Date:   Tue, 9 Nov 2021 22:21:44 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Jason Wang <jasowang@...hat.com>
Cc:     Arnd Bergmann <arnd@...db.de>, mst <mst@...hat.com>,
        kernel-janitors@...r.kernel.org,
        linux-kernel <linux-kernel@...r.kernel.org>,
        virtualization <virtualization@...ts.linux-foundation.org>,
        Wu Zongyong <wuzongyong@...ux.alibaba.com>
Subject: Re: [PATCH 1/2] eni_vdpa: Fix an error handling path in
 'eni_vdpa_probe()'

Le 09/11/2021 à 03:54, Jason Wang a écrit :
> On Tue, Nov 9, 2021 at 3:32 AM Christophe JAILLET
> <christophe.jaillet@...adoo.fr> wrote:
>>
>> Le 08/11/2021 à 06:55, Jason Wang a écrit :
>>> On Mon, Nov 8, 2021 at 12:15 AM Christophe JAILLET
>>> <christophe.jaillet@...adoo.fr> wrote:
>>>>
>>>> In the error handling path, a successful 'vp_legacy_probe()' should be
>>>> balanced by a corresponding 'vp_legacy_remove()' call, as already done in
>>>> the remove function.
>>>>
>>>> Add the missing call and update gotos accordingly.
>>>>
>>>> Fixes: e85087beedca ("eni_vdpa: add vDPA driver for Alibaba ENI")
>>>> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
>>>> ---
>>>>    drivers/vdpa/alibaba/eni_vdpa.c | 6 ++++--
>>>>    1 file changed, 4 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/vdpa/alibaba/eni_vdpa.c b/drivers/vdpa/alibaba/eni_vdpa.c
>>>> index 3f788794571a..12b3db6b4517 100644
>>>> --- a/drivers/vdpa/alibaba/eni_vdpa.c
>>>> +++ b/drivers/vdpa/alibaba/eni_vdpa.c
>>>> @@ -501,7 +501,7 @@ static int eni_vdpa_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>>>           if (!eni_vdpa->vring) {
>>>>                   ret = -ENOMEM;
>>>>                   ENI_ERR(pdev, "failed to allocate virtqueues\n");
>>>> -               goto err;
>>>> +               goto err_remove_vp_legacy;
>>>>           }
>>>>
>>>>           for (i = 0; i < eni_vdpa->queues; i++) {
>>>> @@ -513,11 +513,13 @@ static int eni_vdpa_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>>>           ret = vdpa_register_device(&eni_vdpa->vdpa, eni_vdpa->queues);
>>>>           if (ret) {
>>>>                   ENI_ERR(pdev, "failed to register to vdpa bus\n");
>>>> -               goto err;
>>>> +               goto err_remove_vp_legacy;
>>>>           }
>>>>
>>>>           return 0;
>>>>
>>>> +err_remove_vp_legacy:
>>>> +       vp_legacy_remove(&eni_vdpa->ldev);
>>>
>>> Won't vp_legacy_remove() be triggered by the put_devic() below?
>>
>> Hi, I'm sorry but i don't see how.
>>
>> My understanding is that:
>>     - on "put_device(&eni_vdpa->vdpa.dev);", the corresponding release
>> function will be called.
>>
>>     - This release function is the one recorded in the
>> '__vdpa_alloc_device()' function.
>>
>>     - So it should be 'vdpa_release_dev()'.
>>
>>     - This function, AFAIU, has no knowledge of 'vp_legacy_remove()' or
>> anything that could call it.
>>
>>
>> Unless I misread something or miss something obvious, I don't see how
>> 'vp_legacy_remove() would be called.
>>
>>
>> Could you elaborate?
> 
> I think the device should release the driver (see
> device_release_driver()) during during its deleting.

Hi, I still don't follow the logic and I don't understand how 
'vp_legacy_remove()' will finely be called, but it is not that important.

If it's fine for you, it's fine for me :)

CJ

> 
> Thanks
> 
>>
>> CJ
>>
>>>
>>> Thanks
>>>
>>>>    err:
>>>>           put_device(&eni_vdpa->vdpa.dev);
>>>>           return ret;
>>>> --
>>>> 2.30.2
>>>>
>>>
>>>
>>
> 
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