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 X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11842ECDFB8 for ; Mon, 23 Jul 2018 21:18:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B7BA520685 for ; Mon, 23 Jul 2018 21:18:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="Ubs5zPZ8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B7BA520685 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=HansenPartnership.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388197AbeGWWVt (ORCPT ); Mon, 23 Jul 2018 18:21:49 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:38584 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388133AbeGWWVs (ORCPT ); Mon, 23 Jul 2018 18:21:48 -0400 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 8A7298EE18B; Mon, 23 Jul 2018 14:13:34 -0700 (PDT) Received: from bedivere.hansenpartnership.com ([127.0.0.1]) by localhost (bedivere.hansenpartnership.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id uDYv0H0-iUpp; Mon, 23 Jul 2018 14:13:34 -0700 (PDT) Received: from [153.66.254.194] (unknown [50.35.68.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by bedivere.hansenpartnership.com (Postfix) with ESMTPSA id 1BD588EE0C3; Mon, 23 Jul 2018 14:13:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1532380414; bh=VBHRGfQGfqbW8oFivihL9Dvcfv9EKyehHthOUxuif+w=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Ubs5zPZ8xGPNFd2GUgFGKPMw1bvHFTb+2oPg2KS4A4OkIbc9lyVjCfvZAWs5SMA45 JIzERLgPNEJkTTdyScX/A3FDlTiX2t3xfl5JIWKMA3tRVxlykYms3EAZ+rBt5j07ce IO0cOKly1gDLsNxdUdztqFMcNrFL+xXMh13ANW9U= Message-ID: <1532380412.4112.22.camel@HansenPartnership.com> Subject: Re: [PATCH] tpm: add support for partial reads From: James Bottomley To: Tadeusz Struk , Jarkko Sakkinen Cc: jgg@ziepe.ca, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Date: Mon, 23 Jul 2018 14:13:32 -0700 In-Reply-To: References: <153201555276.20155.1352499992826895966.stgit@tstruk-mobl1.jf.intel.com> <20180723201956.GB26824@linux.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2018-07-23 at 13:53 -0700, Tadeusz Struk wrote: > On 07/23/2018 01:19 PM, Jarkko Sakkinen wrote: > > In this case I do not have any major evidence of any major benefit > > *and* the change breaks the ABI. > > As I said before - this does not break the ABI. The current patch does, you even provided a use case in your last email (it's do command to get sizing followed by do command with correctly sized buffer).  However, if you tie it to O_NONBLOCK, it won't because no-one currently opens the TPM device non blocking so it's an ABI conformant discriminator of the uses. Tying to O_NONBLOCK should be simple because it's in file->f_flags. James