[Cluster-devel] [PATCH v3 1/7] iov_iter: Introduce fault_in_iov_iter helper

[Al Viro]

On Fri, Jul 23, 2021 at 10:58:34PM +0200, Andreas Gruenbacher wrote:
> Introduce a new fault_in_iov_iter helper for manually faulting in an iterator.
> Other than fault_in_pages_writeable(), this function is non-destructive.
> 
> We'll use fault_in_iov_iter in gfs2 once we've determined that the iterator
> passed to .read_iter or .write_iter isn't in memory.

Hmm...  I suspect that this is going to be much heavier for read access
than the existing variant.  Do we ever want it for anything other than
writes?