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Date: Thu, 26 Feb 2026 10:20:37 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Christoph Hellwig <hch@lst.de>
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Subject: Re: cleanup the RAID5 XOR library
Message-Id: <20260226102037.b855483efa0bf23c72d130d3@linux-foundation.org>
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On Thu, 26 Feb 2026 07:10:12 -0800 Christoph Hellwig <hch@lst.de> wrote:

> the XOR library used for the RAID5 parity is a bit of a mess right now.
> The main file sits in crypto/ despite not being cryptography and not
> using the crypto API, with the generic implementations sitting in
> include/asm-generic and the arch implementations sitting in an asm/
> header in theory.  The latter doesn't work for many cases, so
> architectures often build the code directly into the core kernel, or
> create another module for the architecture code.
> 
> Changes this to a single module in lib/ that also contains the
> architecture optimizations, similar to the library work Eric Biggers
> has done for the CRC and crypto libraries later.  After that it changes
> to better calling conventions that allow for smarter architecture
> implementations (although none is contained here yet), and uses
> static_call to avoid indirection function call overhead.

Thanks, I'll add this to mm.git's mm-nonmm-unstable tree for some
testing in linux-next.