rust: add build_error! to the prelude

The sibling `build_assert!` is already in the prelude, it makes sense
that a "core"/"language" facility like this is part of the prelude and
users should not be defining their own one (thus there should be no risk
of future name collisions and we would want to be aware of them anyway).

Thus add `build_error!` into the prelude.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20241123222849.350287-3-ojeda@kernel.org
[ Applied the change to the new miscdevice cases. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

rust/kernel/block/mq/operations.rs

@@ -9,6 +9,7 @@ use crate::{
     block::mq::request::RequestDataWrapper,
     block::mq::Request,
     error::{from_result, Result},
+    prelude::*,
     types::ARef,
 };
 use core::{marker::PhantomData, sync::atomic::AtomicU64, sync::atomic::Ordering};
@@ -35,7 +36,7 @@ pub trait Operations: Sized {
     /// Called by the kernel to poll the device for completed requests. Only
     /// used for poll queues.
     fn poll() -> bool {
-        crate::build_error!(crate::error::VTABLE_DEFAULT_ERROR)
+        build_error!(crate::error::VTABLE_DEFAULT_ERROR)
     }
 }
 

rust/kernel/build_assert.rs

@@ -14,7 +14,6 @@ pub use build_error::build_error;
 /// # Examples
 ///
 /// ```
-/// # use kernel::build_error;
 /// #[inline]
 /// fn foo(a: usize) -> usize {
 ///     a.checked_add(1).unwrap_or_else(|| build_error!("overflow"))

rust/kernel/miscdevice.rs

@@ -116,7 +116,7 @@ pub trait MiscDevice {
         _cmd: u32,
         _arg: usize,
     ) -> Result<isize> {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 
     /// Handler for ioctls.
@@ -132,7 +132,7 @@ pub trait MiscDevice {
         _cmd: u32,
         _arg: usize,
     ) -> Result<isize> {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 }
 

rust/kernel/net/phy.rs

@@ -587,17 +587,17 @@ pub trait Driver {
 
     /// Issues a PHY software reset.
     fn soft_reset(_dev: &mut Device) -> Result {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 
     /// Sets up device-specific structures during discovery.
     fn probe(_dev: &mut Device) -> Result {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 
     /// Probes the hardware to determine what abilities it has.
     fn get_features(_dev: &mut Device) -> Result {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 
     /// Returns true if this is a suitable driver for the given phydev.
@@ -609,32 +609,32 @@ pub trait Driver {
     /// Configures the advertisement and resets auto-negotiation
     /// if auto-negotiation is enabled.
     fn config_aneg(_dev: &mut Device) -> Result {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 
     /// Determines the negotiated speed and duplex.
     fn read_status(_dev: &mut Device) -> Result<u16> {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 
     /// Suspends the hardware, saving state if needed.
     fn suspend(_dev: &mut Device) -> Result {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 
     /// Resumes the hardware, restoring state if needed.
     fn resume(_dev: &mut Device) -> Result {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 
     /// Overrides the default MMD read function for reading a MMD register.
     fn read_mmd(_dev: &mut Device, _devnum: u8, _regnum: u16) -> Result<u16> {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 
     /// Overrides the default MMD write function for writing a MMD register.
     fn write_mmd(_dev: &mut Device, _devnum: u8, _regnum: u16, _val: u16) -> Result {
-        kernel::build_error!(VTABLE_DEFAULT_ERROR)
+        build_error!(VTABLE_DEFAULT_ERROR)
     }
 
     /// Callback for notification of link change.

rust/kernel/prelude.rs

@@ -19,7 +19,7 @@ pub use crate::alloc::{flags::*, Box, KBox, KVBox, KVVec, KVec, VBox, VVec, Vec}
 #[doc(no_inline)]
 pub use macros::{module, pin_data, pinned_drop, vtable, Zeroable};
 
-pub use super::build_assert;
+pub use super::{build_assert, build_error};
 
 // `super::std_vendor` is hidden, which makes the macro inline for some reason.
 #[doc(no_inline)]