From patchwork Mon Sep 11 20:22:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arseniy Krasnov X-Patchwork-Id: 13379642 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3B4EEEB581 for ; Mon, 11 Sep 2023 20:48:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234367AbjIKUsO (ORCPT ); Mon, 11 Sep 2023 16:48:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244424AbjIKU3k (ORCPT ); Mon, 11 Sep 2023 16:29:40 -0400 Received: from mx1.sberdevices.ru (mx1.sberdevices.ru [37.18.73.165]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 244EA1A7; Mon, 11 Sep 2023 13:29:35 -0700 (PDT) Received: from p-infra-ksmg-sc-msk01 (localhost [127.0.0.1]) by mx1.sberdevices.ru (Postfix) with ESMTP id B6CBC100015; Mon, 11 Sep 2023 23:29:33 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.sberdevices.ru B6CBC100015 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=salutedevices.com; s=mail; t=1694464173; bh=ydabQREpbRq8IHz33yeNk7fQnK9tCpQlj2QjNTuHLPs=; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:From; b=qhMs5BL3nGBS51iuupK7j/zZBhqBVPfJ8SaHWpaoH8nDSHd/lVkxh/+uYeZipSX/6 KtS6L6ZVwmXeaVAW7bB8rBDFVwCQ6lcS3grJfIiAl7lcbNbO7jYa0TA1O8Pt1V/uAm q8HrL34VVWrb6rpRFH/LeZYZB1cRB2GclUBOzT2zwnF5FcVWNv2v2G2Dp170VEztH6 Ms4lEfRsNEYbglTYdG5AmOi3K3Je309LfDMiu1m6pXRgOMy062nDoWFhK2jt/R25hC e1lMvqbEGZQKxYQaLGmn3aUrvdd/eWsgx3nI1YYb6XJw7YCIFvNq8vxBCdcd7812lG j1cz4G77YVtjA== Received: from p-i-exch-sc-m01.sberdevices.ru (p-i-exch-sc-m01.sberdevices.ru [172.16.192.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.sberdevices.ru (Postfix) with ESMTPS; Mon, 11 Sep 2023 23:29:33 +0300 (MSK) Received: from localhost.localdomain (100.64.160.123) by p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.30; Mon, 11 Sep 2023 23:29:33 +0300 From: Arseniy Krasnov To: Stefan Hajnoczi , Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , "Michael S. Tsirkin" , Jason Wang , Bobby Eshleman CC: , , , , , , Subject: [PATCH net-next v8 2/4] vsock/virtio: support to send non-linear skb Date: Mon, 11 Sep 2023 23:22:32 +0300 Message-ID: <20230911202234.1932024-3-avkrasnov@salutedevices.com> X-Mailer: git-send-email 2.35.0 In-Reply-To: <20230911202234.1932024-1-avkrasnov@salutedevices.com> References: <20230911202234.1932024-1-avkrasnov@salutedevices.com> MIME-Version: 1.0 X-Originating-IP: [100.64.160.123] X-ClientProxiedBy: p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) To p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) X-KSMG-Rule-ID: 10 X-KSMG-Message-Action: clean X-KSMG-AntiSpam-Lua-Profiles: 179791 [Sep 11 2023] X-KSMG-AntiSpam-Version: 5.9.59.0 X-KSMG-AntiSpam-Envelope-From: avkrasnov@salutedevices.com X-KSMG-AntiSpam-Rate: 0 X-KSMG-AntiSpam-Status: not_detected X-KSMG-AntiSpam-Method: none X-KSMG-AntiSpam-Auth: dkim=none X-KSMG-AntiSpam-Info: LuaCore: 530 530 ecb1547b3f72d1df4c71c0b60e67ba6b4aea5432, {Tracking_from_domain_doesnt_match_to}, d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;salutedevices.com:7.1.1;127.0.0.199:7.1.2;100.64.160.123:7.1.2;p-i-exch-sc-m01.sberdevices.ru:5.0.1,7.1.1, FromAlignment: s, ApMailHostAddress: 100.64.160.123 X-MS-Exchange-Organization-SCL: -1 X-KSMG-AntiSpam-Interceptor-Info: scan successful X-KSMG-AntiPhishing: Clean X-KSMG-LinksScanning: Clean X-KSMG-AntiVirus: Kaspersky Secure Mail Gateway, version 2.0.1.6960, bases: 2023/09/11 15:53:00 #21884588 X-KSMG-AntiVirus-Status: Clean, skipped Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org For non-linear skb use its pages from fragment array as buffers in virtio tx queue. These pages are already pinned by 'get_user_pages()' during such skb creation. Signed-off-by: Arseniy Krasnov Reviewed-by: Stefano Garzarella --- Changelog: v2 -> v3: * Comment about 'page_to_virt()' is updated. I don't remove R-b, as this change is quiet small I guess. v6 -> v7: * Move arrays '*sgs' and 'bufs' to 'virtio_vsock' instead of being local variables. This allows to save stack space in cases of too big MAX_SKB_FRAGS. * Add 'WARN_ON_ONCE()' for handling nonlinear skbs - it checks that linear part of such skb contains only header. * R-b tag removed due to updates above. v7 -> v8: * Add comment in 'struct virtio_vsock' for both 'struct scatterlist' fields. * Rename '*sgs' and 'bufs' to '*out_sgs' and 'out_bufs'. * Initialize '*out_sgs' in 'virtio_vsock_probe()' by always pointing to the corresponding element of 'out_bufs'. net/vmw_vsock/virtio_transport.c | 60 ++++++++++++++++++++++++++++---- 1 file changed, 53 insertions(+), 7 deletions(-) diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index e95df847176b..73d730156349 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -63,6 +63,17 @@ struct virtio_vsock { u32 guest_cid; bool seqpacket_allow; + + /* These fields are used only in tx path in function + * 'virtio_transport_send_pkt_work()', so to save + * stack space in it, place both of them here. Each + * pointer from 'out_sgs' points to the corresponding + * element in 'out_bufs' - this is initialized in + * 'virtio_vsock_probe()'. Both fields are protected + * by 'tx_lock'. +1 is needed for packet header. + */ + struct scatterlist *out_sgs[MAX_SKB_FRAGS + 1]; + struct scatterlist out_bufs[MAX_SKB_FRAGS + 1]; }; static u32 virtio_transport_get_local_cid(void) @@ -100,8 +111,8 @@ virtio_transport_send_pkt_work(struct work_struct *work) vq = vsock->vqs[VSOCK_VQ_TX]; for (;;) { - struct scatterlist hdr, buf, *sgs[2]; int ret, in_sg = 0, out_sg = 0; + struct scatterlist **sgs; struct sk_buff *skb; bool reply; @@ -111,12 +122,43 @@ virtio_transport_send_pkt_work(struct work_struct *work) virtio_transport_deliver_tap_pkt(skb); reply = virtio_vsock_skb_reply(skb); - - sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); - sgs[out_sg++] = &hdr; - if (skb->len > 0) { - sg_init_one(&buf, skb->data, skb->len); - sgs[out_sg++] = &buf; + sgs = vsock->out_sgs; + sg_init_one(sgs[out_sg], virtio_vsock_hdr(skb), + sizeof(*virtio_vsock_hdr(skb))); + out_sg++; + + if (!skb_is_nonlinear(skb)) { + if (skb->len > 0) { + sg_init_one(sgs[out_sg], skb->data, skb->len); + out_sg++; + } + } else { + struct skb_shared_info *si; + int i; + + /* If skb is nonlinear, then its buffer must contain + * only header and nothing more. Data is stored in + * the fragged part. + */ + WARN_ON_ONCE(skb_headroom(skb) != sizeof(*virtio_vsock_hdr(skb))); + + si = skb_shinfo(skb); + + for (i = 0; i < si->nr_frags; i++) { + skb_frag_t *skb_frag = &si->frags[i]; + void *va; + + /* We will use 'page_to_virt()' for the userspace page + * here, because virtio or dma-mapping layers will call + * 'virt_to_phys()' later to fill the buffer descriptor. + * We don't touch memory at "virtual" address of this page. + */ + va = page_to_virt(skb_frag->bv_page); + sg_init_one(sgs[out_sg], + va + skb_frag->bv_offset, + skb_frag->bv_len); + out_sg++; + } } ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL); @@ -621,6 +663,7 @@ static int virtio_vsock_probe(struct virtio_device *vdev) { struct virtio_vsock *vsock = NULL; int ret; + int i; ret = mutex_lock_interruptible(&the_virtio_vsock_mutex); if (ret) @@ -663,6 +706,9 @@ static int virtio_vsock_probe(struct virtio_device *vdev) if (ret < 0) goto out; + for (i = 0; i < ARRAY_SIZE(vsock->out_sgs); i++) + vsock->out_sgs[i] = &vsock->out_bufs[i]; + rcu_assign_pointer(the_virtio_vsock, vsock); mutex_unlock(&the_virtio_vsock_mutex);