[PATCH v25 06/20] nvme-tcp: Add DDP data-path
Aurelien Aptel
aaptel at nvidia.com
Wed May 29 09:00:39 PDT 2024
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>
Reviewed-by: Max Gurtovoy <mgurtovoy at nvidia.com>
Reviewed-by: Sagi Grimberg <sagi at grimberg.me>
---
drivers/nvme/host/tcp.c | 136 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 131 insertions(+), 5 deletions(-)
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 95a36b48fd0c..2f5baeae01b9 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -128,6 +128,9 @@ struct nvme_tcp_request {
struct llist_node lentry;
__le32 ddgst;
+ /* ddp async completion */
+ union nvme_result result;
+
struct bio *curr_bio;
struct iov_iter iter;
@@ -135,6 +138,11 @@ 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;
+#endif
};
enum nvme_tcp_queue_flags {
@@ -341,6 +349,25 @@ static inline size_t nvme_tcp_pdu_last_send(struct nvme_tcp_request *req,
#ifdef CONFIG_ULP_DDP
+static bool nvme_tcp_is_ddp_offloaded(const struct nvme_tcp_request *req)
+{
+ return req->offloaded;
+}
+
+static int nvme_tcp_ddp_alloc_sgl(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 struct net_device *
nvme_tcp_get_ddp_netdev_with_limits(struct nvme_tcp_ctrl *ctrl)
{
@@ -376,10 +403,68 @@ nvme_tcp_get_ddp_netdev_with_limits(struct nvme_tcp_ctrl *ctrl)
}
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->ddp_netdev;
+ struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
+
+ ulp_ddp_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->status, req->result))
+ nvme_complete_rq(rq);
+}
+
+static void nvme_tcp_setup_ddp(struct nvme_tcp_queue *queue,
+ struct request *rq)
+{
+ struct net_device *netdev = queue->ctrl->ddp_netdev;
+ struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
+ int ret;
+
+ if (rq_data_dir(rq) != READ ||
+ queue->ctrl->ddp_threshold > blk_rq_payload_bytes(rq))
+ return;
+
+ /*
+ * DDP offload is best-effort, errors are ignored.
+ */
+
+ req->ddp.command_id = nvme_cid(rq);
+ ret = nvme_tcp_ddp_alloc_sgl(req, rq);
+ if (ret)
+ goto err;
+
+ ret = ulp_ddp_setup(netdev, queue->sock->sk, &req->ddp);
+ if (ret) {
+ sg_free_table_chained(&req->ddp.sg_table, SG_CHUNK_SIZE);
+ goto err;
+ }
+
+ /* if successful, sg table is freed in nvme_tcp_teardown_ddp() */
+ req->offloaded = true;
+
+ return;
+err:
+ WARN_ONCE(ret, "ddp setup failed (queue 0x%x, cid 0x%x, ret=%d)",
+ nvme_tcp_queue_id(queue),
+ nvme_cid(rq),
+ ret);
+}
+
static int nvme_tcp_offload_socket(struct nvme_tcp_queue *queue)
{
struct ulp_ddp_config config = {.type = ULP_DDP_NVME};
@@ -484,6 +569,11 @@ static bool nvme_tcp_resync_request(struct sock *sk, u32 seq, u32 flags)
#else
+static bool nvme_tcp_is_ddp_offloaded(const struct nvme_tcp_request *req)
+{
+ return false;
+}
+
static struct net_device *
nvme_tcp_get_ddp_netdev_with_limits(struct nvme_tcp_ctrl *ctrl)
{
@@ -501,6 +591,14 @@ static int nvme_tcp_offload_socket(struct nvme_tcp_queue *queue)
static void nvme_tcp_unoffload_socket(struct nvme_tcp_queue *queue)
{}
+static void nvme_tcp_setup_ddp(struct nvme_tcp_queue *queue,
+ struct request *rq)
+{}
+
+static void nvme_tcp_teardown_ddp(struct nvme_tcp_queue *queue,
+ struct request *rq)
+{}
+
static void nvme_tcp_resync_response(struct nvme_tcp_queue *queue,
struct sk_buff *skb, unsigned int offset)
{}
@@ -782,6 +880,26 @@ 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)
+{
+ struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
+
+ req->status = status;
+ req->result = result;
+
+ if (nvme_tcp_is_ddp_offloaded(req)) {
+ /* complete when teardown is confirmed to be done */
+ nvme_tcp_teardown_ddp(req->queue, rq);
+ return;
+ }
+
+ 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)
{
@@ -801,10 +919,9 @@ 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;
}
@@ -1002,10 +1119,13 @@ 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,
@@ -2749,6 +2869,9 @@ 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;
@@ -2787,6 +2910,9 @@ static blk_status_t nvme_tcp_setup_cmd_pdu(struct nvme_ns *ns,
return ret;
}
+ if (test_bit(NVME_TCP_Q_OFF_DDP, &queue->flags))
+ nvme_tcp_setup_ddp(queue, rq);
+
return 0;
}
--
2.34.1
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