mirror of https://github.com/torvalds/linux.git
31 lines
973 B
Rust
31 lines
973 B
Rust
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2024 Google LLC.
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//! Logic for static keys.
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//!
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//! C header: [`include/linux/jump_label.h`](srctree/include/linux/jump_label.h).
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/// Branch based on a static key.
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///
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/// Takes three arguments:
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///
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/// * `key` - the path to the static variable containing the `static_key`.
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/// * `keytyp` - the type of `key`.
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/// * `field` - the name of the field of `key` that contains the `static_key`.
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///
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/// # Safety
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///
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/// The macro must be used with a real static key defined by C.
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#[macro_export]
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macro_rules! static_branch_unlikely {
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($key:path, $keytyp:ty, $field:ident) => {{
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let _key: *const $keytyp = ::core::ptr::addr_of!($key);
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let _key: *const $crate::bindings::static_key_false = ::core::ptr::addr_of!((*_key).$field);
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let _key: *const $crate::bindings::static_key = _key.cast();
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$crate::bindings::static_key_count(_key.cast_mut()) > 0
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}};
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}
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pub use static_branch_unlikely;
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