[PATCH v11 08/25] nvme-tcp: Add DDP data-path
Aurelien Aptel
aaptel at nvidia.com
Fri Feb 3 05:26:48 PST 2023
From: Boris Pismenny <borisp at nvidia.com>
Introduce the NVMe-TCP DDP data-path offload.
Using this interface, the NIC hardware will scatter TCP payload directly
to the BIO pages according to the command_id in the PDU.
To maintain the correctness of the network stack, the driver is expected
to construct SKBs that point to the BIO pages.
The data-path interface contains two routines: setup/teardown.
The setup provides the mapping from command_id to the request buffers,
while the teardown removes this mapping.
For efficiency, we introduce an asynchronous nvme completion, which is
split between NVMe-TCP and the NIC driver as follows:
NVMe-TCP performs the specific completion, while NIC driver performs the
generic mq_blk completion.
Signed-off-by: Boris Pismenny <borisp at nvidia.com>
Signed-off-by: Ben Ben-Ishay <benishay at nvidia.com>
Signed-off-by: Or Gerlitz <ogerlitz at nvidia.com>
Signed-off-by: Yoray Zack <yorayz at nvidia.com>
Signed-off-by: Shai Malin <smalin at nvidia.com>
Signed-off-by: Aurelien Aptel <aaptel at nvidia.com>
Reviewed-by: Chaitanya Kulkarni <kch at nvidia.com>
---
drivers/nvme/host/tcp.c | 121 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 116 insertions(+), 5 deletions(-)
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index b350250bf8fb..533177971777 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -102,6 +102,13 @@ struct nvme_tcp_request {
size_t offset;
size_t data_sent;
enum nvme_tcp_send_state state;
+
+#ifdef CONFIG_ULP_DDP
+ bool offloaded;
+ struct ulp_ddp_io ddp;
+ __le16 ddp_status;
+ union nvme_result result;
+#endif
};
enum nvme_tcp_queue_flags {
@@ -307,11 +314,75 @@ static bool nvme_tcp_ddp_query_limits(struct net_device *netdev,
return true;
}
+static int nvme_tcp_req_map_sg(struct nvme_tcp_request *req, struct request *rq)
+{
+ int ret;
+
+ req->ddp.sg_table.sgl = req->ddp.first_sgl;
+ ret = sg_alloc_table_chained(&req->ddp.sg_table,
+ blk_rq_nr_phys_segments(rq),
+ req->ddp.sg_table.sgl, SG_CHUNK_SIZE);
+ if (ret)
+ return -ENOMEM;
+ req->ddp.nents = blk_rq_map_sg(rq->q, rq, req->ddp.sg_table.sgl);
+ return 0;
+}
+
static bool nvme_tcp_resync_request(struct sock *sk, u32 seq, u32 flags);
+static void nvme_tcp_ddp_teardown_done(void *ddp_ctx);
static const struct ulp_ddp_ulp_ops nvme_tcp_ddp_ulp_ops = {
.resync_request = nvme_tcp_resync_request,
+ .ddp_teardown_done = nvme_tcp_ddp_teardown_done,
};
+static void nvme_tcp_teardown_ddp(struct nvme_tcp_queue *queue,
+ struct request *rq)
+{
+ struct net_device *netdev = queue->ctrl->offloading_netdev;
+ struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
+
+ netdev->netdev_ops->ulp_ddp_ops->teardown(netdev, queue->sock->sk,
+ &req->ddp, rq);
+ sg_free_table_chained(&req->ddp.sg_table, SG_CHUNK_SIZE);
+}
+
+static void nvme_tcp_ddp_teardown_done(void *ddp_ctx)
+{
+ struct request *rq = ddp_ctx;
+ struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
+
+ if (!nvme_try_complete_req(rq, req->ddp_status, req->result))
+ nvme_complete_rq(rq);
+}
+
+static int nvme_tcp_setup_ddp(struct nvme_tcp_queue *queue, u16 command_id,
+ struct request *rq)
+{
+ struct net_device *netdev = queue->ctrl->offloading_netdev;
+ struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
+ int ret;
+
+ if (!(rq_data_dir(rq) == READ) ||
