nvme tcp receive errors

[Keith Busch]

On Tue, Apr 20, 2021 at 10:33:30PM -0700, Sagi Grimberg wrote:
> There might be a hidden assumption here that may cause this if multiple
> c2hdata pdus will come per request...
> 
> If that is the case, you can try the following (on top):

This patch is successful for clearing up the observed "no space" issues
observed during read tests.

There are still some issues with write tests that look a bit different.
I'll get more details on that for you today, but it's probably okay if
you want to make a formal patch for the receive data side.

> --
> diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
> index ff39d37e9793..aabec8e6810a 100644
> --- a/drivers/nvme/host/tcp.c
> +++ b/drivers/nvme/host/tcp.c
> @@ -773,19 +773,20 @@ static int nvme_tcp_recv_data(struct nvme_tcp_queue
> *queue, struct sk_buff *skb,
>                 req->data_recvd += recv_len;
>         }
> 
> -       if (!queue->data_remaining) {
> +       if (!queue->data_remaining)
> +               nvme_tcp_init_recv_ctx(queue);
> +
> +       if (req->data_recvd == req->data_len) {
>                 if (queue->data_digest) {
>                         nvme_tcp_ddgst_final(queue->rcv_hash,
> &queue->exp_ddgst);
>                         queue->ddgst_remaining = NVME_TCP_DIGEST_LENGTH;
>                 } else {
> -                       BUG_ON(req->data_recvd != req->data_len);
>                         req->cmd_state = NVME_TCP_CMD_DATA_DONE;
>                         if (pdu->hdr.flags & NVME_TCP_F_DATA_SUCCESS) {
>                                 req->cmd_state = NVME_TCP_CMD_DONE;
>                                 nvme_tcp_end_request(rq, NVME_SC_SUCCESS);
>                                 queue->nr_cqe++;
>                         }
> -                       nvme_tcp_init_recv_ctx(queue);
>                 }
>         }
> --