[PATCH v4 3/6] mm/gup: remove vmas parameter from get_user_pages_remote()

[Janosch Frank]

On 4/18/23 17:49, Lorenzo Stoakes wrote:
> The only instances of get_user_pages_remote() invocations which used the
> vmas parameter were for a single page which can instead simply look up the
> VMA directly. In particular:-
> 
> - __update_ref_ctr() looked up the VMA but did nothing with it so we simply
>    remove it.
> 
> - __access_remote_vm() was already using vma_lookup() when the original
>    lookup failed so by doing the lookup directly this also de-duplicates the
>    code.
> 
> We are able to perform these VMA operations as we already hold the
> mmap_lock in order to be able to call get_user_pages_remote().
> 
> As part of this work we add get_user_page_vma_remote() which abstracts the
> VMA lookup, error handling and decrementing the page reference count should
> the VMA lookup fail.
> 
> This forms part of a broader set of patches intended to eliminate the vmas
> parameter altogether.
> 
> Reviewed-by: Catalin Marinas <catalin.marinas at arm.com> (for arm64)
> Acked-by: David Hildenbrand <david at redhat.com>
> Signed-off-by: Lorenzo Stoakes <lstoakes at gmail.com>
> ---

For the s390 part:
Reviewed-by: Janosch Frank <frankja at linux.ibm.com>