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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 100ABC43461 for ; Mon, 14 Sep 2020 22:04:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3306206F4 for ; Mon, 14 Sep 2020 22:04:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=osandov-com.20150623.gappssmtp.com header.i=@osandov-com.20150623.gappssmtp.com header.b="Gv+hmym6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726040AbgINWEx (ORCPT ); Mon, 14 Sep 2020 18:04:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725999AbgINWEu (ORCPT ); Mon, 14 Sep 2020 18:04:50 -0400 Received: from mail-pf1-x441.google.com (mail-pf1-x441.google.com [IPv6:2607:f8b0:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80E67C061788 for ; Mon, 14 Sep 2020 15:04:50 -0700 (PDT) Received: by mail-pf1-x441.google.com with SMTP id x123so705221pfc.7 for ; Mon, 14 Sep 2020 15:04:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=osandov-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=122QFFwJe2x4F1qdD/MZmQmfxCbAtjAlMJ3u7EEjhaM=; b=Gv+hmym6P3T1YF0qrBPQKtKvs69VswlTODUYCBGaiSTmPffI5qi4UW2/CtgXerQ9vy HCaVI15E9rpFXh3WpVSvK53llmSz7TV3sIcO7WhhTeicFMM25M9NYdIEuZjROj1PCJDG rMecicMm1VCOmIQAKhV2tjZTVUjdZNqj+FIxh8A++01EpGV2co9Rj6XAKNuEwfS1xE92 i/GQCt5HOCyNxw+c7gMJ2O3LfOmWX2UHBgwoPEM7PWn8DJks/y7U10yMGxoolzcmbp2y Vpc5aVFQpWhMoKToop1G7z9Fm9hpsUkq5/4AP0hhA54W1HdvQhvLRA20iRr7WzifsOCx eEuA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=122QFFwJe2x4F1qdD/MZmQmfxCbAtjAlMJ3u7EEjhaM=; b=JbX6QHv8cCxbls/BSMkdP/28pQi8Gs0Bdfutxhl9ZcPOrJajiIjEbmGcKUDM4yEt9s VoZ7Nu0HrhkteToPgvNdR1TMUVw7avk4ZjBamGpvmU866TTFwbSpy1oNjx3Te2pT2k0b j6EaIo05nLnw9kHLNTB1D0o8N7M7cgUtAJNvDlKwKxvxVTOMtOJuIWaVd+VnBkna6enB y4kn471qkVynzqEJIQi4gCw4MNB61slMV/npMN31Bm8uFWDpJlzFJI0eMTLkkANMg1MC PmafWsJgkBLAbvCmRz5tz0zHmJssUlXzUeEoX4t2CsISwPbzTdDEaKz/IjUO/9ehOh0N Jbiw== X-Gm-Message-State: AOAM532keR/rveVIBQXPOaBs0JNL9O3jGH0LRft4A1gKElORmBWt6Q5y rJ7/GeAwLBsbrF4CtXMdcWs8fw== X-Google-Smtp-Source: ABdhPJyAqKKwW7SA2J8rdHjjuMBlV6SJaI3waTYkClyJDUa61weH0xhDtSbPAb94PzCKTkFN8ogZww== X-Received: by 2002:a65:62c3:: with SMTP id m3mr12293650pgv.338.1600121089925; Mon, 14 Sep 2020 15:04:49 -0700 (PDT) Received: from relinquished.localdomain ([2620:10d:c090:400::5:1687]) by smtp.gmail.com with ESMTPSA id s8sm5111982pjm.7.2020.09.14.15.04.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Sep 2020 15:04:49 -0700 (PDT) Date: Mon, 14 Sep 2020 15:04:48 -0700 From: Omar Sandoval To: dsterba@suse.cz, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 2/9] btrfs: send: avoid copying file data Message-ID: <20200914220448.GC148663@relinquished.localdomain> References: <20200911141339.GR18399@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200911141339.GR18399@twin.jikos.cz> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Fri, Sep 11, 2020 at 04:13:39PM +0200, David Sterba wrote: > On Fri, Aug 21, 2020 at 12:39:52AM -0700, Omar Sandoval wrote: > > +static int put_data_header(struct send_ctx *sctx, u32 len) > > +{ > > + struct btrfs_tlv_header *hdr; > > + > > + if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len) > > + return -EOVERFLOW; > > + hdr = (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_size); > > + hdr->tlv_type = cpu_to_le16(BTRFS_SEND_A_DATA); > > + hdr->tlv_len = cpu_to_le16(len); > > I think we need put_unaligned_le16 here, it's mapping a random buffer to > a pointer, this is not alignment safe in general. I think you're right, although tlv_put() seems to have this same problem.