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.stoa...@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 <da...@redhat.com>
Thanks!
>
> --
> Cheers
>
> David / dhildenb
>
Cheers, Lorenzo
