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[PATCH v2 03/16] mm: add vma_desc_size(), vma_desc_pages() helpers

Lorenzo Stoakes posted 16 patches 3 weeks, 1 day ago
There is a newer version of this series
[PATCH v2 03/16] mm: add vma_desc_size(), vma_desc_pages() helpers
Posted by Lorenzo Stoakes 3 weeks, 1 day ago 
It's useful to be able to determine the size of a VMA descriptor range used
on f_op->mmap_prepare, expressed both in bytes and pages, so add helpers
for both and update code that could make use of it to do so.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 fs/ntfs3/file.c    |  2 +-
 include/linux/mm.h | 10 ++++++++++
 mm/secretmem.c     |  2 +-
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index c1ece707b195..86eb88f62714 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -304,7 +304,7 @@ static int ntfs_file_mmap_prepare(struct vm_area_desc *desc)
 
 	if (rw) {
 		u64 to = min_t(loff_t, i_size_read(inode),
-			       from + desc->end - desc->start);
+			       from + vma_desc_size(desc));
 
 		if (is_sparsed(ni)) {
 			/* Allocate clusters for rw map. */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 892fe5dbf9de..0b97589aec6d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3572,6 +3572,16 @@ static inline unsigned long vma_pages(const struct vm_area_struct *vma)
 	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 }
 
+static inline unsigned long vma_desc_size(struct vm_area_desc *desc)
+{
+	return desc->end - desc->start;
+}
+
+static inline unsigned long vma_desc_pages(struct vm_area_desc *desc)
+{
+	return vma_desc_size(desc) >> PAGE_SHIFT;
+}
+
 /* Look up the first VMA which exactly match the interval vm_start ... vm_end */
 static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
 				unsigned long vm_start, unsigned long vm_end)
diff --git a/mm/secretmem.c b/mm/secretmem.c
index 60137305bc20..62066ddb1e9c 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -120,7 +120,7 @@ static int secretmem_release(struct inode *inode, struct file *file)
 
 static int secretmem_mmap_prepare(struct vm_area_desc *desc)
 {
-	const unsigned long len = desc->end - desc->start;
+	const unsigned long len = vma_desc_size(desc);
 
 	if ((desc->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
 		return -EINVAL;
-- 
2.51.0
Re: [PATCH v2 03/16] mm: add vma_desc_size(), vma_desc_pages() helpers
Posted by David Hildenbrand 2 weeks, 6 days ago 
On 10.09.25 22:21, Lorenzo Stoakes wrote:
> It's useful to be able to determine the size of a VMA descriptor range used
> on f_op->mmap_prepare, expressed both in bytes and pages, so add helpers
> for both and update code that could make use of it to do so.
> 
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> ---
>   fs/ntfs3/file.c    |  2 +-
>   include/linux/mm.h | 10 ++++++++++
>   mm/secretmem.c     |  2 +-
>   3 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
> index c1ece707b195..86eb88f62714 100644
> --- a/fs/ntfs3/file.c
> +++ b/fs/ntfs3/file.c
> @@ -304,7 +304,7 @@ static int ntfs_file_mmap_prepare(struct vm_area_desc *desc)
>   
>   	if (rw) {
>   		u64 to = min_t(loff_t, i_size_read(inode),
> -			       from + desc->end - desc->start);
> +			       from + vma_desc_size(desc));
>   
>   		if (is_sparsed(ni)) {
>   			/* Allocate clusters for rw map. */
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 892fe5dbf9de..0b97589aec6d 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -3572,6 +3572,16 @@ static inline unsigned long vma_pages(const struct vm_area_struct *vma)
>   	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
>   }
>   
> +static inline unsigned long vma_desc_size(struct vm_area_desc *desc)
> +{
> +	return desc->end - desc->start;
> +}
> +
> +static inline unsigned long vma_desc_pages(struct vm_area_desc *desc)
> +{
> +	return vma_desc_size(desc) >> PAGE_SHIFT;
> +}

Should parameters in both functions be const * ?

> +
>   /* Look up the first VMA which exactly match the interval vm_start ... vm_end */
>   static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
>   				unsigned long vm_start, unsigned long vm_end)
> diff --git a/mm/secretmem.c b/mm/secretmem.c
> index 60137305bc20..62066ddb1e9c 100644
> --- a/mm/secretmem.c
> +++ b/mm/secretmem.c
> @@ -120,7 +120,7 @@ static int secretmem_release(struct inode *inode, struct file *file)
>   
>   static int secretmem_mmap_prepare(struct vm_area_desc *desc)
>   {
> -	const unsigned long len = desc->end - desc->start;
> +	const unsigned long len = vma_desc_size(desc);
>   
>   	if ((desc->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
>   		return -EINVAL;

