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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3E5A8C433F5 for ; Thu, 6 Oct 2022 22:40:29 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Mk5xR3xlBz3f5S for ; Fri, 7 Oct 2022 09:40:27 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=UJAGwBGm; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=linux.intel.com (client-ip=134.134.136.24; helo=mga09.intel.com; envelope-from=andriy.shevchenko@linux.intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=UJAGwBGm; dkim-atps=neutral Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4MjsC23WkKz3blw for ; Fri, 7 Oct 2022 00:06:21 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1665061582; x=1696597582; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=FGTLdaiXSBCapn2JjYMa8Pm3byrwndmRCKrokbx26S8=; b=UJAGwBGm87u8DRtslnmigB4SCwnVm+CsiOfjbN7xBw1Tlwiluptwc6fp AXFHz7KOr97Kreg6lPXPecNZLmLdlzGZjMKw6dTSNFkqFjJ+g8WomZPA8 XUa+YJG59PLCjwuqq6uegT0Orvin4EciC+mz07EGLf+kznqZ7vRFY3IFh /SSOr8r42lrwHPLm/fweSiSJqp9XM8fYTE81H6gBeV4bVu/iCUqDtWpWU r30twFGYZ2CjVQqGFlXJovuU9AP7fM19fu4ZFShCYixE53GxzmPRxTDzG hnnIqHzLpybQk+0vJZExVnD3D0ZsoThA6/PxwkJcF+PvhkcREl0212q/X w==; X-IronPort-AV: E=McAfee;i="6500,9779,10491"; a="304430056" X-IronPort-AV: E=Sophos;i="5.95,163,1661842800"; d="scan'208";a="304430056" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Oct 2022 06:05:56 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10491"; a="575816142" X-IronPort-AV: E=Sophos;i="5.95,163,1661842800"; d="scan'208";a="575816142" Received: from smile.fi.intel.com ([10.237.72.54]) by orsmga003.jf.intel.com with ESMTP; 06 Oct 2022 06:05:33 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.96) (envelope-from ) id 1ogQZ0-0039VB-0C; Thu, 06 Oct 2022 16:05:22 +0300 Date: Thu, 6 Oct 2022 16:05:21 +0300 From: Andy Shevchenko To: Jason Gunthorpe Subject: Re: [PATCH v1 1/5] treewide: use prandom_u32_max() when possible Message-ID: References: <20221005214844.2699-1-Jason@zx2c4.com> <20221005214844.2699-2-Jason@zx2c4.com> <202210052035.A1020E3@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo X-Mailman-Approved-At: Fri, 07 Oct 2022 09:35:18 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andrew Lunn , "Darrick J . Wong" , Ulf Hansson , dri-devel@lists.freedesktop.org, Andrii Nakryiko , Hans Verkuil , linux-sctp@vger.kernel.org, "Md . Haris Iqbal" , Miquel Raynal , Christoph Hellwig , Andy Gospodarek , Sergey Matyukevich , Rohit Maheshwari , ceph-devel@vger.kernel.org, Jozsef Kadlecsik , Nilesh Javali , Jean-Paul Roubelat , Dick Kennedy , Jay Vosburgh , Potnuri Bharat Teja , Vinay Kumar Yadav , linux-nfs@vger.kernel.org, Nicholas Piggin , Igor Mitsyanko , Andy Lutomirski , linux-hams@vger.kernel.org, Thomas Gleixner , Trond Myklebust , linux-raid@vger.kernel.org, Neil Horman , Hante Meuleman , Greg Kroah-Hartman , linux-usb@vger.kernel.org, Michael Chan , linux-kernel@vger.kernel.org, Varun Prakash , Chuck Lever , netfilter-devel@vger.kernel.org, Masami Hiramatsu , Jiri Olsa , Jan Kara , linux-fsdevel@vger.kernel.org, Lars Ellenberg , linux-media@vger.kernel.org, Claudiu Beznea , Sharvari Harisangam , "Jason A. 