+ queue->ctrl->offload_io_threshold > blk_rq_payload_bytes(rq))
+ return 0;
+
+ req->ddp.command_id = command_id;
+ ret = nvme_tcp_req_map_sg(req, rq);
+ if (ret)
+ return -ENOMEM;
+
+ ret = netdev->netdev_ops->ulp_ddp_ops->setup(netdev, queue->sock->sk,
+ &req->ddp);
+ if (ret) {
+ sg_free_table_chained(&req->ddp.sg_table, SG_CHUNK_SIZE);
+ return ret;
+ }
+
+ /* if successful, sg table is freed in nvme_tcp_teardown_ddp() */
+ req->offloaded = true;
+ return 0;
+}
+
static int nvme_tcp_offload_socket(struct nvme_tcp_queue *queue)
{
struct net_device *netdev = queue->ctrl->offloading_netdev;
@@ -453,6 +524,12 @@ static inline bool is_netdev_ulp_offload_active(struct net_device *netdev)
return false;
}
+static int nvme_tcp_setup_ddp(struct nvme_tcp_queue *queue, u16 command_id,
+ struct request *rq)
+{
+ return 0;
+}
+
static int nvme_tcp_offload_socket(struct nvme_tcp_queue *queue)
{
return 0;
@@ -740,6 +817,26 @@ static void nvme_tcp_error_recovery(struct nvme_ctrl *ctrl)
queue_work(nvme_reset_wq, &to_tcp_ctrl(ctrl)->err_work);
}
+static void nvme_tcp_complete_request(struct request *rq,
+ __le16 status,
+ union nvme_result result,
+ __u16 command_id)
+{
+#ifdef CONFIG_ULP_DDP
+ struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
+
+ if (req->offloaded) {
+ req->ddp_status = status;
+ req->result = result;
+ nvme_tcp_teardown_ddp(req->queue, rq);
+ return;
+ }
+#endif
+
+ if (!nvme_try_complete_req(rq, status, result))
+ nvme_complete_rq(rq);
+}
+
static int nvme_tcp_process_nvme_cqe(struct nvme_tcp_queue *queue,
struct nvme_completion *cqe)
{
@@ -759,10 +856,9 @@ static int nvme_tcp_process_nvme_cqe(struct nvme_tcp_queue *queue,
if (req->status == cpu_to_le16(NVME_SC_SUCCESS))
req->status = cqe->status;
- if (!nvme_try_complete_req(rq, req->status, cqe->result))
- nvme_complete_rq(rq);
+ nvme_tcp_complete_request(rq, req->status, cqe->result,
+ cqe->command_id);
queue->nr_cqe++;
-
return 0;
}
@@ -960,10 +1056,13 @@ static int nvme_tcp_recv_pdu(struct nvme_tcp_queue *queue, struct sk_buff *skb,
static inline void nvme_tcp_end_request(struct request *rq, u16 status)
{
+ struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
+ struct nvme_tcp_queue *queue = req->queue;
+ struct nvme_tcp_data_pdu *pdu = (void *)queue->pdu;
union nvme_result res = {};
- if (!nvme_try_complete_req(rq, cpu_to_le16(status << 1), res))
- nvme_complete_rq(rq);
+ nvme_tcp_complete_request(rq, cpu_to_le16(status << 1), res,
+ pdu->command_id);
}
static int nvme_tcp_recv_data(struct nvme_tcp_queue *queue, struct sk_buff *skb,
@@ -1263,6 +1362,15 @@ static int nvme_tcp_try_send_cmd_pdu(struct nvme_tcp_request *req)
else
flags |= MSG_EOR;
+ if (test_bit(NVME_TCP_Q_OFF_DDP, &queue->flags)) {
+ ret = nvme_tcp_setup_ddp(queue, pdu->cmd.common.command_id,
+ blk_mq_rq_from_pdu(req));
+ WARN_ONCE(ret, "ddp setup failed (queue 0x%x, cid 0x%x, ret=%d)",
+ nvme_tcp_queue_id(queue),
+ pdu->cmd.common.command_id,
+ ret);
+ }
+
if (queue->hdr_digest && !req->offset)
nvme_tcp_hdgst(queue->snd_hash, pdu, sizeof(*pdu));
@@ -2594,6 +2702,9 @@ static blk_status_t nvme_tcp_setup_cmd_pdu(struct nvme_ns *ns,
if (ret)
return ret;
+#ifdef CONFIG_ULP_DDP
+ req->offloaded = false;
+#endif
req->state = NVME_TCP_SEND_CMD_PDU;
req->status = cpu_to_le16(NVME_SC_SUCCESS);
req->offset = 0;
--
2.31.1
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