Re: [PATCH 16/18] nvmet-tcp: rework sendpage for kTLS

[Sagi Grimberg <sagi@grimberg.me>]

> kTLS ->sendpage() doesn't support the MSG_EOR flag, and it's
> questionable whether it makes sense for kTLS as one has to copy
> data anyway.
> So use sock_no_sendpage() for kTLS.

Same comments as the host side.
1. separate MSG_EOR from kernel_sendpage
2. keep kernel_sendpage unless unsupported properly.

> 
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>   drivers/nvme/target/tcp.c | 56 ++++++++++++++++++++++++++++-----------
>   1 file changed, 41 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
> index 6e88e98a2c59..9b69cac84508 100644
> --- a/drivers/nvme/target/tcp.c
> +++ b/drivers/nvme/target/tcp.c
> @@ -570,9 +570,14 @@ static int nvmet_try_send_data_pdu(struct nvmet_tcp_cmd *cmd)
>   	int left = sizeof(*cmd->data_pdu) - cmd->offset + hdgst;
>   	int ret;
>   
> -	ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->data_pdu),
> -			offset_in_page(cmd->data_pdu) + cmd->offset,
> -			left, MSG_DONTWAIT | MSG_MORE | MSG_SENDPAGE_NOTLAST);
> +	if (cmd->queue->tls_psk)
> +		ret = sock_no_sendpage(cmd->queue->sock, virt_to_page(cmd->data_pdu),
> +				      offset_in_page(cmd->data_pdu) + cmd->offset,
> +				      left, MSG_DONTWAIT | MSG_MORE);
> +	else
> +		ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->data_pdu),
> +				      offset_in_page(cmd->data_pdu) + cmd->offset,
> +				      left, MSG_DONTWAIT | MSG_MORE | MSG_SENDPAGE_NOTLAST);
>   	if (ret <= 0)
>   		return ret;
>   
> @@ -600,10 +605,17 @@ static int nvmet_try_send_data(struct nvmet_tcp_cmd *cmd, bool last_in_batch)
>   		if ((!last_in_batch && cmd->queue->send_list_len) ||
>   		    cmd->wbytes_done + left < cmd->req.transfer_len ||
>   		    queue->data_digest || !queue->nvme_sq.sqhd_disabled)
> -			flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
> -
> -		ret = kernel_sendpage(cmd->queue->sock, page, cmd->offset,
> -					left, flags);
> +			flags |= MSG_MORE;
> +
> +		if (queue->tls_psk)
> +			ret = sock_no_sendpage(cmd->queue->sock, page, cmd->offset,
> +					       left, flags);
> +		else {
> +			if (flags & MSG_MORE)
> +				flags |= MSG_SENDPAGE_NOTLAST;
> +			ret = kernel_sendpage(cmd->queue->sock, page, cmd->offset,
> +					      left, flags);
> +		}
>   		if (ret <= 0)
>   			return ret;
>   
> @@ -645,12 +657,19 @@ static int nvmet_try_send_response(struct nvmet_tcp_cmd *cmd,
>   	int ret;
>   
>   	if (!last_in_batch && cmd->queue->send_list_len)
> -		flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
> -	else
> +		flags |= MSG_MORE;
> +	else if (!cmd->queue->tls_psk)
>   		flags |= MSG_EOR;
>   
> -	ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->rsp_pdu),
> -		offset_in_page(cmd->rsp_pdu) + cmd->offset, left, flags);
> +	if (cmd->queue->tls_psk)
> +		ret = sock_no_sendpage(cmd->queue->sock, virt_to_page(cmd->rsp_pdu),
> +			offset_in_page(cmd->rsp_pdu) + cmd->offset, left, flags);
> +	else {
> +		if (flags & MSG_MORE)
> +			flags |= MSG_SENDPAGE_NOTLAST;
> +		ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->rsp_pdu),
> +			offset_in_page(cmd->rsp_pdu) + cmd->offset, left, flags);
> +	}
>   	if (ret <= 0)
>   		return ret;
>   	cmd->offset += ret;
> @@ -673,12 +692,19 @@ static int nvmet_try_send_r2t(struct nvmet_tcp_cmd *cmd, bool last_in_batch)
>   	int ret;
>   
>   	if (!last_in_batch && cmd->queue->send_list_len)
> -		flags |= MSG_MORE | MSG_SENDPAGE_NOTLAST;
> -	else
> +		flags |= MSG_MORE;
> +	else if (!cmd->queue->tls_psk)
>   		flags |= MSG_EOR;
>   
> -	ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->r2t_pdu),
> -		offset_in_page(cmd->r2t_pdu) + cmd->offset, left, flags);
> +	if (cmd->queue->tls_psk)
> +		ret = sock_no_sendpage(cmd->queue->sock, virt_to_page(cmd->r2t_pdu),
> +			offset_in_page(cmd->r2t_pdu) + cmd->offset, left, flags);
> +	else {
> +		if (flags & MSG_MORE)
> +			flags |= MSG_SENDPAGE_NOTLAST;
> +		ret = kernel_sendpage(cmd->queue->sock, virt_to_page(cmd->r2t_pdu),
> +			offset_in_page(cmd->r2t_pdu) + cmd->offset, left, flags);
> +	}
>   	if (ret <= 0)
>   		return ret;
>   	cmd->offset += ret;