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Rao" , Ilya Dryomov , Paolo Abeni , Pablo Neira Ayuso , Marco Elver , Kees Cook , Yury Norov , "James E . J . Bottomley" , Jamal Hadi Salim , KP Singh , Borislav Petkov , Keith Busch , Dan Williams , Mauro Carvalho Chehab , Franky Lin , Arend van Spriel , linux-ext4@vger.kernel.org, Wenpeng Liang , "Martin K . Petersen" , Xinming Hu , linux-stm32@st-md-mailman.stormreply.com, Jeff Layton , linux-xfs@vger.kernel.org, netdev@vger.kernel.org, Ying Xue , Manish Rangankar , "David S . Miller" , Toke =?iso-8859-1?Q?H=F8iland-J=F8rgensen?= , Vignesh Raghavendra , Peter Zijlstra , "H . Peter Anvin" , Alexandre Torgue , Amitkumar Karwar , linux-mm@kvack.org, Andreas Dilger , Ayush Sawal , Andreas Noever , Jiri Pirko , linux-f2fs-devel@lists.sourceforge.net, Jack Wang , Steffen Klassert , rds-devel@oss.oracle.com, Herbert Xu , linux-scsi@vger.kernel.org, dccp@vger.kernel.org, Richard Weinberger , Russell King , Jaehoon Chung , SHA-cyfmac-dev-list@infineon.com, Ingo Molnar , Jakub Kicinski , John Fastabend , Maxime Coquelin , Manivannan Sadhasivam , Michael Jamet , Kalle Valo , Chao Yu , Akinobu Mita , linux-block@vger.kernel.org, dmaengine@vger.kernel.org, Hannes Reinecke , Xiubo Li , Dmitry Vyukov , Jens Axboe , cake@lists.bufferbloat.net, brcm80211-dev-list.pdl@broadcom.com, Yishai Hadas , Hideaki YOSHIFUJI , linuxppc-dev@lists.ozlabs.org, David Ahern , Philipp Reisner , Stephen Hemminger , Christoph =?iso-8859-1?Q?B=F6hmwalder?= , Vinod Koul , tipc-discussion@lists.sourceforge.net, Thomas Graf , Johannes Berg , Sungjong Seo , Martin KaFai Lau Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Oct 06, 2022 at 09:55:19AM -0300, Jason Gunthorpe wrote: > On Thu, Oct 06, 2022 at 06:45:25AM -0600, Jason A. Donenfeld wrote: > > On Wed, Oct 05, 2022 at 09:16:50PM -0700, Kees Cook wrote: > > > On Wed, Oct 05, 2022 at 11:48:40PM +0200, Jason A. Donenfeld wrote: > > > > Rather than incurring a division or requesting too many random bytes for > > > > the given range, use the prandom_u32_max() function, which only takes > > > > the minimum required bytes from the RNG and avoids divisions. > > > > > > Yes please! > > > > > > Since this is a treewide patch, it's helpful for (me at least) doing > > > reviews to detail the mechanism of the transformation. > > > > This is hand done. There were also various wrong seds done. And then I'd > > edit the .diff manually, and then reapply it, as an iterative process. > > No internet on the airplane, and oddly no spatch already on my laptop (I > > think I had some Gentoo ocaml issues at some point and removed it?). > > > > > e.g. I imagine this could be done with something like Coccinelle and > > > > Feel free to check the work here by using Coccinelle if you're into > > that. > > Generally these series are a lot easier to review if it is structured > as a patches doing all the unusual stuff that had to be by hand > followed by an unmodified Coccinelle/sed/etc handling the simple > stuff. > > Especially stuff that is reworking the logic beyond simple > substitution should be one patch per subsystem not rolled into a giant > one patch conversion. > > This makes the whole workflow better because the hand-done stuff can > have a chance to flow through subsystem trees. +1 to all arguments for the splitting. I looked a bit into the code I have the interest to, but I won't spam people with not-so-important questions / comments / tags, etc. -- With Best Regards, Andy Shevchenko