From patchwork Tue Jul 18 18:02:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arseniy Krasnov X-Patchwork-Id: 13317582 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C0CB31642F for ; Tue, 18 Jul 2023 18:08:22 +0000 (UTC) Received: from mx1.sberdevices.ru (mx1.sberdevices.ru [37.18.73.165]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5CECBD; Tue, 18 Jul 2023 11:08:19 -0700 (PDT) Received: from p-infra-ksmg-sc-msk01 (localhost [127.0.0.1]) by mx1.sberdevices.ru (Postfix) with ESMTP id B18D9100015; Tue, 18 Jul 2023 21:08:17 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.sberdevices.ru B18D9100015 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sberdevices.ru; s=mail; t=1689703697; bh=orXX14OPfIpbdl+OCofg0u3TAslJ4Vpwl3Ko0PpRkoo=; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:From; b=DWsNDh8EyKKDlXduPHGWbR3nW6Ul9ozHPbriaTRdeI4Hfm8W9PpTqjKRsyDwjVoet Xw0H7RiSnKBU9frnb6+WrB9UFfop5Q7PRJQzIz1fyybojQpUESxRn0/eZGOi4E3Xz8 eiyMeveXWBQT2gsg6SYZb797NzQg91/F6K9dp512HMJfWsKE9PbNM2WFsEiN4EbJH4 r4xAvXrBlvUq1R5oiWv5paOPtm/wOBZzdyp3NqB8TBeFPe0/oXB6sed/8ws8ZSDsYV uEvruieSfl0UOXzuA7k63K9tqKrnW1qu0Q83dDcqVehf8KX7acWZ7hT0v66dpWTCJv tU+ZFvlmTih7g== 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; Tue, 18 Jul 2023 21:08:17 +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; Tue, 18 Jul 2023 21:08:16 +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: , , , , , , , Arseniy Krasnov Subject: [PATCH net-next v2 1/4] vsock/virtio/vhost: read data from non-linear skb Date: Tue, 18 Jul 2023 21:02:34 +0300 Message-ID: <20230718180237.3248179-2-AVKrasnov@sberdevices.ru> X-Mailer: git-send-email 2.35.0 In-Reply-To: <20230718180237.3248179-1-AVKrasnov@sberdevices.ru> References: <20230718180237.3248179-1-AVKrasnov@sberdevices.ru> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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: 178700 [Jul 18 2023] X-KSMG-AntiSpam-Version: 5.9.59.0 X-KSMG-AntiSpam-Envelope-From: AVKrasnov@sberdevices.ru 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: 524 524 9753033d6953787301affc41bead8ed49c47b39d, {Tracking_from_domain_doesnt_match_to}, p-i-exch-sc-m01.sberdevices.ru:7.1.1,5.0.1;127.0.0.199:7.1.2;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;sberdevices.ru:7.1.1,5.0.1;100.64.160.123:7.1.2, FromAlignment: s, {Tracking_white_helo}, 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: 2023/07/18 13:44:00 #21634370 X-KSMG-AntiVirus-Status: Clean, skipped X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@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 avoid special handling of non-linear skbs: 1) We can't call 'skb_pull()' on it, because it updates 'data' pointer. 2) We need to update 'data_len' also on each read from this skb. 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. drivers/vhost/vsock.c | 14 ++++++++----- include/linux/virtio_vsock.h | 1 + net/vmw_vsock/virtio_transport_common.c | 27 ++++++++++++++++--------- 3 files changed, 28 insertions(+), 14 deletions(-) diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index 817d377a3f36..8c917be32b5d 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 frag_off; 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; + frag_off = VIRTIO_VSOCK_SKB_CB(skb)->frag_off; + payload_len = skb->len - frag_off; 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, + frag_off, + &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)->frag_off += 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)->frag_off < 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..17dbb7176e37 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 frag_off; }; #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 b769fc258931..1a376f808ae6 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -355,7 +355,7 @@ virtio_transport_stream_do_peek(struct vsock_sock *vsk, spin_lock_bh(&vvs->rx_lock); skb_queue_walk_safe(&vvs->rx_queue, skb, tmp) { - off = 0; + off = VIRTIO_VSOCK_SKB_CB(skb)->frag_off; if (total == len) break; @@ -370,7 +370,10 @@ virtio_transport_stream_do_peek(struct vsock_sock *vsk, */ spin_unlock_bh(&vvs->rx_lock); - err = memcpy_to_msg(msg, skb->data + off, bytes); + err = skb_copy_datagram_iter(skb, off, + &msg->msg_iter, + bytes); + if (err) goto out; @@ -413,25 +416,28 @@ 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)->frag_off); /* sk_lock is held by caller so no one else can dequeue. * Unlock rx_lock since memcpy_to_msg() 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)->frag_off, + &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)->frag_off += bytes; + + if (skb->len == VIRTIO_VSOCK_SKB_CB(skb)->frag_off) { u32 pkt_len = le32_to_cpu(virtio_vsock_hdr(skb)->len); virtio_transport_dec_rx_pkt(vvs, pkt_len); @@ -503,7 +509,10 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk, */ 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.