From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF29C2EC099; Fri, 3 Oct 2025 22:27:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759530474; cv=none; b=B0nmWJxK2wpoZfxPhEJGzPF1kIuUBDfuiJ7NhTH1KXbZF3MU3OaxpyIgRAUHnK0xDiR8SaVbOPE26qsCe5OLxfJ+7eThOpQsQoW1CrnX6BwQPScxvZDnW5XdgzYl1M1DwltaO4oNrucRAuakxv2DrZ0QRgN3grPeCTi1xZ58EuQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759530474; c=relaxed/simple; bh=u53Uk/PsduccUptjZR9Ccs65J+jFhHu+M/uud08l/Fc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LwwNRy3t0cpwWguwlb9/CZIXqPuEjBALvrlTJWjKd5kNPh4rTirQzGKGGESS9lM9Sh0QdhOrJXDpdtn+9GQuzDh6rUgxyKal++aulxmMdIM9qyRUZgES3jxLg3XEc/rW22DOfdXfsusTMXDG72sgHuIEfsPDkRdhSDknfwxlcs8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nPIGjXCD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nPIGjXCD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37BD7C4CEFA; Fri, 3 Oct 2025 22:27:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1759530474; bh=u53Uk/PsduccUptjZR9Ccs65J+jFhHu+M/uud08l/Fc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nPIGjXCD2b24WQW+CqGX9OzRI+NTfiO1boYYrR/tZJMHxfJ6txgE5AeXTNClZ2NQ4 loDnYoxQ9M4Rr8kBWxdKjXRPHUr3azREs/VOVxaUmdXM+zy5xCkVYVl8wUtLtaRVgl JP8JwOZzQkPf22nN+PaHfTpBFsiw2RVeOJtGvxRqPZmBEJVkdS7ebRLhTdRJw9VvL+ B5opazvKVW19aMrHgkLrB62cl32rEvqrH/DU5zbbK5r3j4ZvOlt82/41574ZCqKhdS 5w/2v8L4NCcK5FreWzTV2qA22wKksELLK4VmTyKP3yiakLjecFuQqH69xCrGgh2m2X SlOy5WpDpBLmQ== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, lossin@kernel.org, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, mmaurer@google.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Danilo Krummrich Subject: [PATCH 4/7] rust: debugfs: support blobs from smart pointers Date: Sat, 4 Oct 2025 00:26:41 +0200 Message-ID: <20251003222729.322059-5-dakr@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251003222729.322059-1-dakr@kernel.org> References: <20251003222729.322059-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Extend Rust debugfs binary support to allow exposing data stored in common smart pointers and heap-allocated collections. - Implement BinaryWriter for Box, Pin>, Arc, and Vec. - Introduce BinaryReaderMut for mutable binary access with outer locks. - Implement BinaryReaderMut for Box, Vec, and base types. - Update BinaryReader to delegate to BinaryReaderMut for Mutex, Box, Pin> and Arc. This enables debugfs files to directly expose or update data stored inside heap-allocated, reference-counted, or lock-protected containers without manual dereferencing or locking. Signed-off-by: Danilo Krummrich --- rust/kernel/debugfs.rs | 2 +- rust/kernel/debugfs/traits.rs | 145 +++++++++++++++++++++++++++++++++- 2 files changed, 144 insertions(+), 3 deletions(-) diff --git a/rust/kernel/debugfs.rs b/rust/kernel/debugfs.rs index b1a3adca7fd4..3c3bbcc126ef 100644 --- a/rust/kernel/debugfs.rs +++ b/rust/kernel/debugfs.rs @@ -21,7 +21,7 @@ use core::ops::Deref; mod traits; -pub use traits::{BinaryReader, BinaryWriter, Reader, Writer}; +pub use traits::{BinaryReader, BinaryReaderMut, BinaryWriter, Reader, Writer}; mod callback_adapters; use callback_adapters::{FormatAdapter, NoWriter, WritableAdapter}; diff --git a/rust/kernel/debugfs/traits.rs b/rust/kernel/debugfs/traits.rs index 60a6ee6c6b58..bcd0a9db3cc9 100644 --- a/rust/kernel/debugfs/traits.rs +++ b/rust/kernel/debugfs/traits.rs @@ -3,11 +3,14 @@ //! Traits for rendering or updating values exported to DebugFS. +use crate::alloc::Allocator; use crate::prelude::*; +use crate::sync::Arc; use crate::sync::Mutex; use crate::transmute::{AsBytes, FromBytes}; use crate::uaccess::{UserSliceReader, UserSliceWriter}; use core::fmt::{self, Debug, Formatter}; +use core::ops::{Deref, DerefMut}; use core::str::FromStr; use core::sync::atomic::{ AtomicI16, AtomicI32, AtomicI64, AtomicI8, AtomicIsize, AtomicU16, AtomicU32, AtomicU64, @@ -50,12 +53,14 @@ pub trait BinaryWriter { fn write_to_slice(&self, writer: &mut UserSliceWriter, offset: usize) -> Result; } +// Base implementation for any `T: AsBytes`. impl BinaryWriter for T { fn write_to_slice(&self, writer: &mut UserSliceWriter, offset: usize) -> Result { writer.write_slice_partial(self.as_bytes(), offset) } } +// Delegate for `Mutex`: Support a `T` with an outer mutex. impl BinaryWriter for Mutex { fn write_to_slice(&self, writer: &mut UserSliceWriter, offset: usize) -> Result { let guard = self.lock(); @@ -64,6 +69,56 @@ fn write_to_slice(&self, writer: &mut UserSliceWriter, offset: usize) -> Result< } } +// Delegate for `Box`: