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

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Message-ID: <4579940c-27dc-733e-4022-ebea4671c839@lucaceresoli.net>
Date:   Tue, 11 Jan 2022 11:35:48 +0100
From:   Luca Ceresoli <luca@...aceresoli.net>
To:     Rob Herring <robh@...nel.org>
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

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.

About your request to try: I only have hardware with phy_count==1, and
anyway I cannot access it at the moment. :(

Regards.
-- 
Luca