[PATCH RFC] nvme-tcp: Implement recvmsg() receive flow
Hannes Reinecke
hare at kernel.org
Fri Sep 12 04:58:29 PDT 2025
Switch to use recvmsg() so that we get access to TLS control
messages eg for handling TLS KeyUpdate.
Signed-off-by: Hannes Reinecke <hare at kernel.org>
---
drivers/nvme/host/tcp.c | 204 ++++++++++++++++++++++------------------
1 file changed, 111 insertions(+), 93 deletions(-)
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index c0fe8cfb7229..9ef1d4aea838 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -17,6 +17,7 @@
#include <net/tls_prot.h>
#include <net/handshake.h>
#include <linux/blk-mq.h>
+#include <linux/iov_iter.h>
#include <net/busy_poll.h>
#include <trace/events/sock.h>
@@ -476,6 +477,28 @@ static inline void nvme_tcp_ddgst_update(u32 *crcp,
}
}
+static size_t nvme_tcp_ddgst_step(void *iter_base, size_t progress, size_t len,
+ void *priv, void *priv2)
+{
+ u32 *crcp = priv;
+
+ *crcp = crc32c(*crcp, iter_base, len);
+ return 0;
+}
+
+static int nvme_tcp_ddgst_calc(struct nvme_tcp_request *req, u32 *crcp,
+ size_t maxsize)
+{
+ struct iov_iter tmp = req->iter;
+ int err = 0;
+
+ tmp.count = maxsize;
+ if (iterate_and_advance_kernel(&tmp, maxsize, crcp, &err,
+ nvme_tcp_ddgst_step) != maxsize)
+ return err;
+ return 0;
+}
+
static inline __le32 nvme_tcp_ddgst_final(u32 crc)
{
return cpu_to_le32(~crc);
@@ -827,23 +850,26 @@ static void nvme_tcp_handle_c2h_term(struct nvme_tcp_queue *queue,
"Received C2HTermReq (FES = %s)\n", msg);
}
-static int nvme_tcp_recv_pdu(struct nvme_tcp_queue *queue, struct sk_buff *skb,
- unsigned int *offset, size_t *len)
+static int nvme_tcp_recvmsg_pdu(struct nvme_tcp_queue *queue)
{
- struct nvme_tcp_hdr *hdr;
char *pdu = queue->pdu;
- size_t rcv_len = min_t(size_t, *len, queue->pdu_remaining);
+ struct msghdr msg = {
+ .msg_flags = MSG_DONTWAIT,
+ };
+ struct kvec iov = {
+ .iov_base = pdu + queue->pdu_offset,
+ .iov_len = queue->pdu_remaining,
+ };
+ struct nvme_tcp_hdr *hdr;
int ret;
- ret = skb_copy_bits(skb, *offset,
- &pdu[queue->pdu_offset], rcv_len);
- if (unlikely(ret))
+ ret = kernel_recvmsg(queue->sock, &msg, &iov, 1,
+ iov.iov_len, msg.msg_flags);
+ if (ret <= 0)
return ret;
- queue->pdu_remaining -= rcv_len;
- queue->pdu_offset += rcv_len;
- *offset += rcv_len;
- *len -= rcv_len;
+ queue->pdu_remaining -= ret;
+ queue->pdu_offset += ret;
if (queue->pdu_remaining)
return 0;
@@ -907,20 +933,19 @@ static inline void nvme_tcp_end_request(struct request *rq, u16 status)
nvme_complete_rq(rq);
}
-static int nvme_tcp_recv_data(struct nvme_tcp_queue *queue, struct sk_buff *skb,
- unsigned int *offset, size_t *len)
+static int nvme_tcp_recvmsg_data(struct nvme_tcp_queue *queue)
{
struct nvme_tcp_data_pdu *pdu = (void *)queue->pdu;
struct request *rq =
nvme_cid_to_rq(nvme_tcp_tagset(queue), pdu->command_id);
struct nvme_tcp_request *req = blk_mq_rq_to_pdu(rq);
- while (true) {
- int recv_len, ret;
+ if (nvme_tcp_recv_state(queue) != NVME_TCP_RECV_DATA)
+ return 0;
- recv_len = min_t(size_t, *len, queue->data_remaining);
