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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 ABBB2C04AB6 for ; Fri, 31 May 2019 15:16:09 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8401C26B6F for ; Fri, 31 May 2019 15:16:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8401C26B6F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:45114 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWjGK-0003nG-RG for qemu-devel@archiver.kernel.org; Fri, 31 May 2019 11:16:08 -0400 Received: from eggs.gnu.org ([209.51.188.92]:54373) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWjEQ-0002k1-V3 for qemu-devel@nongnu.org; Fri, 31 May 2019 11:14:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hWjEP-000127-Vb for qemu-devel@nongnu.org; Fri, 31 May 2019 11:14:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50810) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hWjEM-0000uA-AI; Fri, 31 May 2019 11:14:06 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1613820276; Fri, 31 May 2019 15:13:54 +0000 (UTC) Received: from [10.3.116.169] (ovpn-116-169.phx2.redhat.com [10.3.116.169]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 39B13643D6; Fri, 31 May 2019 15:13:52 +0000 (UTC) To: Denis Plotnikov , sgarzare@redhat.com, kwolf@redhat.com, mreitz@redhat.com, qemu-block@nongnu.org References: <20190531074620.24934-1-dplotnikov@virtuozzo.com> From: Eric Blake Openpgp: preference=signencrypt Autocrypt: addr=eblake@redhat.com; keydata= xsBNBEvHyWwBCACw7DwsQIh0kAbUXyqhfiKAKOTVu6OiMGffw2w90Ggrp4bdVKmCaEXlrVLU xphBM8mb+wsFkU+pq9YR621WXo9REYVIl0FxKeQo9dyQBZ/XvmUMka4NOmHtFg74nvkpJFCD TUNzmqfcjdKhfFV0d7P/ixKQeZr2WP1xMcjmAQY5YvQ2lUoHP43m8TtpB1LkjyYBCodd+LkV GmCx2Bop1LSblbvbrOm2bKpZdBPjncRNob73eTpIXEutvEaHH72LzpzksfcKM+M18cyRH+nP sAd98xIbVjm3Jm4k4d5oQyE2HwOur+trk2EcxTgdp17QapuWPwMfhaNq3runaX7x34zhABEB AAHNHkVyaWMgQmxha2UgPGVibGFrZUByZWRoYXQuY29tPsLAegQTAQgAJAIbAwULCQgHAwUV CgkICwUWAgMBAAIeAQIXgAUCS8fL9QIZAQAKCRCnoWtKJSdDahBHCACbl/5FGkUqJ89GAjeX RjpAeJtdKhujir0iS4CMSIng7fCiGZ0fNJCpL5RpViSo03Q7l37ss+No+dJI8KtAp6ID+PMz wTJe5Egtv/KGUKSDvOLYJ9WIIbftEObekP+GBpWP2+KbpADsc7EsNd70sYxExD3liwVJYqLc Rw7so1PEIFp+Ni9A1DrBR5NaJBnno2PHzHPTS9nmZVYm/4I32qkLXOcdX0XElO8VPDoVobG6 gELf4v/vIImdmxLh/w5WctUpBhWWIfQDvSOW2VZDOihm7pzhQodr3QP/GDLfpK6wI7exeu3P pfPtqwa06s1pae3ad13mZGzkBdNKs1HEm8x6zsBNBEvHyWwBCADGkMFzFjmmyqAEn5D+Mt4P zPdO8NatsDw8Qit3Rmzu+kUygxyYbz52ZO40WUu7EgQ5kDTOeRPnTOd7awWDQcl1gGBXgrkR pAlQ0l0ReO57Q0eglFydLMi5bkwYhfY+TwDPMh3aOP5qBXkm4qIYSsxb8A+i00P72AqFb9Q7 3weG/flxSPApLYQE5qWGSXjOkXJv42NGS6o6gd4RmD6Ap5e8ACo1lSMPfTpGzXlt4aRkBfvb NCfNsQikLZzFYDLbQgKBA33BDeV6vNJ9Cj0SgEGOkYyed4I6AbU0kIy1hHAm1r6+sAnEdIKj cHi3xWH/UPrZW5flM8Kqo14OTDkI9EtlABEBAAHCwF8EGAEIAAkFAkvHyWwCGwwACgkQp6Fr SiUnQ2q03wgAmRFGDeXzc58NX0NrDijUu0zx3Lns/qZ9VrkSWbNZBFjpWKaeL1fdVeE4TDGm I5mRRIsStjQzc2R9b+2VBUhlAqY1nAiBDv0Qnt+9cLiuEICeUwlyl42YdwpmY0ELcy5+u6wz mK/jxrYOpzXKDwLq5k4X+hmGuSNWWAN3gHiJqmJZPkhFPUIozZUCeEc76pS/IUN72NfprZmF