From patchwork Sat Sep 16 13:09:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arseniy Krasnov X-Patchwork-Id: 13388408 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 B6532CD37BD for ; Sat, 16 Sep 2023 13:17:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239300AbjIPNQs (ORCPT ); Sat, 16 Sep 2023 09:16:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50204 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239219AbjIPNQ0 (ORCPT ); Sat, 16 Sep 2023 09:16:26 -0400 Received: from mx1.sberdevices.ru (mx1.sberdevices.ru [37.18.73.165]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E5C1191; Sat, 16 Sep 2023 06:16:18 -0700 (PDT) Received: from p-infra-ksmg-sc-msk01 (localhost [127.0.0.1]) by mx1.sberdevices.ru (Postfix) with ESMTP id 547EB100005; Sat, 16 Sep 2023 16:16:16 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.sberdevices.ru 547EB100005 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=salutedevices.com; s=mail; t=1694870176; bh=5OHjENHJqBc545OR08t8yaqpCAXkMEyH3r1Qh4h3sJw=; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:From; b=fIk279utCQfa0bRmLkPzsHYU5gtMB0AEcFReKrAdpaD5f3kxz/Mh0HzQgOiM4IEQb ddcedWjMOFdMpQdJeUmojasJcXi/nquVE7hnYvB/TRnKORayKRxbWcSO/JmN6c5iyN 0KEpErtwVLPxXrsPvfWGhuCdbWZNjS4XqaOPU2Iye2IZOm/+4y9hgG3kpONLZhshzQ sRmwFf3EPQD3jHE8VhHCgIEPQTYFfi1E+7YMN9+JlcEGKeHng4CDccnePxuMbKTA+I qv+cRkTNB9aAZc2TsVZ0yThXH7hAS4ViFJaaAGu9rlzbmorJuEqyp9tw7yQtggRWrb byJ2t1Bn4gqSw== 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; Sat, 16 Sep 2023 16:16:16 +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; Sat, 16 Sep 2023 16:16:15 +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 v9 1/4] vsock/virtio/vhost: read data from non-linear skb Date: Sat, 16 Sep 2023 16:09:15 +0300 Message-ID: <20230916130918.4105122-2-avkrasnov@salutedevices.com> X-Mailer: git-send-email 2.35.0 In-Reply-To: <20230916130918.4105122-1-avkrasnov@salutedevices.com> References: <20230916130918.4105122-1-avkrasnov@salutedevices.com> MIME-Version: 1.0 X-Originating-IP: [100.64.160.123] X-ClientProxiedBy: p-i-exch-sc-m02.sberdevices.ru (172.16.192.103) 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: 179905 [Sep 16 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;100.64.160.123:7.1.2;127.0.0.199:7.1.2;salutedevices.com:7.1.1;p-i-exch-sc-m01.sberdevices.ru:7.1.1,5.0.1, 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: 2023/09/16 12:14:00 #21905676 X-KSMG-AntiVirus-Status: Clean, skipped Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This is preparation patch for MSG_ZEROCOPY support. It adds handling of non-linear skbs by replacing direct calls of 'memcpy_to_msg()' with 'skb_copy_datagram_iter()'. Main advantage of the second one is that it can handle paged part of the skb by using 'kmap()' on each page, but if there are no pages in the skb, it behaves like simple copying to iov iterator. This patch also adds new field to the control block of skb - this value shows current offset in the skb to read next portion of data (it doesn't matter linear it or not). Idea behind this field is that 'skb_copy_datagram_iter()' handles both types of skb internally - it just needs an offset from which to copy data from the given skb. This offset is incremented on each read from skb. This approach allows to simplify handling of both linear and non-linear skbs, because for linear skb we need to call 'skb_pull()' after reading data from it, while in non-linear case we need to update 'data_len'. Signed-off-by: Arseniy Krasnov Reviewed-by: Stefano Garzarella --- Changelog: v5(big patchset) -> v1: * Merge 'virtio_transport_common.c' and 'vhost/vsock.c' patches into this single patch. * Commit message update: grammar fix and remark that this patch is MSG_ZEROCOPY preparation. * Use 'min_t()' instead of comparison using '<>' operators. v1 -> v2: * R-b tag added. v3 -> v4: * R-b tag removed due to rebase: * Part for 'virtio_transport_stream_do_peek()' is changed. * Part for 'virtio_transport_seqpacket_do_peek()' is added. * Comments about sleep in 'memcpy_to_msg()' now describe sleep in 'skb_copy_datagram_iter()'. v5 -> v6: * Commit message update. * Rename 'frag_off' to 'offset' in 'virtio_vsock_skb_cb'. drivers/vhost/vsock.c | 14 +++++++---- include/linux/virtio_vsock.h | 1 + net/vmw_vsock/virtio_transport_common.c | 32 +++++++++++++++---------- 3 files changed, 29 insertions(+), 18 