| Message ID | YsftwaVowtU9/pgn@kili (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | PCI: endpoint: IS_ERR() vs NULL bug in pci_epf_test_init_dma_chan() | expand |
This patch changes for a tx dma channel. There is a similar problem for a rx one too. The code doesn't cause an error, but it is likely better to change to just NULL checking. 2022年7月8日(金) 17:41 Dan Carpenter <dan.carpenter@oracle.com>: > > The dma_request_channel() function doesn't return error pointers, it > returns NULL. > > Fixes: fff86dfbbf82 ("PCI: endpoint: Enable DMA tests for endpoints with DMA capabilities") > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > --- > It's surprising and unfortunate that dma_request_channel() returns NULL > while dma_request_chan_by_mask() returns error pointers. These days > static checkers will catch this so it's not as bad as it could be but > still not ideal. > > 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; > } > -- > 2.35.1 > Thanks, Shunsuke.
On Mon, Jul 11, 2022 at 02:50:14PM +0900, Shunsuke Mie wrote: > This patch changes for a tx dma channel. There is a similar problem for a > rx one too. The code doesn't cause an error, but it is likely better to > change to just NULL checking. > Yep. Thanks. I will resend. regards, dan carpenter
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; }
The dma_request_channel() function doesn't return error pointers, it returns NULL. Fixes: fff86dfbbf82 ("PCI: endpoint: Enable DMA tests for endpoints with DMA capabilities") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- It's surprising and unfortunate that dma_request_channel() returns NULL while dma_request_chan_by_mask() returns error pointers. These days static checkers will catch this so it's not as bad as it could be but still not ideal. drivers/pci/endpoint/functions/pci-epf-test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)