Re: cleanup the RAID5 XOR library

Andrew Morton
2026-02-26T18:20:45Z

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.