From: FUJITA Tomonori <[email protected]>
Macros whose expansion depends on the kernel configuration end up
ignoring some of their arguments, resulting in unused warnings.
Add a macro for the `if false { _ = ...; }` idiom used to avoid them,
and convert the existing open-coded users in `warn_flags!` and
`declare_trace!`.
Signed-off-by: FUJITA Tomonori <[email protected]>
---
rust/kernel/bug.rs | 18 ++++--------------
rust/kernel/lib.rs | 12 ++++++++++++
rust/kernel/tracepoint.rs | 5 ++---
3 files changed, 18 insertions(+), 17 deletions(-)
diff --git a/rust/kernel/bug.rs b/rust/kernel/bug.rs
index 3566f0234ca4..c1e4eb7d4a70 100644
--- a/rust/kernel/bug.rs
+++ b/rust/kernel/bug.rs
@@ -55,9 +55,7 @@ macro_rules! warn_flags {
($file:expr, $flags:expr) => {
const FLAGS: u32 = $crate::bindings::BUGFLAG_WARNING | $flags;
- if false {
- _ = $file;
- }
+ $crate::mark_used!($file);
// SAFETY:
// - `flags` and `size` are all compile-time constants, preventing
@@ -83,9 +81,7 @@ macro_rules! warn_flags {
#[cfg(all(CONFIG_BUG, CONFIG_UML))]
macro_rules! warn_flags {
($file:expr, $flags:expr) => {
- if false {
- _ = $file;
- }
+ $crate::mark_used!($file);
// SAFETY: It is always safe to call `warn_slowpath_fmt()`
// with a valid null-terminated string.
@@ -106,10 +102,7 @@ macro_rules! warn_flags {
#[cfg(all(CONFIG_BUG, any(CONFIG_LOONGARCH, CONFIG_ARM)))]
macro_rules! warn_flags {
($file:expr, $flags:expr) => {
- if false {
- _ = $file;
- _ = $flags;
- }
+ $crate::mark_used!($file, $flags);
// SAFETY: It is always safe to call `WARN_ON()`.
unsafe { $crate::bindings::WARN_ON(true) }
@@ -121,10 +114,7 @@ macro_rules! warn_flags {
#[cfg(any(testlib, not(CONFIG_BUG)))]
macro_rules! warn_flags {
($file:expr, $flags:expr) => {
- if false {
- _ = $file;
- _ = $flags;
- }
+ $crate::mark_used!($file, $flags);
};
}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 9512af7156df..2f770d80bd8a 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -266,6 +266,18 @@ macro_rules! container_of {
#[doc(hidden)]
pub fn assert_same_type<T>(_: T, _: T) {}
+/// Marks the given expressions as used.
+///
+/// This avoids "unused" warnings in kernel configurations that do not
otherwise use them.
+#[macro_export]
+macro_rules! mark_used {
+ ($($e:expr),* $(,)?) => {
+ if false {
+ $( _ = $e; )*
+ }
+ };
+}
+
/// Helper for `.rs.S` files.
#[doc(hidden)]
#[macro_export]
diff --git a/rust/kernel/tracepoint.rs b/rust/kernel/tracepoint.rs
index c6e80aa99e8e..cb06fec4c4d9 100644
--- a/rust/kernel/tracepoint.rs
+++ b/rust/kernel/tracepoint.rs
@@ -38,9 +38,8 @@ macro_rules! declare_trace {
#[cfg(not(CONFIG_TRACEPOINTS))]
{
- // If tracepoints are disabled, insert a trivial use of each
argument
- // to avoid unused argument warnings.
- $( let _unused = $argname; )*
+ // If tracepoints are disabled, the arguments are unused.
+ $crate::mark_used!($($argname),*);
}
}
)*}
base-commit: d8973c47544371613313ecb9a8c3e7b244aa9bbf
--
2.43.0
