linux-kernel - Re: [PATCH 1/2] PCI: dra7xx: Fix link removal on probe error

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Message-ID: <CAL_JsqJ5nr6xJoTv3A6UPMMDXhWKcwSEUA3ux3kK8OMWQxdc6w@mail.gmail.com>
Date:   Sat, 15 Jan 2022 10:02:00 -0600
From:   Rob Herring <robh@...nel.org>
To:     Luca Ceresoli <luca@...aceresoli.net>,
        Saravana Kannan <saravanak@...gle.com>
Cc:     PCI <linux-pci@...r.kernel.org>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        linux-omap <linux-omap@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Sekhar Nori <nsekhar@...com>
Subject: Re: [PATCH 1/2] PCI: dra7xx: Fix link removal on probe error

+Saravana

On Tue, Jan 11, 2022 at 4:35 AM Luca Ceresoli <luca@...aceresoli.net> wrote:
>
> Hi Rob,
>
> On 16/12/21 10:08, Luca Ceresoli wrote:
> > Hi Rob,
> >
> > thanks for the quick feedback!
> >
> > On 14/12/21 23:42, Rob Herring wrote:
> >> On Tue, Dec 14, 2021 at 4:15 PM Luca Ceresoli <luca@...aceresoli.net> wrote:
> >>>
> >>> If a devm_phy_get() calls fails with phy_count==N (N > 0), then N links
> >>> have already been added by device_link_add() and won't be deleted by
> >>> device_link_del() because the code calls 'return' and not 'goto err_link'.
> >>>
> >>> Fix in a very simple way by doing all the devm_phy_get() calls before all
> >>> the device_link_add() calls.
> >>>
> >>> Fixes: 7a4db656a635 ("PCI: dra7xx: Create functional dependency between PCIe and PHY")
> >>> Signed-off-by: Luca Ceresoli <luca@...aceresoli.net>
> >>> ---
> >>>  drivers/pci/controller/dwc/pci-dra7xx.c | 2 ++
> >>>  1 file changed, 2 insertions(+)
> >>>
> >>> diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c
> >>> index f7f1490e7beb..2ccc53869e13 100644
> >>> --- a/drivers/pci/controller/dwc/pci-dra7xx.c
> >>> +++ b/drivers/pci/controller/dwc/pci-dra7xx.c
> >>> @@ -757,7 +757,9 @@ static int dra7xx_pcie_probe(struct platform_device *pdev)
> >>>                 phy[i] = devm_phy_get(dev, name);
> >>>                 if (IS_ERR(phy[i]))
> >>>                         return PTR_ERR(phy[i]);
> >>> +       }
> >>>
> >>> +       for (i = 0; i < phy_count; i++) {
> >>>                 link[i] = device_link_add(dev, &phy[i]->dev, DL_FLAG_STATELESS);
> >>
> >> I think this should happen automatically now with fw_devlink being
> >> enabled by default. Can you try?
> >
> > Do you mean removal should be done automatically? I think they are not
> > due to the DL_FLAG_STATELESS flag.
>
> I would love to have feedback because, as said, I think my patch is
> correct, but if I'm wrong (which might well be) I have to drop patch 1
> and rewrite patch 2 in a slightly more complex form.

I mean that why do you need explicit dependency tracking here when
dependencies on a PHY should happen automatically now. IOW, what is
special about this driver and dependency?

Rob