device: rust: rename Device::as_ref() to Device::from_raw()

The prefix as_* should not be used for a constructor. Constructors
usually use the prefix from_* instead.

Some prior art in the stdlib: Box::from_raw, CString::from_raw,
Rc::from_raw, Arc::from_raw, Waker::from_raw, File::from_raw_fd.

There is also prior art in the kernel crate: cpufreq::Policy::from_raw,
fs::File::from_raw_file, Kuid::from_raw, ARef::from_raw,
SeqFile::from_raw, VmaNew::from_raw, Io::from_raw.

Link: https://lore.kernel.org/r/aCd8D5IA0RXZvtcv@pollux
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250711-device-as-ref-v2-1-1b16ab6402d7@google.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

rust/kernel/auxiliary.rs

@@ -270,7 +270,7 @@ impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
         let dev = unsafe { addr_of_mut!((*self.as_raw()).dev) };
 
         // SAFETY: `dev` points to a valid `struct device`.
-        unsafe { device::Device::as_ref(dev) }
+        unsafe { device::Device::from_raw(dev) }
     }
 }
 

rust/kernel/cpu.rs

@@ -147,5 +147,5 @@ pub unsafe fn from_cpu(cpu: CpuId) -> Result<&'static Device> {
 
     // SAFETY: The pointer returned by `get_cpu_device()`, if not `NULL`, is a valid pointer to
     // a `struct device` and is never freed by the C code.
-    Ok(unsafe { Device::as_ref(ptr) })
+    Ok(unsafe { Device::from_raw(ptr) })
 }

rust/kernel/device.rs

@@ -58,7 +58,7 @@ impl Device {
     /// While not officially documented, this should be the case for any `struct device`.
     pub unsafe fn get_device(ptr: *mut bindings::device) -> ARef<Self> {
         // SAFETY: By the safety requirements ptr is valid
-        unsafe { Self::as_ref(ptr) }.into()
+        unsafe { Self::from_raw(ptr) }.into()
     }
 
     /// Convert a [`&Device`](Device) into a [`&Device<Bound>`](Device<Bound>).
@@ -149,7 +149,7 @@ impl<Ctx: DeviceContext> Device<Ctx> {
             // - Since `parent` is not NULL, it must be a valid pointer to a `struct device`.
             // - `parent` is valid for the lifetime of `self`, since a `struct device` holds a
             //   reference count of its parent.
-            Some(unsafe { Self::as_ref(parent) })
+            Some(unsafe { Self::from_raw(parent) })
         }
     }
 
@@ -161,7 +161,7 @@ impl<Ctx: DeviceContext> Device<Ctx> {
     /// i.e. it must be ensured that the reference count of the C `struct device` `ptr` points to
     /// can't drop to zero, for the duration of this function call and the entire duration when the
     /// returned reference exists.
-    pub unsafe fn as_ref<'a>(ptr: *mut bindings::device) -> &'a Self {
+    pub unsafe fn from_raw<'a>(ptr: *mut bindings::device) -> &'a Self {
         // SAFETY: Guaranteed by the safety requirements of the function.
         unsafe { &*ptr.cast() }
     }

rust/kernel/drm/device.rs

@@ -190,7 +190,7 @@ impl<T: drm::Driver> AsRef<device::Device> for Device<T> {
     fn as_ref(&self) -> &device::Device {
         // SAFETY: `bindings::drm_device::dev` is valid as long as the DRM device itself is valid,
         // which is guaranteed by the type invariant.
-        unsafe { device::Device::as_ref((*self.as_raw()).dev) }
+        unsafe { device::Device::from_raw((*self.as_raw()).dev) }
     }
 }
 

rust/kernel/faux.rs

@@ -54,7 +54,7 @@ impl AsRef<device::Device> for Registration {
     fn as_ref(&self) -> &device::Device {
         // SAFETY: The underlying `device` in `faux_device` is guaranteed by the C API to be
         // a valid initialized `device`.
-        unsafe { device::Device::as_ref(addr_of_mut!((*self.as_raw()).dev)) }
+        unsafe { device::Device::from_raw(addr_of_mut!((*self.as_raw()).dev)) }
     }
 }
 

rust/kernel/miscdevice.rs

@@ -98,7 +98,7 @@ impl<T: MiscDevice> MiscDeviceRegistration<T> {
         // function tells the borrow-checker that the `&Device` reference must not outlive the
         // `&MiscDeviceRegistration<T>` used to obtain it, so the last use of the reference must be
         // before the underlying `struct miscdevice` is destroyed.
-        unsafe { Device::as_ref((*self.as_raw()).this_device) }
+        unsafe { Device::from_raw((*self.as_raw()).this_device) }
     }
 }
 

rust/kernel/net/phy.rs

@@ -285,7 +285,7 @@ impl AsRef<kernel::device::Device> for Device {
     fn as_ref(&self) -> &kernel::device::Device {
         let phydev = self.0.get();
         // SAFETY: The struct invariant ensures that `mdio.dev` is valid.
-        unsafe { kernel::device::Device::as_ref(addr_of_mut!((*phydev).mdio.dev)) }
+        unsafe { kernel::device::Device::from_raw(addr_of_mut!((*phydev).mdio.dev)) }
     }
 }
 

rust/kernel/pci.rs

@@ -468,7 +468,7 @@ impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
         let dev = unsafe { addr_of_mut!((*self.as_raw()).dev) };
 
         // SAFETY: `dev` points to a valid `struct device`.
-        unsafe { device::Device::as_ref(dev) }
+        unsafe { device::Device::from_raw(dev) }
     }
 }
 

rust/kernel/platform.rs

@@ -251,7 +251,7 @@ impl<Ctx: device::DeviceContext> AsRef<device::Device<Ctx>> for Device<Ctx> {
         let dev = unsafe { addr_of_mut!((*self.as_raw()).dev) };
 
         // SAFETY: `dev` points to a valid `struct device`.
-        unsafe { device::Device::as_ref(dev) }
+        unsafe { device::Device::from_raw(dev) }
     }
 }