Before Rust 1.29.0, Clippy introduced the `cast_lossless` lint [1]:
Rust’s `as` keyword will perform many kinds of conversions, including silently lossy conversions. Conversion functions such as `i32::from` will only perform lossless conversions. Using the conversion functions prevents conversions from becoming silently lossy if the input types ever change, and makes it clear for people reading the code that the conversion is lossless.
While this doesn't eliminate unchecked `as` conversions, it makes such conversions easier to scrutinize. It also has the slight benefit of removing a degree of freedom on which to bikeshed. Thus apply the changes and enable the lint -- no functional change intended.
Link: https://rust-lang.github.io/rust-clippy/master/index.html#cast_lossless [1] Suggested-by: Benno Lossin benno.lossin@proton.me Link: https://lore.kernel.org/all/D8ORTXSUTKGL.1KOJAGBM8F8TN@proton.me/ Reviewed-by: Benno Lossin benno.lossin@proton.me Signed-off-by: Tamir Duberstein tamird@gmail.com --- Makefile | 1 + drivers/gpu/drm/drm_panic_qr.rs | 10 +++++----- rust/bindings/lib.rs | 1 + rust/kernel/net/phy.rs | 4 ++-- rust/uapi/lib.rs | 1 + 5 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/Makefile b/Makefile index 2af40bfed9ce..2e9eca8b7671 100644 --- a/Makefile +++ b/Makefile @@ -479,6 +479,7 @@ export rust_common_flags := --edition=2021 \ -Wclippy::all \ -Wclippy::as_ptr_cast_mut \ -Wclippy::as_underscore \ + -Wclippy::cast_lossless \ -Wclippy::ignored_unit_patterns \ -Wclippy::mut_mut \ -Wclippy::needless_bitwise_bool \ diff --git a/drivers/gpu/drm/drm_panic_qr.rs b/drivers/gpu/drm/drm_panic_qr.rs index ecd87e8ffe05..01337ce896df 100644 --- a/drivers/gpu/drm/drm_panic_qr.rs +++ b/drivers/gpu/drm/drm_panic_qr.rs @@ -305,15 +305,15 @@ fn get_next_13b(data: &[u8], offset: usize) -> Option<(u16, usize)> { // `b` is 20 at max (`bit_off` <= 7 and `size` <= 13). let b = (bit_off + size) as u16;
- let first_byte = (data[byte_off] << bit_off >> bit_off) as u16; + let first_byte = u16::from(data[byte_off] << bit_off >> bit_off);
let number = match b { 0..=8 => first_byte >> (8 - b), - 9..=16 => (first_byte << (b - 8)) + (data[byte_off + 1] >> (16 - b)) as u16, + 9..=16 => (first_byte << (b - 8)) + u16::from(data[byte_off + 1] >> (16 - b)), _ => { (first_byte << (b - 8)) - + ((data[byte_off + 1] as u16) << (b - 16)) - + (data[byte_off + 2] >> (24 - b)) as u16 + + u16::from(data[byte_off + 1] << (b - 16)) + + u16::from(data[byte_off + 2] >> (24 - b)) } }; Some((number, size)) @@ -414,7 +414,7 @@ fn next(&mut self) -> OptionSelf::Item { match self.segment { Segment::Binary(data) => { if self.offset < data.len() { - let byte = data[self.offset] as u16; + let byte = data[self.offset].into(); self.offset += 1; Some((byte, 8)) } else { diff --git a/rust/bindings/lib.rs b/rust/bindings/lib.rs index 0486a32ed314..b105a0d899cc 100644 --- a/rust/bindings/lib.rs +++ b/rust/bindings/lib.rs @@ -25,6 +25,7 @@ )]
#[allow(dead_code)] +#[allow(clippy::cast_lossless)] #[allow(clippy::ptr_as_ptr)] #[allow(clippy::undocumented_unsafe_blocks)] mod bindings_raw { diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs index a59469c785e3..abc58b4d1bf4 100644 --- a/rust/kernel/net/phy.rs +++ b/rust/kernel/net/phy.rs @@ -142,7 +142,7 @@ pub fn is_autoneg_enabled(&self) -> bool { // SAFETY: The struct invariant ensures that we may access // this field without additional synchronization. let bit_field = unsafe { &(*self.0.get())._bitfield_1 }; - bit_field.get(13, 1) == bindings::AUTONEG_ENABLE as u64 + bit_field.get(13, 1) == bindings::AUTONEG_ENABLE.into() }
/// Gets the current auto-negotiation state. @@ -426,7 +426,7 @@ impl<T: Driver> Adapter<T> { // where we hold `phy_device->lock`, so the accessors on // `Device` are okay to call. let dev = unsafe { Device::from_raw(phydev) }; - T::match_phy_device(dev) as i32 + T::match_phy_device(dev).into() }
/// # Safety diff --git a/rust/uapi/lib.rs b/rust/uapi/lib.rs index f03b7aead35a..d5dab4dfabec 100644 --- a/rust/uapi/lib.rs +++ b/rust/uapi/lib.rs @@ -14,6 +14,7 @@ #![cfg_attr(test, allow(unsafe_op_in_unsafe_fn))] #![allow( clippy::all, + clippy::cast_lossless, clippy::ptr_as_ptr, clippy::undocumented_unsafe_blocks, dead_code,