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To:     Jerome Glisse <jglisse@redhat.com>
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From:   Logan Gunthorpe <logang@deltatee.com>
Message-ID: <25034ee7-de03-ed77-78e0-2333f46897cc@deltatee.com>
Date:   Thu, 1 Mar 2018 14:22:56 -0700
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Subject: Re: [PATCH v2 00/10] Copy Offload in NVMe Fabrics with P2P PCI Memory
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On 01/03/18 02:18 PM, Jerome Glisse wrote:
> This is pretty easy to do with HMM:
> 
> unsigned long hmm_page_to_phys_pfn(struct page *page)
This is not useful unless you want to go through all the kernel paths we 
are using and replace page_to_phys() and friends with something else 
that calls an HMM function when appropriate...

The problem isn't getting the physical address from a page, it's that we 
are passing these pages through various kernel interfaces which expect 
pages that work in the usual manner. (Look at the code: we quite simply 
provide a way to get the PCI bus address from a page when necessary).

Logan