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Date: Thu, 30 Jan 2025 13:54:21 +0100
From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Kanchan Joshi <joshi.k@samsung.com>,
	josef@toxicpanda.com, dsterba@suse.com, clm@fb.com, axboe@kernel.dk,
	linux-btrfs@vger.kernel.org, linux-nvme@lists.infradead.org,
	linux-block@vger.kernel.org, gost.dev@samsung.com
Subject: Re: [RFC 0/3] Btrfs checksum offload
Message-ID: <20250130125421.GB19390@lst.de>
References: <CGME20250129141039epcas5p11feb1be4124c0db3c5223325924183a3@epcas5p1.samsung.com> <20250129140207.22718-1-joshi.k@samsung.com> <Z5pJGHAR7AWCC0T4@kbusch-mbp> <20250129154025.GA7047@lst.de> <Z5pteC56jYBRDupP@kbusch-mbp>
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On Wed, Jan 29, 2025 at 11:03:36AM -0700, Keith Busch wrote:
> > away.  But we also lose integrity protection over the wire, which would
> > be unfortunate.
> 
> If the "wire" is only PCIe, I don't see why it matters. What kind of
> wire corruption gets undetected by the protocol's encoding and LCRC that
> would get caught by the host's CRC payload?

The "wire" could be anything.  And includes a little more than than
than the wire, like the entire host side driver stack and the device
data path between the phy and wherever in the stack the PI insert/strip
accelerator sits.