Re: [PATCH 2/2] mmc: rtsx: add support for async request

[micky <micky_ching@realsil.com.cn>]

On 06/16/2014 04:42 PM, Ulf Hansson wrote:
>> @@ -36,7 +37,10 @@ struct realtek_pci_sdmmc {
>> >         struct rtsx_pcr         *pcr;
>> >         struct mmc_host         *mmc;
>> >         struct mmc_request      *mrq;
>> >+       struct workqueue_struct *workq;
>> >+#define SDMMC_WORKQ_NAME       "rtsx_pci_sdmmc_workq"
>> >
>> >+       struct work_struct      work;
> I am trying to understand why you need a work/workqueue to implement
> this feature. Is that really the case?
>
> Could you elaborate on the reasons?
Hi Uffe,

we need return as fast as possible in mmc_host_ops request(ops->request) 
callback,
so the mmc core can continue handle next request.
when next request everything is ready, it will wait previous done(if not 
done),
then call ops->request().

we can't use atomic context, because we use mutex_lock() to protect
resource, and we have to hold the lock during handle request.
So I use workq, we just queue a work and return in ops->request(),
The mmc core can continue without blocking at ops->request().

Best Regards.
micky.