Let T be the actual private driver data type without the surrounding
box, as it leaves less room for potential bugs.
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
---
rust/kernel/auxiliary.rs | 2 +-
rust/kernel/device.rs | 4 ++--
rust/kernel/pci.rs | 2 +-
rust/kernel/platform.rs | 2 +-
rust/kernel/usb.rs | 4 ++--
5 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
index e12f78734606..a6a2b23befce 100644
--- a/rust/kernel/auxiliary.rs
+++ b/rust/kernel/auxiliary.rs
@@ -85,7 +85,7 @@ extern "C" fn remove_callback(adev: *mut bindings::auxiliary_device) {
// SAFETY: `remove_callback` is only ever called after a successful call to
// `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
// and stored a `Pin<KBox<T>>`.
- drop(unsafe { adev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() });
+ drop(unsafe { adev.as_ref().drvdata_obtain::<T>() });
}
}
diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index 343996027c89..106aa57a6385 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -215,7 +215,7 @@ pub fn set_drvdata<T: 'static>(&self, data: impl PinInit<T, Error>) -> Result {
/// - Must only be called once after a preceding call to [`Device::set_drvdata`].
/// - The type `T` must match the type of the `ForeignOwnable` previously stored by
/// [`Device::set_drvdata`].
- pub unsafe fn drvdata_obtain<T: ForeignOwnable>(&self) -> T {
+ pub unsafe fn drvdata_obtain<T: 'static>(&self) -> Pin<KBox<T>> {
// SAFETY: By the type invariants, `self.as_raw()` is a valid pointer to a `struct device`.
let ptr = unsafe { bindings::dev_get_drvdata(self.as_raw()) };
@@ -224,7 +224,7 @@ pub unsafe fn drvdata_obtain<T: ForeignOwnable>(&self) -> T {
// `into_foreign()`.
// - `dev_get_drvdata()` guarantees to return the same pointer given to `dev_set_drvdata()`
// in `into_foreign()`.
- unsafe { T::from_foreign(ptr.cast()) }
+ unsafe { Pin::<KBox<T>>::from_foreign(ptr.cast()) }
}
/// Borrow the driver's private data bound to this [`Device`].
diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index 83e19bcec46e..e90b13aebac8 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -148,7 +148,7 @@ extern "C" fn remove_callback(pdev: *mut bindings::pci_dev) {
// SAFETY: `remove_callback` is only ever called after a successful call to
// `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
// and stored a `Pin<KBox<T>>`.
- let data = unsafe { pdev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() };
+ let data = unsafe { pdev.as_ref().drvdata_obtain::<T>() };
T::unbind(pdev, data.as_ref());
}
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 043721fdb6d8..8f7522c4cf89 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -91,7 +91,7 @@ extern "C" fn remove_callback(pdev: *mut bindings::platform_device) {
// SAFETY: `remove_callback` is only ever called after a successful call to
// `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
// and stored a `Pin<KBox<T>>`.
- let data = unsafe { pdev.as_ref().drvdata_obtain::<Pin<KBox<T>>>() };
+ let data = unsafe { pdev.as_ref().drvdata_obtain::<T>() };
T::unbind(pdev, data.as_ref());
}
diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
index 9238b96c2185..05eed3f4f73e 100644
--- a/rust/kernel/usb.rs
+++ b/rust/kernel/usb.rs
@@ -87,9 +87,9 @@ extern "C" fn disconnect_callback(intf: *mut bindings::usb_interface) {
// SAFETY: `disconnect_callback` is only ever called after a successful call to
// `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
// and stored a `Pin<KBox<T>>`.
- let data = unsafe { dev.drvdata_obtain::<Pin<KBox<T>>>() };
+ let data = unsafe { dev.drvdata_obtain::<T>() };
- T::disconnect(intf, data.as_ref());
+ T::disconnect(intf, data.data());
}
}
--
2.51.0On 10/21/25 00:34, Danilo Krummrich wrote:
> Let T be the actual private driver data type without the surrounding
> box, as it leaves less room for potential bugs.
