Re: [PATCH v2 1/2] mm/vmalloc: export __vmalloc_node_range

[Christoph Hellwig]

On Tue, Jun 08, 2021 at 08:06:17PM +0200, Claudio Imbrenda wrote:
> The recent patches to add support for hugepage vmalloc mappings added a
> flag for __vmalloc_node_range to allow to request small pages.
> This flag is not accessible when calling vmalloc, the only option is to
> call directly __vmalloc_node_range, which is not exported.
> 
> This means that a module can't vmalloc memory with small pages.
> 
> Case in point: KVM on s390x needs to vmalloc a large area, and it needs
> to be mapped with small pages, because of a hardware limitation.
> 
> This patch exports __vmalloc_node_range so it can be used in modules
> too.

No.  I spent a lot of effort to mak sure such a low-level API is
not exported.