Re: [PATCH v1 15/16] mm: rename zap_vma_ptes() to zap_special_vma_range()

["Lorenzo Stoakes (Oracle)" <ljs@kernel.org>]

On Fri, Feb 27, 2026 at 09:08:46PM +0100, David Hildenbrand (Arm) wrote:
> zap_vma_ptes() is the only zapping function we export to modules.
>
> It's essentially a wrapper around zap_vma_range(), however, with some
> safety checks:
> * That the passed range fits fully into the VMA
> * That it's only used for VM_PFNMAP
>
> We might want to support VM_MIXEDMAP soon as well, so use the

I think you should say we _are_ going to since patch 16/16 does that :)

> more-generic term "special vma", although "special" is a bit overloaded.
> Maybe we'll later just support any VM_SPECIAL flag.

Yeah I hate the name, but I guess it's probably the best we can manage
because VM_SPECIAL and both VM_PFNMAP and VM_MIXEDMAP _are_ 'special' in
this sense so meh I guess it's the best we can do.

>
> While at it, improve the kerneldoc.
>
> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>

LGTM, so:

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

> ---
>  arch/x86/kernel/cpu/sgx/encl.c        |  2 +-
>  drivers/comedi/comedi_fops.c          |  2 +-
>  drivers/gpu/drm/i915/i915_mm.c        |  4 ++--
>  drivers/infiniband/core/uverbs_main.c |  6 +++---
>  drivers/misc/sgi-gru/grumain.c        |  2 +-
>  include/linux/mm.h                    |  2 +-
>  mm/memory.c                           | 16 +++++++---------
>  7 files changed, 16 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> index ac60ebde5d9b..3f0222d10f6e 100644
> --- a/arch/x86/kernel/cpu/sgx/encl.c
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -1220,7 +1220,7 @@ void sgx_zap_enclave_ptes(struct sgx_encl *encl, unsigned long addr)
>
>  			ret = sgx_encl_find(encl_mm->mm, addr, &vma);
>  			if (!ret && encl == vma->vm_private_data)
> -				zap_vma_ptes(vma, addr, PAGE_SIZE);
> +				zap_special_vma_range(vma, addr, PAGE_SIZE);
>
>  			mmap_read_unlock(encl_mm->mm);
>
> diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c
> index 48a8a607a84c..b91e0b5ac394 100644
> --- a/drivers/comedi/comedi_fops.c
> +++ b/drivers/comedi/comedi_fops.c
> @@ -2588,7 +2588,7 @@ static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
>  	 * remap_pfn_range() because we call remap_pfn_range() in a loop.
>  	 */
>  	if (retval)
> -		zap_vma_ptes(vma, vma->vm_start, size);
> +		zap_special_vma_range(vma, vma->vm_start, size);
>  #endif
>
>  	if (retval == 0) {
> diff --git a/drivers/gpu/drm/i915/i915_mm.c b/drivers/gpu/drm/i915/i915_mm.c
> index c33bd3d83069..fd89e7c7d8d6 100644
> --- a/drivers/gpu/drm/i915/i915_mm.c
> +++ b/drivers/gpu/drm/i915/i915_mm.c
> @@ -108,7 +108,7 @@ int remap_io_mapping(struct vm_area_struct *vma,
>
>  	err = apply_to_page_range(r.mm, addr, size, remap_pfn, &r);
>  	if (unlikely(err)) {
> -		zap_vma_ptes(vma, addr, (r.pfn - pfn) << PAGE_SHIFT);
> +		zap_special_vma_range(vma, addr, (r.pfn - pfn) << PAGE_SHIFT);
>  		return err;
>  	}
>
> @@ -156,7 +156,7 @@ int remap_io_sg(struct vm_area_struct *vma,
>
>  	err = apply_to_page_range(r.mm, addr, size, remap_sg, &r);
>  	if (unlikely(err)) {
> -		zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT);
> +		zap_special_vma_range(vma, addr, r.pfn << PAGE_SHIFT);
>  		return err;
>  	}
>
> diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
> index 7b68967a6301..f5837da47299 100644
> --- a/drivers/infiniband/core/uverbs_main.c
> +++ b/drivers/infiniband/core/uverbs_main.c
> @@ -756,7 +756,7 @@ static void rdma_umap_open(struct vm_area_struct *vma)
>  	 * point, so zap it.
