Re: [RFC PATCH] blk-integrity: support arbitrary buffer alignment

[Christoph Hellwig <hch@lst.de>]

On Wed, Nov 05, 2025 at 07:42:41AM -0700, Keith Busch wrote:
> This generally does pass 'void *' to contiguous protection data. If the
> actual protection payload is spread across multiple segments, though, we
> don't have contiguous data, so we have to bounce it through something.
> Declaring the union on the stack provides this memory for that unusual
> case. If the bip segment is big enough, we point the 'void *' directly
> at it; if not, we point it to the temporary onstack allocation. Using
> a union ensures that it's definitely big enough for any checksum type.

The union contains pointers, which are always 8 bytes.  But I guess
I can see now how this didn't blow up, assuming this was only tested
on classic PI, as the tuples are just 8 bytes and you just used the
pointer as storage?  I.e. these aren't supposed to be pointers, but
values?