From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 327C6C00140 for ; Wed, 24 Aug 2022 06:11:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234876AbiHXGLD (ORCPT ); Wed, 24 Aug 2022 02:11:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43370 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234878AbiHXGKz (ORCPT ); Wed, 24 Aug 2022 02:10:55 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BCACB186C6; Tue, 23 Aug 2022 23:10:53 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4EB136113E; Wed, 24 Aug 2022 06:10:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1DDF9C433C1; Wed, 24 Aug 2022 06:10:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661321452; bh=8S6Si2CVUJ4bQuqVJVuhcS4NYT/mUhhFJIemYGM+Tj8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SUU/Qui5+M+d1pUl90i10WbuQR+64BKtYzBovldhlc/9v9b3LW3t+IQz7nAocdEAg MTe3FnXrIqS+8nu7ls3FRJPB1ICFNPiyNfQzNg6lFFKLA98K9iq1KUmd6SVA0tGzZN W5HLy6u7SL7IN4UByqNW/8qYc7Fao7keDlu0ckq0= Date: Wed, 24 Aug 2022 08:10:49 +0200 From: Greg Kroah-Hartman To: Paul Moore Cc: linux-security-module@vger.kernel.org, selinux@vger.kernel.org, io-uring@vger.kernel.org, Arnd Bergmann , Luis Chamberlain Subject: Re: [PATCH 3/3] /dev/null: add IORING_OP_URING_CMD support Message-ID: References: <166120321387.369593.7400426327771894334.stgit@olly> <166120327984.369593.8371751426301540450.stgit@olly> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Tue, Aug 23, 2022 at 01:02:08PM -0400, Paul Moore wrote: > On Tue, Aug 23, 2022 at 2:52 AM Greg Kroah-Hartman > wrote: > > On Mon, Aug 22, 2022 at 05:21:19PM -0400, Paul Moore wrote: > > > This patch adds support for the io_uring command pass through, aka > > > IORING_OP_URING_CMD, to the /dev/null driver. As with all of the > > > /dev/null functionality, the implementation is just a simple sink > > > where commands go to die, but it should be useful for developers who > > > need a simple IORING_OP_URING_CMD test device that doesn't require > > > any special hardware. > > > > Also, shouldn't you document this somewhere? > > > > At least in the code itself saying "this is here so that /dev/null works > > as a io_uring sink" or something like that? Otherwise it just looks > > like it does nothing at all. > > What about read_null() and write_null()? I can definitely add a > comment (there is no /dev/null documentation in the kernel source tree > that I can see), but there is clearly precedence for /dev/null having > "do nothing" file_operations functions. Yes, they should "do nothing". write_null() does report that it consumed everything, why doesn't this function have to also do that? thanks, greg k-h