>  	 */
>  	vma->vm_private_data = NULL;
> -	zap_vma_ptes(vma, vma->vm_start, vma->vm_end - vma->vm_start);
> +	zap_special_vma_range(vma, vma->vm_start, vma->vm_end - vma->vm_start);
>  }
>
>  static void rdma_umap_close(struct vm_area_struct *vma)
> @@ -782,7 +782,7 @@ static void rdma_umap_close(struct vm_area_struct *vma)
>  }
>
>  /*
> - * Once the zap_vma_ptes has been called touches to the VMA will come here and
> + * Once the zap_special_vma_range has been called touches to the VMA will come here and
>   * we return a dummy writable zero page for all the pfns.
>   */
>  static vm_fault_t rdma_umap_fault(struct vm_fault *vmf)
> @@ -878,7 +878,7 @@ void uverbs_user_mmap_disassociate(struct ib_uverbs_file *ufile)
>  				continue;
>  			list_del_init(&priv->list);
>
> -			zap_vma_ptes(vma, vma->vm_start,
> +			zap_special_vma_range(vma, vma->vm_start,
>  				     vma->vm_end - vma->vm_start);
>
>  			if (priv->entry) {
> diff --git a/drivers/misc/sgi-gru/grumain.c b/drivers/misc/sgi-gru/grumain.c
> index 8d749f345246..278b76cbd281 100644
> --- a/drivers/misc/sgi-gru/grumain.c
> +++ b/drivers/misc/sgi-gru/grumain.c
> @@ -542,7 +542,7 @@ void gru_unload_context(struct gru_thread_state *gts, int savestate)
>  	int ctxnum = gts->ts_ctxnum;
>
>  	if (!is_kernel_context(gts))
> -		zap_vma_ptes(gts->ts_vma, UGRUADDR(gts), GRU_GSEG_PAGESIZE);
> +		zap_special_vma_range(gts->ts_vma, UGRUADDR(gts), GRU_GSEG_PAGESIZE);
>  	cch = get_cch(gru->gs_gru_base_vaddr, ctxnum);
>
>  	gru_dbg(grudev, "gts %p, cbrmap 0x%lx, dsrmap 0x%lx\n",
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 833bedd3f739..07f6819db02d 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2833,7 +2833,7 @@ struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
>  struct page *vm_normal_page_pud(struct vm_area_struct *vma, unsigned long addr,
>  		pud_t pud);
>
> -void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
> +void zap_special_vma_range(struct vm_area_struct *vma, unsigned long address,
>  		  unsigned long size);
>  void zap_vma_range(struct vm_area_struct *vma, unsigned long address,
>  			   unsigned long size);
> diff --git a/mm/memory.c b/mm/memory.c
> index dd737b6d28c0..f3b7b7e16138 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2233,17 +2233,15 @@ void zap_vma_range(struct vm_area_struct *vma, unsigned long address,
>  }
>
>  /**
> - * zap_vma_ptes - remove ptes mapping the vma
> - * @vma: vm_area_struct holding ptes to be zapped
> - * @address: starting address of pages to zap
> + * zap_special_vma_range - zap all page table entries in a special vma range
> + * @vma: the vma covering the range to zap
> + * @address: starting address of the range to zap
>   * @size: number of bytes to zap
>   *
> - * This function only unmaps ptes assigned to VM_PFNMAP vmas.
> - *
> - * The entire address range must be fully contained within the vma.
> - *
> + * This function does nothing when the provided address range is not fully
> + * contained in @vma, or when the @vma is not VM_PFNMAP.
>   */
> -void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
> +void zap_special_vma_range(struct vm_area_struct *vma, unsigned long address,
>  		unsigned long size)
>  {
>  	if (!range_in_vma(vma, address, address + size) ||
> @@ -2252,7 +2250,7 @@ void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
>
>  	zap_vma_range(vma, address, size);
>  }
> -EXPORT_SYMBOL_GPL(zap_vma_ptes);
> +EXPORT_SYMBOL_GPL(zap_special_vma_range);
>
>  static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr)
>  {
> --
> 2.43.0
>