[PATCH v11 1/6] rust: enable `clippy::ptr_as_ptr` lint

[Tamir Duberstein]

In Rust 1.51.0, Clippy introduced the `ptr_as_ptr` lint [1]:

> Though `as` casts between raw pointers are not terrible,
> `pointer::cast` is safer because it cannot accidentally change the
> pointer's mutability, nor cast the pointer to other types like `usize`.

There are a few classes of changes required:
- Modules generated by bindgen are marked
`#[allow(clippy::ptr_as_ptr)]`.
- Inferred casts (` as _`) are replaced with `.cast()`.
- Ascribed casts (` as *... T`) are replaced with `.cast::<T>()`.
- Multistep casts from references (` as *const _ as *const T`) are
replaced with `core::ptr::from_ref(&x).cast()` with or without `::<T>`
according to the previous rules. The `core::ptr::from_ref` call is
required because `(x as *const _).cast::<T>()` results in inference
failure.
- Native literal C strings are replaced with `c_str!().as_char_ptr()`.
- `*mut *mut T as _` is replaced with `let *mut *const T = (*mut *mut
T)`.cast();` since pointer to pointer can be confusing.

Apply these changes and enable the lint -- no functional change
intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr [1]
Reviewed-by: Benno Lossin <benno....@proton.me>
Reviewed-by: Boqun Feng <boqun...@gmail.com>
Signed-off-by: Tamir Duberstein <tam...@gmail.com>
---
Makefile | 1 +
rust/bindings/lib.rs | 1 +
rust/kernel/alloc/allocator_test.rs | 2 +-
rust/kernel/alloc/kvec.rs | 4 ++--
rust/kernel/device.rs | 4 ++--
rust/kernel/devres.rs | 2 +-
rust/kernel/dma.rs | 4 ++--
rust/kernel/error.rs | 2 +-
rust/kernel/firmware.rs | 3 ++-
rust/kernel/fs/file.rs | 2 +-
rust/kernel/kunit.rs | 11 +++++++----
rust/kernel/list/impl_list_item_mod.rs | 2 +-
rust/kernel/pci.rs | 2 +-
rust/kernel/platform.rs | 4 +++-
rust/kernel/print.rs | 6 +++---
rust/kernel/seq_file.rs | 2 +-
rust/kernel/str.rs | 2 +-
rust/kernel/sync/poll.rs | 2 +-
rust/kernel/time/hrtimer/pin.rs | 2 +-
rust/kernel/time/hrtimer/pin_mut.rs | 2 +-
rust/kernel/workqueue.rs | 6 +++---
rust/uapi/lib.rs | 1 +
22 files changed, 38 insertions(+), 29 deletions(-)

diff --git a/Makefile b/Makefile
index 35e6e5240c61..21cc6e312ec9 100644
--- a/Makefile
+++ b/Makefile
@@ -484,6 +484,7 @@ export rust_common_flags := --edition=2021 \
-Wclippy::needless_bitwise_bool \
-Aclippy::needless_lifetimes \
-Wclippy::no_mangle_with_rust_abi \
+ -Wclippy::ptr_as_ptr \
-Wclippy::undocumented_unsafe_blocks \
-Wclippy::unnecessary_safety_comment \
-Wclippy::unnecessary_safety_doc \
diff --git a/rust/bindings/lib.rs b/rust/bindings/lib.rs
index a08eb5518cac..81b6c7aa4916 100644
--- a/rust/bindings/lib.rs
+++ b/rust/bindings/lib.rs
@@ -25,6 +25,7 @@
)]

#[allow(dead_code)]
+#[allow(clippy::ptr_as_ptr)]
#[allow(clippy::undocumented_unsafe_blocks)]
#[cfg_attr(CONFIG_RUSTC_HAS_UNNECESSARY_TRANSMUTES, allow(unnecessary_transmutes))]
mod bindings_raw {
diff --git a/rust/kernel/alloc/allocator_test.rs b/rust/kernel/alloc/allocator_test.rs
index d19c06ef0498..a3074480bd8d 100644
--- a/rust/kernel/alloc/allocator_test.rs
+++ b/rust/kernel/alloc/allocator_test.rs
@@ -82,7 +82,7 @@ unsafe fn realloc(

