From 5e30550558b1eace5fa4af4e2257216fa8a7c90f Mon Sep 17 00:00:00 2001 From: Tamir Duberstein Date: Sun, 15 Jun 2025 16:55:08 -0400 Subject: rust: enable `clippy::as_underscore` lint In Rust 1.63.0, Clippy introduced the `as_underscore` lint [1]: > The conversion might include lossy conversion or a dangerous cast that > might go undetected due to the type being inferred. > > The lint is allowed by default as using `_` is less wordy than always > specifying the type. Always specifying the type is especially helpful in function call contexts where the inferred type may change at a distance. Specifying the type also allows Clippy to spot more cases of `useless_conversion`. The primary downside is the need to specify the type in trivial getters. There are 4 such functions: 3 have become slightly less ergonomic, 1 was revealed to be a `useless_conversion`. While this doesn't eliminate unchecked `as` conversions, it makes such conversions easier to scrutinize. It also has the slight benefit of removing a degree of freedom on which to bikeshed. Thus apply the changes and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_underscore [1] Reviewed-by: Benno Lossin Reviewed-by: Boqun Feng Signed-off-by: Tamir Duberstein Acked-by: Greg Kroah-Hartman Acked-by: Danilo Krummrich Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-4-f43b024581e8@gmail.com [ Changed `isize` to `c_long`. - Miguel ] Signed-off-by: Miguel Ojeda --- rust/kernel/miscdevice.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'rust/kernel/miscdevice.rs') diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs index 939278bc7b03..288f40e79906 100644 --- a/rust/kernel/miscdevice.rs +++ b/rust/kernel/miscdevice.rs @@ -34,7 +34,7 @@ impl MiscDeviceOptions { pub const fn into_raw(self) -> bindings::miscdevice { // SAFETY: All zeros is valid for this C type. let mut result: bindings::miscdevice = unsafe { MaybeUninit::zeroed().assume_init() }; - result.minor = bindings::MISC_DYNAMIC_MINOR as _; + result.minor = bindings::MISC_DYNAMIC_MINOR as ffi::c_int; result.name = self.name.as_char_ptr(); result.fops = MiscdeviceVTable::::build(); result -- cgit From b9ff1c2a26fa31216be18e9b14c419ff8fe39e72 Mon Sep 17 00:00:00 2001 From: Shankari Anand Date: Thu, 26 Jun 2025 16:15:20 +0530 Subject: rust: miscdevice: clarify invariant for `MiscDeviceRegistration` Reword and expand the invariant documentation for `MiscDeviceRegistration` to clarify what it means for the inner device to be "registered". It expands to explain: - `inner` points to a `miscdevice` registered via `misc_register`. - This registration stays valid for the entire lifetime of the object. - Deregistration is guaranteed on `Drop`, via `misc_deregister`. Reported-by: Benno Lossin Closes: https://github.com/Rust-for-Linux/linux/issues/1168 Fixes: f893691e7426 ("rust: miscdevice: add base miscdevice abstraction") Signed-off-by: Shankari Anand Link: https://lore.kernel.org/r/20250626104520.563036-1-shankari.ak0208@gmail.com Signed-off-by: Greg Kroah-Hartman --- rust/kernel/miscdevice.rs | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'rust/kernel/miscdevice.rs') diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs index 939278bc7b03..4f7a8714ad36 100644 --- a/rust/kernel/miscdevice.rs +++ b/rust/kernel/miscdevice.rs @@ -45,7 +45,13 @@ impl MiscDeviceOptions { /// /// # Invariants /// -/// `inner` is a registered misc device. +/// - `inner` contains a `struct miscdevice` that is registered using +/// `misc_register()`. +/// - This registration remains valid for the entire lifetime of the +/// [`MiscDeviceRegistration`] instance. +/// - Deregistration occurs exactly once in [`Drop`] via `misc_deregister()`. +/// - `inner` wraps a valid, pinned `miscdevice` created using +/// [`MiscDeviceOptions::into_raw`]. #[repr(transparent)] #[pin_data(PinnedDrop)] pub struct MiscDeviceRegistration { -- cgit From db15ec7abd33ce245120f36be91f56f0ba0b247e Mon Sep 17 00:00:00 2001 From: Tamir Duberstein Date: Fri, 4 Jul 2025 15:50:11 -0400 Subject: rust: miscdevice: remove unnecessary import `kernel::str::CStr` is included in the prelude. Signed-off-by: Tamir Duberstein Link: https://lore.kernel.org/r/20250704-cstr-include-miscdevice-v1-1-bb9e9b17c892@gmail.com Signed-off-by: Greg Kroah-Hartman --- rust/kernel/miscdevice.rs | 1 - 1 file changed, 1 deletion(-) (limited to 'rust/kernel/miscdevice.rs') diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs index 939278bc7b03..f5b9a6130a7a 100644 --- a/rust/kernel/miscdevice.rs +++ b/rust/kernel/miscdevice.rs @@ -17,7 +17,6 @@ use crate::{ mm::virt::VmaNew, prelude::*, seq_file::SeqFile, - str::CStr, types::{ForeignOwnable, Opaque}, }; use core::{marker::PhantomData, mem::MaybeUninit, pin::Pin}; -- cgit From 12717ebeffcf3e34063dbc1e1b7f34924150c7c9 Mon Sep 17 00:00:00 2001 From: Andreas Hindborg Date: Thu, 12 Jun 2025 15:09:43 +0200 Subject: rust: types: add FOREIGN_ALIGN to ForeignOwnable MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The current implementation of `ForeignOwnable` is leaking the type of the opaque pointer to consumers of the API. This allows consumers of the opaque pointer to rely on the information that can be extracted from the pointer type. To prevent this, change the API to the version suggested by Maira Canal (link below): Remove `ForeignOwnable::PointedTo` in favor of a constant, which specifies the alignment of the pointers returned by `into_foreign`. With this change, `ArcInner` no longer needs `pub` visibility, so change it to private. Suggested-by: Alice Ryhl Suggested-by: Maíra Canal Link: https://lore.kernel.org/r/20240309235927.168915-3-mcanal@igalia.com Acked-by: Danilo Krummrich Reviewed-by: Benno Lossin Signed-off-by: Andreas Hindborg Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20250612-pointed-to-v3-1-b009006d86a1@kernel.org Signed-off-by: Miguel Ojeda --- rust/kernel/miscdevice.rs | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'rust/kernel/miscdevice.rs') diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs index 288f40e79906..ad51ffc549b8 100644 --- a/rust/kernel/miscdevice.rs +++ b/rust/kernel/miscdevice.rs @@ -217,7 +217,7 @@ impl MiscdeviceVTable { // type. // // SAFETY: The open call of a file can access the private data. - unsafe { (*raw_file).private_data = ptr.into_foreign().cast() }; + unsafe { (*raw_file).private_data = ptr.into_foreign() }; 0 } @@ -228,7 +228,7 @@ impl MiscdeviceVTable { /// must be associated with a `MiscDeviceRegistration`. unsafe extern "C" fn release(_inode: *mut bindings::inode, file: *mut bindings::file) -> c_int { // SAFETY: The release call of a file owns the private data. - let private = unsafe { (*file).private_data }.cast(); + let private = unsafe { (*file).private_data }; // SAFETY: The release call of a file owns the private data. let ptr = unsafe { ::from_foreign(private) }; @@ -272,7 +272,7 @@ impl MiscdeviceVTable { /// `file` must be a valid file that is associated with a `MiscDeviceRegistration`. unsafe extern "C" fn ioctl(file: *mut bindings::file, cmd: c_uint, arg: c_ulong) -> c_long { // SAFETY: The ioctl call of a file can access the private data. - let private = unsafe { (*file).private_data }.cast(); + let private = unsafe { (*file).private_data }; // SAFETY: Ioctl calls can borrow the private data of the file. let device = unsafe { ::borrow(private) }; @@ -297,7 +297,7 @@ impl MiscdeviceVTable { arg: c_ulong, ) -> c_long { // SAFETY: The compat ioctl call of a file can access the private data. - let private = unsafe { (*file).private_data }.cast(); + let private = unsafe { (*file).private_data }; // SAFETY: Ioctl calls can borrow the private data of the file. let device = unsafe { ::borrow(private) }; @@ -318,7 +318,7 @@ impl MiscdeviceVTable { /// - `seq_file` must be a valid `struct seq_file` that we can write to. unsafe extern "C" fn show_fdinfo(seq_file: *mut bindings::seq_file, file: *mut bindings::file) { // SAFETY: The release call of a file owns the private data. - let private = unsafe { (*file).private_data }.cast(); + let private = unsafe { (*file).private_data }; // SAFETY: Ioctl calls can borrow the private data of the file. let device = unsafe { ::borrow(private) }; // SAFETY: -- cgit From 2f5606afa4c2bcabd45cb34c92faf93ca5ffe75e Mon Sep 17 00:00:00 2001 From: Alice Ryhl Date: Fri, 11 Jul 2025 08:04:37 +0000 Subject: device: rust: rename Device::as_ref() to Device::from_raw() The prefix as_* should not be used for a constructor. Constructors usually use the prefix from_* instead. Some prior art in the stdlib: Box::from_raw, CString::from_raw, Rc::from_raw, Arc::from_raw, Waker::from_raw, File::from_raw_fd. There is also prior art in the kernel crate: cpufreq::Policy::from_raw, fs::File::from_raw_file, Kuid::from_raw, ARef::from_raw, SeqFile::from_raw, VmaNew::from_raw, Io::from_raw. Link: https://lore.kernel.org/r/aCd8D5IA0RXZvtcv@pollux Signed-off-by: Alice Ryhl Reviewed-by: Benno Lossin Reviewed-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20250711-device-as-ref-v2-1-1b16ab6402d7@google.com Signed-off-by: Danilo Krummrich --- rust/kernel/miscdevice.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'rust/kernel/miscdevice.rs') diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs index 4f7a8714ad36..443e5a3c3fe0 100644 --- a/rust/kernel/miscdevice.rs +++ b/rust/kernel/miscdevice.rs @@ -98,7 +98,7 @@ impl MiscDeviceRegistration { // function tells the borrow-checker that the `&Device` reference must not outlive the // `&MiscDeviceRegistration` used to obtain it, so the last use of the reference must be // before the underlying `struct miscdevice` is destroyed. - unsafe { Device::as_ref((*self.as_raw()).this_device) } + unsafe { Device::from_raw((*self.as_raw()).this_device) } } } -- cgit