Commit 33d19f62 authored by Alexandre Courbot's avatar Alexandre Courbot Committed by Danilo Krummrich
Browse files

rust: io: always inline functions using build_assert with arguments 



`build_assert` relies on the compiler to optimize out its error path.
Functions using it with its arguments must thus always be inlined,
otherwise the error path of `build_assert` might not be optimized out,
triggering a build error.

Cc: stable@vger.kernel.org
Fixes: ce30d94e ("rust: add `io::{Io, IoRaw}` base types")
Reviewed-by: default avatarDaniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Tested-by: default avatarTimur Tabi <ttabi@nvidia.com>
Link: https://patch.msgid.link/20251208-io-build-assert-v3-2-98aded02c1ea@nvidia.com


Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent 0f61b186

rust/kernel/io.rs

+6 −3
Original line number Diff line number Diff line
@@ -142,7 +142,8 @@ macro_rules! define_read { 
        /// Bound checks are performed on compile time, hence if the offset is not known at compile

        /// time, the build will fail.

        $(#[$attr])*

        #[inline]

        // Always inline to optimize out error path of `io_addr_assert`.

        #[inline(always)]

        pub fn $name(&self, offset: usize) -> $type_name {

            let addr = self.io_addr_assert::<$type_name>(offset);
@@ -171,7 +172,8 @@ macro_rules! define_write { 
        /// Bound checks are performed on compile time, hence if the offset is not known at compile

        /// time, the build will fail.

        $(#[$attr])*

        #[inline]

        // Always inline to optimize out error path of `io_addr_assert`.

        #[inline(always)]

        pub fn $name(&self, value: $type_name, offset: usize) {

            let addr = self.io_addr_assert::<$type_name>(offset);
@@ -239,7 +241,8 @@ fn io_addr<U>(&self, offset: usize) -> Result<usize> { 
        self.addr().checked_add(offset).ok_or(EINVAL)

    }



    #[inline]

    // Always inline to optimize out error path of `build_assert`.

    #[inline(always)]

    fn io_addr_assert<U>(&self, offset: usize) -> usize {

        build_assert!(Self::offset_valid::<U>(offset, SIZE));

rust/kernel/io/resource.rs

+2 −0
Original line number Diff line number Diff line
@@ -226,6 +226,8 @@ impl Flags { 
    /// Resource represents a memory region that must be ioremaped using `ioremap_np`.

    pub const IORESOURCE_MEM_NONPOSTED: Flags = Flags::new(bindings::IORESOURCE_MEM_NONPOSTED);



    // Always inline to optimize out error path of `build_assert`.

    #[inline(always)]

    const fn new(value: u32) -> Self {

        crate::build_assert!(value as u64 <= c_ulong::MAX as u64);

        Flags(value as c_ulong)