From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753668AbcEPNIP (ORCPT ); Mon, 16 May 2016 09:08:15 -0400 Received: from mail-wm0-f45.google.com ([74.125.82.45]:37084 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753400AbcEPNIM convert rfc822-to-8bit (ORCPT ); Mon, 16 May 2016 09:08:12 -0400 From: Michal Nazarewicz To: Felipe Balbi , Alan Stern Cc: "Du\, Changbin" , Al Viro , "gregkh\@linuxfoundation.org" , "rui.silva\@linaro.org" , "k.opasiak\@samsung.com" , "lars\@metafoo.de" , "linux-usb\@vger.kernel.org" , "linux-kernel\@vger.kernel.org" Subject: Re: [PATCH] usb: gadget: f_fs: report error if excess data received In-Reply-To: <87eg92p3cn.fsf@linux.intel.com> Organization: http://mina86.com/ References: <87eg92p3cn.fsf@linux.intel.com> User-Agent: Notmuch/0.19+53~g2e63a09 (http://notmuchmail.org) Emacs/25.1.50.1 (x86_64-unknown-linux-gnu) Face: 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 X-Face: -TR8(rDTHy/(xl?SfWd1|3:TTgDIatE^t'vop%*gVg[kn$t{EpK(P"VQ=~T2#ysNmJKN$"yTRLB4YQs$4{[.]Fc1)*O]3+XO^oXM>Q#b^ix,O)Zbn)q[y06$`e3?C)`CwR9y5riE=fv^X@x$y?D:XO6L&x4f-}}I4=VRNwiA^t1-ZrVK^07.Pi/57c_du'& X-PGP: 50751FF4 X-PGP-FP: AC1F 5F5C D418 88F8 CC84 5858 2060 4012 5075 1FF4 X-Hashcash: 1:20:160516:lars@metafoo.de::DSyW32KdQN0HKDhP:001ovS X-Hashcash: 1:20:160516:changbin.du@intel.com::Fpw16xCk/jj2FYYa:00000000000000000000000000000000000000001AkE X-Hashcash: 1:20:160516:linux-kernel@vger.kernel.org::u2k0ACC1ReT177zl:0000000000000000000000000000000004D0M X-Hashcash: 1:20:160516:linux-usb@vger.kernel.org::WDKJ2UlHyOdtX5yr:0000000000000000000000000000000000007wYl X-Hashcash: 1:20:160516:k.opasiak@samsung.com::GEQmwFO1o63YpIQI:00000000000000000000000000000000000000005HEb X-Hashcash: 1:20:160516:rui.silva@linaro.org::ncbSs6302ilvBnwC:000000000000000000000000000000000000000001J3o X-Hashcash: 1:20:160516:gregkh@linuxfoundation.org::9QKKaF4iycoh+oYY:000000000000000000000000000000000002of+ X-Hashcash: 1:20:160516:viro@zeniv.linux.org.uk::kgqR4q5wxJXKdgoy:00000000000000000000000000000000000000BI0M X-Hashcash: 1:20:160516:stern@rowland.harvard.edu::mP97Wr8KJb1ckwnP:0000000000000000000000000000000000009lsB X-Hashcash: 1:20:160516:felipe.balbi@linux.intel.com::YuCwrftAvNr6apkl:000000000000000000000000000000000BQZt Date: Mon, 16 May 2016 15:08:08 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Alan Stern writes: >> The point is that you don't know whether the host sent more data than >> expected. All you know is that the host sent more data than the user >> asked the kernel for -- but maybe the user didn't ask for all the >> data that he expected. Maybe the user wanted to retrieve the full >> set of data using two read() system calls. On Mon, May 16 2016, Felipe Balbi wrote: > right, but that just means we need to buffer the data instead of bailing > out of the first read() completely. Correct. I have a ~4h bus ride ahead of me so I’ll try to implement it. If you don’t hear from me by the end of the day, there probably wasn’t enough space/comfort in the bus to use a laptop. -- Best regards ミハウ “𝓶𝓲𝓷𝓪86” ナザレヴイツ «If at first you don’t succeed, give up skydiving»