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Date: Tue, 4 Jun 2024 04:44:34 -0700
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Subject: Re: [PATCH v20 02/12] Add infrastructure for copy offload in block
 and request layer.
To: Christoph Hellwig <hch@lst.de>
Cc: Nitesh Shetty <nj.shetty@samsung.com>, Damien Le Moal
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From: Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <20240604044042.GA29094@lst.de>
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On 6/3/24 21:40, Christoph Hellwig wrote:
> There is no requirement to process them synchronously, there is just
> a requirement to preserve the order.  Note that my suggestion a few
> arounds ago also included a copy id to match them up.  If we don't
> need that I'm happy to leave it away.  If need it it to make stacking
> drivers' lifes easier that suggestion still stands.

Including an ID in REQ_OP_COPY_DST and REQ_OP_COPY_SRC operations sounds
much better to me than abusing the merge infrastructure for combining
these two operations into a single request. With the ID-based approach
stacking drivers are allowed to process copy bios asynchronously and it
is no longer necessary to activate merging for copy operations if
merging is disabled (QUEUE_FLAG_NOMERGES).

Thanks,

Bart.