// SAFETY: Returns either NULL or a pointer to a memory allocation that satisfies or
// exceeds the given size and alignment requirements.
- let dst = unsafe { libc_aligned_alloc(layout.align(), layout.size()) } as *mut u8;
+ let dst = unsafe { libc_aligned_alloc(layout.align(), layout.size()) }.cast::<u8>();
let dst = NonNull::new(dst).ok_or(AllocError)?;

if flags.contains(__GFP_ZERO) {
diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs
index 1a0dd852a468..0477041cbc03 100644
--- a/rust/kernel/alloc/kvec.rs
+++ b/rust/kernel/alloc/kvec.rs
@@ -288,7 +288,7 @@ pub fn spare_capacity_mut(&mut self) -> &mut [MaybeUninit<T>] {
// - `self.len` is smaller than `self.capacity` by the type invariant and hence, the
// resulting pointer is guaranteed to be part of the same allocated object.
// - `self.len` can not overflow `isize`.
- let ptr = unsafe { self.as_mut_ptr().add(self.len) } as *mut MaybeUninit<T>;
+ let ptr = unsafe { self.as_mut_ptr().add(self.len) }.cast::<MaybeUninit<T>>();

// SAFETY: The memory between `self.len` and `self.capacity` is guaranteed to be allocated
// and valid, but uninitialized.
@@ -847,7 +847,7 @@ fn drop(&mut self) {
// - `ptr` points to memory with at least a size of `size_of::<T>() * len`,
// - all elements within `b` are initialized values of `T`,
// - `len` does not exceed `isize::MAX`.
- unsafe { Vec::from_raw_parts(ptr as _, len, len) }
+ unsafe { Vec::from_raw_parts(ptr.cast(), len, len) }
}
}

diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
index dea06b79ecb5..5c946af3a4d5 100644
--- a/rust/kernel/device.rs
+++ b/rust/kernel/device.rs
@@ -195,10 +195,10 @@ unsafe fn printk(&self, klevel: &[u8], msg: fmt::Arguments<'_>) {
#[cfg(CONFIG_PRINTK)]
unsafe {
bindings::_dev_printk(
- klevel as *const _ as *const crate::ffi::c_char,
+ klevel.as_ptr().cast::<crate::ffi::c_char>(),
self.as_raw(),
c_str!("%pA").as_char_ptr(),
- &msg as *const _ as *const crate::ffi::c_void,
+ core::ptr::from_ref(&msg).cast::<crate::ffi::c_void>(),
)
};
}
diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs
index 0f79a2ec9474..e5475ff62da3 100644
--- a/rust/kernel/devres.rs
+++ b/rust/kernel/devres.rs
@@ -154,7 +154,7 @@ fn remove_action(this: &Arc<Self>) {

#[allow(clippy::missing_safety_doc)]
unsafe extern "C" fn devres_callback(ptr: *mut kernel::ffi::c_void) {
- let ptr = ptr as *mut DevresInner<T>;
+ let ptr = ptr.cast::<DevresInner<T>>();
// Devres owned this memory; now that we received the callback, drop the `Arc` and hence the
// reference.
// SAFETY: Safe, since we leaked an `Arc` reference to devm_add_action() in
diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs
index a33261c62e0c..666bf2d64f9a 100644
--- a/rust/kernel/dma.rs
+++ b/rust/kernel/dma.rs
@@ -186,7 +186,7 @@ pub fn alloc_attrs(
dev: dev.into(),
dma_handle,
count,
- cpu_addr: ret as *mut T,
+ cpu_addr: ret.cast::<T>(),
dma_attrs,
})
}
@@ -293,7 +293,7 @@ fn drop(&mut self) {
bindings::dma_free_attrs(
self.dev.as_raw(),
size,
- self.cpu_addr as _,
+ self.cpu_addr.cast(),
self.dma_handle,
self.dma_attrs.as_raw(),
)
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index 3dee3139fcd4..afcb00cb6a75 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -153,7 +153,7 @@ pub(crate) fn to_blk_status(self) -> bindings::blk_status_t {
/// Returns the error encoded as a pointer.
pub fn to_ptr<T>(self) -> *mut T {
// SAFETY: `self.0` is a valid error due to its invariant.
- unsafe { bindings::ERR_PTR(self.0.get() as _) as *mut _ }
+ unsafe { bindings::ERR_PTR(self.0.get() as _).cast() }
}

