[PATCH v12 1/6] rust: enable `clippy::ptr_as_ptr` lint
From: Tamir Duberstein <hidden>
Date: 2025-06-15 20:55:13
Also in:
dri-devel, linux-block, linux-devicetree, linux-kbuild, linux-kselftest, linux-mm, linux-pci, linux-pm, lkml, nouveau, rust-for-linux
Subsystem:
configfs, cpu frequency scaling framework, delay, sleep, timekeeping, timers [rust], dma mapping & scatterlist api [rust], driver core, kobjects, debugfs and sysfs, filesystems (vfs and infrastructure), firmware loader (request_firmware), kernel build + files below scripts/ (unless maintained elsewhere), kernel unit testing framework (kunit), pci subsystem [rust], rust, rust [alloc], rust [sync], the rest · Maintainers:
Andreas Hindborg, "Rafael J. Wysocki", Viresh Kumar, Danilo Krummrich, Greg Kroah-Hartman, Alexander Viro, Christian Brauner, Luis Chamberlain, Russ Weight, Nathan Chancellor, Nicolas Schier, Brendan Higgins, David Gow, Miguel Ojeda, Boqun Feng, Gary Guo, Alice Ryhl, Linus Torvalds
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 <redacted> Reviewed-by: Boqun Feng <redacted> Signed-off-by: Tamir Duberstein <redacted> --- Makefile | 1 + rust/bindings/lib.rs | 1 + rust/kernel/alloc/allocator_test.rs | 2 +- rust/kernel/alloc/kvec.rs | 4 ++-- rust/kernel/configfs.rs | 2 +- rust/kernel/cpufreq.rs | 2 +- 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 + 24 files changed, 40 insertions(+), 31 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/configfs.rs b/rust/kernel/configfs.rs
index 34d0bea4f9a5..bc8e15dcec18 100644
--- a/rust/kernel/configfs.rs
+++ b/rust/kernel/configfs.rs@@ -561,7 +561,7 @@ impl<const ID: u64, O, Data> Attribute<ID, O, Data> let data: &Data = unsafe { get_group_data(c_group) }; // SAFETY: By function safety requirements, `page` is writable for `PAGE_SIZE`. - let ret = O::show(data, unsafe { &mut *(page as *mut [u8; PAGE_SIZE]) }); + let ret = O::show(data, unsafe { &mut *(page.cast::<[u8; PAGE_SIZE]>()) }); match ret { Ok(size) => size as isize,
diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs
index b0a9c6182aec..1cb1f29630e5 100644
--- a/rust/kernel/cpufreq.rs
+++ b/rust/kernel/cpufreq.rs@@ -647,7 +647,7 @@ pub fn data<T: ForeignOwnable>(&mut self) -> Option<<T>::Borrowed<'_>> { fn set_data<T: ForeignOwnable>(&mut self, data: T) -> Result { if self.as_ref().driver_data.is_null() { // Transfer the ownership of the data to the foreign interface. - self.as_mut_ref().driver_data = <T as ForeignOwnable>::into_foreign(data) as _; + self.as_mut_ref().driver_data = <T as ForeignOwnable>::into_foreign(data).cast(); Ok(()) } else { Err(EBUSY)
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