Re: [PATCH V5 03/13] mmc: host: Add CQE interface

Ulf Hansson
2017-08-24T09:24:42Z

On 24 August 2017 at 08:53, Adrian Hunter <adrian.hunter@intel.com> wrote:
> On 23/08/17 15:48, Ulf Hansson wrote:
>> On 23 August 2017 at 08:54, Adrian Hunter <adrian.hunter@intel.com> wrote:
>>> On 22/08/17 14:13, Ulf Hansson wrote:
>>>> On 10 August 2017 at 14:08, Adrian Hunter <adrian.hunter@intel.com> wrote:
>>>>> + void (*cqe_recovery_notifier)(struct mmc_host *,
>>>>> + struct mmc_request *);
>>>>
>>>> Normally we don't put callbacks in the struct mmc_host that someone
>>>> else than the host driver should assign - so this feels a bit upside
>>>> down.
>>>>
>>>> Is there any reason to why you didn't want to add a new API? Something
>>>> like mmc_cqe_recover(), which the host driver could call.
>>>
>>> That would make the host driver dependent on the block driver. There needs
>>> to be a function pointer, even if we wrap it in an API.
>>
>> Okay, I see. I guess we could put such pointer somewhere closer to the
>> mmc request queue.
>
> Another possibility is to put in into struct mmc_request like the "done"
> callback.

Yes, I think like that.

That would also solve the problem of having to protect the pointer as
the request would then have a corresponding life cycle to the block
device driver.

>
>>
>> Anyway, I didn't find out how this pointer was being protected from
>> concurrent access or perhaps that is managed via
>> mmc_claim|release_host()?
>
> It is assumed CQE is only used by the card driver so the callback can be set
> / reset in the card driver's probe / remove.
>
>> Moreover, I could find it ever it being
>> reset to NULL.
>
> Yeah, doesn't look like it gets reset.

Kind regards
Uffe