From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 3EE27322776 for ; Mon, 18 Aug 2025 13:59:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755525590; cv=none; b=ebDHaQf2jTJdzFazVafyqVip8nNsQZIpVj1sHfUyqNa8THcRlAiF5Z6c3jlQagFtPy/QQy92RKwkq9PsjJkDEemNecQiUc9v1rM9+MIuWeN9n0drfHQo6gCu33pe1ZdrEJpWJk4ilckks0rSY2SfO4mjf/C6j7aXneRvNp58Z1c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755525590; c=relaxed/simple; bh=cgwwu95M0/PjQLKh9VcFW9sZO8JImGY2MFIZ04G52J4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:content-type; b=Dh32/7AzYErocCQ/kOEQ0AE/t7dxPjzpkR91Jo6zLWqrVu8NHbD5eJi7y+aH5ppuFYlUSdPixPRAbbR2Sy+rEgCUFUdd6osHBXe+ml7c0WpwbW9Jb7nd/ExZGtsIOQ0w9dKs2IWEbcGMboacFSilVCK15cx8whi4Vss4uUM/5Mk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=JiTPcYiu; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JiTPcYiu" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755525588; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=n2CKq6YUad3/DjmNn/azhMuZRDmF+l+ZwOAVkMKXPNs=; b=JiTPcYiuU12H1hPLym1RT6tqmFUE8B68nfdlElsUhvH72d4bLpMDFR3h5GDcpvC0PnolHv PZdjvBLpY44SJTgDm1qKDjgxukr0H5DV7wI6gBY9j20VgrSs11b4uVmt0mCfgfV24VcppS hIQXyoVnmAMqYSPuOvePR+WIdbhFWL8= Received: from mail-pg1-f200.google.com (mail-pg1-f200.google.com [209.85.215.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-62-OywncE7uPYip3Npo-Ze8dA-1; Mon, 18 Aug 2025 09:59:46 -0400 X-MC-Unique: OywncE7uPYip3Npo-Ze8dA-1 X-Mimecast-MFC-AGG-ID: OywncE7uPYip3Npo-Ze8dA_1755525586 Received: by mail-pg1-f200.google.com with SMTP id 41be03b00d2f7-b4731a95beeso5406216a12.0 for ; Mon, 18 Aug 2025 06:59:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1755525586; x=1756130386; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=n2CKq6YUad3/DjmNn/azhMuZRDmF+l+ZwOAVkMKXPNs=; b=fpSuYfp5TYeP1f/VPjqthsuuDGx3cOKjU/uf1v3IeAleRsmqPZE7Y2hR+dHjfn2RTP Mi1JLGNhtzODjsTkCYKyUZgnyjoY/IrvFoGwpOgV5TngTUPMtcvgxraekisFF92tlDuo Qs6Whpmpi/3ZOf2yJCwPNWYHwmjIh1QsKMYrbv/5fmEjGu3pJxHZ/H9nHzmwim60sFRz lLn1XTjWzVdm/wjQrYE7B3Vdcvv7tFkUwfvVzpiv4VJF+rTfl9DE6smaVMcxLTLgQDnB 6MK8EKnRrpi5yJgu1rdm4zmQ9QyGv+VgUfZYM+u9EGkP6cS3SdwGf7wP6MiE7NPBPF3s +4qQ== X-Forwarded-Encrypted: i=1; AJvYcCUWDZ0bwiOGRDTJtIsA8GrIxr2ffAgjCNwhMyEcuJ7pVxSD1lLv1yJY+/8z+aqE3fLKW68e78MW4Fa/ZX8AaQ==@vger.kernel.org X-Gm-Message-State: AOJu0Yw433cyB2WgylgQkK6P4oh5p3curTqGPP3fIFlm/o0D8i0fIrf2 ZC0nD1gx2ONNcMtFoJ2O/tlWYJvPeyd7L+xB9dkAOkhx1skUYstKKEQ2pXN6D5krcAIiIzSqY5Z ujacsrhJLIanSCz2RiwOrrsSPS1qkT5Q3GVRERgK/bUGRtpFw2zf1MdprjWKk6HQba6Je X-Gm-Gg: ASbGnctH97pV3vtggd0YK9f1pD9hm4w92uzYoBuk3WrNy9P3pQrd02gGeU/2Kual5R3 fhddvI6FiNEcb4v/XM4XlaBymZ8By1dxGWKj9VwBS8NFNzgEZj5oVZZB15HKX8eDZBfbzlPUphj J0IzF/28ZZIe/IgKvWpjV67T2dQ5R81ZdajB8Z+S1xvpaSJzR26RT3MJQxXnJ8RtqW31D7d7b46 AIQ8FTLSgIWSZ7q0UWjShBv3G9XPKSrM8iF77YZXsKrRREBc8hafLH67dbA+XMfqqTWkUfvRVaA wGU/pkWpPo3+8RkgPCp0GUcue9abwKLxnQ== X-Received: by 2002:a05:6a20:939f:b0:240:a53:79fc with SMTP id adf61e73a8af0-240d2fb95ffmr17025516637.29.1755525585651; Mon, 18 Aug 2025 06:59:45 -0700 (PDT) X-Google-Smtp-Source: AGHT+IELiXPnW7YPO4rEF/tv+C6PkkDunFLclnjtOiZ6LrUtYCR63sCROrCmDGY+0H8Di4y4hwCxWg== X-Received: by 2002:a05:6a20:939f:b0:240:a53:79fc with SMTP id adf61e73a8af0-240d2fb95ffmr17025476637.29.1755525585240; Mon, 18 Aug 2025 06:59:45 -0700 (PDT) Received: from zeus ([2405:6580:83a0:7600:6e93:a15a:9134:ae1f]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-b472d60978fsm8269896a12.26.2025.08.18.06.59.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Aug 2025 06:59:44 -0700 (PDT) From: Ryosuke Yasuoka To: arnd@arndb.de, gregkh@linuxfoundation.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, dakr@kernel.org, lee@kernel.org Cc: Ryosuke Yasuoka , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH rust-next 1/2] rust: miscdevice: add llseek support Date: Mon, 18 Aug 2025 22:58:38 +0900 Message-ID: <20250818135846.133722-2-ryasuoka@redhat.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250818135846.133722-1-ryasuoka@redhat.com> References: <20250818135846.133722-1-ryasuoka@redhat.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: yCAkDwX7rXWz9fbfWODvzn4qML5HinfBOdOXj9wRP-Q_1755525586 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true Add the ability to write a file_operations->llseek hook in Rust when using the miscdevice abstraction. Signed-off-by: Ryosuke Yasuoka --- rust/kernel/miscdevice.rs | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/rust/kernel/miscdevice.rs b/rust/kernel/miscdevice.rs index 6373fe183b27..597e7b66e493 100644 --- a/rust/kernel/miscdevice.rs +++ b/rust/kernel/miscdevice.rs @@ -125,6 +125,16 @@ fn release(device: Self::Ptr, _file: &File) { drop(device); } + /// Handler for llseek. + fn llseek( + _device: ::Borrowed<'_>, + _file: &File, + _offset: i64, + _whence: i32, + ) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + /// Handle for mmap. /// /// This function is invoked when a user space process invokes the `mmap` system call on @@ -245,6 +255,27 @@ impl MiscdeviceVTable { 0 } + /// # Safety + /// + /// `file` must be a valid file that is associated with a `MiscDeviceRegistration`. + unsafe extern "C" fn llseek(file: *mut bindings::file, offset: i64, whence: c_int) -> i64 { + // SAFETY: The llseek call of a file can access the private data. + let private = unsafe { (*file).private_data }; + // SAFETY: This is a Rust Miscdevice, so we call `into_foreign` in `open` and + // `from_foreign` in `release`, and `fops_llseek` is guaranteed to be called between those + // two operations. + let device = unsafe { ::borrow(private) }; + // SAFETY: + // * The file is valid for the duration of this call. + // * There is no active fdget_pos region on the file on this thread. + let file = unsafe { File::from_raw_file(file) }; + + match T::llseek(device, file, offset, whence) { + Ok(res) => res as i64, + Err(err) => i64::from(err.to_errno()), + } + } + /// # Safety /// /// `file` must be a valid file that is associated with a `MiscDeviceRegistration`. @@ -340,6 +371,11 @@ impl MiscdeviceVTable { const VTABLE: bindings::file_operations = bindings::file_operations { open: Some(Self::open), release: Some(Self::release), + llseek: if T::HAS_LLSEEK { + Some(Self::llseek) + } else { + None + }, mmap: if T::HAS_MMAP { Some(Self::mmap) } else { None }, unlocked_ioctl: if T::HAS_IOCTL { Some(Self::ioctl) -- 2.50.1