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Subject: Re: [PATCH] PCI: dwc: fix reference leak in
 pex_ep_event_pex_rst_deassert
To:     Vidya Sagar <vidyas@nvidia.com>,
        Zhang Qilong <zhangqilong3@huawei.com>,
        <lorenzo.pieralisi@arm.com>, <robh@kernel.org>,
        <bhelgaas@google.com>, <thierry.reding@gmail.com>
CC:     <linux-pci@vger.kernel.org>, <linux-tegra@vger.kernel.org>
References: <20201102143045.142121-1-zhangqilong3@huawei.com>
 <f09c0801-d584-3c27-d3e7-ca59a64a30d1@nvidia.com>
From:   Jon Hunter <jonathanh@nvidia.com>
Message-ID: <fa858756-8fe4-5049-b280-410d225a58a8@nvidia.com>
Date:   Mon, 25 Jan 2021 19:30:13 +0000
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On 03/11/2020 02:52, Vidya Sagar wrote:
>=20
>=20
> On 11/2/2020 8:00 PM, Zhang Qilong wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> pm_runtime_get_sync will increment pm usage counter even it
>> failed. Forgetting to pm_runtime_put_noidle will result in
>> reference leak in pex_ep_event_pex_rst_deassert, so we should
>> fix it.
>>
>> Fixes: c57247f940e8e ("PCI: tegra: Add support for PCIe endpoint mode
>> in Tegra194")
>> Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com>
>> ---
>> =C2=A0 drivers/pci/controller/dwc/pcie-tegra194.c | 1 +
>> =C2=A0 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c
>> b/drivers/pci/controller/dwc/pcie-tegra194.c
>> index f920e7efe118..936510b5c649 100644
>> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
>> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
>> @@ -1662,6 +1662,7 @@ static void pex_ep_event_pex_rst_deassert(struct
>> tegra_pcie_dw *pcie)
>>
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ret =3D pm_runtime_get_=
sync(dev);
>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (ret < 0) {
>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=
=A0=C2=A0=C2=A0 pm_runtime_put_noidle(dev);
> Why can't we call pm_runtime_put_sync(dev) as that is what is being
> called in failure cases anyway further down in this API?


Simply because this is a failure case where the get_sync did not
complete. So this change is correct, however, now we have
pm_runtime_resume_and_get(), it is better/simpler just to replace the
pm_runtime_get_sync with pm_runtime_resume_and_get.

Cheers
Jon

--=20
nvpublic