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Date: Sun, 24 Mar 2024 16:37:10 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Mina Almasry <almasrymina@google.com>
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Subject: Re: [RFC PATCH net-next v6 02/15] net: page_pool: create hooks for
 custom page providers
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 <CAHS8izOUi6qGp=LSQb_o5oph-EnhNOuhLkPSfbQRU3eniZvbdA@mail.gmail.com>
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On Fri, Mar 22, 2024 at 10:54:54AM -0700, Mina Almasry wrote:
> Sorry I don't mean to argue but as David mentioned, there are some
> plans in the works and ones not in the works to extend this to other
> memory types. David mentioned io_uring & Jakub's huge page use cases
> which may want to re-use this design. I have an additional one in
> mind, which is extending devmem TCP for storage devices. Currently
> storage devices do not support dmabuf and my understanding is that
> it's very hard to do so, and NVMe uses pci_p2pdma instead. I wonder if
> it's possible to extend devmem TCP in the future to support pci_p2pdma
> to support nvme devices in the future.

The block layer needs to suppotr dmabuf for this kind of I/O.
Any special netdev to block side channel will be NAKed before you can
even send it out.