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Date: Fri, 20 Dec 2024 18:17:09 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: David Wei <dw@davidwei.uk>, io-uring@vger.kernel.org,
 netdev@vger.kernel.org, Jens Axboe <axboe@kernel.dk>, Paolo Abeni
 <pabeni@redhat.com>, "David S. Miller" <davem@davemloft.net>, Eric Dumazet
 <edumazet@google.com>, Jesper Dangaard Brouer <hawk@kernel.org>, David
 Ahern <dsahern@kernel.org>, Mina Almasry <almasrymina@google.com>,
 Stanislav Fomichev <stfomichev@gmail.com>, Joe Damato <jdamato@fastly.com>,
 Pedro Tammela <pctammela@mojatatu.com>
Subject: Re: [PATCH net-next v9 03/20] net: generalise net_iov chunk owners
Message-ID: <20241220181709.3e48c266@kernel.org>
In-Reply-To: <5d308d1b-4c9d-430e-b116-e669bd778b30@gmail.com>
References: <20241218003748.796939-1-dw@davidwei.uk>
	<20241218003748.796939-4-dw@davidwei.uk>
	<20241220141436.65513ff7@kernel.org>
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On Sat, 21 Dec 2024 00:50:37 +0000 Pavel Begunkov wrote:
> > Is there a good reason why dma addr is not part of net_iov_area?
> > net_iov_area is one chunk of continuous address space.
> > Instead of looping over pages in io_zcrx_map_area we could map
> > the whole thing in one go.  
> 
> It's not physically contiguous. The registration API takes
> contig user addresses, but that's not a hard requirement
> either.

Okay, I was thrown off by the base_virtual being in the common struct.
But it appears you don't use that?

AFAIR for devmem each area is physically contiguous if the region is 
not it gets split into areas.