEV" few lines above?
>
> On the top of that, the code stores the pointer to the dev:
> param->dma_dev = &dma_dev->dev;
>
> So we should likely put the device in ->exit(), not ->setup().

I think I may fix all these and send a new version.

--
With Best Regards,
Andy Shevchenko