[PATCH 0/4] Rust: Fix typedefs for resource_size_t and phys_addr_t

[PATCH 0/4] Rust: Fix typedefs for resource_size_t and phys_addr_t

[Alice Ryhl]

This changes ResourceSize to use the resource_size_t typedef (currently
ResourceSize is defined as phys_addr_t), and moves ResourceSize to
kernel::io and defines PhysAddr next to it. Any usage of ResourceSize or
bindings::phys_addr_t that references a physical address is updated to
use the new PhysAddr typedef.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
Alice Ryhl (4):
      rust: io: define ResourceSize as resource_size_t
      rust: io: move ResourceSize to top-level io module
      rust: scatterlist: import ResourceSize from kernel::io
      rust: io: add typedef for phys_addr_t

 rust/kernel/devres.rs      | 18 +++++++++++++++---
 rust/kernel/io.rs          | 26 +++++++++++++++++++++++---
 rust/kernel/io/resource.rs | 13 ++++++-------
 rust/kernel/scatterlist.rs |  2 +-
 4 files changed, 45 insertions(+), 14 deletions(-)
---
base-commit: 211ddde0823f1442e4ad052a2f30f050145ccada
change-id: 20251106-resource-phys-typedefs-6db37927d159

Best regards,
-- 
Alice Ryhl <aliceryhl@google.com>

[PATCH 1/4] rust: io: define ResourceSize as resource_size_t

[Alice Ryhl]

These typedefs are always equivalent so this should not change anything,
but the code makes a lot more sense like this.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 rust/kernel/io/resource.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/kernel/io/resource.rs b/rust/kernel/io/resource.rs
index bea3ee0ed87b51816e2afb5a8a36fedee60d0e06..11b6bb9678b4e36603cc26fa2d6552c0a7e8276c 100644
--- a/rust/kernel/io/resource.rs
+++ b/rust/kernel/io/resource.rs
@@ -16,7 +16,7 @@
 ///
 /// This is a type alias to either `u32` or `u64` depending on the config option
 /// `CONFIG_PHYS_ADDR_T_64BIT`, and it can be a u64 even on 32-bit architectures.
-pub type ResourceSize = bindings::phys_addr_t;
+pub type ResourceSize = bindings::resource_size_t;
 
 /// A region allocated from a parent [`Resource`].
 ///

-- 
2.51.2.1026.g39e6a42477-goog

[PATCH 2/4] rust: io: move ResourceSize to top-level io module

[Alice Ryhl]

Resource sizes are a general concept for dealing with physical
addresses, and not specific to the Resource type, which is just one way
to access physical addresses. Thus, move the typedef to the io module.

Still keep a re-export under resource. This avoids this commit from
being a flag-day, but I also think it's a useful re-export in general so
that you can import

	use kernel::io::resource::{Resource, ResourceSize};

instead of having to write

	use kernel::io::{
	    resource::Resource,
	    ResourceSize,
	};

in the specific cases where you need ResourceSize because you are using
the Resource type. Therefore I think it makes sense to keep this
re-export indefinitely and it is *not* intended as a temporary re-export
for migration purposes.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 rust/kernel/io.rs          | 6 ++++++
 rust/kernel/io/resource.rs | 6 +-----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs
index ee182b0b5452dfcc9891d46cc6cd84d0cf7cdae7..6465ea94e85d689aef1f9031a4a5cc9505b9af6e 100644
--- a/rust/kernel/io.rs
+++ b/rust/kernel/io.rs
@@ -13,6 +13,12 @@
 
 pub use resource::Resource;
 
+/// Resource Size type.
+///
+/// This is a type alias to either `u32` or `u64` depending on the config option
+/// `CONFIG_PHYS_ADDR_T_64BIT`, and it can be a u64 even on 32-bit architectures.
+pub type ResourceSize = bindings::resource_size_t;
+
 /// Raw representation of an MMIO region.
 ///
 /// By itself, the existence of an instance of this structure does not provide any guarantees that
diff --git a/rust/kernel/io/resource.rs b/rust/kernel/io/resource.rs
index 11b6bb9678b4e36603cc26fa2d6552c0a7e8276c..7fed41fc20307fa7ce230da4b7841743631c965e 100644
--- a/rust/kernel/io/resource.rs
+++ b/rust/kernel/io/resource.rs
@@ -12,11 +12,7 @@
 use crate::str::{CStr, CString};
 use crate::types::Opaque;
 
