Re: [PATCH v3] mmc: Convert from tasklet to BH workqueue

[Christian Loehle <christian.loehle@arm.com>]

On 6/21/24 10:53, Wolfram Sang wrote:
> Hi,
> 
> On Tue, Jun 18, 2024 at 03:52:07PM GMT, Allen Pais wrote:
>> The only generic interface to execute asynchronously in the BH context is
>> tasklet; however, it's marked deprecated and has some design flaws. To
>> replace tasklets, BH workqueue support was recently added. A BH workqueue
>> behaves similarly to regular workqueues except that the queued work items
>> are executed in the BH context.
>>
>> This patch converts drivers/mmc/* from tasklet to BH workqueue.
>>
>> Based on the work done by Tejun Heo <tj@kernel.org>
> 
> Has this been fully build-tested?

Obviously not, FWIW I noted this on v1:
https://lore.kernel.org/linux-mmc/9c31b697-3d80-407a-82b3-cfbb19fafb31@arm.com/
But hadn't looked at the patch since then, sorry.

> 
> ===
> drivers/mmc/host/renesas_sdhi_internal_dmac.c: In function ‘renesas_sdhi_internal_dmac_complete_work_fn’:
> ./include/linux/container_of.h:20:54: error: ‘struct tmio_mmc_host’ has no member named ‘dma_complete’
> ===
> 
> In deed, 'dma_complete' is only in 'struct renesas_sdhi_dma'. From
> there, we can get to the parent 'struct renesas_sdhi' using
> container_of. But then, I don't see a way to go to 'struct
> tmio_mmc_host' from there. The other way around is possible because
> there is the pointer 'struct tmio_mmc_data *pdata' in the TMIO struct
> pointing to the data contained in 'struct renesas_sdhi'. 'host_to_priv()'
> does the math. But I don't see a path the other way around.
> 
> So, it doesn't look like the workqueue interface can provide a
> generic pointer like tasklets could do? This means we have to add a
> pointer from 'struct renesas_sdhi' to 'struct tmio_mmc_host'?
> 
> All the best,
> 
>    Wolfram
>