From 426c92ca1bdd33dcbc01d6d66bb5bb4a356f2c54 Mon Sep 17 00:00:00 2001 From: Gary Guo Date: Mon, 6 Jul 2026 13:44:14 +0100 Subject: rust: io: add dynamically-sized `Region` type Currently many I/O related structs carry a `SIZE` parameter to denote the minimum size of the I/O region, while they also carry a field indicating the actual size. Proliferation of the pattern creates a lot of duplicated code, and makes it hard to create typed views of I/O. Introduce a `Region` type that carries the `SIZE` parameter. It is a wrapper of `[u8]`, which makes it dynamically sized with a metadata of `usize`. This way, pointers to `Region` naturally carry size information. This type is required to be 4-byte aligned. Expose the minimum size information via `MIN_SIZE` constant of the `KnownSize` trait. Similarly, expose the minimum alignment information via `KnownSize::MIN_ALIGN`. With these changes, it is possible to add an associated type to `Io` trait to represent the type of I/O region. For untyped regions, this is the newly added `Region` type. Remove `IoKnownSize` as it is no longer necessary. Use the same mechanism to indicate minimum size of PCI config spaces. Reviewed-by: Alexandre Courbot Signed-off-by: Gary Guo Reviewed-by: Daniel Almeida Link: https://patch.msgid.link/20260706-io_projection-v6-1-72cd5d055d54@garyguo.net [ Add brief explanation on MIN_ALIGN. - Danilo ] Signed-off-by: Danilo Krummrich --- rust/kernel/devres.rs | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) (limited to 'rust/kernel/devres.rs') diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs index 11ce500e9b76..ed30ccc6e68e 100644 --- a/rust/kernel/devres.rs +++ b/rust/kernel/devres.rs @@ -68,7 +68,6 @@ struct Inner { /// devres::Devres, /// io::{ /// Io, -/// IoKnownSize, /// Mmio, /// MmioRaw, /// PhysAddr, // @@ -297,10 +296,7 @@ impl Devres { /// use kernel::{ /// device::Core, /// devres::Devres, - /// io::{ - /// Io, - /// IoKnownSize, // - /// }, + /// io::Io, /// pci, // /// }; /// -- cgit v1.2.3