/// Returns a string representing the error, if one exists.
diff --git a/rust/kernel/firmware.rs b/rust/kernel/firmware.rs
index 2494c96e105f..94fa1ea17ef0 100644
--- a/rust/kernel/firmware.rs
+++ b/rust/kernel/firmware.rs
@@ -62,10 +62,11 @@ impl Firmware {
fn request_internal(name: &CStr, dev: &Device, func: FwFunc) -> Result<Self> {
let mut fw: *mut bindings::firmware = core::ptr::null_mut();
let pfw: *mut *mut bindings::firmware = &mut fw;
+ let pfw: *mut *const bindings::firmware = pfw.cast();

// SAFETY: `pfw` is a valid pointer to a NULL initialized `bindings::firmware` pointer.
// `name` and `dev` are valid as by their type invariants.
- let ret = unsafe { func.0(pfw as _, name.as_char_ptr(), dev.as_raw()) };
+ let ret = unsafe { func.0(pfw, name.as_char_ptr(), dev.as_raw()) };
if ret != 0 {
return Err(Error::from_errno(ret));
}
diff --git a/rust/kernel/fs/file.rs b/rust/kernel/fs/file.rs
index 72d84fb0e266..e9bfbad00755 100644
--- a/rust/kernel/fs/file.rs
+++ b/rust/kernel/fs/file.rs
@@ -366,7 +366,7 @@ fn deref(&self) -> &LocalFile {
//
// By the type invariants, there are no `fdget_pos` calls that did not take the
// `f_pos_lock` mutex.
- unsafe { LocalFile::from_raw_file(self as *const File as *const bindings::file) }
+ unsafe { LocalFile::from_raw_file((self as *const Self).cast()) }
}
}

diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
index 4b8cdcb21e77..6930e86d98a9 100644
--- a/rust/kernel/kunit.rs
+++ b/rust/kernel/kunit.rs
@@ -9,6 +9,9 @@
use crate::prelude::*;
use core::{ffi::c_void, fmt};

+#[cfg(CONFIG_PRINTK)]
+use crate::c_str;
+
/// Prints a KUnit error-level message.
///
/// Public but hidden since it should only be used from KUnit generated code.
@@ -19,8 +22,8 @@ pub fn err(args: fmt::Arguments<'_>) {
#[cfg(CONFIG_PRINTK)]
unsafe {
bindings::_printk(
- c"\x013%pA".as_ptr() as _,
- &args as *const _ as *const c_void,
+ c_str!("\x013%pA").as_char_ptr(),
+ core::ptr::from_ref(&args).cast::<c_void>(),
);
}
}
@@ -35,8 +38,8 @@ pub fn info(args: fmt::Arguments<'_>) {
#[cfg(CONFIG_PRINTK)]
unsafe {
bindings::_printk(
- c"\x016%pA".as_ptr() as _,
- &args as *const _ as *const c_void,
+ c_str!("\x016%pA").as_char_ptr(),
+ core::ptr::from_ref(&args).cast::<c_void>(),
);
}
}
diff --git a/rust/kernel/list/impl_list_item_mod.rs b/rust/kernel/list/impl_list_item_mod.rs
index a0438537cee1..1f9498c1458f 100644
--- a/rust/kernel/list/impl_list_item_mod.rs
+++ b/rust/kernel/list/impl_list_item_mod.rs
@@ -34,7 +34,7 @@ pub unsafe trait HasListLinks<const ID: u64 = 0> {
unsafe fn raw_get_list_links(ptr: *mut Self) -> *mut ListLinks<ID> {
// SAFETY: The caller promises that the pointer is valid. The implementer promises that the
// `OFFSET` constant is correct.
- unsafe { (ptr as *mut u8).add(Self::OFFSET) as *mut ListLinks<ID> }
+ unsafe { ptr.cast::<u8>().add(Self::OFFSET).cast() }
}
}

diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs
index 8435f8132e38..33ae0bdc433d 100644
--- a/rust/kernel/pci.rs
+++ b/rust/kernel/pci.rs
@@ -78,7 +78,7 @@ extern "C" fn probe_callback(
// Let the `struct pci_dev` own a reference of the driver's private data.
// SAFETY: By the type invariant `pdev.as_raw` returns a valid pointer to a
// `struct pci_dev`.
- unsafe { bindings::pci_set_drvdata(pdev.as_raw(), data.into_foreign() as _) };
+ unsafe { bindings::pci_set_drvdata(pdev.as_raw(), data.into_foreign().cast()) };
}
Err(err) => return Error::to_errno(err),
}
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
index 5b21fa517e55..4b06f9fbc172 100644
--- a/rust/kernel/platform.rs
+++ b/rust/kernel/platform.rs
@@ -69,7 +69,9 @@ extern "C" fn probe_callback(pdev: *mut bindings::platform_device) -> kernel::ff
// Let the `struct platform_device` own a reference of the driver's private data.
// SAFETY: By the type invariant `pdev.as_raw` returns a valid pointer to a
// `struct platform_device`.
- unsafe { bindings::platform_set_drvdata(pdev.as_raw(), data.into_foreign() as _) };
+ unsafe {
+ bindings::platform_set_drvdata(pdev.as_raw(), data.into_foreign().cast())
+ };
}
Err(err) => return Error::to_errno(err),
}
diff --git a/rust/kernel/print.rs b/rust/kernel/print.rs
index 9783d960a97a..ecdcee43e5a5 100644
--- a/rust/kernel/print.rs
+++ b/rust/kernel/print.rs
@@ -25,7 +25,7 @@
// SAFETY: The C contract guarantees that `buf` is valid if it's less than `end`.
let mut w = unsafe { RawFormatter::from_ptrs(buf.cast(), end.cast()) };
// SAFETY: TODO.
- let _ = w.write_fmt(unsafe { *(ptr as *const fmt::Arguments<'_>) });
+ let _ = w.write_fmt(unsafe { *ptr.cast::<fmt::Arguments<'_>>() });
w.pos().cast()
}

@@ -109,7 +109,7 @@ pub unsafe fn call_printk(
bindings::_printk(
format_string.as_ptr(),
module_name.as_ptr(),
- &args as *const _ as *const c_void,
+ core::ptr::from_ref(&args).cast::<c_void>(),
);
}
}
@@ -129,7 +129,7 @@ pub fn call_printk_cont(args: fmt::Arguments<'_>) {
unsafe {
bindings::_printk(
format_strings::CONT.as_ptr(),
- &args as *const _ as *const c_void,
+ core::ptr::from_ref(&args).cast::<c_void>(),
);
}
}
diff --git a/rust/kernel/seq_file.rs b/rust/kernel/seq_file.rs
index 7a9403eb6e5b..8f199b1a3bb1 100644
--- a/rust/kernel/seq_file.rs
+++ b/rust/kernel/seq_file.rs
@@ -37,7 +37,7 @@ pub fn call_printf(&self, args: core::fmt::Arguments<'_>) {
bindings::seq_printf(
self.inner.get(),
c_str!("%pA").as_char_ptr(),
- &args as *const _ as *const crate::ffi::c_void,
+ core::ptr::from_ref(&args).cast::<crate::ffi::c_void>(),
);
}
}
diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
index a927db8e079c..6a3cb607b332 100644
--- a/rust/kernel/str.rs
+++ b/rust/kernel/str.rs
@@ -237,7 +237,7 @@ pub unsafe fn from_char_ptr<'a>(ptr: *const crate::ffi::c_char) -> &'a Self {
// to a `NUL`-terminated C string.
let len = unsafe { bindings::strlen(ptr) } + 1;
// SAFETY: Lifetime guaranteed by the safety precondition.
- let bytes = unsafe { core::slice::from_raw_parts(ptr as _, len) };
+ let bytes = unsafe { core::slice::from_raw_parts(ptr.cast(), len) };
// SAFETY: As `len` is returned by `strlen`, `bytes` does not contain interior `NUL`.
// As we have added 1 to `len`, the last byte is known to be `NUL`.
unsafe { Self::from_bytes_with_nul_unchecked(bytes) }
diff --git a/rust/kernel/sync/poll.rs b/rust/kernel/sync/poll.rs
index d7e6e59e124b..339ab6097be7 100644
--- a/rust/kernel/sync/poll.rs
+++ b/rust/kernel/sync/poll.rs
@@ -73,7 +73,7 @@ pub fn register_wait(&mut self, file: &File, cv: &PollCondVar) {
// be destroyed, the destructor must run. That destructor first removes all waiters,
// and then waits for an rcu grace period. Therefore, `cv.wait_queue_head` is valid for
// long enough.
- unsafe { qproc(file.as_ptr() as _, cv.wait_queue_head.get(), self.0.get()) };
+ unsafe { qproc(file.as_ptr().cast(), cv.wait_queue_head.get(), self.0.get()) };
}
}
}
diff --git a/rust/kernel/time/hrtimer/pin.rs b/rust/kernel/time/hrtimer/pin.rs
index 293ca9cf058c..2f29fd75d63a 100644
--- a/rust/kernel/time/hrtimer/pin.rs
+++ b/rust/kernel/time/hrtimer/pin.rs
@@ -79,7 +79,7 @@ impl<'a, T> RawHrTimerCallback for Pin<&'a T>