>
> Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This patch showed up in linux-next today and I wonder if that caused my
build to break on arm64 and x86:64. The error message looked like this
during "make bzimage":
"""
error[E0599]: no method named `data` found for struct `core::pin::Pin<kbox::Box<T, Kmalloc>>` in the current scope
--> rust/kernel/usb.rs:92:34
|
92 | T::disconnect(intf, data.data());
| ^^^^ method not found in `core::pin::Pin<kbox::Box<T, Kmalloc>>`
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0599`.
make[2]: *** [rust/Makefile:553: rust/kernel.o] Error 1
make[1]: *** [/builddir/build/BUILD/kernel-6.18.0-build/kernel-next-20251103/linux-6.18.0-0.0.next.20251103.436.vanilla.fc44.x86_64/Makefile:1316: prepare] Error 2
make: *** [Makefile:256: __sub-make] Error 2
"""
Full log:
https://download.copr.fedorainfracloud.org/results/@kernel-vanilla/next/fedora-rawhide-aarch64/09759703-next-next-all/builder-live.log.gz
A quick search for "T::disconnect(intf, data.data());" on lore
lead me here:
> diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
> index 9238b96c2185..05eed3f4f73e 100644
> --- a/rust/kernel/usb.rs
> +++ b/rust/kernel/usb.rs
> @@ -87,9 +87,9 @@ extern "C" fn disconnect_callback(intf: *mut bindings::usb_interface) {
> // SAFETY: `disconnect_callback` is only ever called after a successful call to
> // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
> // and stored a `Pin<KBox<T>>`.
> - let data = unsafe { dev.drvdata_obtain::<Pin<KBox<T>>>() };
> + let data = unsafe { dev.drvdata_obtain::<T>() };
>
> - T::disconnect(intf, data.as_ref());
> + T::disconnect(intf, data.data());
> }
> }
Ciao, Thorsten
On 11/3/25 7:43 AM, Thorsten Leemhuis wrote:
> """
> error[E0599]: no method named `data` found for struct `core::pin::Pin<kbox::Box<T, Kmalloc>>` in the current scope
> --> rust/kernel/usb.rs:92:34
> |
> 92 | T::disconnect(intf, data.data());
> | ^^^^ method not found in `core::pin::Pin<kbox::Box<T, Kmalloc>>`
>
> error: aborting due to 1 previous error
>
> For more information about this error, try `rustc --explain E0599`.
> make[2]: *** [rust/Makefile:553: rust/kernel.o] Error 1
> make[1]: *** [/builddir/build/BUILD/kernel-6.18.0-build/kernel-next-20251103/linux-6.18.0-0.0.next.20251103.436.vanilla.fc44.x86_64/Makefile:1316: prepare] Error 2
> make: *** [Makefile:256: __sub-make] Error 2
> """
>
> Full log:
> https://download.copr.fedorainfracloud.org/results/@kernel-vanilla/next/fedora-rawhide-aarch64/09759703-next-next-all/builder-live.log.gz
>
> A quick search for "T::disconnect(intf, data.data());" on lore
> lead me here:
>
>> diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
>> index 9238b96c2185..05eed3f4f73e 100644
>> --- a/rust/kernel/usb.rs
>> +++ b/rust/kernel/usb.rs
>> @@ -87,9 +87,9 @@ extern "C" fn disconnect_callback(intf: *mut bindings::usb_interface) {
>> // SAFETY: `disconnect_callback` is only ever called after a successful call to
>> // `probe_callback`, hence it's guaranteed that `Device::set_drvdata()` has been called
>> // and stored a `Pin<KBox<T>>`.
>> - let data = unsafe { dev.drvdata_obtain::<Pin<KBox<T>>>() };
>> + let data = unsafe { dev.drvdata_obtain::<T>() };
>>
>> - T::disconnect(intf, data.as_ref());
>> + T::disconnect(intf, data.data());
>> }
>> }
This error is cause by commit 6bbaa93912bf ("rust: device: narrow the generic of
drvdata_obtain()").
It seems it slipped through, since the USB abstractions are disabled in all
trees other than the USB tree. I tested with enabling them locally, but it seems
I forgot to re-enable them after a rebase etc.
I will send a patch with the following fix:
diff --git a/rust/kernel/usb.rs b/rust/kernel/usb.rs
index 92215fdc3c6a..534e3ded5442 100644
--- a/rust/kernel/usb.rs
+++ b/rust/kernel/usb.rs
@@ -89,7 +89,7 @@ extern "C" fn disconnect_callback(intf: *mut
bindings::usb_interface) {
// and stored a `Pin<KBox<T>>`.
let data = unsafe { dev.drvdata_obtain::<T>() };
- T::disconnect(intf, data.data());
+ T::disconnect(intf, data.as_ref());
}
}
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