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charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 03DB04001C X-Stat-Signature: 9igugherakzibqrkraayq57auniw4uyq X-Rspam-User: X-HE-Tag: 1727357027-702563 X-HE-Meta: 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 4lEeXHHU 90zpRoT/cuAHhgcgT/CjFM9XVzjujycU2UrenvUuaG/KsBcrlir0unv/enhy1U3xy+2ROaTaE/E8W+dmo7Xckq5rJOvrMXlUE9nD//nqPQ4ULIIB8Oxk6eBNbyUp7zH059DKt9Kgjg2WmnjS/OxbnmEITlnO6wjZhmbozuNkrxf6HcWFnnYitHRE+mEc7D5jkjBB/ywL73tB99u3wKT3rGVWND4n32cj8aYID/ApFoTOmu77tSmuT8++If3zOQHZ8y79oq4o+6tbkhD2Zw5Qi0uFbFivl0HCCcHkmSfVI6/vxVzq5PlX5wOy76YR8K8KkaYRuJKZ6xaiNBXs9IEz9KKVINMaA/5Fkbcg0b7Fg+SeY86N5hXI073twlD31+o5jIwaMY06js7PejA3bPj7v3uTgM3uhZrkD+4ti9MHyCoAawv+tkPxCjIZBIsmja8lWzWj2 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 12.09.24 00:52, Danilo Krummrich wrote: > `Box` provides the simplest way to allocate memory for a generic type > with one of the kernel's allocators, e.g. `Kmalloc`, `Vmalloc` or > `KVmalloc`. >=20 > In contrast to Rust's `Box` type, the kernel `Box` type considers the > kernel's GFP flags for all appropriate functions, always reports > allocation failures through `Result<_, AllocError>` and remains > independent from unstable features. >=20 > Signed-off-by: Danilo Krummrich > --- > rust/kernel/alloc.rs | 6 + > rust/kernel/alloc/kbox.rs | 465 ++++++++++++++++++++++++++++++++++++++ > rust/kernel/prelude.rs | 2 +- > 3 files changed, 472 insertions(+), 1 deletion(-) > create mode 100644 rust/kernel/alloc/kbox.rs I have two nits below. I think the safety documentation can be improved later, when we have decided on a better approach (I have to to spend a significant amount of time coming up with a suggestion and even then I am not satisfied with it). So Reviewed-by: Benno Lossin --- Cheers, Benno > +impl Box > +where > + T: ?Sized, > + A: Allocator, > +{ > + /// Creates a new `Box` from a raw pointer. > + /// > + /// # Safety > + /// > + /// For non-ZSTs, `raw` must point at an allocation allocated with `= A`that is sufficiently Missing space after "with `A`". > + /// aligned for and holds a valid `T`. The caller passes ownership o= f the allocation to the > + /// `Box`. > + /// > + /// For ZSTs, `raw` must be a dangling, well aligned pointer. > + #[inline] > + pub const unsafe fn from_raw(raw: *mut T) -> Self { > + // INVARIANT: Validity of `raw` is guaranteed by the safety prec= onditions of this function. > + // SAFETY: By the safety preconditions of this function, `raw` i= s not a NULL pointer. > + Self(unsafe { NonNull::new_unchecked(raw) }, PhantomData::) > + } > + > + /// Consumes the `Box` and returns a raw pointer. > + /// > + /// This will not run the destructor of `T` and for non-ZSTs the all= ocation will stay alive > + /// indefinitely. Use [`Box::from_raw`] to recover the [`Box`], drop= the value and free the > + /// allocation, if any. > + /// > + /// # Examples > + /// > + /// ``` > + /// let x =3D KBox::new(24, GFP_KERNEL)?; > + /// let ptr =3D KBox::into_raw(x); > + /// let x =3D unsafe { KBox::from_raw(ptr) }; > + /// > + /// assert_eq!(*x, 24); > + /// # Ok::<(), Error>(()) > + /// ``` > + #[inline] > + pub fn into_raw(b: Self) -> *mut T { > + let b =3D ManuallyDrop::new(b); > + > + b.0.as_ptr() Why not a single line `ManuallyDrop::new().0.as_ptr()`? > + } > + > + /// Consumes and leaks the `Box` and returns a mutable referen= ce. > + /// > + /// See [Box::into_raw] for more details. > + #[inline] > + pub fn leak<'a>(b: Self) -> &'a mut T { > + // SAFETY: `Box::into_raw` always returns a properly aligned and= dereferenceable pointer > + // which points to an initialized instance of `T`. > + unsafe { &mut *Box::into_raw(b) } > + } > +}