Re: [PATCH v5 10/16] iio: buffer-dmaengine: add devm_iio_dmaengine_buffer_setup_ext2()

[David Lechner]

On 12/6/24 3:36 PM, David Lechner wrote:
> On 11/24/24 11:16 AM, Jonathan Cameron wrote:
>> On Fri, 15 Nov 2024 14:18:49 -0600
>> David Lechner <dlechner@xxxxxxxxxxxx> wrote:
>>
>>> Add a new devm_iio_dmaengine_buffer_setup_ext2() function to handle
>>> cases where the DMA channel is managed by the caller rather than being
>>> requested and released by the iio_dmaengine module.
>>>
>>> Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx>
>> Fresh read and I'm wondering if the lifetimes in here can be managed
>> more simply either by pushing the DMA channel get down, or dragging
>> the release up.   Basically I'd like to see them at the same level
>> of nesting in the code.  If it ends up being necessary to duplicate
>> more code that is fine if it makes this easier to reason about.
>>
> 
> One option could be instead of introducing a 2nd function, change

Oops. The new function is devm_ so would still need a 2nd function
but changing iio_dmaengine_buffer_setup_ext() to have basically
the same signature would still avoid the asymmetry.

> the existing iio_dmaengine_buffer_setup_ext() to use the signature
> of the proposed devm_iio_dmaengine_buffer_setup_ext2(). There are
> only two users of these functions. So we could move the dma chan
> request/release out to the drivers for those.
> 
> Otherwise, we can't completely get rid of the owns_chan bit.
>