mainline build failure due to 6c77676645ad ("iov_iter: Fix iter_xarray_get_pages{,_alloc}()")

[David Howells]

Al Viro <viro at zeniv.linux.org.uk> wrote:

> The reason we can't overflow on multiplication there, BTW, is that we have
> nr <= count, and count has come from weirdly open-coded
> 	DIV_ROUND_UP(size + offset, PAGE_SIZE)
> IMO we'd better make it explicit, so how about the following:
> 
> Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>

It seems reasonable.

Reviewed-by: David Howells <dhowells at redhat.com>