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 6EA0535BDC8; Wed, 22 Oct 2025 14:32:36 +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=1761143556; cv=none; b=JSf9cRHpodFP8mLFqxfBU6aIkeyp0GCWGqpWYl1pQLkYfZh4x3MyGOqxTYiiPkJGz36cEIi+4jIeSnazLJOH6lUNEkGWx2x+/FUKy/8pat4Ql8m755rR/qUadJR7Msgkj4uTEXKXaSn29Ni6xGbKCdl8anOALnFW6B+FamB1BVo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761143556; c=relaxed/simple; bh=FjKY9QsB1XFo54VLaBgstN2S0XKDdqqOijiLBegPaAw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RBVFzV+M3o+rrdaECy3kxD9vn/wG8OU4PN2JsS2PFIR3P1CBtc+n6EPWSaM7sjrpUYCI9IzlNhlSBXvVnC7BWApXq/RoukK7AX8VY6+TRO5kpU/TIa+L6lvUpQE4I4tLFfpt7ve5n7r5Z1foepCukLDrSeWymuXHxKZ57vFhr/M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nyqiDjFB; 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="nyqiDjFB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B7B65C116B1; Wed, 22 Oct 2025 14:32:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761143555; bh=FjKY9QsB1XFo54VLaBgstN2S0XKDdqqOijiLBegPaAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nyqiDjFBytQpSgJmSXDgQFEKaGx0l3mo4PhCXT4AcKUhWmN8NRZEleYNrrwlqFzyj QAFWdZsa+VJjvZWw7mzUn2DTIxBr8m0C6vKJ5mn/B6kdhlaHxf02tJkcfi8SZtfcFW 6K9CDC6+WDfZIZom+dJ5NiDFBa92kdktYWgincCQaFUL6D167dZwIhWjHRFTPo1R0E t42xzirrz4UiVZHZBVsQeGIm89KB0wUeseROrUhXLBngKriMWXyvZUiN1nU+ivhypT QnESxd1riZuEGXQfMs0lWUAuJVhDZZtZ9IRAQNcMXqilzt9Dx1dsqY32oOPU7dLhyX iB+WnQ/gCcsOw== 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-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Danilo Krummrich Subject: [PATCH v3 07/10] rust: debugfs: support blobs from smart pointers Date: Wed, 22 Oct 2025 16:30:41 +0200 Message-ID: <20251022143158.64475-8-dakr@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251022143158.64475-1-dakr@kernel.org> References: <20251022143158.64475-1-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. Reviewed-by: Greg Kroah-Hartman Reviewed-by: Matthew Maurer Signed-off-by: Danilo Krummrich --- rust/kernel/debugfs.rs | 2 +- rust/kernel/debugfs/traits.rs | 174 +++++++++++++++++++++++++++++++++- 2 files changed, 173 insertions(+), 3 deletions(-) diff --git a/rust/kernel/debugfs.rs b/rust/kernel/debugfs.rs index 95cd3376ecbe..d2bc7550d81e 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 bd38eb988d51..2c32ddf9826f 100644 --- a/rust/kernel/debugfs/traits.rs +++ b/rust/kernel/debugfs/traits.rs @@ -3,12 +3,15 @@ //! Traits for rendering or updating values exported to DebugFS. +use crate::alloc::Allocator; use crate::fs::file; 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, @@ -79,6 +82,72 @@ fn write_to_slice( } } +// 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: &mut file::Offset, + ) -> 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: &mut file::Offset, + ) -> 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: &mut file::Offset, + ) -> 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: &mut file::Offset, + ) -> 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_file(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. @@ -107,6 +176,73 @@ 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: &mut file::Offset, + ) -> Result; +} + +// Base implementation for any `T: AsBytes + FromBytes`. +impl BinaryReaderMut for T { + fn read_from_slice_mut( + &mut self, + reader: &mut UserSliceReader, + offset: &mut file::Offset, + ) -> Result { + reader.read_slice_file(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: &mut file::Offset, + ) -> 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: &mut file::Offset, + ) -> Result { + let slice = self.as_mut_slice(); + + // SAFETY: `T: AsBytes + FromBytes` allows us to treat `&mut [T]` as `&mut [u8]`. + let buffer = unsafe { + core::slice::from_raw_parts_mut( + slice.as_mut_ptr().cast(), + core::mem::size_of_val(slice), + ) + }; + + reader.read_slice_file(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`. /// @@ -120,7 +256,8 @@ fn read_from_slice( ) -> 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, @@ -128,7 +265,40 @@ fn read_from_slice( ) -> Result { let mut this = self.lock(); - reader.read_slice_file(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: &mut file::Offset, + ) -> 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: &mut file::Offset, + ) -> 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: &mut file::Offset, + ) -> Result { + self.deref().read_from_slice(reader, offset) } } -- 2.51.0