- if (!recv_len)
- break;
+ while (queue->data_remaining) {
+ struct msghdr msg;
+ int ret;
if (!iov_iter_count(&req->iter)) {
req->curr_bio = req->curr_bio->bi_next;
@@ -940,25 +965,22 @@ static int nvme_tcp_recv_data(struct nvme_tcp_queue *queue, struct sk_buff *skb,
}
/* we can read only from what is left in this bio */
- recv_len = min_t(size_t, recv_len,
- iov_iter_count(&req->iter));
+ memset(&msg, 0, sizeof(msg));
+ msg.msg_iter = req->iter;
+ msg.msg_flags = MSG_DONTWAIT;
- if (queue->data_digest)
- ret = skb_copy_and_crc32c_datagram_iter(skb, *offset,
- &req->iter, recv_len, &queue->rcv_crc);
- else
- ret = skb_copy_datagram_iter(skb, *offset,
- &req->iter, recv_len);
- if (ret) {
+ ret = sock_recvmsg(queue->sock, &msg, msg.msg_flags);
+ if (ret < 0) {
dev_err(queue->ctrl->ctrl.device,
- "queue %d failed to copy request %#x data",
+ "queue %d failed to receive request %#x data",
nvme_tcp_queue_id(queue), rq->tag);
return ret;
}
-
- *len -= recv_len;
- *offset += recv_len;
- queue->data_remaining -= recv_len;
+ if (queue->data_digest)
+ nvme_tcp_ddgst_calc(req, &queue->rcv_crc, ret);
+ queue->data_remaining -= ret;
+ if (queue->data_remaining)
+ nvme_tcp_advance_req(req, ret);
}
if (!queue->data_remaining) {
@@ -968,7 +990,7 @@ static int nvme_tcp_recv_data(struct nvme_tcp_queue *queue, struct sk_buff *skb,
} else {
if (pdu->hdr.flags & NVME_TCP_F_DATA_SUCCESS) {
nvme_tcp_end_request(rq,
- le16_to_cpu(req->status));
+ le16_to_cpu(req->status));
queue->nr_cqe++;
}
nvme_tcp_init_recv_ctx(queue);
@@ -978,24 +1000,9 @@ static int nvme_tcp_recv_data(struct nvme_tcp_queue *queue, struct sk_buff *skb,
return 0;
}
-static int nvme_tcp_recv_ddgst(struct nvme_tcp_queue *queue,
- struct sk_buff *skb, unsigned int *offset, size_t *len)
+static int __nvme_tcp_recv_ddgst(struct nvme_tcp_queue *queue)
{
struct nvme_tcp_data_pdu *pdu = (void *)queue->pdu;
- char *ddgst = (char *)&queue->recv_ddgst;
- size_t recv_len = min_t(size_t, *len, queue->ddgst_remaining);
- off_t off = NVME_TCP_DIGEST_LENGTH - queue->ddgst_remaining;
- int ret;
-
- ret = skb_copy_bits(skb, *offset, &ddgst[off], recv_len);
- if (unlikely(ret))
- return ret;
-
- queue->ddgst_remaining -= recv_len;
- *offset += recv_len;
- *len -= recv_len;
- if (queue->ddgst_remaining)
- return 0;
if (queue->recv_ddgst != queue->exp_ddgst) {
struct request *rq = nvme_cid_to_rq(nvme_tcp_tagset(queue),
@@ -1023,40 +1030,32 @@ static int nvme_tcp_recv_ddgst(struct nvme_tcp_queue *queue,
return 0;
}
-static int nvme_tcp_recv_skb(read_descriptor_t *desc, struct sk_buff *skb,
- unsigned int offset, size_t len)
+static int nvme_tcp_recvmsg_ddgst(struct nvme_tcp_queue *queue)
{
- struct nvme_tcp_queue *queue = desc->arg.data;
- size_t consumed = len;
- int result;
+ char *ddgst = (char *)&queue->recv_ddgst;
+ off_t off = NVME_TCP_DIGEST_LENGTH - queue->ddgst_remaining;
+ struct msghdr msg = {
+ .msg_flags = MSG_WAITALL,
+ };
+ struct kvec iov = {
+ .iov_base = (u8 *)ddgst + off,
+ .iov_len = queue->ddgst_remaining,
