Re: [PATCHv2 6/6] block: validate user space vectors during extraction

[Christoph Hellwig <hch@lst.de>]

On Tue, Jun 23, 2026 at 10:17:37AM -0600, Keith Busch wrote:
> Exactly, the in-kernel users of ITER_BVEC that allocate their own
> buffers are, as far as I know, aligned already. Fabric storage targets
> like nvme allocate their own SGLs on page boundaries so the bio is
> aligned at the point it was constructed.
> 
> The ones that forward user buffers like loop and zloop are addressed in
> the previous two patches. They generally should have been fine for most
> hardware without those updates, but they're included in case a backing
> device has more restrictive constraints than 512b "sector_t" aligned.
> 
> The only other user space provided alignment that I think may trip this
> up is the io_uring registered buffer, so that's what I'm trying to call
> out here.

Sounds reasonable, but it would be really helpful to have this in
the API documentation somewhere..

Talking about documented APIs and related bits:  do you still plan
to get back to exposing our pre-vector alignment requirements and
add tests to blktests/xfstests based on that?