[PATCH v15 9/9] rust: page: add `from_raw()`

[Andreas Hindborg <a.hindborg@kernel.org>]

Add a method to `Page` that allows construction of an instance from `struct
page` pointer.

Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
---
 rust/kernel/page.rs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/rust/kernel/page.rs b/rust/kernel/page.rs
index 4591b7b01c3d2..803f3e3d76b22 100644
--- a/rust/kernel/page.rs
+++ b/rust/kernel/page.rs
@@ -191,6 +191,17 @@ pub fn nid(&self) -> i32 {
         unsafe { bindings::page_to_nid(self.as_ptr()) }
     }
 
+    /// Create a `&Page` from a raw `struct page` pointer
+    ///
+    /// # Safety
+    ///
+    /// `ptr` must be valid for use as a reference for the duration of `'a`.
+    pub unsafe fn from_raw<'a>(ptr: *const bindings::page) -> &'a Self {
+        // SAFETY: By function safety requirements, ptr is not null and is
+        // valid for use as a reference.
+        unsafe { &*Opaque::cast_from(ptr).cast::<Self>() }
+    }
+
     /// Runs a piece of code with this page mapped to an address.
     ///
     /// The page is unmapped when this call returns.

-- 
2.51.2