From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B3DD2F39B7 for ; Thu, 23 Oct 2025 08:26:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761207986; cv=none; b=PBgIO8oSjbEmuX5ZhLREJ1VKARqqKeaF2IM3eTCGdk04y76yw5WGm3E8PYoOykoyIC3VeFcUjXNcOaEYk8jC3Cwq4FBpjqaAGwWukoXkNMY+bvJopseVJJ0iDqakfZVkeFZu6i+MKl63Nnp8XnbbY1KLDOQjmjmL1O+zBTIEV/A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761207986; c=relaxed/simple; bh=9Fg3vMFXwJtcWe+pZJoXoz30yGJyrxHbyL+TfUSepZk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=XavNZ++Fd1bPAu8kNzIbpWmyAmKig1FyhWEzPeuPAqVXOpLTA9Tjne+UhMclyS6b2Q4VCSyAmIu5ubrjU0igeEjeMP4COFY6ZE02Zy+ksveBlJv8ipD4yGhfdQkV0Oz/Gvvom+I5u3DcgGrUsvmny7YOMgcYLneospReohOfhzo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=JZ56sywL; arc=none smtp.client-ip=209.85.128.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="JZ56sywL" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-46fa88b5760so2009585e9.3 for ; Thu, 23 Oct 2025 01:26:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1761207983; x=1761812783; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=pF3XqRoNHj3sZR7wlPcBDSDjMHwfDCCUCqxTkrzKgUo=; b=JZ56sywLgKjFz0ylKSOJoQaAAuF9p3N1lKlh8SaQzooOdjz76LkM0vDIEN1lZNAbaT AgOQpT48469WkEP+mpEYsrJIsi5RoRnBZRNo1eZxleL2/34TfPpZ26sOxAnTSW8FgctE veHgdBOYX2/gXmXnsjJe1SSmVDUSrOJtJwXEpN0wFwsP1U9kJxrMPfSJOhnShaW9MPpA gP7PwXRDUoT+tQfUSKRX5I5iJYBWhADRBShnd5s6A8Ee58EWcMnHleeS7ALV0yfY/9NT YF3C3o4OEb7DgkhNpItzgRLhUPwT2R5qDrwjQY4awpVUnV+vfqcCZn/FcYE7Ew12WOko sRcA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761207983; x=1761812783; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=pF3XqRoNHj3sZR7wlPcBDSDjMHwfDCCUCqxTkrzKgUo=; b=OiEQomrkmzmw9J7bhLIbMRBUNNjiLvNWlV/rO89sNlAjqE0aEyluth1m78VCpRqhzP M3c+Zl56GRKFWDTTZUw9lZy3MDeAx8x68S4yyXQAepm9Scaf3nAacgsfB//dWM4UbNUa db1R6/hP+h5QD28XGB1PGaPMFXaWxGh/7QPZJlptW4tTzyP82ZgK7wjJPuQUnalc3FTF uhvo33MY9c7MG97OoGXYvcEqxLjKc0l5xwERqZ9WPV0g/zliuG1TbNhml2kqRbuOVuyl sbWUoiA9W9VvtZI4xh/UubVlcaOUXvuDFZgGZ547ZGP9rATzPUq681mYedPx7R5DJLwI BK1A== X-Forwarded-Encrypted: i=1; AJvYcCWFHmunvsSFe5kW6clr3bdXJ94ONhVwmz5jtMYkg9EjO06uCh/m27oNjt821UEqWM9k8ynuibG6ZtrgPek1@vger.kernel.org X-Gm-Message-State: AOJu0Yw+NXXAfyAG5zJZwpjFb3LH98EUMGpKXZSy4tiW9n/o/JA3laMW LBdqAWo390xdGhiYYsnUH4D6RtH1C46TIX709vwaZaPfaVyHiK+dHKFzV6hhbUBlK+u0vsToIon nqB4YbBjqLDpTaKk+0w== X-Google-Smtp-Source: AGHT+IFL9mUzN1PJl3xW0LdYWHYYrR/keeaUlrS5f2myPn0lmPkjh9byHtmWsbcyr63o7ILjU4oor7YsRWX3pCg= X-Received: from wmwr4.prod.google.com ([2002:a05:600d:8384:b0:46e:3d73:fc5f]) (user=aliceryhl job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:820b:b0:46e:27fb:17f0 with SMTP id 5b1f17b1804b1-47117877244mr173618305e9.9.1761207983525; Thu, 23 Oct 2025 01:26:23 -0700 (PDT) Date: Thu, 23 Oct 2025 08:26:22 +0000 In-Reply-To: <20251022143158.64475-7-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251022143158.64475-1-dakr@kernel.org> <20251022143158.64475-7-dakr@kernel.org> Message-ID: Subject: Re: [PATCH v3 06/10] rust: debugfs: support for binary large objects From: Alice Ryhl To: Danilo Krummrich Cc: 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, tmgross@umich.edu, mmaurer@google.com, rust-for-linux@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" On Wed, Oct 22, 2025 at 04:30:40PM +0200, Danilo Krummrich wrote: > Introduce support for read-only, write-only, and read-write binary files > in Rust debugfs. This adds: > > - BinaryWriter and BinaryReader traits for writing to and reading from > user slices in binary form. > - New Dir methods: read_binary_file(), write_binary_file(), > `read_write_binary_file`. > - Corresponding FileOps implementations: BinaryReadFile, > BinaryWriteFile, BinaryReadWriteFile. > > This allows kernel modules to expose arbitrary binary data through > debugfs, with proper support for offsets and partial reads/writes. > > Reviewed-by: Greg Kroah-Hartman > Reviewed-by: Matthew Maurer > Signed-off-by: Danilo Krummrich > +extern "C" fn blob_read( > + file: *mut bindings::file, > + buf: *mut c_char, > + count: usize, > + ppos: *mut bindings::loff_t, > +) -> isize { > + // SAFETY: > + // - `file` is a valid pointer to a `struct file`. > + // - The type invariant of `FileOps` guarantees that `private_data` points to a valid `T`. > + let this = unsafe { &*((*file).private_data.cast::()) }; > + > + // SAFETY: > + // `ppos` is a valid `file::Offset` pointer. > + // We have exclusive access to `ppos`. > + let pos = unsafe { file::Offset::from_raw(ppos) }; > + > + let mut writer = UserSlice::new(UserPtr::from_ptr(buf.cast()), count).writer(); > + > + let ret = || -> Result { > + let written = this.write_to_slice(&mut writer, pos)?; > + > + Ok(written.try_into()?) Hmm ... a conversion? Sounds like write_to_slice() has the wrong return type. Alice