Re: [PATCH v2] drivers: spi: Insert the missing pci_dev_put()before return

Geert Uytterhoeven
2024-08-30T08:55:20Z

Hi Yang,

On Thu, Aug 29, 2024 at 5:35 AM Yang Ruibin <11162571@vivo.com> wrote:
> Increase the reference count by calling pci_get_slot(), and remember to
> decrement the reference count by calling pci_dev_put().
>
> Signed-off-by: Yang Ruibin <11162571@vivo.com>

Thanks for your patch, which is now commit 8a0ec8c2d736961f ("spi:
Insert the missing pci_dev_put()before return") in spi/for-next.

> --- a/drivers/spi/spi-pxa2xx-pci.c
> +++ b/drivers/spi/spi-pxa2xx-pci.c
> @@ -146,8 +146,10 @@ static int lpss_spi_setup(struct pci_dev *dev, struct pxa2xx_spi_controller *c)
> c->num_chipselect = 1;
>
> ret = pxa2xx_spi_pci_clk_register(dev, ssp, 50000000);
> - if (ret)
> + if (ret) {
> + pci_dev_put(dma_dev);

dma_dev is still uninitialized at this point.

> return ret;
> + }
>
> dma_dev = pci_get_slot(dev->bus, PCI_DEVFN(PCI_SLOT(dev->devfn), 0));

dma_dev is initialized only here...

> ret = devm_add_action_or_reset(&dev->dev, lpss_dma_put_device, dma_dev);

... and freed automatically by lpss_dma_put_device() in case of
any later failures since commit 609d7ffdc42199a0 ("spi: pxa2xx-pci:
Balance reference count for PCI DMA device") in v5.18.

> @@ -222,8 +224,10 @@ static int mrfld_spi_setup(struct pci_dev *dev, struct pxa2xx_spi_controller *c)
> }
>
> ret = pxa2xx_spi_pci_clk_register(dev, ssp, 25000000);
> - if (ret)
> + if (ret) {
> + pci_dev_put(dma_dev);
> return ret;
> + }
>
> dma_dev = pci_get_slot(dev->bus, PCI_DEVFN(21, 0));
> ret = devm_add_action_or_reset(&dev->dev, lpss_dma_put_device, dma_dev);

Likewise.

Hence this patch is not needed, and introduced two bugs.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds