[PATCH v1 10/16] mm/memory: use __zap_vma_range() in zap_vma_for_reaping()

[Lorenzo Stoakes (Oracle)]

On Fri, Feb 27, 2026 at 09:08:41PM +0100, David Hildenbrand (Arm) wrote:
> Let's call __zap_vma_range() instead of unmap_page_range() to prepare
> for further cleanups.
>
> To keep the existing behavior, whereby we do not call uprobe_munmap()
> which could block, add a new "reaping" member to zap_details and use it.

I am always in favour of making further use of helper structs :)

>
> Likely we should handle the possible blocking in uprobe_munmap()
> differently, but for now keep it unchanged.
>
> Signed-off-by: David Hildenbrand (Arm) <david at kernel.org>

OK this looks like it's doing the equivalent of what was there before, so:

Reviewed-by: Lorenzo Stoakes (Oracle) <ljs at kernel.org>

> ---
>  include/linux/mm.h |  1 +
>  mm/memory.c        | 13 +++++++++----
>  2 files changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 21b67c203e62..4710f7c7495a 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2800,6 +2800,7 @@ struct zap_details {
>  	struct folio *single_folio;	/* Locked folio to be unmapped */
>  	bool skip_cows;			/* Do not zap COWed private pages */
>  	bool reclaim_pt;		/* Need reclaim page tables? */
> +	bool reaping;			/* Reaping, do not block. */
>  	zap_flags_t zap_flags;		/* Extra flags for zapping */
>  };
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 7d7c24c6917c..394b2e931974 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2079,14 +2079,18 @@ static void __zap_vma_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
>  		unsigned long start, unsigned long end,
>  		struct zap_details *details)
>  {
> +	const bool reaping = details && details->reaping;
> +
>  	VM_WARN_ON_ONCE(start >= end || !range_in_vma(vma, start, end));
>
> -	if (vma->vm_file)
> +	/* uprobe_munmap() might sleep, so skip it when reaping. */
> +	if (vma->vm_file && !reaping)
>  		uprobe_munmap(vma, start, end);
>
>  	if (unlikely(is_vm_hugetlb_page(vma))) {
>  		zap_flags_t zap_flags = details ? details->zap_flags : 0;
>
> +		VM_WARN_ON_ONCE(reaping);
>  		/*
>  		 * vm_file will be NULL when we fail early while instantiating
>  		 * a new mapping. In this case, no pages were mapped yet and
> @@ -2111,11 +2115,12 @@ static void __zap_vma_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
>   */
>  int zap_vma_for_reaping(struct vm_area_struct *vma)
>  {
> +	struct zap_details details = {
> +		.reaping = true,
> +	};
>  	struct mmu_notifier_range range;
>  	struct mmu_gather tlb;
>
> -	VM_WARN_ON_ONCE(is_vm_hugetlb_page(vma));
> -

I guess because you've moved this safety check into __zap_vma_range()?

>  	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm,
>  				vma->vm_start, vma->vm_end);
>  	tlb_gather_mmu(&tlb, vma->vm_mm);
> @@ -2123,7 +2128,7 @@ int zap_vma_for_reaping(struct vm_area_struct *vma)
>  		tlb_finish_mmu(&tlb);
>  		return -EBUSY;
>  	}
> -	unmap_page_range(&tlb, vma, range.start, range.end, NULL);
> +	__zap_vma_range(&tlb, vma, range.start, range.end, &details);
>  	mmu_notifier_invalidate_range_end(&range);
>  	tlb_finish_mmu(&tlb);
>  	return 0;
> --
> 2.43.0
>