From patchwork Thu Feb 11 21:10:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris Pismenny X-Patchwork-Id: 12084143 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A412DC433E0 for ; Thu, 11 Feb 2021 21:14:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 747B264E42 for ; Thu, 11 Feb 2021 21:14:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230315AbhBKVNo convert rfc822-to-8bit (ORCPT ); Thu, 11 Feb 2021 16:13:44 -0500 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:9245 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229678AbhBKVMP (ORCPT ); Thu, 11 Feb 2021 16:12:15 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Thu, 11 Feb 2021 13:11:35 -0800 Received: from HQMAIL109.nvidia.com (172.20.187.15) by HQMAIL111.nvidia.com (172.20.187.18) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 11 Feb 2021 21:11:22 +0000 Received: from vdi.nvidia.com (172.20.145.6) by mail.nvidia.com (172.20.187.15) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 11 Feb 2021 21:11:18 +0000 From: Boris Pismenny To: , , , , , , , , , , CC: , , , , , , Boris Pismenny , Ben Ben-Ishay , Or Gerlitz , Yoray Zack Subject: [PATCH v4 net-next 06/21] nvme-tcp: Add DDP offload control path Date: Thu, 11 Feb 2021 23:10:29 +0200 Message-ID: <20210211211044.32701-7-borisp@mellanox.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20210211211044.32701-1-borisp@mellanox.com> References: <20210211211044.32701-1-borisp@mellanox.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org This commit introduces direct data placement offload to NVME TCP. There is a context per queue, which is established after the handshake using the tcp_ddp_sk_add/del NDOs. Additionally, a resynchronization routine is used to assist hardware recovery from TCP OOO, and continue the offload. Resynchronization operates as follows: 1. TCP OOO causes the NIC HW to stop the offload 2. NIC HW identifies a PDU header at some TCP sequence number, and asks NVMe-TCP to confirm it. This request is delivered from the NIC driver to NVMe-TCP by first finding the socket for the packet that triggered the request, and then finding the nvme_tcp_queue that is used by this routine. Finally, the request is recorded in the nvme_tcp_queue. 3. When NVMe-TCP observes the requested TCP sequence, it will compare it with the PDU header TCP sequence, and report the result to the NIC driver (tcp_ddp_resync), which will update the HW, and resume offload when all is successful. Furthermore, we let the offloading driver advertise what is the max hw sectors/segments via tcp_ddp_limits. A follow-up patch introduces the data-path changes required for this offload. Signed-off-by: Boris Pismenny Signed-off-by: Ben Ben-Ishay Signed-off-by: Or Gerlitz Signed-off-by: Yoray Zack --- drivers/nvme/host/tcp.c | 177 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 175 insertions(+), 2 deletions(-) diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 881d28eb15e9..36de4391ba76 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "nvme.h" #include "fabrics.h" @@ -62,6 +63,7 @@ enum nvme_tcp_queue_flags { NVME_TCP_Q_ALLOCATED = 0, NVME_TCP_Q_LIVE = 1, NVME_TCP_Q_POLLING = 2, + NVME_TCP_Q_OFF_DDP = 3, }; enum nvme_tcp_recv_state { @@ -111,6 +113,8 @@ struct nvme_tcp_queue { void (*state_change)(struct sock *); void (*data_ready)(struct sock *); void (*write_space)(struct sock *); + + atomic64_t resync_req; }; struct nvme_tcp_ctrl { @@ -129,6 +133,8 @@ struct nvme_tcp_ctrl { struct delayed_work connect_work; struct nvme_tcp_request async_req; u32 io_queues[HCTX_MAX_TYPES]; + + struct net_device *offloading_netdev; }; static LIST_HEAD(nvme_tcp_ctrl_list); @@ -223,6 +229,164 @@ static inline size_t nvme_tcp_pdu_last_send(struct nvme_tcp_request *req, return nvme_tcp_pdu_data_left(req) <= len; } +#ifdef CONFIG_TCP_DDP + +static bool nvme_tcp_resync_request(struct sock *sk, u32 seq, u32 flags); +static const struct tcp_ddp_ulp_ops nvme_tcp_ddp_ulp_ops = { + .resync_request = nvme_tcp_resync_request, +}; + +static int nvme_tcp_offload_socket(struct nvme_tcp_queue *queue) +{ + struct net_device *netdev = queue->ctrl->offloading_netdev; + struct nvme_tcp_ddp_config config = {}; + int ret; + + if (!