{"id":817375,"url":"http://patchwork.ozlabs.org/api/patches/817375/?format=json","web_url":"http://patchwork.ozlabs.org/project/netdev/patch/1506067355-5771-4-git-send-email-jasowang@redhat.com/","project":{"id":7,"url":"http://patchwork.ozlabs.org/api/projects/7/?format=json","name":"Linux network development","link_name":"netdev","list_id":"netdev.vger.kernel.org","list_email":"netdev@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<1506067355-5771-4-git-send-email-jasowang@redhat.com>","list_archive_url":null,"date":"2017-09-22T08:02:33","name":"[net-next,RFC,3/5] vhost: introduce vhost_add_used_idx()","commit_ref":null,"pull_url":null,"state":"rfc","archived":true,"hash":"63f5a299fdf2515d0ff4fe01e21a8745c0f21ae6","submitter":{"id":5225,"url":"http://patchwork.ozlabs.org/api/people/5225/?format=json","name":"Jason Wang","email":"jasowang@redhat.com"},"delegate":{"id":34,"url":"http://patchwork.ozlabs.org/api/users/34/?format=json","username":"davem","first_name":"David","last_name":"Miller","email":"davem@davemloft.net"},"mbox":"http://patchwork.ozlabs.org/project/netdev/patch/1506067355-5771-4-git-send-email-jasowang@redhat.com/mbox/","series":[{"id":4565,"url":"http://patchwork.ozlabs.org/api/series/4565/?format=json","web_url":"http://patchwork.ozlabs.org/project/netdev/list/?series=4565","date":"2017-09-22T08:02:35","name":"batched tx processing in vhost_net","version":1,"mbox":"http://patchwork.ozlabs.org/series/4565/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/817375/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/817375/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=netdev-owner@vger.kernel.org;\n\treceiver=)","ext-mx06.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com","ext-mx06.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=jasowang@redhat.com"],"Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xz5bf2zcWz9sP1\n\tfor ;\n\tFri, 22 Sep 2017 18:04:13 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1751875AbdIVID7 (ORCPT );\n\tFri, 22 Sep 2017 04:03:59 -0400","from mx1.redhat.com ([209.132.183.28]:57206 \"EHLO mx1.redhat.com\"\n\trhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP\n\tid S1751704AbdIVICy (ORCPT );\n\tFri, 22 Sep 2017 04:02:54 -0400","from smtp.corp.redhat.com\n\t(int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id 405DD1F57C;\n\tFri, 22 Sep 2017 08:02:54 +0000 (UTC)","from jason-ThinkPad-T450s.redhat.com (ovpn-12-19.pek2.redhat.com\n\t[10.72.12.19])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id BDA926266E;\n\tFri, 22 Sep 2017 08:02:51 +0000 (UTC)"],"DMARC-Filter":"OpenDMARC Filter v1.3.2 mx1.redhat.com 405DD1F57C","From":"Jason Wang ","To":"mst@redhat.com, jasowang@redhat.com,\n\tvirtualization@lists.linux-foundation.org, netdev@vger.kernel.org,\n\tlinux-kernel@vger.kernel.org","Cc":"kvm@vger.kernel.org","Subject":"[PATCH net-next RFC 3/5] vhost: introduce vhost_add_used_idx()","Date":"Fri, 22 Sep 2017 16:02:33 +0800","Message-Id":"<1506067355-5771-4-git-send-email-jasowang@redhat.com>","In-Reply-To":"<1506067355-5771-1-git-send-email-jasowang@redhat.com>","References":"<1506067355-5771-1-git-send-email-jasowang@redhat.com>","X-Scanned-By":"MIMEDefang 2.79 on 10.5.11.15","X-Greylist":"Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.30]);\n\tFri, 22 Sep 2017 08:02:54 +0000 (UTC)","Sender":"netdev-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"netdev@vger.kernel.org"},"content":"This patch introduces a helper which just increase the used idx. This\nwill be used in pair with vhost_prefetch_desc_indices() by batching\ncode.\n\nSigned-off-by: Jason Wang \n---\n drivers/vhost/vhost.c | 33 +++++++++++++++++++++++++++++++++\n drivers/vhost/vhost.h | 1 +\n 2 files changed, 34 insertions(+)","diff":"diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c\nindex 8424166d..6532cda 100644\n--- a/drivers/vhost/vhost.c\n+++ b/drivers/vhost/vhost.c\n@@ -2178,6 +2178,39 @@ int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)\n }\n EXPORT_SYMBOL_GPL(vhost_add_used);\n \n+int vhost_add_used_idx(struct vhost_virtqueue *vq, int n)\n+{\n+\tu16 old, new;\n+\n+\told = vq->last_used_idx;\n+\tnew = (vq->last_used_idx += n);\n+\t/* If the driver never bothers to signal in a very long while,\n+\t * used index might wrap around. If that happens, invalidate\n+\t * signalled_used index we stored. TODO: make sure driver\n+\t * signals at least once in 2^16 and remove this.\n+\t */\n+\tif (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))\n+\t\tvq->signalled_used_valid = false;\n+\n+\t/* Make sure buffer is written before we update index. */\n+\tsmp_wmb();\n+\tif (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),\n+\t\t\t &vq->used->idx)) {\n+\t\tvq_err(vq, \"Failed to increment used idx\");\n+\t\treturn -EFAULT;\n+\t}\n+\tif (unlikely(vq->log_used)) {\n+\t\t/* Log used index update. */\n+\t\tlog_write(vq->log_base,\n+\t\t\t vq->log_addr + offsetof(struct vring_used, idx),\n+\t\t\t sizeof(vq->used->idx));\n+\t\tif (vq->log_ctx)\n+\t\t\teventfd_signal(vq->log_ctx, 1);\n+\t}\n+\treturn 0;\n+}\n+EXPORT_SYMBOL_GPL(vhost_add_used_idx);\n+\n static int __vhost_add_used_n(struct vhost_virtqueue *vq,\n \t\t\t struct vring_used_elem *heads,\n \t\t\t unsigned count)\ndiff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h\nindex 16c2cb6..5dd6c05 100644\n--- a/drivers/vhost/vhost.h\n+++ b/drivers/vhost/vhost.h\n@@ -199,6 +199,7 @@ int __vhost_get_vq_desc(struct vhost_virtqueue *vq,\n void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);\n \n int vhost_vq_init_access(struct vhost_virtqueue *);\n+int vhost_add_used_idx(struct vhost_virtqueue *vq, int n);\n int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);\n int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,\n \t\t unsigned count);\n","prefixes":["net-next","RFC","3/5"]}