Acked-by: David Hildenbrand <david@redhat.com>

-- 
Cheers

David / dhildenb
Re: [PATCH v2 03/16] mm: add vma_desc_size(), vma_desc_pages() helpers
Posted by Lorenzo Stoakes 2 weeks, 3 days ago 
On Fri, Sep 12, 2025 at 07:56:46PM +0200, David Hildenbrand wrote:
> On 10.09.25 22:21, Lorenzo Stoakes wrote:
> > It's useful to be able to determine the size of a VMA descriptor range used
> > on f_op->mmap_prepare, expressed both in bytes and pages, so add helpers
> > for both and update code that could make use of it to do so.
> >
> > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> > ---
> >   fs/ntfs3/file.c    |  2 +-
> >   include/linux/mm.h | 10 ++++++++++
> >   mm/secretmem.c     |  2 +-
> >   3 files changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
> > index c1ece707b195..86eb88f62714 100644
> > --- a/fs/ntfs3/file.c
> > +++ b/fs/ntfs3/file.c
> > @@ -304,7 +304,7 @@ static int ntfs_file_mmap_prepare(struct vm_area_desc *desc)
> >   	if (rw) {
> >   		u64 to = min_t(loff_t, i_size_read(inode),
> > -			       from + desc->end - desc->start);
> > +			       from + vma_desc_size(desc));
> >   		if (is_sparsed(ni)) {
> >   			/* Allocate clusters for rw map. */
> > diff --git a/include/linux/mm.h b/include/linux/mm.h
> > index 892fe5dbf9de..0b97589aec6d 100644
> > --- a/include/linux/mm.h
> > +++ b/include/linux/mm.h
> > @@ -3572,6 +3572,16 @@ static inline unsigned long vma_pages(const struct vm_area_struct *vma)
> >   	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
> >   }
> > +static inline unsigned long vma_desc_size(struct vm_area_desc *desc)
> > +{
> > +	return desc->end - desc->start;
> > +}
> > +
> > +static inline unsigned long vma_desc_pages(struct vm_area_desc *desc)
> > +{
> > +	return vma_desc_size(desc) >> PAGE_SHIFT;
> > +}
>
> Should parameters in both functions be const * ?

Can do, will fix up if respin.

>
> > +
> >   /* Look up the first VMA which exactly match the interval vm_start ... vm_end */
> >   static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
> >   				unsigned long vm_start, unsigned long vm_end)
> > diff --git a/mm/secretmem.c b/mm/secretmem.c
> > index 60137305bc20..62066ddb1e9c 100644
> > --- a/mm/secretmem.c
> > +++ b/mm/secretmem.c
> > @@ -120,7 +120,7 @@ static int secretmem_release(struct inode *inode, struct file *file)
> >   static int secretmem_mmap_prepare(struct vm_area_desc *desc)
> >   {
> > -	const unsigned long len = desc->end - desc->start;
> > +	const unsigned long len = vma_desc_size(desc);
> >   	if ((desc->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
> >   		return -EINVAL;
>
> Acked-by: David Hildenbrand <david@redhat.com>

Thanks!

>
> --
> Cheers
>
> David / dhildenb
>

Cheers, Lorenzo
Re: [PATCH v2 03/16] mm: add vma_desc_size(), vma_desc_pages() helpers
Posted by Jan Kara 3 weeks ago 
On Wed 10-09-25 21:21:58, Lorenzo Stoakes wrote:
> It's useful to be able to determine the size of a VMA descriptor range used
> on f_op->mmap_prepare, expressed both in bytes and pages, so add helpers
> for both and update code that could make use of it to do so.
> 
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

Looks good, I presume more users will come later in the series :). Feel
free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/ntfs3/file.c    |  2 +-
>  include/linux/mm.h | 10 ++++++++++
>  mm/secretmem.c     |  2 +-
>  3 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
> index c1ece707b195..86eb88f62714 100644
> --- a/fs/ntfs3/file.c
> +++ b/fs/ntfs3/file.c
> @@ -304,7 +304,7 @@ static int ntfs_file_mmap_prepare(struct vm_area_desc *desc)
>  
>  	if (rw) {
>  		u64 to = min_t(loff_t, i_size_read(inode),
> -			       from + desc->end - desc->start);
> +			       from + vma_desc_size(desc));
>  
>  		if (is_sparsed(ni)) {
>  			/* Allocate clusters for rw map. */
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 892fe5dbf9de..0b97589aec6d 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -3572,6 +3572,16 @@ static inline unsigned long vma_pages(const struct vm_area_struct *vma)
>  	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
>  }
>  
> +static inline unsigned long vma_desc_size(struct vm_area_desc *desc)
> +{
> +	return desc->end - desc->start;
> +}
> +
> +static inline unsigned long vma_desc_pages(struct vm_area_desc *desc)
> +{
> +	return vma_desc_size(desc) >> PAGE_SHIFT;
> +}
> +
>  /* Look up the first VMA which exactly match the interval vm_start ... vm_end */
>  static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
>  				unsigned long vm_start, unsigned long vm_end)
> diff --git a/mm/secretmem.c b/mm/secretmem.c
> index 60137305bc20..62066ddb1e9c 100644
> --- a/mm/secretmem.c
> +++ b/mm/secretmem.c
> @@ -120,7 +120,7 @@ static int secretmem_release(struct inode *inode, struct file *file)
>  
>  static int secretmem_mmap_prepare(struct vm_area_desc *desc)
>  {
> -	const unsigned long len = desc->end - desc->start;
> +	const unsigned long len = vma_desc_size(desc);
>  
>  	if ((desc->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
>  		return -EINVAL;
> -- 
> 2.51.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Patchew 2.1-devel-b67e4c2

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