(netdev->features & NETIF_F_HW_TCP_DDP)) + return -EOPNOTSUPP; + + config.cfg.type = TCP_DDP_NVME; + config.pfv = NVME_TCP_PFV_1_0; + config.cpda = 0; + config.dgst = queue->hdr_digest ? + NVME_TCP_HDR_DIGEST_ENABLE : 0; + config.dgst |= queue->data_digest ? + NVME_TCP_DATA_DIGEST_ENABLE : 0; + config.queue_size = queue->queue_size; + config.queue_id = nvme_tcp_queue_id(queue); + config.io_cpu = queue->io_cpu; + + dev_hold(netdev); /* put by unoffload_socket */ + ret = netdev->tcp_ddp_ops->tcp_ddp_sk_add(netdev, + queue->sock->sk, + &config.cfg); + if (ret) { + dev_put(netdev); + return ret; + } + + inet_csk(queue->sock->sk)->icsk_ulp_ddp_ops = &nvme_tcp_ddp_ulp_ops; + if (netdev->features & NETIF_F_HW_TCP_DDP) + set_bit(NVME_TCP_Q_OFF_DDP, &queue->flags); + + return ret; +} + +static void nvme_tcp_unoffload_socket(struct nvme_tcp_queue *queue) +{ + struct net_device *netdev = queue->ctrl->offloading_netdev; + + if (!netdev) { + dev_info_ratelimited(queue->ctrl->ctrl.device, "netdev not found\n"); + return; + } + + netdev->tcp_ddp_ops->tcp_ddp_sk_del(netdev, queue->sock->sk); + + inet_csk(queue->sock->sk)->icsk_ulp_ddp_ops = NULL; + dev_put(netdev); /* held by offload_socket */ +} + +static int nvme_tcp_offload_limits(struct nvme_tcp_queue *queue) +{ + struct net_device *netdev = get_netdev_for_sock(queue->sock->sk, true); + struct tcp_ddp_limits limits; + int ret = 0; + + if (!netdev) { + dev_info_ratelimited(queue->ctrl->ctrl.device, "netdev not found\n"); + queue->ctrl->offloading_netdev = NULL; + return -ENODEV; + } + + if (netdev->features & NETIF_F_HW_TCP_DDP && + netdev->tcp_ddp_ops && + netdev->tcp_ddp_ops->tcp_ddp_limits) + ret = netdev->tcp_ddp_ops->tcp_ddp_limits(netdev, &limits); + else + ret = -EOPNOTSUPP; + + if (!ret) { + queue->ctrl->offloading_netdev = netdev; + dev_dbg_ratelimited(queue->ctrl->ctrl.device, + "netdev %s offload limits: max_ddp_sgl_len %d\n", + netdev->name, limits.max_ddp_sgl_len); + queue->ctrl->ctrl.max_segments = limits.max_ddp_sgl_len; + queue->ctrl->ctrl.max_hw_sectors = + limits.max_ddp_sgl_len << (ilog2(SZ_4K) - 9); + } else { + queue->ctrl->offloading_netdev = NULL; + } + + /* release the device as no offload context is established yet. */ + dev_put(netdev); + + return ret; +} + +static void nvme_tcp_resync_response(struct nvme_tcp_queue *queue, + struct sk_buff *skb, unsigned int offset) +{ + u64 pdu_seq = TCP_SKB_CB(skb)->seq + offset - queue->pdu_offset; + struct net_device *netdev = queue->ctrl->offloading_netdev; + u64 resync_val; + u32 resync_seq; + + resync_val = atomic64_read(&queue->resync_req); + /* Lower 32 bit flags. Check validity of the request */ + if ((resync_val & TCP_DDP_RESYNC_REQ) == 0) + return; + + /* Obtain and check requested sequence number: is this PDU header before the request? */ + resync_seq = resync_val >> 32; + if (before(pdu_seq, resync_seq)) + return; + + if (unlikely(!netdev)) { + pr_info_ratelimited("%s: netdev not found\n", __func__); + return; + } + + /** + * The atomic operation gurarantees that we don't miss any NIC driver + * resync requests submitted after the above checks. + */ + if (atomic64_cmpxchg(&queue->resync_req, resync_val, + resync_val & ~TCP_DDP_RESYNC_REQ)) + netdev->tcp_ddp_ops->tcp_ddp_resync(netdev, queue->sock->sk, pdu_seq); +} + +static bool nvme_tcp_resync_request(struct sock *sk, u32 seq, u32 flags) +{ + struct nvme_tcp_queue *queue = sk->sk_user_data; + + atomic64_set(&queue->resync_req, + (((uint64_t)seq << 32) | flags)); + + return true; +} + +#else + +static int nvme_tcp_offload_socket(struct nvme_tcp_queue *queue) +{ + return -EINVAL; +} + +static void nvme_tcp_unoffload_socket(struct nvme_tcp_queue *queue) +{} + +static int nvme_tcp_offload_limits(struct nvme_tcp_queue *queue) +{ + return -EINVAL; +} + +static void nvme_tcp_resync_response(struct nvme_tcp_queue *queue, + struct sk_buff *skb, unsigned int offset) +{} + +#endif + static void nvme_tcp_init_iter(struct nvme_tcp_request *req, unsigned int dir) { @@ -638,6 +802,9 @@ static int nvme_tcp_recv_pdu(struct nvme_tcp_queue *queue, struct sk_buff *skb, size_t rcv_len = min_t(size_t, *len, queue->pdu_remaining); int ret; + if (test_bit(NVME_TCP_Q_OFF_DDP, &queue->flags)) + nvme_tcp_resync_response(queue, skb, *offset); + ret = skb_copy_bits(skb, *offset, &pdu[queue->pdu_offset], rcv_len); if (unlikely(ret)) @@ -1532,6 +1699,9 @@ static void __nvme_tcp_stop_queue(struct nvme_tcp_queue *queue) kernel_sock_shutdown(queue->sock, SHUT_RDWR); nvme_tcp_restore_sock_calls(queue); cancel_work_sync(&queue->io_work); + + if (test_bit(NVME_TCP_Q_OFF_DDP, &queue->flags)) + nvme_tcp_unoffload_socket(queue); } static void nvme_tcp_stop_queue(struct nvme_ctrl *nctrl, int qid) @@ -1550,10 +1720,13 @@ static int nvme_tcp_start_queue(struct nvme_ctrl *nctrl, int idx) struct nvme_tcp_ctrl *ctrl = to_tcp_ctrl(nctrl); int ret; - if (idx) + if (idx) { ret = nvmf_connect_io_queue(nctrl, idx, false); - else + nvme_tcp_offload_socket(&ctrl->queues[idx]); + } else { ret = nvmf_connect_admin_queue(nctrl); + nvme_tcp_offload_limits(&ctrl->queues[idx]); + } if (!ret) { set_bit(NVME_TCP_Q_LIVE, &ctrl->queues[idx].flags);