08d3f54928
Make fallible versions of `new` and `new_uninit` methods available in `Box` even though it doesn't implement them because we build `alloc` with the `no_global_oom_handling` config. They also have an extra `flags` parameter that allows callers to pass flags to the allocator. Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20240328013603.206764-7-wedsonaf@gmail.com [ Used `Box::write()` to avoid one `unsafe` block as suggested by Boqun. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
71 lines
2.1 KiB
Rust
71 lines
2.1 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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//! Extensions to the [`alloc`] crate.
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#[cfg(not(test))]
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#[cfg(not(testlib))]
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mod allocator;
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pub mod box_ext;
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pub mod vec_ext;
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/// Flags to be used when allocating memory.
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///
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/// They can be combined with the operators `|`, `&`, and `!`.
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///
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/// Values can be used from the [`flags`] module.
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#[derive(Clone, Copy)]
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pub struct Flags(u32);
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impl core::ops::BitOr for Flags {
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type Output = Self;
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fn bitor(self, rhs: Self) -> Self::Output {
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Self(self.0 | rhs.0)
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}
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}
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impl core::ops::BitAnd for Flags {
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type Output = Self;
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fn bitand(self, rhs: Self) -> Self::Output {
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Self(self.0 & rhs.0)
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}
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}
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impl core::ops::Not for Flags {
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type Output = Self;
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fn not(self) -> Self::Output {
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Self(!self.0)
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}
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}
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/// Allocation flags.
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///
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/// These are meant to be used in functions that can allocate memory.
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pub mod flags {
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use super::Flags;
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use crate::bindings;
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/// Zeroes out the allocated memory.
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///
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/// This is normally or'd with other flags.
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pub const __GFP_ZERO: Flags = Flags(bindings::__GFP_ZERO);
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/// Users can not sleep and need the allocation to succeed.
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///
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/// A lower watermark is applied to allow access to "atomic reserves". The current
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/// implementation doesn't support NMI and few other strict non-preemptive contexts (e.g.
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/// raw_spin_lock). The same applies to [`GFP_NOWAIT`].
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pub const GFP_ATOMIC: Flags = Flags(bindings::GFP_ATOMIC);
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/// Typical for kernel-internal allocations. The caller requires ZONE_NORMAL or a lower zone
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/// for direct access but can direct reclaim.
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pub const GFP_KERNEL: Flags = Flags(bindings::GFP_KERNEL);
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/// The same as [`GFP_KERNEL`], except the allocation is accounted to kmemcg.
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pub const GFP_KERNEL_ACCOUNT: Flags = Flags(bindings::GFP_KERNEL_ACCOUNT);
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/// Ror kernel allocations that should not stall for direct reclaim, start physical IO or
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/// use any filesystem callback. It is very likely to fail to allocate memory, even for very
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/// small allocations.
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pub const GFP_NOWAIT: Flags = Flags(bindings::GFP_NOWAIT);
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}
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