netdev - Re: Networking people smell funny and make poor life choices

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Message-ID: <Z9Gjnl5tfpY7xgea@infradead.org>
Date: Wed, 12 Mar 2025 08:09:18 -0700
From: Christoph Hellwig <hch@...radead.org>
To: Matthew Wilcox <willy@...radead.org>
Cc: Hannes Reinecke <hare@...e.de>, Vlastimil Babka <vbabka@...e.cz>,
	Hannes Reinecke <hare@...e.com>, Boris Pismenny <borisp@...dia.com>,
	John Fastabend <john.fastabend@...il.com>,
	Jakub Kicinski <kuba@...nel.org>, Sagi Grimberg <sagi@...mberg.me>,
	"linux-nvme@...ts.infradead.org" <linux-nvme@...ts.infradead.org>,
	"linux-block@...r.kernel.org" <linux-block@...r.kernel.org>,
	linux-mm@...ck.org, Harry Yoo <harry.yoo@...cle.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: Networking people smell funny and make poor life choices

On Wed, Mar 05, 2025 at 06:11:24PM +0000, Matthew Wilcox wrote:
> Networking needs to follow block's lead and STOP GETTING REFCOUNTS ON
> PAGES.

The block layer never took references on pages.  The direct I/O helpers
that just happened to set in block/ did hold references and abused some
field in the bio for it (and still do for the pinning), but the reference
was (and the pin now is) owned by the submitter.

The block layer model has always been that the submitter needs to ensure
memory stays allocated until the I/O has completed.  Which IMHO is the
only sane model for dealing with memory lifetimes vs I/O, and something
networking absolutely should follow.