Restrict the cases where ptr_eq triggers
#14526
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r? @Centri3 good to have a second perspective on this |
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`ptr_eq` was recently enhanced to lint on more cases of raw pointers comparison: - lint on all raw pointer comparison, by proposing to use `[core|std]::ptr::eq(lhs, rhs)` instead of `lhs == rhs`; - removing one symetric `as usize` on each size if needed - peeling any level of `as *[const|mut] _` if the remaining expression can still be coerced into the original one (i.e., is a ref or raw pointer to the same type as before) The current change restricts the lint to the cases where at least one level of symetric `as usize`, or any conversion to a raw pointer, could be removed. For example, a direct comparaison of two raw pointers will not trigger the lint anymore.
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Rebased now that #14527 has been merged. |
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ptr_eq triggersptr_eq triggers
Alexendoo
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Apr 22, 2025
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Did we want to backport this? |
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Yeah I nominated it since it's fairly wide reaching |
ojeda
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May 2, 2025
Starting with Rust 1.87.0 (expected 2025-05-15) [1], Clippy may expand
the `ptr_eq` lint, e.g.:
error: use `core::ptr::eq` when comparing raw pointers
--> rust/kernel/list.rs:438:12
|
438 | if self.first == item {
| ^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(self.first, item)`
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= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_eq
= note: `-D clippy::ptr-eq` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::ptr_eq)]`
Thus clean the few cases we have.
This patch may not be actually needed by the time Rust 1.87.0 releases
since a PR to relax the lint has been beta nominated [2] due to reports
of being too eager (at least by default) [3].
Cc: [email protected] # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: rust-lang/rust-clippy#14339 [1]
Link: rust-lang/rust-clippy#14526 [2]
Link: rust-lang/rust-clippy#14525 [3]
Signed-off-by: Miguel Ojeda <[email protected]>
intel-lab-lkp
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May 2, 2025
Starting with Rust 1.87.0 (expected 2025-05-15) [1], Clippy may expand
the `ptr_eq` lint, e.g.:
error: use `core::ptr::eq` when comparing raw pointers
--> rust/kernel/list.rs:438:12
|
438 | if self.first == item {
| ^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(self.first, item)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_eq
= note: `-D clippy::ptr-eq` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::ptr_eq)]`
Thus clean the few cases we have.
This patch may not be actually needed by the time Rust 1.87.0 releases
since a PR to relax the lint has been beta nominated [2] due to reports
of being too eager (at least by default) [3].
Cc: [email protected] # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: rust-lang/rust-clippy#14339 [1]
Link: rust-lang/rust-clippy#14526 [2]
Link: rust-lang/rust-clippy#14525 [3]
Signed-off-by: Miguel Ojeda <[email protected]>
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Did the beta backport happen? |
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@flip1995 should be able to tell us more |
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I will do it on Thursday 👍 |
ojeda
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May 6, 2025
Starting with Rust 1.87.0 (expected 2025-05-15) [1], Clippy may expand
the `ptr_eq` lint, e.g.:
error: use `core::ptr::eq` when comparing raw pointers
--> rust/kernel/list.rs:438:12
|
438 | if self.first == item {
| ^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(self.first, item)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_eq
= note: `-D clippy::ptr-eq` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::ptr_eq)]`
It is expected that a PR to relax the lint will be backported [2] by
the time Rust 1.87.0 releases, since the lint was considered too eager
(at least by default) [3].
Thus allow the lint temporarily just in case.
Cc: [email protected] # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: rust-lang/rust-clippy#14339 [1]
Link: rust-lang/rust-clippy#14526 [2]
Link: rust-lang/rust-clippy#14525 [3]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>
ojeda
added a commit
to Rust-for-Linux/linux
that referenced
this pull request
May 6, 2025
Starting with Rust 1.87.0 (expected 2025-05-15) [1], Clippy may expand
the `ptr_eq` lint, e.g.:
error: use `core::ptr::eq` when comparing raw pointers
--> rust/kernel/list.rs:438:12
|
438 | if self.first == item {
| ^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(self.first, item)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_eq
= note: `-D clippy::ptr-eq` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::ptr_eq)]`
It is expected that a PR to relax the lint will be backported [2] by
the time Rust 1.87.0 releases, since the lint was considered too eager
(at least by default) [3].
Thus allow the lint temporarily just in case.
Cc: [email protected] # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: rust-lang/rust-clippy#14339 [1]
Link: rust-lang/rust-clippy#14526 [2]
Link: rust-lang/rust-clippy#14525 [3]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>
ojeda
added a commit
to Rust-for-Linux/linux
that referenced
this pull request
May 6, 2025
Starting with Rust 1.87.0 (expected 2025-05-15) [1], Clippy may expand
the `ptr_eq` lint, e.g.:
error: use `core::ptr::eq` when comparing raw pointers
--> rust/kernel/list.rs:438:12
|
438 | if self.first == item {
| ^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(self.first, item)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_eq
= note: `-D clippy::ptr-eq` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::ptr_eq)]`
It is expected that a PR to relax the lint will be backported [2] by
the time Rust 1.87.0 releases, since the lint was considered too eager
(at least by default) [3].
Thus allow the lint temporarily just in case.
Cc: [email protected] # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: rust-lang/rust-clippy#14339 [1]
Link: rust-lang/rust-clippy#14526 [2]
Link: rust-lang/rust-clippy#14525 [3]
Link: https://lore.kernel.org/r/[email protected]
[ Converted to `allow`s since backport was confirmed. - Miguel ]
Signed-off-by: Miguel Ojeda <[email protected]>
flip1995
added
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mj22226
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to mj22226/linux
that referenced
this pull request
May 12, 2025
commit a39f308 upstream. Starting with Rust 1.87.0 (expected 2025-05-15) [1], Clippy may expand the `ptr_eq` lint, e.g.: error: use `core::ptr::eq` when comparing raw pointers --> rust/kernel/list.rs:438:12 | 438 | if self.first == item { | ^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(self.first, item)` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_eq = note: `-D clippy::ptr-eq` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::ptr_eq)]` It is expected that a PR to relax the lint will be backported [2] by the time Rust 1.87.0 releases, since the lint was considered too eager (at least by default) [3]. Thus allow the lint temporarily just in case. Cc: [email protected] # Needed in 6.12.y and later (Rust is pinned in older LTSs). Link: rust-lang/rust-clippy#14339 [1] Link: rust-lang/rust-clippy#14526 [2] Link: rust-lang/rust-clippy#14525 [3] Link: https://lore.kernel.org/r/[email protected] [ Converted to `allow`s since backport was confirmed. - Miguel ] Signed-off-by: Miguel Ojeda <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
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ptr_eqwas recently enhanced to lint on more cases of raw pointers comparison:[core|std]::ptr::eq(lhs, rhs)instead oflhs == rhs;as usizeon each size if neededas *[const|mut] _if the remaining expression can still be coerced into the original one (i.e., is a ref or raw pointer to the same type as before)The current change restricts the lint to the cases where at least one level of symetric
as usize, or any conversion to a raw pointer, could be removed. For example, a direct comparaison of two raw pointers will not trigger the lint anymore.changelog: [
ptr_eq]: do not lint when comparing two raw pointers directly with no casts involvedFixes #14525