Re: [RFC PATCH v2 05/47] hugetlb: make hugetlb_vma_lock_alloc return its failure reason

[Mike Kravetz]

On 10/21/22 16:36, James Houghton wrote:
> Currently hugetlb_vma_lock_alloc doesn't return anything, as there is no
> need: if it fails, PMD sharing won't be enabled. However, HGM requires
> that the VMA lock exists, so we need to verify that
> hugetlb_vma_lock_alloc actually succeeded. If hugetlb_vma_lock_alloc
> fails, then we can pass that up to the caller that is attempting to
> enable HGM.

No serious objections to this change ...

However, there are currently only two places today where hugetlb_vma_lock_alloc
is called: hugetlb_reserve_pages and hugetlb_vm_op_open.  hugetlb_reserve_pages
is not an issue.  Since hugetlb_vm_op_open (as a defined vm_operation) returns
void, I am not sure how you plan to pass up an allocation failure.
Suspect this will become evident in subsequent patches.
-- 
Mike Kravetz