Support a `Box` with no lock or an inner lock. +impl BinaryWriter for Box +where + T: BinaryWriter, + A: Allocator, +{ + fn write_to_slice(&self, writer: &mut UserSliceWriter, offset: usize) -> Result { + self.deref().write_to_slice(writer, offset) + } +} + +// Delegate for `Pin>`: Support a `Pin>` with no lock or an inner lock. +impl BinaryWriter for Pin> +where + T: BinaryWriter, + A: Allocator, +{ + fn write_to_slice(&self, writer: &mut UserSliceWriter, offset: usize) -> Result { + self.deref().write_to_slice(writer, offset) + } +} + +// Delegate for `Arc`: Support a `Arc` with no lock or an inner lock. +impl BinaryWriter for Arc +where + T: BinaryWriter, +{ + fn write_to_slice(&self, writer: &mut UserSliceWriter, offset: usize) -> Result { + self.deref().write_to_slice(writer, offset) + } +} + +// Delegate for `Vec`. +impl BinaryWriter for Vec +where + T: AsBytes, + A: Allocator, +{ + fn write_to_slice(&self, writer: &mut UserSliceWriter, offset: usize) -> Result { + let slice = self.as_slice(); + + // SAFETY: `T: AsBytes` allows us to treat `&[T]` as `&[u8]`. + let buffer = unsafe { + core::slice::from_raw_parts(slice.as_ptr().cast(), core::mem::size_of_val(slice)) + }; + + writer.write_slice_partial(buffer, offset) + } +} + /// A trait for types that can be updated from a user slice. /// /// This works similarly to `FromStr`, but operates on a `UserSliceReader` rather than a &str. @@ -92,6 +147,70 @@ fn read_from_slice(&self, reader: &mut UserSliceReader) -> Result { } /// Trait for types that can be constructed from a binary representation. +/// +/// See also [`BinaryReader`] for interior mutability. +pub trait BinaryReaderMut { + /// Reads the binary form of `self` from `reader`. + /// + /// Same as [`BinaryReader::read_from_slice`], but takes a mutable reference. + /// + /// `offset` is the requested offset into the binary representation of `self`. + /// + /// On success, returns the number of bytes read from `reader`. + fn read_from_slice_mut(&mut self, reader: &mut UserSliceReader, offset: usize) + -> Result; +} + +// Base implementation for any `T: AsBytes + FromBytes`. +impl BinaryReaderMut for T { + fn read_from_slice_mut( + &mut self, + reader: &mut UserSliceReader, + offset: usize, + ) -> Result { + reader.read_slice_partial(self.as_bytes_mut(), offset) + } +} + +// Delegate for `Box`: Support a `Box` with an outer lock. +impl BinaryReaderMut for Box { + fn read_from_slice_mut( + &mut self, + reader: &mut UserSliceReader, + offset: usize, + ) -> Result { + self.deref_mut().read_from_slice_mut(reader, offset) + } +} + +// Delegate for `Vec`: Support a `Vec` with an outer lock. +impl BinaryReaderMut for Vec +where + T: AsBytes + FromBytes, + A: Allocator, +{ + fn read_from_slice_mut( + &mut self, + reader: &mut UserSliceReader, + offset: usize, + ) -> Result { + let slice = self.as_mut_slice(); + + // SAFETY: `T: AsBytes` allows us to treat `&[T]` as `&[u8]`. + let buffer = unsafe { + core::slice::from_raw_parts_mut( + slice.as_mut_ptr().cast(), + core::mem::size_of_val(slice), + ) + }; + + reader.read_slice_partial(buffer, offset) + } +} + +/// Trait for types that can be constructed from a binary representation. +/// +/// See also [`BinaryReaderMut`] for the mutable version. pub trait BinaryReader { /// Reads the binary form of `self` from `reader`. /// @@ -101,11 +220,33 @@ pub trait BinaryReader { fn read_from_slice(&self, reader: &mut UserSliceReader, offset: usize) -> Result; } -impl BinaryReader for Mutex { +// Delegate for `Mutex`: Support a `T` with an outer `Mutex`. +impl BinaryReader for Mutex { fn read_from_slice(&self, reader: &mut UserSliceReader, offset: usize) -> Result { let mut this = self.lock(); - reader.read_slice_partial(this.as_bytes_mut(), offset) + this.read_from_slice_mut(reader, offset) + } +} + +// Delegate for `Box`: Support a `Box` with an inner lock. +impl BinaryReader for Box { + fn read_from_slice(&self, reader: &mut UserSliceReader, offset: usize) -> Result { + self.deref().read_from_slice(reader, offset) + } +} + +// Delegate for `Pin>`: Support a `Pin>` with an inner lock. +impl BinaryReader for Pin> { + fn read_from_slice(&self, reader: &mut UserSliceReader, offset: usize) -> Result { + self.deref().read_from_slice(reader, offset) + } +} + +// Delegate for `Arc`: Support an `Arc` with an inner lock. +impl BinaryReader for Arc { + fn read_from_slice(&self, reader: &mut UserSliceReader, offset: usize) -> Result { + self.deref().read_from_slice(reader, offset) } } -- 2.51.0