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(gen-l-vrt-133.mtl.labs.mlnx [10.237.11.160]) by labmailer.mlnx (8.13.8/8.13.8) with ESMTP id 08UGKR2G032498; Wed, 30 Sep 2020 19:20:27 +0300 From: Boris Pismenny To: kuba@kernel.org, davem@davemloft.net, saeedm@nvidia.com, hch@lst.de, sagi@grimberg.me, axboe@fb.com, kbusch@kernel.org, viro@zeniv.linux.org.uk, edumazet@google.com Cc: boris.pismenny@gmail.com, linux-nvme@lists.infradead.org, netdev@vger.kernel.org, Ben Ben-Ishay , Or Gerlitz , Yoray Zack Subject: [PATCH net-next RFC v1 05/10] nvme-tcp: Add DDP offload control path Date: Wed, 30 Sep 2020 19:20:05 +0300 Message-Id: <20200930162010.21610-6-borisp@mellanox.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200930162010.21610-1-borisp@mellanox.com> References: <20200930162010.21610-1-borisp@mellanox.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.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 fiding 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 | 188 +++++++++++++++++++++++++++++++++++++++ include/linux/nvme-tcp.h | 2 + 2 files changed, 190 insertions(+) diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 8f4f29f18b8c..06711ac095f2 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -62,6 +62,7 @@ enum nvme_tcp_queue_flags { NVME_TCP_Q_ALLOCATED = 0, NVME_TCP_Q_LIVE = 1, NVME_TCP_Q_POLLING = 2, + NVME_TCP_Q_OFFLOADS = 3, }; enum nvme_tcp_recv_state { @@ -110,6 +111,8 @@ 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 +132,8 @@ 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 +228,159 @@ 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 + +bool nvme_tcp_resync_request(struct sock *sk, u32 seq, u32 flags); +const struct tcp_ddp_ulp_ops nvme_tcp_ddp_ulp_ops __read_mostly = { + .resync_request = nvme_tcp_resync_request, +}; + +static +int nvme_tcp_offload_socket(struct nvme_tcp_queue *queue, + struct nvme_tcp_config *config) +{ + struct net_device *netdev = get_netdev_for_sock(queue->sock->sk, true); + struct tcp_ddp_config *ddp_config = (struct tcp_ddp_config *)config; + int ret; + + if (unlikely(!netdev)) { + pr_info_ratelimited("%s: netdev not found\n", __func__); + return -EINVAL; + } + + if (!(netdev->features & NETIF_F_HW_TCP_DDP)) { + dev_put(netdev); + return -EINVAL; + } + + ret = netdev->tcp_ddp_ops->tcp_ddp_sk_add(netdev, + queue->sock->sk, + ddp_config); + if (!ret) + inet_csk(queue->sock->sk)->icsk_ulp_ddp_ops = &nvme_tcp_ddp_ulp_ops; + else + dev_put(netdev); + return ret; +} + +static +void nvme_tcp_unoffload_socket(struct nvme_tcp_queue *queue) +{ + struct net_device *netdev = queue->ctrl->offloading_netdev; + + if (unlikely(!netdev)) { + pr_info_ratelimited("%s: netdev not found\n", __func__); + 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); /* put the queue_init get_netdev_for_sock() */ +} + +static +int nvme_tcp_offload_limits(struct nvme_tcp_queue *queue, + struct tcp_ddp_limits *limits) +{ + struct net_device *netdev = get_netdev_for_sock(queue->sock->sk, true); + int ret = 0; + + if (unlikely(!netdev)) { + pr_info_ratelimited("%s: netdev not found\n", __func__); + return -EINVAL; + } + + 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; + pr_info("%s netdev %s offload limits: max_ddp_sgl_len %d\n", + __func__, 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; + } + + dev_put(netdev); + + return ret; +} + +static +void nvme_tcp_resync_response(struct nvme_tcp_queue *queue, + unsigned int pdu_seq) +{ + struct net_device *netdev = queue->ctrl->offloading_netdev; + u64 resync_val; + u32 resync_seq; + + if (unlikely(!netdev)) { + pr_info_ratelimited("%s: netdev not found\n", __func__); + return; + } + + resync_val = atomic64_read(&queue->resync_req); + if ((resync_val & TCP_DDP_RESYNC_REQ) == 0) + return; + + resync_seq = resync_val >> 32; + if (before(pdu_seq, resync_seq)) + return; + + if (atomic64_cmpxchg(&queue->resync_req, resync_val, (resync_val - 1))) + netdev->tcp_ddp_ops->tcp_ddp_resync(netdev, queue->sock->sk, pdu_seq); +} + +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, + struct nvme_tcp_config *config) +{ + return -EINVAL; +} + +static +void nvme_tcp_unoffload_socket(struct nvme_tcp_queue *queue) +{} + +static +int nvme_tcp_offload_limits(struct nvme_tcp_queue *queue, + struct tcp_ddp_limits *limits) +{ + return -EINVAL; +} + +static +void nvme_tcp_resync_response(struct nvme_tcp_queue *queue, + unsigned int pdu_seq) +{} + +bool nvme_tcp_resync_request(struct sock *sk, u32 seq, u32 flags) +{ + return false; +} + +#endif + static void nvme_tcp_init_iter(struct nvme_tcp_request *req, unsigned int dir) { @@ -628,6 +786,11 @@ 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; + u64 pdu_seq = TCP_SKB_CB(skb)->seq + *offset - queue->pdu_offset; + + if (test_bit(NVME_TCP_Q_OFFLOADS, &queue->flags)) + nvme_tcp_resync_response(queue, pdu_seq); + ret = skb_copy_bits(skb, *offset, &pdu[queue->pdu_offset], rcv_len); if (unlikely(ret)) @@ -1370,6 +1533,8 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl, { struct nvme_tcp_ctrl *ctrl = to_tcp_ctrl(nctrl); struct nvme_tcp_queue *queue = &ctrl->queues[qid]; + struct nvme_tcp_config config; + struct tcp_ddp_limits limits; int ret, rcv_pdu_size; queue->ctrl = ctrl; @@ -1487,6 +1652,26 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl, #endif write_unlock_bh(&queue->sock->sk->sk_callback_lock); + if (nvme_tcp_queue_id(queue) != 0) { + 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; + + ret = nvme_tcp_offload_socket(queue, &config); + if (!ret) + set_bit(NVME_TCP_Q_OFFLOADS, &queue->flags); + } else { + ret = nvme_tcp_offload_limits(queue, &limits); + } + /* offload is opportunistic - failure is non-critical */ + return 0; err_init_connect: @@ -1519,6 +1704,9 @@ 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_OFFLOADS, &queue->flags)) + nvme_tcp_unoffload_socket(queue); } static void nvme_tcp_stop_queue(struct nvme_ctrl *nctrl, int qid) diff --git a/include/linux/nvme-tcp.h b/include/linux/nvme-tcp.h index 959e0bd9a913..65df64c34ecd 100644 --- a/include/linux/nvme-tcp.h +++ b/include/linux/nvme-tcp.h @@ -8,6 +8,8 @@ #define _LINUX_NVME_TCP_H #include +#include +#include #define NVME_TCP_DISC_PORT 8009 #define NVME_TCP_ADMIN_CCSZ SZ_8K