unsafe extern "C" fn run(ptr: *mut bindings::hrtimer) -> bindings::hrtimer_restart {
// `HrTimer` is `repr(C)`
- let timer_ptr = ptr as *mut HrTimer<T>;
+ let timer_ptr = ptr.cast::<HrTimer<T>>();

// SAFETY: By the safety requirement of this function, `timer_ptr`
// points to a `HrTimer<T>` contained in an `T`.
diff --git a/rust/kernel/time/hrtimer/pin_mut.rs b/rust/kernel/time/hrtimer/pin_mut.rs
index 6033572d35ad..d05d68be55e9 100644
--- a/rust/kernel/time/hrtimer/pin_mut.rs
+++ b/rust/kernel/time/hrtimer/pin_mut.rs
@@ -83,7 +83,7 @@ impl<'a, T> RawHrTimerCallback for Pin<&'a mut T>

unsafe extern "C" fn run(ptr: *mut bindings::hrtimer) -> bindings::hrtimer_restart {
// `HrTimer` is `repr(C)`
- let timer_ptr = ptr as *mut HrTimer<T>;
+ let timer_ptr = ptr.cast::<HrTimer<T>>();

// SAFETY: By the safety requirement of this function, `timer_ptr`
// points to a `HrTimer<T>` contained in an `T`.
diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
index d092112d843f..de61374e36bd 100644
--- a/rust/kernel/workqueue.rs
+++ b/rust/kernel/workqueue.rs
@@ -170,7 +170,7 @@ impl Queue {
pub unsafe fn from_raw<'a>(ptr: *const bindings::workqueue_struct) -> &'a Queue {
// SAFETY: The `Queue` type is `#[repr(transparent)]`, so the pointer cast is valid. The
// caller promises that the pointer is not dangling.
- unsafe { &*(ptr as *const Queue) }
+ unsafe { &*ptr.cast::<Queue>() }
}

/// Enqueues a work item.
@@ -522,7 +522,7 @@ unsafe impl<T, const ID: u64> WorkItemPointer<ID> for Arc<T>
{
unsafe extern "C" fn run(ptr: *mut bindings::work_struct) {
// The `__enqueue` method always uses a `work_struct` stored in a `Work<T, ID>`.
- let ptr = ptr as *mut Work<T, ID>;
+ let ptr = ptr.cast::<Work<T, ID>>();
// SAFETY: This computes the pointer that `__enqueue` got from `Arc::into_raw`.
let ptr = unsafe { T::work_container_of(ptr) };
// SAFETY: This pointer comes from `Arc::into_raw` and we've been given back ownership.
@@ -575,7 +575,7 @@ unsafe impl<T, const ID: u64> WorkItemPointer<ID> for Pin<KBox<T>>
{
unsafe extern "C" fn run(ptr: *mut bindings::work_struct) {
// The `__enqueue` method always uses a `work_struct` stored in a `Work<T, ID>`.
- let ptr = ptr as *mut Work<T, ID>;
+ let ptr = ptr.cast::<Work<T, ID>>();
// SAFETY: This computes the pointer that `__enqueue` got from `Arc::into_raw`.
let ptr = unsafe { T::work_container_of(ptr) };
// SAFETY: This pointer comes from `Arc::into_raw` and we've been given back ownership.
diff --git a/rust/uapi/lib.rs b/rust/uapi/lib.rs
index c98d7a8cde77..e79a1f49f055 100644
--- a/rust/uapi/lib.rs
+++ b/rust/uapi/lib.rs
@@ -14,6 +14,7 @@
#![cfg_attr(test, allow(unsafe_op_in_unsafe_fn))]
#![allow(
clippy::all,
+ clippy::ptr_as_ptr,
clippy::undocumented_unsafe_blocks,
dead_code,
missing_docs,

--
2.49.0