+ };
+ int ret;
- if (unlikely(!queue->rd_enabled))
- return -EFAULT;
+ if (nvme_tcp_recv_state(queue) != NVME_TCP_RECV_DDGST)
+ return 0;
- while (len) {
- switch (nvme_tcp_recv_state(queue)) {
- case NVME_TCP_RECV_PDU:
- result = nvme_tcp_recv_pdu(queue, skb, &offset, &len);
- break;
- case NVME_TCP_RECV_DATA:
- result = nvme_tcp_recv_data(queue, skb, &offset, &len);
- break;
- case NVME_TCP_RECV_DDGST:
- result = nvme_tcp_recv_ddgst(queue, skb, &offset, &len);
- break;
- default:
- result = -EFAULT;
- }
- if (result) {
- dev_err(queue->ctrl->ctrl.device,
- "receive failed: %d\n", result);
- queue->rd_enabled = false;
- nvme_tcp_error_recovery(&queue->ctrl->ctrl);
- return result;
- }
- }
+ ret = kernel_recvmsg(queue->sock, &msg, &iov, 1, iov.iov_len,
+ msg.msg_flags);
+ if (ret <= 0)
+ return ret;
+
+ queue->ddgst_remaining -= ret;
+ if (queue->ddgst_remaining)
+ return 0;
- return consumed;
+ return __nvme_tcp_recv_ddgst(queue);
}
static void nvme_tcp_data_ready(struct sock *sk)
@@ -1353,20 +1352,39 @@ static int nvme_tcp_try_send(struct nvme_tcp_queue *queue)
return ret;
}
-static int nvme_tcp_try_recv(struct nvme_tcp_queue *queue)
+static int nvme_tcp_try_recvmsg(struct nvme_tcp_queue *queue)
{
- struct socket *sock = queue->sock;
- struct sock *sk = sock->sk;
- read_descriptor_t rd_desc;
- int consumed;
+ int result;
+ int nr_cqe = queue->nr_cqe;
+
+ if (unlikely(!queue->rd_enabled))
+ return -EFAULT;
+
+ do {
+ switch (nvme_tcp_recv_state(queue)) {
+ case NVME_TCP_RECV_PDU:
+ result = nvme_tcp_recvmsg_pdu(queue);
+ break;
+ case NVME_TCP_RECV_DATA:
+ result = nvme_tcp_recvmsg_data(queue);
+ break;
+ case NVME_TCP_RECV_DDGST:
+ result = nvme_tcp_recvmsg_ddgst(queue);
+ break;
+ default:
+ result = -EFAULT;
+ }
+ } while (result >= 0);
+
+ if (result < 0 && result != -EAGAIN) {
+ dev_err(queue->ctrl->ctrl.device,
+ "receive failed: %d\n", result);
+ queue->rd_enabled = false;
+ nvme_tcp_error_recovery(&queue->ctrl->ctrl);
+ } else if (result == -EAGAIN)
+ result = 0;
- rd_desc.arg.data = queue;
- rd_desc.count = 1;
- lock_sock(sk);
- queue->nr_cqe = 0;
- consumed = sock->ops->read_sock(sk, &rd_desc, nvme_tcp_recv_skb);
- release_sock(sk);
- return consumed == -EAGAIN ? 0 : consumed;
+ return result < 0 ? result : (queue->nr_cqe = nr_cqe);
}
static void nvme_tcp_io_work(struct work_struct *w)
@@ -1388,7 +1406,7 @@ static void nvme_tcp_io_work(struct work_struct *w)
break;
}
- result = nvme_tcp_try_recv(queue);
+ result = nvme_tcp_try_recvmsg(queue);
if (result > 0)
pending = true;
else if (unlikely(result < 0))
@@ -2794,7 +2812,7 @@ static int nvme_tcp_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
set_bit(NVME_TCP_Q_POLLING, &queue->flags);
if (sk_can_busy_loop(sk) && skb_queue_empty_lockless(&sk->sk_receive_queue))
sk_busy_loop(sk, true);
- ret = nvme_tcp_try_recv(queue);
+ ret = nvme_tcp_try_recvmsg(queue);
clear_bit(NVME_TCP_Q_POLLING, &queue->flags);
return ret < 0 ? ret : queue->nr_cqe;
}
--
2.43.0
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