Merge tag 'rust-rustfmt' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

Pull rustfmt fixes from Miguel Ojeda: "Rust 'rustfmt' cleanup 'rustfmt', by default, formats imports in a way that is prone to conflicts while merging and rebasing, since in some cases it condenses several items into the same line. Document in our guidelines that we will handle this for the moment with the trailing empty comment workaround and make the tree 'rustfmt'-clean again" * tag 'rust-rustfmt' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: rust: bitmap: fix formatting rust: cpufreq: fix formatting rust: alloc: employ a trailing comment to keep vertical layout docs: rust: add section on imports formatting

Linus Torvalds committed 1 year ago

Commit 1c64efc2 parents 648937f 1f1d3e14 files · +83 −5Browse files

Unified · Split

4 files

Documentation/rust/coding-guidelines.rst +75 −0
rust/kernel/alloc/kvec.rs +1 −1
rust/kernel/bitmap.rs +6 −2
rust/kernel/cpufreq.rs +1 −2

Documentation/rust/coding-guidelines.rst+75−0

@@ -38,6 +38,81 @@ Like ``clang-format`` for the rest of the kernel, ``rustfmt`` works on · 37 unmodified lines
38	individual files, and does not require a kernel configuration. Sometimes it may	38	individual files, and does not require a kernel configuration. Sometimes it may
39	even work with broken code.	39	even work with broken code.
40		40
		41	Imports
		42	~~~~~~~
		43
		44	``rustfmt``, by default, formats imports in a way that is prone to conflicts
		45	while merging and rebasing, since in some cases it condenses several items into
		46	the same line. For instance:
		47
		48	.. code-block:: rust
		49
		50	// Do not use this style.
		51	use crate::{
		52	example1,
		53	example2::{example3, example4, example5},
		54	example6, example7,
		55	example8::example9,
		56	};
		57
		58	Instead, the kernel uses a vertical layout that looks like this:
		59
		60	.. code-block:: rust
		61
		62	use crate::{
		63	example1,
		64	example2::{
		65	example3,
		66	example4,
		67	example5, //
		68	},
		69	example6,
		70	example7,
		71	example8::example9, //
		72	};
		73
		74	That is, each item goes into its own line, and braces are used as soon as there
		75	is more than one item in a list.
		76
		77	The trailing empty comment allows to preserve this formatting. Not only that,
		78	``rustfmt`` will actually reformat imports vertically when the empty comment is
		79	added. That is, it is possible to easily reformat the original example into the
		80	expected style by running ``rustfmt`` on an input like:
		81
		82	.. code-block:: rust
		83
		84	// Do not use this style.
		85	use crate::{
		86	example1,
		87	example2::{example3, example4, example5, //
		88	},
		89	example6, example7,
		90	example8::example9, //
		91	};
		92
		93	The trailing empty comment works for nested imports, as shown above, as well as
		94	for single item imports -- this can be useful to minimize diffs within patch
		95	series:
		96
		97	.. code-block:: rust
		98
		99	use crate::{
		100	example1, //
		101	};
		102
		103	The trailing empty comment works in any of the lines within the braces, but it
		104	is preferred to keep it in the last item, since it is reminiscent of the
		105	trailing comma in other formatters. Sometimes it may be simpler to avoid moving
		106	the comment several times within a patch series due to changes in the list.
		107
		108	There may be cases where exceptions may need to be made, i.e. none of this is
		109	a hard rule. There is also code that is not migrated to this style yet, but
		110	please do not introduce code in other styles.
		111
		112	Eventually, the goal is to get ``rustfmt`` to support this formatting style (or
		113	a similar one) automatically in a stable release without requiring the trailing
		114	empty comment. Thus, at some point, the goal is to remove those comments.
		115
41		116
42	Comments	117	Comments
43	--------	118	--------

rust/kernel/alloc/kvec.rs+1−1

@@ -9,7 +9,7 @@ use super::{ · 8 unmodified lines
9	};	9	};
10	use crate::{	10	use crate::{
11	fmt,	11	fmt,
12	page::AsPageIter,	12	page::AsPageIter, //
13	};	13	};
14	use core::{	14	use core::{
15	borrow::{Borrow, BorrowMut},	15	borrow::{Borrow, BorrowMut},

rust/kernel/bitmap.rs+6−2

         let ptr = if self.nbits <= BITS_PER_LONG {
             // SAFETY: Bitmap is represented inline.
             #[allow(unused_unsafe, reason = "Safe since Rust 1.92.0")]
-            unsafe { core::ptr::addr_of!(self.repr.bitmap) }
+            unsafe {
+                core::ptr::addr_of!(self.repr.bitmap)
+            }
         } else {
             // SAFETY: Bitmap is represented as array of `unsigned long`.
             unsafe { self.repr.ptr.as_ptr() }
         let ptr = if self.nbits <= BITS_PER_LONG {
             // SAFETY: Bitmap is represented inline.
             #[allow(unused_unsafe, reason = "Safe since Rust 1.92.0")]
-            unsafe { core::ptr::addr_of_mut!(self.repr.bitmap) }
+            unsafe {
+                core::ptr::addr_of_mut!(self.repr.bitmap)
+            }
         } else {
             // SAFETY: Bitmap is represented as array of `unsigned long`.
             unsafe { self.repr.ptr.as_ptr() }

rust/kernel/cpufreq.rs+1−2

@@ -38,8 +38,7 @@ use macros::vtable; · 37 unmodified lines
38	const CPUFREQ_NAME_LEN: usize = bindings::CPUFREQ_NAME_LEN as usize;	38	const CPUFREQ_NAME_LEN: usize = bindings::CPUFREQ_NAME_LEN as usize;
39		39
40	/// Default transition latency value in nanoseconds.	40	/// Default transition latency value in nanoseconds.
41	pub const DEFAULT_TRANSITION_LATENCY_NS: u32 =	41	pub const DEFAULT_TRANSITION_LATENCY_NS: u32 = bindings::CPUFREQ_DEFAULT_TRANSITION_LATENCY_NS;
42	bindings::CPUFREQ_DEFAULT_TRANSITION_LATENCY_NS;
43		42
44	/// CPU frequency driver flags.	43	/// CPU frequency driver flags.
45	pub mod flags {	44	pub mod flags {