Re: cleanup the RAID5 XOR library

On Thu, 26 Feb 2026 07:10:12 -0800 Christoph Hellwig [off-list ref] 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.