Add Box::zeroed() for T: Zeroable types. This allocates with __GFP_ZERO directly, letting the underlying allocator deal with zeroing out the memory compared to Box::new(T::zeroed(), flags).
Signed-off-by: Danilo Krummrich <[email protected]> --- rust/kernel/alloc/kbox.rs | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs index bd6da02c7ab8..c824ed6e1523 100644 --- a/rust/kernel/alloc/kbox.rs +++ b/rust/kernel/alloc/kbox.rs @@ -19,6 +19,7 @@ use crate::fmt; use crate::init::InPlaceInit; use crate::page::AsPageIter; +use crate::prelude::*; use crate::types::ForeignOwnable; use pin_init::{InPlaceWrite, Init, PinInit, ZeroableOption}; @@ -256,6 +257,27 @@ pub fn new_uninit(flags: Flags) -> Result<Box<MaybeUninit<T>, A>, AllocError> { Ok(Box(ptr.cast(), PhantomData)) } + /// Creates a new zero-initialized `Box<T, A>`. + /// + /// New memory is allocated with `A` and the [`__GFP_ZERO`] flag. The allocation may fail, in + /// which case an error is returned. For ZSTs no memory is allocated. + /// + /// # Examples + /// + /// ``` + /// let b = KBox::<[u8; 128]>::zeroed(GFP_KERNEL)?; + /// assert_eq!(*b, [0; 128]); + /// # Ok::<(), Error>(()) + /// ``` + pub fn zeroed(flags: Flags) -> Result<Self, AllocError> + where + T: Zeroable, + { + // SAFETY: `__GFP_ZERO` guarantees the memory is zeroed; `T: Zeroable` guarantees that + // all-zeroes is a valid bit pattern for `T`. + Ok(unsafe { Self::new_uninit(flags | __GFP_ZERO)?.assume_init() }) + } + /// Constructs a new `Pin<Box<T, A>>`. If `T` does not implement [`Unpin`], then `x` will be /// pinned in memory and can't be moved. #[inline] -- 2.54.0
