Currently, Revocable::new() only supports infallible PinInit
implementations, i.e. impl PinInit<T, Infallible>.

This has been sufficient so far, since users such as Devres do not
support fallibility.

Since this is about to change, make Revocable::new() generic over the
error type E.

Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
 rust/kernel/devres.rs    | 2 +-
 rust/kernel/revocable.rs | 7 +++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs
index 0f79a2ec9474..2dbe17d6ea1f 100644
--- a/rust/kernel/devres.rs
+++ b/rust/kernel/devres.rs
@@ -98,7 +98,7 @@ struct DevresInner<T> {
 impl<T> DevresInner<T> {
     fn new(dev: &Device<Bound>, data: T, flags: Flags) -> Result<Arc<DevresInner<T>>> {
         let inner = Arc::pin_init(
-            pin_init!( DevresInner {
+            try_pin_init!( DevresInner {
                 dev: dev.into(),
                 callback: Self::devres_callback,
                 data <- Revocable::new(data),
diff --git a/rust/kernel/revocable.rs b/rust/kernel/revocable.rs
index db4aa46bb121..ca738f75dc10 100644
--- a/rust/kernel/revocable.rs
+++ b/rust/kernel/revocable.rs
@@ -80,8 +80,11 @@ unsafe impl<T: Sync + Send> Sync for Revocable<T> {}
 
 impl<T> Revocable<T> {
     /// Creates a new revocable instance of the given data.
-    pub fn new(data: impl PinInit<T>) -> impl PinInit<Self> {
-        pin_init!(Self {
+    pub fn new<E>(data: impl PinInit<T, E>) -> impl PinInit<Self, Error>
+    where
+        Error: From<E>,
+    {
+        try_pin_init!(Self {
             is_available: AtomicBool::new(true),
             data <- Opaque::pin_init(data),
         })
-- 
2.49.0

On Fri May 30, 2025 at 4:24 PM CEST, Danilo Krummrich wrote:
> Currently, Revocable::new() only supports infallible PinInit
> implementations, i.e. impl PinInit<T, Infallible>.
>
> This has been sufficient so far, since users such as Devres do not
> support fallibility.
>
> Since this is about to change, make Revocable::new() generic over the
> error type E.

You could add some information about the design decisions, ie choosing
`Error` & asking for `Error: From<E>` vs just using `E`.

> Signed-off-by: Danilo Krummrich <dakr@kernel.org>

Reviewed-by: Benno Lossin <lossin@kernel.org>

---
Cheers,
Benno

> ---
>  rust/kernel/devres.rs    | 2 +-
>  rust/kernel/revocable.rs | 7 +++++--
>  2 files changed, 6 insertions(+), 3 deletions(-)

On 30.05.25 4:24 PM, Danilo Krummrich wrote:
> Currently, Revocable::new() only supports infallible PinInit
> implementations, i.e. impl PinInit<T, Infallible>.
> 
> This has been sufficient so far, since users such as Devres do not
> support fallibility.
> 
> Since this is about to change, make Revocable::new() generic over the
> error type E.
> 
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
> ---

Reviewed-by: Christian Schrefl <chrisi.schrefl@gmail.com>

>  rust/kernel/devres.rs    | 2 +-
>  rust/kernel/revocable.rs | 7 +++++--
>  2 files changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs
> index 0f79a2ec9474..2dbe17d6ea1f 100644
> --- a/rust/kernel/devres.rs
> +++ b/rust/kernel/devres.rs
> @@ -98,7 +98,7 @@ struct DevresInner<T> {
>  impl<T> DevresInner<T> {
>      fn new(dev: &Device<Bound>, data: T, flags: Flags) -> Result<Arc<DevresInner<T>>> {
>          let inner = Arc::pin_init(
> -            pin_init!( DevresInner {
> +            try_pin_init!( DevresInner {
>                  dev: dev.into(),
>                  callback: Self::devres_callback,
>                  data <- Revocable::new(data),
> diff --git a/rust/kernel/revocable.rs b/rust/kernel/revocable.rs
> index db4aa46bb121..ca738f75dc10 100644
> --- a/rust/kernel/revocable.rs
> +++ b/rust/kernel/revocable.rs
> @@ -80,8 +80,11 @@ unsafe impl<T: Sync + Send> Sync for Revocable<T> {}
>  
>  impl<T> Revocable<T> {
>      /// Creates a new revocable instance of the given data.
> -    pub fn new(data: impl PinInit<T>) -> impl PinInit<Self> {
> -        pin_init!(Self {
> +    pub fn new<E>(data: impl PinInit<T, E>) -> impl PinInit<Self, Error>
> +    where
> +        Error: From<E>,
> +    {
> +        try_pin_init!(Self {
>              is_available: AtomicBool::new(true),
>              data <- Opaque::pin_init(data),
>          })