rust: enable `clippy::undocumented_unsafe_blocks` lint

Checking that we are not missing any `// SAFETY` comments in our `unsafe` blocks is something we have wanted to do for a long time, as well as cleaning up the remaining cases that were not documented [1]. Back when Rust for Linux started, this was something that could have been done via a script, like Rust's `tidy`. Soon after, in Rust 1.58.0, Clippy implemented the `undocumented_unsafe_blocks` lint [2]. Even though the lint has a few false positives, e.g. in some cases where attributes appear between the comment and the `unsafe` block [3], there are workarounds and the lint seems quite usable already. Thus enable the lint now. We still have a few cases to clean up, so just allow those for the moment by writing a `TODO` comment -- some of those may be good candidates for new contributors.

Miguel Ojeda committed 2 years ago

Commit db4f72c1 parent 567cdff16 files · +47 −10Browse files

Showing the changes to rust/kernel/init (2 of 16 files). Show all

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2 files

rust/kernel/init/__internal.rs +2 −0
rust/kernel/init/macros.rs +9 −0

rust/kernel/init/__internal.rs+2−0

 impl<T: ?Sized> Copy for AllData<T> {}
+// SAFETY: TODO.
 unsafe impl<T: ?Sized> InitData for AllData<T> {
     type Datee = T;
 }
+// SAFETY: TODO.
 unsafe impl<T: ?Sized> HasInitData for T {
     type InitData = AllData<T>;

rust/kernel/init/macros.rs+9−0

             }
         ),
     ) => {
+        // SAFETY: TODO.
         unsafe $($impl_sig)* {
             // Inherit all attributes and the type/ident tokens for the signature.
             $(#[$($attr)*])*
                 }
             }
+            // SAFETY: TODO.
             unsafe impl<$($impl_generics)*>
                 $crate::init::__internal::PinData for __ThePinData<$($ty_generics)*>
             where $($whr)*
                     slot: *mut $p_type,
                     init: impl $crate::init::PinInit<$p_type, E>,
                 ) -> ::core::result::Result<(), E> {
+                    // SAFETY: TODO.
                     unsafe { $crate::init::PinInit::__pinned_init(init, slot) }
                 }
             )*
                     slot: *mut $type,
                     init: impl $crate::init::Init<$type, E>,
                 ) -> ::core::result::Result<(), E> {
+                    // SAFETY: TODO.
                     unsafe { $crate::init::Init::__init(init, slot) }
                 }
             )*
         // no possibility of returning without `unsafe`.
         struct __InitOk;
         // Get the data about fields from the supplied type.
+        //
+        // SAFETY: TODO.
         let data = unsafe {
             use $crate::init::__internal::$has_data;
             // Here we abuse `paste!` to retokenize `$t`. Declarative macros have some internal
         let init = move |slot| -> ::core::result::Result<(), $err> {
             init(slot).map(|__InitOk| ())
         };
+        // SAFETY: TODO.
         let init = unsafe { $crate::init::$construct_closure::<_, $err>(init) };
         init
     }};
         // Endpoint, nothing more to munch, create the initializer.
         // Since we are in the closure that is never called, this will never get executed.
         // We abuse `slot` to get the correct type inference here:
+        //
+        // SAFETY: TODO.
         unsafe {
             // Here we abuse `paste!` to retokenize `$t`. Declarative macros have some internal
             // information that is associated to already parsed fragments, so a path fragment