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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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68aabb29a5
There is currently an inconsistency between C and Rust, which is that when Rust requires cfg(CONFIG_COMPAT) on compat_ioctl when using the compat_ptr_ioctl symbol because '#define compat_ptr_ioctl NULL' does not get translated to anything by bindgen. But it's not *just* a matter of translating the '#define' into Rust when CONFIG_COMPAT=n. This is because when CONFIG_COMPAT=y, the type of compat_ptr_ioctl is a non-nullable function pointer, and to seamlessly use it regardless of the config, we need a nullable function pointer. I think it's important to do something about this; I've seen the mistake of accidentally forgetting '#[cfg(CONFIG_COMPAT)]' when compat_ptr_ioctl is used multiple times now. This explicitly declares 'bindings::compat_ptr_ioctl' as an Option that is always defined but might be None. This matches C, but isn't ideal: it modifies the bindings crate. But I'm not sure if there's a better way to do it. If we just redefine in kernel/, then people may still use the one in bindings::, since that is where you would normally find it. I am open to suggestions. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://patch.msgid.link/20260105-redefine-compat_ptr_ioctl-v1-1-25edb3d91acc@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
83 lines
2.4 KiB
Rust
83 lines
2.4 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Bindings.
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//!
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//! Imports the generated bindings by `bindgen`.
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//!
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//! This crate may not be directly used. If you need a kernel C API that is
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//! not ported or wrapped in the `kernel` crate, then do so first instead of
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//! using this crate.
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#![no_std]
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// See <https://github.com/rust-lang/rust-bindgen/issues/1651>.
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#![cfg_attr(test, allow(deref_nullptr))]
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#![cfg_attr(test, allow(unaligned_references))]
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#![cfg_attr(test, allow(unsafe_op_in_unsafe_fn))]
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#![allow(
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clippy::all,
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missing_docs,
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non_camel_case_types,
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non_upper_case_globals,
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non_snake_case,
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improper_ctypes,
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unreachable_pub,
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unsafe_op_in_unsafe_fn
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)]
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#[allow(dead_code)]
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#[allow(clippy::cast_lossless)]
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#[allow(clippy::ptr_as_ptr)]
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#[allow(clippy::ref_as_ptr)]
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#[allow(clippy::undocumented_unsafe_blocks)]
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#[cfg_attr(CONFIG_RUSTC_HAS_UNNECESSARY_TRANSMUTES, allow(unnecessary_transmutes))]
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mod bindings_raw {
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use pin_init::{MaybeZeroable, Zeroable};
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// Manual definition for blocklisted types.
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type __kernel_size_t = usize;
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type __kernel_ssize_t = isize;
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type __kernel_ptrdiff_t = isize;
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// `bindgen` doesn't automatically do this, see
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// <https://github.com/rust-lang/rust-bindgen/issues/3196>
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//
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// SAFETY: `__BindgenBitfieldUnit<Storage>` is a newtype around `Storage`.
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unsafe impl<Storage> Zeroable for __BindgenBitfieldUnit<Storage> where Storage: Zeroable {}
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// Use glob import here to expose all helpers.
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// Symbols defined within the module will take precedence to the glob import.
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pub use super::bindings_helper::*;
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include!(concat!(
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env!("OBJTREE"),
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"/rust/bindings/bindings_generated.rs"
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));
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}
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// When both a directly exposed symbol and a helper exists for the same function,
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// the directly exposed symbol is preferred and the helper becomes dead code, so
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// ignore the warning here.
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#[allow(dead_code)]
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mod bindings_helper {
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// Import the generated bindings for types.
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use super::bindings_raw::*;
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include!(concat!(
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env!("OBJTREE"),
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"/rust/bindings/bindings_helpers_generated.rs"
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));
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}
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pub use bindings_raw::*;
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pub const compat_ptr_ioctl: Option<
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unsafe extern "C" fn(*mut file, ffi::c_uint, ffi::c_ulong) -> ffi::c_long,
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> = {
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#[cfg(CONFIG_COMPAT)]
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{
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Some(bindings_raw::compat_ptr_ioctl)
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}
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#[cfg(not(CONFIG_COMPAT))]
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{
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None
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}
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};
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