nvmet-tcp: implement C2HData SUCCESS optimization (70583295) · Commits · 戴 / test

TP 8000 says that the use of the SUCCESS flag depends on weather the controller support disabling sq_head pointer updates. Given that we support it by default, makes sense that we go the extra mile to actually use the SUCCESS flag. When we create the C2HData PDU header, we check if sqhd_disabled is set on our queue, if so, we set the SUCCESS flag in the PDU header and skip sending a completion response capsule. Signed-off-by:

Sagi Grimberg <sagi@grimberg.me> Reviewed-by:

Oliver Smith-Denny <osmithde@cisco.com> Tested-by:

Oliver Smith-Denny <osmithde@cisco.com> Signed-off-by:

Christoph Hellwig <hch@lst.de>

drivers/nvme/target/tcp.c

+21 −3

Original line number	Diff line number	Diff line
		@@ -371,7 +371,8 @@ static void nvmet_setup_c2h_data_pdu(struct nvmet_tcp_cmd *cmd)
		cmd->state = NVMET_TCP_SEND_DATA_PDU;

		pdu->hdr.type = nvme_tcp_c2h_data;
		pdu->hdr.flags = NVME_TCP_F_DATA_LAST;
		pdu->hdr.flags = NVME_TCP_F_DATA_LAST \| (queue->nvme_sq.sqhd_disabled ?
		NVME_TCP_F_DATA_SUCCESS : 0);
		pdu->hdr.hlen = sizeof(*pdu);
		pdu->hdr.pdo = pdu->hdr.hlen + hdgst;
		pdu->hdr.plen =
		@@ -541,9 +542,20 @@ static int nvmet_try_send_data(struct nvmet_tcp_cmd *cmd)
		if (queue->data_digest) {
		cmd->state = NVMET_TCP_SEND_DDGST;
		cmd->offset = 0;
		} else {
		if (queue->nvme_sq.sqhd_disabled) {
		cmd->queue->snd_cmd = NULL;
		nvmet_tcp_put_cmd(cmd);
		} else {
		nvmet_setup_response_pdu(cmd);
		}
		}

		if (queue->nvme_sq.sqhd_disabled) {
		kfree(cmd->iov);
		sgl_free(cmd->req.sg);
		}

		return 1;

		}
		@@ -619,7 +631,13 @@ static int nvmet_try_send_ddgst(struct nvmet_tcp_cmd *cmd)
		return ret;

		cmd->offset += ret;

		if (queue->nvme_sq.sqhd_disabled) {
		cmd->queue->snd_cmd = NULL;
		nvmet_tcp_put_cmd(cmd);
		} else {
		nvmet_setup_response_pdu(cmd);
		}
		return 1;
		}

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