Dp6/QDjDFtfS39bHSWXKVZUbqaMPqlj/z6Ugk027/3GUjHHr8WkeL1ezWepYDY7WSoXwfoAL 2UXYsMAr/uUncSKlfjvArhsej0S4zbqim2ZY6S8aRWw94J3bSvJR+Nwbs34GPTD4Pg== Organization: Red Hat, Inc. Message-ID: Date: Fri, 31 May 2019 10:13:52 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190531074620.24934-1-dplotnikov@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="WgyPkxeuzGgaEKQWlINMRAhA8OBl21fvl" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 31 May 2019 15:13:59 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 X-Content-Filtered-By: Mailman/MimeDel 2.1.21 Subject: Re: [Qemu-devel] [PATCH v5] qemu-io: add pattern file for write command X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: vsementsov@virtuozzo.com, qemu-devel@nongnu.org, den@virtuozzo.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --WgyPkxeuzGgaEKQWlINMRAhA8OBl21fvl From: Eric Blake To: Denis Plotnikov , sgarzare@redhat.com, kwolf@redhat.com, mreitz@redhat.com, qemu-block@nongnu.org Cc: vsementsov@virtuozzo.com, qemu-devel@nongnu.org, den@virtuozzo.com Message-ID: Subject: Re: [Qemu-devel] [PATCH v5] qemu-io: add pattern file for write command References: <20190531074620.24934-1-dplotnikov@virtuozzo.com> In-Reply-To: <20190531074620.24934-1-dplotnikov@virtuozzo.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 5/31/19 2:46 AM, Denis Plotnikov wrote: > The patch allows to provide a pattern file for write > command. There was no similar ability before. >=20 > Signed-off-by: Denis Plotnikov > --- > v5: > * file name initiated with null to make compilers happy >=20 > +static void *qemu_io_alloc_from_file(BlockBackend *blk, size_t len, > + char *file_name) > +{ > + char *buf, *buf_pos; > + FILE *f =3D fopen(file_name, "r"); > + int l; > + > + if (!f) { > + printf("'%s': %s\n", file_name, strerror(errno)); > + return NULL; > + } > + > + if (qemuio_misalign) { > + len +=3D MISALIGN_OFFSET; > + } > + buf =3D blk_blockalign(blk, len); > + memset(buf, 0, len); > + > + buf_pos =3D buf; > + > + while (len > 0) { > + l =3D fread(buf_pos, sizeof(char), len, f); > + > + if (feof(f)) { > + rewind(f); > + } Why are we reading the file more than once? Once we've read it once, it's more efficient to switch to a loop that memcpy()s the prefix into the rest of the buffer, rather than to perform repeated I/O. --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org --WgyPkxeuzGgaEKQWlINMRAhA8OBl21fvl Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAlzxRLAACgkQp6FrSiUn Q2qhcwf/VoYX4JjGmIdTcHzGvFefpbRFxJmQ6oJhQtDUF1agc95KQuqMt+C+/Sry yg+SztVmhXtEQcZPR+fc38Yrb4IaqvzfdXlNDzjpXoynYMUL2vgAuYN1d9ksKmjZ uJFg9r03UJYkRoO0k79GhqzvpBW87cxgKXFp8+HLCoItwh1IZO7KBNo5C7rLq2sz vlUGjXUV3i2bw5nZywk46SimMY8OAbVWELdE+KOaFglOTOEJPJl6S9FTGO/g1NaQ AnMkUQS3gmozN2/zpEFkRFuzJc77Dp03gK7HB5Y83cWaiRhs0nwvDhPvmkcAJWt8 ZAHxaZCbP6ozcglfyrxnvUJ2CzRnNw== =4DLl -----END PGP SIGNATURE----- --WgyPkxeuzGgaEKQWlINMRAhA8OBl21fvl--