[PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[FUJITA Tomonori]

Fix a compile error in the `impl_has_hr_timer!` macro as follows:

error[E0599]: no method named cast_mut found for raw pointer *mut Foo in the current scope

The `container_of!` macro already returns a mutable pointer when used
in a `*mut T` context so the `.cast_mut()` method is not available.

Fixes: 74d6a606c2b3 ("rust: retain pointer mut-ness in `container_of!`")
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
 rust/kernel/time/hrtimer.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/kernel/time/hrtimer.rs b/rust/kernel/time/hrtimer.rs
index 9df3dcd2fa39..36e1290cd079 100644
--- a/rust/kernel/time/hrtimer.rs
+++ b/rust/kernel/time/hrtimer.rs
@@ -517,7 +517,7 @@ unsafe fn timer_container_of(
             ) -> *mut Self {
                 // SAFETY: As per the safety requirement of this function, `ptr`
                 // is pointing inside a `$timer_type`.
-                unsafe { ::kernel::container_of!(ptr, $timer_type, $field).cast_mut() }
+                unsafe { ::kernel::container_of!(ptr, $timer_type, $field) }
             }
         }
     }

base-commit: e271ed52b344ac02d4581286961d0c40acc54c03
-- 
2.43.0

Re: [PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[Miguel Ojeda]

On Fri, Jun 6, 2025 at 4:06 AM FUJITA Tomonori
<fujita.tomonori@gmail.com> wrote:
>
> Fix a compile error in the `impl_has_hr_timer!` macro as follows:
>
> error[E0599]: no method named cast_mut found for raw pointer *mut Foo in the current scope
>
> The `container_of!` macro already returns a mutable pointer when used
> in a `*mut T` context so the `.cast_mut()` method is not available.
>
> Fixes: 74d6a606c2b3 ("rust: retain pointer mut-ness in `container_of!`")
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>

Ah, right, we missed this one because there is no caller yet and it is
a macro, sorry about that. So, just to confirm, the build error is
with extra code on top, right?

The Fixes tag seems right, since the code already existed back then.
We should probably backport too, even if there are no upstream users,
since there should be no downside and it is easy, so:

Cc: stable@vger.kernel.org

Thanks Tomo, I will take it as a fix then.

Cheers,
Miguel

Re: [PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[Benno Lossin]

On Fri Jun 6, 2025 at 4:05 AM CEST, FUJITA Tomonori wrote:
> Fix a compile error in the `impl_has_hr_timer!` macro as follows:
>
> error[E0599]: no method named cast_mut found for raw pointer *mut Foo in the current scope
>
> The `container_of!` macro already returns a mutable pointer when used
> in a `*mut T` context so the `.cast_mut()` method is not available.
>
> Fixes: 74d6a606c2b3 ("rust: retain pointer mut-ness in `container_of!`")
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>

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

---
Cheers,
Benno

> ---
>  rust/kernel/time/hrtimer.rs | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Re: [PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[FUJITA Tomonori]

On Fri, 6 Jun 2025 17:34:03 +0200
Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> wrote:

> On Fri, Jun 6, 2025 at 4:06 AM FUJITA Tomonori
> <fujita.tomonori@gmail.com> wrote:
>>
>> Fix a compile error in the `impl_has_hr_timer!` macro as follows:
>>
>> error[E0599]: no method named cast_mut found for raw pointer *mut Foo in the current scope
>>
>> The `container_of!` macro already returns a mutable pointer when used
>> in a `*mut T` context so the `.cast_mut()` method is not available.
>>
>> Fixes: 74d6a606c2b3 ("rust: retain pointer mut-ness in `container_of!`")
>> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
> 
> Ah, right, we missed this one because there is no caller yet and it is
> a macro, sorry about that. So, just to confirm, the build error is
> with extra code on top, right?

That's right.

> The Fixes tag seems right, since the code already existed back then.
> We should probably backport too, even if there are no upstream users,
> since there should be no downside and it is easy, so:
> 
> Cc: stable@vger.kernel.org

The commit was merged into mainline in the pull request for
v6.16. Isn't there no stable kernel version that this should be
backported to?


> Thanks Tomo, I will take it as a fix then.

Thanks!

Re: [PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[Miguel Ojeda]

On Fri, Jun 6, 2025 at 11:36 PM FUJITA Tomonori
<fujita.tomonori@gmail.com> wrote:
>
> The commit was merged into mainline in the pull request for
> v6.16. Isn't there no stable kernel version that this should be
> backported to?

Yeah, you are right, sorry. I guess I wrote that thinking about the
hrtimer commit, not the other one.

Cheers,
Miguel

Re: [PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[Miguel Ojeda]

On Fri, Jun 6, 2025 at 5:34 PM Miguel Ojeda
<miguel.ojeda.sandonis@gmail.com> wrote:
>
> Thanks Tomo, I will take it as a fix then.

Andreas: anything against this? (Acked-by?)

Thanks!

Cheers,
Miguel

Re: [PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[Andreas Hindborg]

"Miguel Ojeda" <miguel.ojeda.sandonis@gmail.com> writes:

> On Fri, Jun 6, 2025 at 5:34 PM Miguel Ojeda
> <miguel.ojeda.sandonis@gmail.com> wrote:
>>
>> Thanks Tomo, I will take it as a fix then.
>
> Andreas: anything against this? (Acked-by?)


Acked-by: Andreas Hindborg <a.hindborg@kernel.org>

You want to take it directly in the rust fixes PR?


Best regards,
Andreas Hindborg

Re: [PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[Miguel Ojeda]

On Tue, Jun 10, 2025 at 9:36 AM Andreas Hindborg <a.hindborg@kernel.org> wrote:
>
> Acked-by: Andreas Hindborg <a.hindborg@kernel.org>

Thanks!

> You want to take it directly in the rust fixes PR?

Yeah, since it is a fix, or what do you mean?

I guess there is no rush given there is no in-tree user, so you could
pick it in your -next one, but perhaps someone else wants to start
using it in another branch?

Cheers,
Miguel

Re: [PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[Andreas Hindborg]

"Miguel Ojeda" <miguel.ojeda.sandonis@gmail.com> writes:

> On Tue, Jun 10, 2025 at 9:36 AM Andreas Hindborg <a.hindborg@kernel.org> wrote:
>>
>> Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
>
> Thanks!
>
>> You want to take it directly in the rust fixes PR?
>
> Yeah, since it is a fix, or what do you mean?

Yes, I thought we might want to get it in for v6.16-rc2.

> I guess there is no rush given there is no in-tree user, so you could
> pick it in your -next one, but perhaps someone else wants to start
> using it in another branch?

Either way is fine, just let me know.


Best regards,
Andreas Hindborg

Re: [PATCH v1] rust: time: Fix compile error in impl_has_hr_timer macro

[Miguel Ojeda]

On Fri, Jun 6, 2025 at 4:06 AM FUJITA Tomonori
<fujita.tomonori@gmail.com> wrote:
>
> Fix a compile error in the `impl_has_hr_timer!` macro as follows:
>
> error[E0599]: no method named cast_mut found for raw pointer *mut Foo in the current scope
>
> The `container_of!` macro already returns a mutable pointer when used
> in a `*mut T` context so the `.cast_mut()` method is not available.
>
> Fixes: 74d6a606c2b3 ("rust: retain pointer mut-ness in `container_of!`")
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>

Applied to `rust-fixes`, thanks everyone!

    [ We missed this one because there is no caller yet and it is
      a macro. - Miguel ]

Cheers,
Miguel