-/// Resource Size type.
-///
-/// This is a type alias to either `u32` or `u64` depending on the config option
-/// `CONFIG_PHYS_ADDR_T_64BIT`, and it can be a u64 even on 32-bit architectures.
-pub type ResourceSize = bindings::resource_size_t;
+pub use super::ResourceSize;
 
 /// A region allocated from a parent [`Resource`].
 ///

-- 
2.51.2.1026.g39e6a42477-goog

[PATCH 3/4] rust: scatterlist: import ResourceSize from kernel::io

[Alice Ryhl]

Now that ResourceSize has been moved to kernel::io, import it from the
io module instead of the io::resource sub-module. It makes sense in this
case since the dma_len isn't really related to the Resource type even
though both are sizes of allocations in physical ram.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 rust/kernel/scatterlist.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rust/kernel/scatterlist.rs b/rust/kernel/scatterlist.rs
index 9709dff60b5a9a02ab466f3e4f1f52ab2e440d5c..196fdb9a75e788cc31093d83e412ff4d6ca56b75 100644
--- a/rust/kernel/scatterlist.rs
+++ b/rust/kernel/scatterlist.rs
@@ -35,7 +35,7 @@
     device::{Bound, Device},
     devres::Devres,
     dma, error,
-    io::resource::ResourceSize,
+    io::ResourceSize,
     page,
     prelude::*,
     types::{ARef, Opaque},

-- 
2.51.2.1026.g39e6a42477-goog

[PATCH 4/4] rust: io: add typedef for phys_addr_t

[Alice Ryhl]

The C typedef phys_addr_t is missing an analogue in Rust, meaning that
we end up using bindings::phys_addr_t or ResourceSize as a replacement
in various places throughout the kernel. Fix that by introducing a new
typedef on the Rust side. Place it next to the existing ResourceSize
typedef since they're quite related to each other.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 rust/kernel/devres.rs      | 18 +++++++++++++++---
 rust/kernel/io.rs          | 20 +++++++++++++++++---
 rust/kernel/io/resource.rs |  9 ++++++---
 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs
index 10a6a17898541d4a0f01af41f68e3ab3d6bb0aca..e01e0d36702d38e9530a2fa4be884c935c6b5d0c 100644
--- a/rust/kernel/devres.rs
+++ b/rust/kernel/devres.rs
@@ -52,8 +52,20 @@ struct Inner<T: Send> {
 /// # Examples
 ///
 /// ```no_run
-/// # use kernel::{bindings, device::{Bound, Device}, devres::Devres, io::{Io, IoRaw}};
-/// # use core::ops::Deref;
+/// use kernel::{
+///     bindings,
+///     device::{
+///         Bound,
+///         Device,
+///     },
+///     devres::Devres,
+///     io::{
+///         Io,
+///         IoRaw,
+///         PhysAddr,
+///     },
+/// };
+/// use core::ops::Deref;
 ///
 /// // See also [`pci::Bar`] for a real example.
 /// struct IoMem<const SIZE: usize>(IoRaw<SIZE>);
@@ -66,7 +78,7 @@ struct Inner<T: Send> {
 ///     unsafe fn new(paddr: usize) -> Result<Self>{
 ///         // SAFETY: By the safety requirements of this function [`paddr`, `paddr` + `SIZE`) is
 ///         // valid for `ioremap`.
-///         let addr = unsafe { bindings::ioremap(paddr as bindings::phys_addr_t, SIZE) };
+///         let addr = unsafe { bindings::ioremap(paddr as PhysAddr, SIZE) };
 ///         if addr.is_null() {
 ///             return Err(ENOMEM);
 ///         }
diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs
index 6465ea94e85d689aef1f9031a4a5cc9505b9af6e..56a435eb14e3a1ce72dd58b88cbf296041f1703e 100644
--- a/rust/kernel/io.rs
+++ b/rust/kernel/io.rs
@@ -13,6 +13,12 @@
 
 pub use resource::Resource;
 