deletions(-) diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 817d377a3f36..83711aad855c 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -114,6 +114,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock, struct sk_buff *skb; unsigned out, in; size_t nbytes; + u32 offset; int head; skb = virtio_vsock_skb_dequeue(&vsock->send_pkt_queue); @@ -156,7 +157,8 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock, } iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[out], in, iov_len); - payload_len = skb->len; + offset = VIRTIO_VSOCK_SKB_CB(skb)->offset; + payload_len = skb->len - offset; hdr = virtio_vsock_hdr(skb); /* If the packet is greater than the space available in the @@ -197,8 +199,10 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock, break; } - nbytes = copy_to_iter(skb->data, payload_len, &iov_iter); - if (nbytes != payload_len) { + if (skb_copy_datagram_iter(skb, + offset, + &iov_iter, + payload_len)) { kfree_skb(skb); vq_err(vq, "Faulted on copying pkt buf\n"); break; @@ -212,13 +216,13 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock, vhost_add_used(vq, head, sizeof(*hdr) + payload_len); added = true; - skb_pull(skb, payload_len); + VIRTIO_VSOCK_SKB_CB(skb)->offset += payload_len; total_len += payload_len; /* If we didn't send all the payload we can requeue the packet * to send it with the next available buffer. */ - if (skb->len > 0) { + if (VIRTIO_VSOCK_SKB_CB(skb)->offset < skb->len) { hdr->flags |= cpu_to_le32(flags_to_restore); /* We are queueing the same skb to handle diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h index c58453699ee9..a91fbdf233e4 100644 --- a/include/linux/virtio_vsock.h +++ b/include/linux/virtio_vsock.h @@ -12,6 +12,7 @@ struct virtio_vsock_skb_cb { bool reply; bool tap_delivered; + u32 offset; }; #define VIRTIO_VSOCK_SKB_CB(skb) ((struct virtio_vsock_skb_cb *)((skb)->cb)) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 352d042b130b..3e08d52a9355 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -364,9 +364,10 @@ virtio_transport_stream_do_peek(struct vsock_sock *vsk, spin_unlock_bh(&vvs->rx_lock); /* sk_lock is held by caller so no one else can dequeue. - * Unlock rx_lock since memcpy_to_msg() may sleep. + * Unlock rx_lock since skb_copy_datagram_iter() may sleep. */ - err = memcpy_to_msg(msg, skb->data, bytes); + err = skb_copy_datagram_iter(skb, VIRTIO_VSOCK_SKB_CB(skb)->offset, + &msg->msg_iter, bytes); if (err) goto out; @@ -410,25 +411,27 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk, while (total < len && !skb_queue_empty(&vvs->rx_queue)) { skb = skb_peek(&vvs->rx_queue); - bytes = len - total; - if (bytes > skb->len) - bytes = skb->len; + bytes = min_t(size_t, len - total, + skb->len - VIRTIO_VSOCK_SKB_CB(skb)->offset); /* sk_lock is held by caller so no one else can dequeue. - * Unlock rx_lock since memcpy_to_msg() may sleep. + * Unlock rx_lock since skb_copy_datagram_iter() may sleep. */ spin_unlock_bh(&vvs->rx_lock); - err = memcpy_to_msg(msg, skb->data, bytes); + err = skb_copy_datagram_iter(skb, + VIRTIO_VSOCK_SKB_CB(skb)->offset, + &msg->msg_iter, bytes); if (err) goto out; spin_lock_bh(&vvs->rx_lock); total += bytes; - skb_pull(skb, bytes); - if (skb->len == 0) { + VIRTIO_VSOCK_SKB_CB(skb)->offset += bytes; + + if (skb->len == VIRTIO_VSOCK_SKB_CB(skb)->offset) { u32 pkt_len = le32_to_cpu(virtio_vsock_hdr(skb)->len); virtio_transport_dec_rx_pkt(vvs, pkt_len); @@ -492,9 +495,10 @@ virtio_transport_seqpacket_do_peek(struct vsock_sock *vsk, spin_unlock_bh(&vvs->rx_lock); /* sk_lock is held by caller so no one else can dequeue. - * Unlock rx_lock since memcpy_to_msg() may sleep. + * Unlock rx_lock since skb_copy_datagram_iter() may sleep. */ - err = memcpy_to_msg(msg, skb->data, bytes); + err = skb_copy_datagram_iter(skb, VIRTIO_VSOCK_SKB_CB(skb)->offset, + &msg->msg_iter, bytes); if (err) return err; @@ -553,11 +557,13 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk, int err; /* sk_lock is held by caller so no one else can dequeue. - * Unlock rx_lock since memcpy_to_msg() may sleep. + * Unlock rx_lock since skb_copy_datagram_iter() may sleep. */ spin_unlock_bh(&vvs->rx_lock); - err = memcpy_to_msg(msg, skb->data, bytes_to_copy); + err = skb_copy_datagram_iter(skb, 0, + &msg->msg_iter, + bytes_to_copy); if (err) { /* Copy of message failed. Rest of * fragments will be freed without copy.