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 9B28321FF41 for ; Wed, 6 Aug 2025 20:51:20 +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=1754513480; cv=none; b=THcihG5rLbEdV8oeQyfoW/KiUuibqu6LOaiSyRfA+1Hxx3zEAQAQEe+8m8+tsiYBLV/85WE7QndMTrvDphyIj0M41OctYyS8NzULqXp9Zunc0PLkDAJ9ZzT4ywF6rUgDrX9Er1DVXkHt0IN5tX0wmvEvINKScpYZAf7Bdd2yY5Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754513480; c=relaxed/simple; bh=9wcD4F0DkiQgqCaUR621MLsQ5Kr9Nf9Dh77BDozgqrQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PPusYeMuIg4ozfaW/h1ZupQdSrN/Lo3h1F0rzX7gsd9AQFXTDh5Xjka+t3Lsw02LSwpJK2vnqNK6DQUBVsKel9V8JYuN+1Arv+cs5neHxiALzpCqqvsH/4OQs1BwjDiYEcUXVoVZ759L4pBLswsbNMlHCnhPZYrJ7m/tqOvoID8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=f68ZKMuI; 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="f68ZKMuI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 93E80C4CEED; Wed, 6 Aug 2025 20:51:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754513480; bh=9wcD4F0DkiQgqCaUR621MLsQ5Kr9Nf9Dh77BDozgqrQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f68ZKMuIgkrDhmXhomVATauMRTUoiISBeylj9sIcWIvlnV+LzKkIlDp49RUS/+JVK Qf2IkCHa7Msb5rMok+Pwb8aI+C5fJsYCBIbJXZPG0GFIzFkWD6SCGQa5zAGSowPZIy N7hk+yvBiaTSot9IFQYBeRQWAmti8ciF+GMlY1m5QliBFElv+e6gfdJJayITeBxP+q wEf6e7Tp85YH/MW8II4MN19j23TedWqm3pbkXqnmWgbOwoRdbDbIUE45wI0tEQTBKi QwAz381RXgaC2UdRM65FAhkzwALyGOOlFCqdCzttS6wKHF08qXT5QtOaxme3VBKiRm DVEY9tTE9gdTw== From: Danilo Krummrich To: lorenzo.stoakes@oracle.com, vbabka@suse.cz, Liam.Howlett@oracle.com, urezki@gmail.com, 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, abdiel.janulgue@gmail.com, acourbot@nvidia.com Cc: rust-for-linux@vger.kernel.org, Danilo Krummrich Subject: [PATCH v2 6/6] rust: alloc: kvec: implement PageOwner for VVec Date: Wed, 6 Aug 2025 22:50:15 +0200 Message-ID: <20250806205044.85085-7-dakr@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250806205044.85085-1-dakr@kernel.org> References: <20250806205044.85085-1-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 Implement the PageOwner trait for VVec; it allows to iterate and borrow the backing pages of a VVec. This, for instance, is useful in combination with VBox backing a scatterlist. Signed-off-by: Danilo Krummrich --- rust/kernel/alloc/kvec.rs | 40 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/rust/kernel/alloc/kvec.rs b/rust/kernel/alloc/kvec.rs index 3c72e0bdddb8..88ad30cfc427 100644 --- a/rust/kernel/alloc/kvec.rs +++ b/rust/kernel/alloc/kvec.rs @@ -21,6 +21,7 @@ slice, slice::SliceIndex, }; +use kernel::page; mod errors; pub use self::errors::{InsertError, PushError, RemoveError}; @@ -1017,6 +1018,45 @@ fn into_iter(self) -> Self::IntoIter { } } +/// # Examples +/// +/// ``` +/// # use kernel::{page, prelude::*}; +/// use kernel::page::PageOwner; +/// +/// let mut vec = VVec::::new(); +/// vec.reserve(page::PAGE_SIZE, GFP_KERNEL)?; +/// +/// let page = vec.page_iter().next().expect("At least one page should be available.\n"); +/// +/// // SAFETY: There is no concurrent read or write to the same page. +/// unsafe { page.fill_zero_raw(0, page::PAGE_SIZE)? }; +/// # Ok::<(), Error>(()) +/// ``` +impl page::PageOwner for VVec { + fn page_iter<'a>(&'a mut self) -> impl Iterator> { + (0..self.page_count()).map(|idx| { + let ptr = self.as_mut_ptr().cast::(); + + // SAFETY: `idx` is in the interval `[0, self.page_count())`, hence the resulting + // pointer is guaranteed to be within the same allocation. + let ptr = unsafe { ptr.add(idx * page::PAGE_SIZE) }; + + // SAFETY: `ptr` is guaranteed to be non-null given that it is derived from `self.0`. + let ptr = unsafe { NonNull::new_unchecked(ptr) }; + + // SAFETY: + // - `ptr` is a valid pointer to a `Vmalloc` allocation. + // - `ptr` is valid for the duration of `'a`. + unsafe { Vmalloc::to_page(ptr) } + }) + } + + fn page_count(&self) -> usize { + self.layout.size().div_ceil(page::PAGE_SIZE) + } +} + /// An [`Iterator`] implementation for [`Vec`] that moves elements out of a vector. /// /// This structure is created by the [`Vec::into_iter`] method on [`Vec`] (provided by the -- 2.50.1