+/// Physical address type.
+///
+/// This is a type alias to either `u32` or `u64` depending on the config option
+/// `CONFIG_PHYS_ADDR_T_64BIT`, and it can be a u64 even on 32-bit architectures.
+pub type PhysAddr = bindings::phys_addr_t;
+
 /// Resource Size type.
 ///
 /// This is a type alias to either `u32` or `u64` depending on the config option
@@ -68,8 +74,16 @@ pub fn maxsize(&self) -> usize {
 /// # Examples
 ///
 /// ```no_run
-/// # use kernel::{bindings, ffi::c_void, io::{Io, IoRaw}};
-/// # use core::ops::Deref;
+/// use kernel::{
+///     bindings,
+///     ffi::c_void,
+///     io::{
+///         Io,
+///         IoRaw,
+///         PhysAddr,
+///     },
+/// };
+/// use core::ops::Deref;
 ///
 /// // See also [`pci::Bar`] for a real example.
 /// struct IoMem<const SIZE: usize>(IoRaw<SIZE>);
@@ -82,7 +96,7 @@ pub fn maxsize(&self) -> usize {
 ///     unsafe fn new(paddr: usize) -> Result<Self>{
 ///         // SAFETY: By the safety requirements of this function [`paddr`, `paddr` + `SIZE`) is
 ///         // valid for `ioremap`.
-///         let addr = unsafe { bindings::ioremap(paddr as bindings::phys_addr_t, SIZE) };
+///         let addr = unsafe { bindings::ioremap(paddr as PhysAddr, SIZE) };
 ///         if addr.is_null() {
 ///             return Err(ENOMEM);
 ///         }
diff --git a/rust/kernel/io/resource.rs b/rust/kernel/io/resource.rs
index 7fed41fc20307fa7ce230da4b7841743631c965e..5d9d9f01d91c3b8b13e4837d4fb19a786d7720c8 100644
--- a/rust/kernel/io/resource.rs
+++ b/rust/kernel/io/resource.rs
@@ -12,7 +12,10 @@
 use crate::str::{CStr, CString};
 use crate::types::Opaque;
 
-pub use super::ResourceSize;
+pub use super::{
+    PhysAddr,
+    ResourceSize, \\
+};
 
 /// A region allocated from a parent [`Resource`].
 ///
@@ -93,7 +96,7 @@ impl Resource {
     /// the region, or a part of it, is already in use.
     pub fn request_region(
         &self,
-        start: ResourceSize,
+        start: PhysAddr,
         size: ResourceSize,
         name: CString,
         flags: Flags,
@@ -127,7 +130,7 @@ pub fn size(&self) -> ResourceSize {
     }
 
     /// Returns the start address of the resource.
-    pub fn start(&self) -> ResourceSize {
+    pub fn start(&self) -> PhysAddr {
         let inner = self.0.get();
         // SAFETY: Safe as per the invariants of `Resource`.
         unsafe { (*inner).start }

-- 
2.51.2.1026.g39e6a42477-goog

Re: [PATCH 4/4] rust: io: add typedef for phys_addr_t

[kernel test robot]

Hi Alice,

kernel test robot noticed the following build errors:

[auto build test ERROR on 211ddde0823f1442e4ad052a2f30f050145ccada]

url:    https://github.com/intel-lab-lkp/linux/commits/Alice-Ryhl/rust-io-define-ResourceSize-as-resource_size_t/20251106-201954
base:   211ddde0823f1442e4ad052a2f30f050145ccada
patch link:    https://lore.kernel.org/r/20251106-resource-phys-typedefs-v1-4-0c0edc7301ce%40google.com
patch subject: [PATCH 4/4] rust: io: add typedef for phys_addr_t
config: x86_64-rhel-9.4-rust (https://download.01.org/0day-ci/archive/20251111/202511110532.BF1f9LTs-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
rustc: rustc 1.88.0 (6b00bc388 2025-06-23)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251111/202511110532.BF1f9LTs-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511110532.BF1f9LTs-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from kernel/sched/rq-offsets.c:5:
   kernel/sched/sched.h:3743:18: warning: variable 'cpumask' set but not used [-Wunused-but-set-variable]
   3743 |         struct cpumask *cpumask;
   |                         ^
   1 warning generated.
>> error: unknown start of token:   --> rust/kernel/io/resource.rs:17:19
   |
   17 |     ResourceSize, \
   |                   ^^
   |
   = note: character appears once more

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki