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 8B214226861; Thu, 18 Sep 2025 17:43:04 +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=1758217384; cv=none; b=f/cFhVKm+w72J/2ZJPNswfcGOr16ql/0YCTGasfvNfYYEnj/GW9ofM4AEEL/06NS5p4zaq4cx3i0OIB8issNvf9OvaTjRdtE4NuavWkmJgy/4umCtjmOCAWP++CtkhvVepFJDfsANFXe/FHrSJneKxP+UxbGBmhVakndVfyfY5Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758217384; c=relaxed/simple; bh=aqt/STK2MY4NAA1pNa8ksM315kMkdAYPPKarct8YglQ=; h=Mime-Version:Content-Type:Date:Message-Id:Subject:Cc:To:From: References:In-Reply-To; b=cPoOyCHSI+C/tjfYFfcevIuMPivvNwwWt2zOC/uN6s3bhSpZ0OKv0u0rXCRoL5PA1mM6wjFupbX6U9JCeU+mHBUQ98/ERcDPQITJd2EcWfCnowBvdG906fIzGW20stwZk3un3RZhwMd0iP77Tfrns32CTIHjJVChPNnmHEhlmxs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JQtfbQBs; 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="JQtfbQBs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 90051C4CEE7; Thu, 18 Sep 2025 17:42:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758217384; bh=aqt/STK2MY4NAA1pNa8ksM315kMkdAYPPKarct8YglQ=; h=Date:Subject:Cc:To:From:References:In-Reply-To:From; b=JQtfbQBsX7ZiKtFj3kGNXIk1dhsxkTnQTeg+6yucD1JPLkrrUdThs7Ltc30UT5405 +x0vCyTADa14o7iKqasb8bvcJeR2sPH27oH/o2MA+nW7jeeQUa43MTNAJo3Xvb25oJ PAe3diaqeVDONigTDw8M5oNAvLo0jfVfhFlxVHOh08XzabDYFtL0lWVEXDqbDrb6SJ PCwnAL6VSotWCYYsvDyRdyfhAMrqwM1QQrReMl3GKZ22poOo/8HsIflyx/8anUp/mx rA3CHIYspGL390UFHApbLlzeVjxaxJ+2GgO7IBVPK8OGnfHrnrzXf6e+gkgYrpIQuG vlCGfumKKKchw== Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Thu, 18 Sep 2025 19:42:54 +0200 Message-Id: Subject: Re: [PATCH] rust_binder: add Rust Binder driver Cc: "Greg Kroah-Hartman" , =?utf-8?q?Arve_Hj=C3=B8nnev=C3=A5g?= , "Todd Kjos" , "Martijn Coenen" , "Joel Fernandes" , "Christian Brauner" , "Carlos Llamas" , "Suren Baghdasaryan" , "Miguel Ojeda" , "Boqun Feng" , "Gary Guo" , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , "Benno Lossin" , "Andreas Hindborg" , "Trevor Gross" , "Lorenzo Stoakes" , "Liam R. Howlett" , "Paul Moore" , "Serge Hallyn" , , , "Wedson Almeida Filho" , "Matt Gilbride" To: "Alice Ryhl" From: "Danilo Krummrich" References: <20250918-rust-binder-v1-1-7a5559e8c6bb@google.com> In-Reply-To: <20250918-rust-binder-v1-1-7a5559e8c6bb@google.com> (Far from a full review, but two minor drive-by comments.) On Thu Sep 18, 2025 at 12:19 PM CEST, Alice Ryhl wrote: > + /// Register a vma with this page range. Returns the size of the reg= ion. > + pub(crate) fn register_with_vma(&self, vma: &virt::VmaNew) -> Result= { > + let num_bytes =3D usize::min(vma.end() - vma.start(), bindings::= SZ_4M as usize); > + let num_pages =3D num_bytes >> PAGE_SHIFT; > + > + if !ptr::eq::(&*self.mm, &**vma.mm()) { > + pr_debug!("Failed to register with vma: invalid vma->vm_mm")= ; > + return Err(EINVAL); > + } > + if num_pages =3D=3D 0 { > + pr_debug!("Failed to register with vma: size zero"); > + return Err(EINVAL); > + } > + > + let layout =3D Layout::array::(num_pages).map_err(|_| = ENOMEM)?; > + let pages =3D KVmalloc::alloc(layout, GFP_KERNEL)?.cast::(); > + > + // SAFETY: This just initializes the pages array. > + unsafe { > + let self_ptr =3D self as *const ShrinkablePageRange; > + for i in 0..num_pages { > + let info =3D pages.as_ptr().add(i); > + ptr::addr_of_mut!((*info).range).write(self_ptr); > + ptr::addr_of_mut!((*info).page).write(None); > + let lru =3D ptr::addr_of_mut!((*info).lru); > + ptr::addr_of_mut!((*lru).next).write(lru); > + ptr::addr_of_mut!((*lru).prev).write(lru); I think we should prefer &raw in new code. > + } > + } > + > + let mut inner =3D self.lock.lock(); > + if inner.size > 0 { > + pr_debug!("Failed to register with vma: already registered")= ; > + drop(inner); > + // SAFETY: The `pages` array was allocated with the same lay= out. > + unsafe { KVmalloc::free(pages.cast(), layout) }; NIT: If you use KVBox instead, even though you convert to a raw pointer lat= er, you can probably safe one unsafe. > + return Err(EBUSY); > + } > + > + inner.pages =3D pages.as_ptr(); > + inner.size =3D num_pages; > + inner.vma_addr =3D vma.start(); > + > + Ok(num_pages) > + }