2022-07-07 13:48:50

by Peng Wu

Subject: [PATCH] PCI: endpoint: Fix a NULL vs IS_ERR() check in pci_epf_test_init_dma_chan()

On failure, dma_request_channel() returns NULL and not a
ERR_PTR() value. Fix return value checking by using is NULL.

Signed-off-by: Peng Wu <[email protected]>
---
drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 34aac220dd4c..eed6638ab71d 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -221,7 +221,7 @@ static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test)
filter.dma_mask = BIT(DMA_MEM_TO_DEV);
dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter);

- if (IS_ERR(dma_chan)) {
+ if (!dma_chan) {
dev_info(dev, "Failed to get private DMA tx channel. Falling back to generic one\n");
goto fail_back_rx;
}
--
2.17.1

2022-07-11 22:49:46

by Bjorn Helgaas

Subject: Re: [PATCH] PCI: endpoint: Fix a NULL vs IS_ERR() check in pci_epf_test_init_dma_chan()

[+cc Dan, Shunsuke]

On Thu, Jul 07, 2022 at 01:12:15PM +0000, Peng Wu wrote:
> On failure, dma_request_channel() returns NULL and not a
> ERR_PTR() value. Fix return value checking by using is NULL.
>
> Signed-off-by: Peng Wu <[email protected]>

Thanks for the patch. Dan posted the same thing later [1].

I'd be happy to do this, but Shunsuke suggested that the rx path
should be changed similarly, so I'll look for a patch that does both.

[1] https://lore.kernel.org/r/YsftwaVowtU9/pgn@kili
[2] https://lore.kernel.org/r/CANXvt5rK98-cEMgpzopY9POOK8a5=VDib8uKPLgJakOG=hRfwQ@mail.gmail.com

> ---
> drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 34aac220dd4c..eed6638ab71d 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -221,7 +221,7 @@ static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test)
> filter.dma_mask = BIT(DMA_MEM_TO_DEV);
> dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter);
>
> - if (IS_ERR(dma_chan)) {
> + if (!dma_chan) {
> dev_info(dev, "Failed to get private DMA tx channel. Falling back to generic one\n");
> goto fail_back_rx;
> }
> --
> 2.17.1
>