linux-kernel - Re: [PATCH v4 1/2] staging: most: dim2: read done

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Date:   Thu, 20 Oct 2022 22:11:44 +0530
From:   Deepak R Varma <drv@...lo.com>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     outreachy@...ts.linux.dev, linux-staging@...ts.linux.dev,
        linux-kernel@...r.kernel.org, kumarpraveen@...ux.microsoft.com,
        saurabh.truth@...il.com
Subject: Re: [PATCH v4 1/2] staging: most: dim2: read done_buffers count
 locally from HDM channel

On Thu, Oct 20, 2022 at 05:03:14PM +0200, Greg KH wrote:
> On Thu, Oct 20, 2022 at 01:24:53AM +0530, Deepak R Varma wrote:
> > The function dim_get_channel_state only serves to initialize the ready and
> > done_buffers fields of the structure passed as its second argument. In
> > service_done_flag, this structure is never used again and the only purpose
> > of the call is to get the value that is put in the done_buffers field.
> > But that value is just the done_sw_buffers_number field of the call's
> > first argument.  So the whole call is useless, and we can just replace it
> > with an access to this field.
>
> Are you sure it is useless?

Hello,
pardon my limited understanding, but I think this function call is not
necessary.

>
> You have changed the logic here, you are now thinking that this value
> can never change, while before you were ensured of getting the "correct"
> value as it is under the lock when the function is called.

I may be wrong, but I do not think there is a change in the long, but I may
entirely wrong. The function was called from inside the lock scope, now we are
extracting the value directly, still inside the lock scope. This should be safe.

>
> I can't take this type of change as a "cleanup" patch for outreachy
> unless you have the hardware as it is NOT a basic "checkpatch" style
> cleanup at all.

Sure. That is fine.

>
> If you want to get this change accepted, please work with the maintainer
> of the code and get them to agree that the change is correct.  And if it
> is, odds are more things also would need to be cleaned up at the same
> time, right?

I am eagerly waiting for a feedback from the maintainer. If they agree with my
viewpoint, I will continue to work on this change outside of the clean up patch
tasks. I will be happy to :)

Thank you Greg!
./drv

>
> thanks,
>
> greg k-h
>