From: Alistair Francis <redacted>

If the nvme_tcp_try_send() or nvme_tcp_try_recv() functions return
EKEYEXPIRED then the underlying TLS keys need to be updated. This occurs
on an KeyUpdate event.

If the NVMe Target (TLS server) initiates a KeyUpdate this patch will
allow the NVMe layer to process the KeyUpdate request and forward the
request to userspace. Userspace must then update the key to keep the
connection alive.

This patch allows us to handle the NVMe target sending a KeyUpdate
request without aborting the connection. At this time we don't support
initiating a KeyUpdate.

Link: https://datatracker.ietf.org/doc/html/rfc8446#section-4.6.3
Signed-off-by: Alistair Francis <redacted>
---
  drivers/nvme/host/tcp.c | 63 ++++++++++++++++++++++++++++++++++++++++-
  1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index cc3332529355..0c14d3ad58af 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c

@@ -171,6 +171,7 @@ struct nvme_tcp_queue {
  	bool			tls_enabled;
  	u32			rcv_crc;
  	u32			snd_crc;
+	key_serial_t		user_key_serial;
  	__le32			exp_ddgst;
  	__le32			recv_ddgst;
  	struct completion       tls_complete;

@@ -1313,6 +1314,7 @@ static int nvme_tcp_try_send(struct nvme_tcp_queue *queue)
  	struct nvme_tcp_request *req;
  	unsigned int noreclaim_flag;
  	int ret = 1;
+	enum nvme_ctrl_state state = nvme_ctrl_state(&(queue->ctrl->ctrl));
  
  	if (!queue->request) {
  		queue->request = nvme_tcp_fetch_request(queue);

@@ -1347,6 +1349,29 @@ static int nvme_tcp_try_send(struct nvme_tcp_queue *queue)
  done:
  	if (ret == -EAGAIN) {
  		ret = 0;
+	} else if (ret == -EKEYEXPIRED &&
+		state != NVME_CTRL_CONNECTING &&
+		state != NVME_CTRL_RESETTING) {
+		int qid = nvme_tcp_queue_id(queue);
+
+		dev_dbg(queue->ctrl->ctrl.device,
+			"updating key for queue %d\n", qid);
+
+		nvme_change_ctrl_state(&(queue->ctrl->ctrl), NVME_CTRL_RESETTING);