[PATCH] rust: configfs: fix release safety documentation

[PATCH] rust: configfs: fix release safety documentation

[Yilin Chen]

The old Safety docs of ItemOperationsVTable<Group<Data>, Data>::release() 
described this as a config_group pointer embedded in Group<Parent>. 

But the inner code implies the implementation first gets the containing 
config_group pointer through the cg_item field. It then gets Group<Data> 
pointer from that group pointer.

The new Safety docs fix this by describing the actual pointer chain and
concrete Group<Data> type, not Group<Parent>.

Assisted-by: Codex:GPT-5
Signed-off-by: Yilin Chen <1479826151@qq.com>
---
 rust/kernel/configfs.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/rust/kernel/configfs.rs b/rust/kernel/configfs.rs
index 2339c6467..2ac75c628 100644
--- a/rust/kernel/configfs.rs
+++ b/rust/kernel/configfs.rs
@@ -437,8 +437,10 @@ impl<Data> ItemOperationsVTable<Group<Data>, Data>
 {
     /// # Safety
     ///
-    /// `this` must be a pointer to a `bindings::config_group` embedded in a
-    /// `Group<Parent>`.
+    /// `this` must be a valid pointer to the `bindings::config_item` embedded in
+    /// the `cg_item` field of a `bindings::config_group`.
+    ///
+    /// That `bindings::config_group` must be embedded in a `Group<Data>`.
     ///
     /// This function will destroy the pointee of `this`. The pointee of `this`
     /// must not be accessed after the function returns.
-- 
2.25.1

Re: [PATCH] rust: configfs: fix release safety documentation

[Andreas Hindborg]

"Yilin Chen" <1479826151@qq.com> writes:

> The old Safety docs of ItemOperationsVTable<Group<Data>, Data>::release()
> described this as a config_group pointer embedded in Group<Parent>.
>
> But the inner code implies the implementation first gets the containing
> config_group pointer through the cg_item field. It then gets Group<Data>
> pointer from that group pointer.
>
> The new Safety docs fix this by describing the actual pointer chain and
> concrete Group<Data> type, not Group<Parent>.
>
> Assisted-by: Codex:GPT-5
> Signed-off-by: Yilin Chen <1479826151@qq.com>
> ---
>  rust/kernel/configfs.rs | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/rust/kernel/configfs.rs b/rust/kernel/configfs.rs
> index 2339c6467..2ac75c628 100644
> --- a/rust/kernel/configfs.rs
> +++ b/rust/kernel/configfs.rs
> @@ -437,8 +437,10 @@ impl<Data> ItemOperationsVTable<Group<Data>, Data>
>  {
>      /// # Safety
>      ///
> -    /// `this` must be a pointer to a `bindings::config_group` embedded in a
> -    /// `Group<Parent>`.
> +    /// `this` must be a valid pointer to the `bindings::config_item` embedded in
> +    /// the `cg_item` field of a `bindings::config_group`.
> +    ///
> +    /// That `bindings::config_group` must be embedded in a `Group<Data>`.
>      ///
>      /// This function will destroy the pointee of `this`. The pointee of `this`
>      /// must not be accessed after the function returns.

I think it should also be `Group<Data>` instead of `Group<Parent>`.

How about:

  `this` must be a pointer to the `cg_item` field of a
  `bindings::config_group` embedded in a valid `Group<Data>`.


Best regards,
Andreas Hindborg

[PATCH v2] rust: configfs: fix release safety documentation

[Yilin Chen]

ItemOperationsVTable<Group<Data>, Data>::release() receives a pointer
to a config_item, not a config_group.

The old Safety docs described the pointer as a config_group embedded in
Group<Parent>. Update them to state that the pointer must be the cg_item
field of a config_group embedded in a valid Group<Data>.

Assisted-by: Codex:GPT-5
Signed-off-by: Yilin Chen <1479826151@qq.com>
---
Changes in v2:
- Use the wording suggested in review: describe `this` as the `cg_item`
  field of a `bindings::config_group` embedded in a valid `Group<Data>`.

 rust/kernel/configfs.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/rust/kernel/configfs.rs b/rust/kernel/configfs.rs
index 2339c6467..b626eb7dc 100644
--- a/rust/kernel/configfs.rs
+++ b/rust/kernel/configfs.rs
@@ -437,8 +437,8 @@ impl<Data> ItemOperationsVTable<Group<Data>, Data>
 {
     /// # Safety
     ///
-    /// `this` must be a pointer to a `bindings::config_group` embedded in a
-    /// `Group<Parent>`.
+    /// `this` must be a pointer to the `cg_item` field of a `bindings::config_group` embedded in a
+    /// valid `Group<Data>`.
     ///
     /// This function will destroy the pointee of `this`. The pointee of `this`
     /// must not be accessed after the function returns.
-- 
2.25.1

Re: [PATCH v2] rust: configfs: fix release safety documentation

[Andreas Hindborg]

Yilin Chen <1479826151@qq.com> writes:

> ItemOperationsVTable<Group<Data>, Data>::release() receives a pointer
> to a config_item, not a config_group.
>
> The old Safety docs described the pointer as a config_group embedded in
> Group<Parent>. Update them to state that the pointer must be the cg_item
> field of a config_group embedded in a valid Group<Data>.
>
> Assisted-by: Codex:GPT-5
> Signed-off-by: Yilin Chen <1479826151@qq.com>

Due to vacation activity, I missed v6.3 for this one. I plan on queuing
it for v6.4.

Best regards,
Andreas Hindborg

Re: [PATCH v2] rust: configfs: fix release safety documentation

[Andreas Hindborg]

Andreas Hindborg <a.hindborg@kernel.org> writes:

> Yilin Chen <1479826151@qq.com> writes:
>
>> ItemOperationsVTable<Group<Data>, Data>::release() receives a pointer
>> to a config_item, not a config_group.
>>
>> The old Safety docs described the pointer as a config_group embedded in
>> Group<Parent>. Update them to state that the pointer must be the cg_item
>> field of a config_group embedded in a valid Group<Data>.
>>
>> Assisted-by: Codex:GPT-5
>> Signed-off-by: Yilin Chen <1479826151@qq.com>
>
> Due to vacation activity, I missed v6.3 for this one. I plan on queuing
> it for v6.4.

v7.4 of course.


Best regards,
Andreas Hindborg

Re: [PATCH v2] rust: configfs: fix release safety documentation

[Andreas Hindborg]

On Wed, 08 Jul 2026 07:21:06 +0000, Yilin Chen wrote:
> ItemOperationsVTable<Group<Data>, Data>::release() receives a pointer
> to a config_item, not a config_group.
> 
> The old Safety docs described the pointer as a config_group embedded in
> Group<Parent>. Update them to state that the pointer must be the cg_item
> field of a config_group embedded in a valid Group<Data>.
> 
> [...]

Applied, thanks!

[1/1] rust: configfs: fix release safety documentation
      commit: 17ca0bc06bb246d9488556f3f16ad6f37a4fc5ad

Best regards,
-- 
Andreas Hindborg <a.hindborg@kernel.org>