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Date: Fri, 2 Feb 2024 17:09:18 +0200
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Howard Yen <howardyen@google.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
	Robin Murphy <robin.murphy@arm.com>, hch@lst.de,
	m.szyprowski@samsung.com, petr.tesarik.ext@huawei.com,
	rafael@kernel.org, broonie@kernel.org, james@equiv.tech,
	james.clark@arm.com, masahiroy@kernel.org,
	linux-kernel@vger.kernel.org, iommu@lists.linux.dev
Subject: Re: [PATCH] dma-coherent: add support for multi coherent rmems per
 dev
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References: <20240201093515.849873-1-howardyen@google.com>
 <f5b626ae-bda1-479f-bc14-b1fd7ba043cf@arm.com>
 <2024020156-reshuffle-salvaging-8161@gregkh>
 <CAJDAHvZ=XVZ-Ea1LVqfTnDXJ+J=PLbZNCZkuSpvdOtEsreguWw@mail.gmail.com>
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On Fri, Feb 02, 2024 at 12:40:59PM +0800, Howard Yen wrote:
> On Thu, Feb 1, 2024 at 11:41 PM Greg KH <gregkh@linuxfoundation.org> wrote:
> > On Thu, Feb 01, 2024 at 10:45:30AM +0000, Robin Murphy wrote:
> > > On 2024-02-01 9:35 am, Howard Yen wrote:

..

> I'm considering to modify the change to
> 
> 1. Move it into the dma_coherent_mem structure, like
> 
>      HEAD
> mem0->node
> 
> This case, if I check list_empty(mem0->node), it would give me the
> list is empty, but actually there is one rmem.
> 
> 2. Replace the pointer to a list_head.
> 
>     HEAD
> dma_mems ---> mem0->node
> 
> This case, if I check list_empty(dma_mems), it would give me the list
> is non-empty, it matches the actual status.
> 
> So, the 2nd looks reasonable, I'm going to upload a v2 patch with the
> 2nd approach, does that make sense?

I believe this is exactly what Robin told about "list to replace the pointer".

-- 
With Best Regards,
Andy Shevchenko