From patchwork Thu May 21 12:24:15 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Dr. David Alan Gilbert" X-Patchwork-Id: 474994 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4B45B14007F for ; Thu, 21 May 2015 22:27:51 +1000 (AEST) Received: from localhost ([::1]:57334 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YvPZl-00071y-Fi for incoming@patchwork.ozlabs.org; Thu, 21 May 2015 08:27:49 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54874) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YvPWZ-00017O-M1 for qemu-devel@nongnu.org; Thu, 21 May 2015 08:24:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YvPWY-0001nm-L5 for qemu-devel@nongnu.org; Thu, 21 May 2015 08:24:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58852) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YvPWY-0001nY-Ef for qemu-devel@nongnu.org; Thu, 21 May 2015 08:24:30 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t4LCOShk021796 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 21 May 2015 08:24:28 -0400 Received: from dgilbert-t530.redhat.com (ovpn-116-101.ams2.redhat.com [10.36.116.101]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t4LCOHsF002227; Thu, 21 May 2015 08:24:26 -0400 From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org Date: Thu, 21 May 2015 13:24:15 +0100 Message-Id: <1432211056-6265-6-git-send-email-dgilbert@redhat.com> In-Reply-To: <1432211056-6265-1-git-send-email-dgilbert@redhat.com> References: <1432211056-6265-1-git-send-email-dgilbert@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: amit.shah@redhat.com, david@gibson.dropbear.id.au, quintela@redhat.com Subject: [Qemu-devel] [PATCH 5/6] Move copy out of qemu_peek_buffer X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: "Dr. David Alan Gilbert" qemu_peek_buffer currently copies the data it reads into a buffer, however a future patch wants access to the buffer without the copy, hence rework to remove the copy to the layer above. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Amit Shah Reviewed-by: Juan Quintela --- include/migration/qemu-file.h | 2 +- migration/qemu-file.c | 12 +++++++----- migration/vmstate.c | 5 +++-- 3 files changed, 11 insertions(+), 8 deletions(-) diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h index 318aa1e..4f67d79 100644 --- a/include/migration/qemu-file.h +++ b/include/migration/qemu-file.h @@ -157,7 +157,7 @@ static inline void qemu_put_ubyte(QEMUFile *f, unsigned int v) void qemu_put_be16(QEMUFile *f, unsigned int v); void qemu_put_be32(QEMUFile *f, unsigned int v); void qemu_put_be64(QEMUFile *f, uint64_t v); -int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size, size_t offset); +int qemu_peek_buffer(QEMUFile *f, uint8_t **buf, int size, size_t offset); int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size); ssize_t qemu_put_compression_data(QEMUFile *f, const uint8_t *p, size_t size, int level); diff --git a/migration/qemu-file.c b/migration/qemu-file.c index 0ef543a..965a757 100644 --- a/migration/qemu-file.c +++ b/migration/qemu-file.c @@ -349,14 +349,14 @@ void qemu_file_skip(QEMUFile *f, int size) } /* - * Read 'size' bytes from file (at 'offset') into buf without moving the - * pointer. + * Read 'size' bytes from file (at 'offset') without moving the + * pointer and set 'buf' to point to that data. * * It will return size bytes unless there was an error, in which case it will * return as many as it managed to read (assuming blocking fd's which * all current QEMUFile are) */ -int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size, size_t offset) +int qemu_peek_buffer(QEMUFile *f, uint8_t **buf, int size, size_t offset) { int pending; int index; @@ -392,7 +392,7 @@ int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size, size_t offset) size = pending; } - memcpy(buf, f->buf + index, size); + *buf = f->buf + index; return size; } @@ -411,11 +411,13 @@ int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size) while (pending > 0) { int res; + uint8_t *src; - res = qemu_peek_buffer(f, buf, MIN(pending, IO_BUF_SIZE), 0); + res = qemu_peek_buffer(f, &src, MIN(pending, IO_BUF_SIZE), 0); if (res == 0) { return done; } + memcpy(buf, src, res); qemu_file_skip(f, res); buf += res; pending -= res; diff --git a/migration/vmstate.c b/migration/vmstate.c index e5388f0..a64ebcc 100644 --- a/migration/vmstate.c +++ b/migration/vmstate.c @@ -358,7 +358,7 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, trace_vmstate_subsection_load(vmsd->name); while (qemu_peek_byte(f, 0) == QEMU_VM_SUBSECTION) { - char idstr[256]; + char idstr[256], *idstr_ret; int ret; uint8_t version_id, len, size; const VMStateDescription *sub_vmsd; @@ -369,11 +369,12 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, trace_vmstate_subsection_load_bad(vmsd->name, "(short)"); return 0; } - size = qemu_peek_buffer(f, (uint8_t *)idstr, len, 2); + size = qemu_peek_buffer(f, (uint8_t **)&idstr_ret, len, 2); if (size != len) { trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)"); return 0; } + memcpy(idstr, idstr_ret, size); idstr[size] = 0; if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) {