Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
rust: dma: add Coherent:init() and Coherent::init_with_attrs()
Analogous to Coherent::zeroed() and Coherent::zeroed_with_attrs(), add
Coherent:init() and Coherent::init_with_attrs() which both take an impl
Init<T, E> argument initializing the DMA coherent memory.
Compared to CoherentInit, Coherent::init() is a one-shot constructor
that runs an Init closure and immediately exposes the DMA handle,
whereas CoherentInit is a multi-stage initializer that provides safe
&mut T access by withholding the DMA address until converted to
Coherent.
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Link: https://patch.msgid.link/20260320194626.36263-6-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
+38
+38
rust/kernel/dma.rs
+38
rust/kernel/dma.rs
···
715
715
Self::zeroed_with_attrs(dev, gfp_flags, Attrs(0))
716
716
}
717
717
718
+
/// Same as [`Coherent::zeroed_with_attrs`], but instead of a zero-initialization the memory is
719
+
/// initialized with `init`.
720
+
pub fn init_with_attrs<E>(
721
+
dev: &device::Device<Bound>,
722
+
gfp_flags: kernel::alloc::Flags,
723
+
dma_attrs: Attrs,
724
+
init: impl Init<T, E>,
725
+
) -> Result<Self>
726
+
where
727
+
Error: From<E>,
728
+
{
729
+
let dmem = Self::alloc_with_attrs(dev, gfp_flags, dma_attrs)?;
730
+
let ptr = dmem.as_mut_ptr();
731
+
732
+
// SAFETY:
733
+
// - `ptr` is valid, properly aligned, and points to exclusively owned memory.
734
+
// - If `__init` fails, `self` is dropped, which safely frees the underlying `Coherent`'s
735
+
// DMA memory. `T: AsBytes + FromBytes` ensures there are no complex `Drop` requirements
736
+
// we are bypassing.
737
+
unsafe { init.__init(ptr)? };
738
+
739
+
Ok(dmem)
740
+
}
741
+
742
+
/// Same as [`Coherent::zeroed`], but instead of a zero-initialization the memory is initialized
743
+
/// with `init`.
744
+
#[inline]
745
+
pub fn init<E>(
746
+
dev: &device::Device<Bound>,
747
+
gfp_flags: kernel::alloc::Flags,
748
+
init: impl Init<T, E>,
749
+
) -> Result<Self>
750
+
where
751
+
Error: From<E>,
752
+
{
753
+
Self::init_with_attrs(dev, gfp_flags, Attrs(0), init)
754
+
}
755
+
718
756
/// Allocates a region of `[T; len]` of coherent memory.
719
757
fn alloc_slice_with_attrs(
720
758
dev: &device::Device<Bound>,