Messages in this thread | | | From | Bobby Jones <> | Date | Thu, 30 Jan 2020 12:26:01 -0800 | Subject | Re: [PATCH net] net: thunderx: workaround BGX TX Underflow issue |
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On Thu, Jan 30, 2020 at 9:10 AM Jakub Kicinski <kuba@kernel.org> wrote: > > On Wed, 29 Jan 2020 14:36:09 -0800, Robert Jones wrote: > > From: Tim Harvey <tharvey@gateworks.com> > > > > While it is not yet understood why a TX underflow can easily occur > > for SGMII interfaces resulting in a TX wedge. It has been found that > > disabling/re-enabling the LMAC resolves the issue. > > > > Signed-off-by: Tim Harvey <tharvey@gateworks.com> > > Reviewed-by: Robert Jones <rjones@gateworks.com> > > Sunil or Robert (i.e. one of the maintainers) will have to review this > patch (as indicated by Dave by marking it with "Needs Review / ACK" in > patchwork). > > At a quick look there are some things which jump out at me: > > > +static int bgx_register_intr(struct pci_dev *pdev) > > +{ > > + struct bgx *bgx = pci_get_drvdata(pdev); > > + struct device *dev = &pdev->dev; > > + int num_vec, ret; > > + > > + /* Enable MSI-X */ > > + num_vec = pci_msix_vec_count(pdev); > > + ret = pci_alloc_irq_vectors(pdev, num_vec, num_vec, PCI_IRQ_MSIX); > > + if (ret < 0) { > > + dev_err(dev, "Req for #%d msix vectors failed\n", num_vec); > > + return 1; > > Please propagate real error codes, or make this function void as the > caller never actually checks the return value. > > > + } > > + sprintf(bgx->irq_name, "BGX%d", bgx->bgx_id); > > + ret = request_irq(pci_irq_vector(pdev, GMPX_GMI_TX_INT), > > There is a alloc_irq and request_irq call added in this patch but there > is never any freeing. Are you sure this is fine? Devices can be > reprobed (unbound and bound to drivers via sysfs).
I agree there needs to be accompanying free calls. I'm referencing drivers/net/ethernet/cavium/thunder/nic_main.c and see instances of both pci_free_irq_vectors() and free_irq(). My initial thought was that I should use pci_free_irq_vectors() in the error check conditional of the above request irq and also in the bgx_remove() function. Would that be appropriate in this case?
I'd also plan on using a conditional like this for the free calls:
if (bgx->irq_name) pci_free_irq_vectors(pdev);
I'm new to kernel development so suggestions are welcome.
> > > + bgx_intr_handler, 0, bgx->irq_name, bgx); > > Please align the continuation line with the opening bracket (checkpatch > --strict should help catch this). > > > + if (ret) > > + return 1; > > + > > + return 0; > > +}
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