On Tue, Dec 17, 2024 at 10:31 AM Andreas Hindborg <a.hindborg@xxxxxxxxxx> wrote:
>
> "Alice Ryhl" <aliceryhl@xxxxxxxxxx> writes:
>
> > This type will be used when setting up a new vma in an f_ops->mmap()
> > hook. Using a separate type from VmAreaRef allows us to have a separate
> > set of operations that you are only able to use during the mmap() hook.
> > For example, the VM_MIXEDMAP flag must not be changed after the initial
> > setup that happens during the f_ops->mmap() hook.
> >
> > To avoid setting invalid flag values, the methods for clearing
> > VM_MAYWRITE and similar involve a check of VM_WRITE, and return an error
> > if VM_WRITE is set. Trying to use `try_clear_maywrite` without checking
> > the return value results in a compilation error because the `Result`
> > type is marked #[must_use].
> >
> > For now, there's only a method for VM_MIXEDMAP and not VM_PFNMAP. When
> > we add a VM_PFNMAP method, we will need some way to prevent you from
> > setting both VM_MIXEDMAP and VM_PFNMAP on the same vma.
> >
> > Acked-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> (for mm bits)
> > Reviewed-by: Jann Horn <jannh@xxxxxxxxxx>
> > Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx>
> > ---
> > rust/kernel/mm/virt.rs | 181 ++++++++++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 180 insertions(+), 1 deletion(-)
> >
> > diff --git a/rust/kernel/mm/virt.rs b/rust/kernel/mm/virt.rs
> > index 3a23854e14f4..6d9ba56d4f95 100644
> > --- a/rust/kernel/mm/virt.rs
> > +++ b/rust/kernel/mm/virt.rs
>
> [cut]
>
> > + /// Returns whether `VM_READ` is set.
> > + ///
> > + /// This flag indicates whether userspace is mapping this vma as readable.
> > + #[inline]
> > + pub fn get_read(&self) -> bool {
> > + (self.flags() & flags::READ) != 0
> > + }
>
> As an afterthought, should we name these getters according to RFC344 [1]
> (remove get_ prefix)?
Well, perhaps is_readable?
Alice
