Date:   Tue, 11 Jan 2022 19:02:24 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Logan Gunthorpe <logang@deltatee.com>
Cc:     Matthew Wilcox <willy@infradead.org>, linux-kernel@vger.kernel.org,
        Christoph Hellwig <hch@lst.de>,
        Joao Martins <joao.m.martins@oracle.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Ming Lei <ming.lei@redhat.com>, linux-block@vger.kernel.org,
        netdev@vger.kernel.org, linux-mm@kvack.org,
        linux-rdma@vger.kernel.org, dri-devel@lists.freedesktop.org,
        nvdimm@lists.linux.dev
Subject: Re: Phyr Starter
Message-ID: <20220111230224.GT2328285@nvidia.com>
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On Tue, Jan 11, 2022 at 03:57:07PM -0700, Logan Gunthorpe wrote:
> 
> 
> On 2022-01-11 3:53 p.m., Jason Gunthorpe wrote:
> > I just want to share the whole API that will have to exist to
> > reasonably support this flexible array of intervals data structure..
> 
> Is that really worth it? I feel like type safety justifies replicating a
> bit of iteration and allocation infrastructure. Then there's no silly
> mistakes of thinking one array is one thing when it is not.

If it is a 'a bit' then sure, but I suspect doing a good job here will
be a lot of code here.

Look at how big scatterlist is, for instance.

Maybe we could have a generic 64 bit interval arry and then two type
wrappers that do dma and physaddr casting? IDK.

Not sure type safety of DMA vs CPU address is critical?

Jason