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/alloc (1 of 16 files). Show all

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rust/kernel/alloc/allocator.rs+2−0

@@ -31,6 +31,7 @@ pub(crate) unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: F · 30 unmodified lines
31	31	unsafe { bindings::krealloc(ptr as const core::ffi::c_void, size, flags.0) as mut u8 }
32	32	}
33	33
	34	+// SAFETY: TODO.
34	35	unsafe impl GlobalAlloc for KernelAllocator {
35	36	unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
36	37	// SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
@@ -39,6 +40,7 @@ unsafe impl GlobalAlloc for KernelAllocator { · 2 unmodified lines
39	40	}
40	41
41	42	unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
	43	+ // SAFETY: TODO.
42	44	unsafe {
43	45	bindings::kfree(ptr as *const core::ffi::c_void);
44	46	}