I'd it one step back. For BVECS we never need a get or pin. The block layer already does this, an the other callers should as well. For KVEC the same is true. For PIPE and xarray as you pointed out we can probably just do the pin, it is not like these are performance paths. So, I'd suggest to: - factor out the user backed and bvec cases from __iov_iter_get_pages_alloc into helper just to keep __iov_iter_get_pages_alloc readable. - for the pin case don't use the existing bvec helper at all, but copy the logic for the block layer for not pinning.
