nvmet-tcp: implement C2HData SUCCESS optimization

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>
This commit is contained in:
Sagi Grimberg 2019-03-08 15:41:21 -08:00 committed by Christoph Hellwig
parent 6b80f1d2cc
commit 7058329538

View file

@ -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 =
@ -542,8 +543,19 @@ static int nvmet_try_send_data(struct nvmet_tcp_cmd *cmd)
cmd->state = NVMET_TCP_SEND_DDGST;
cmd->offset = 0;
} else {
nvmet_setup_response_pdu(cmd);
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;
nvmet_setup_response_pdu(cmd);
if (queue->nvme_sq.sqhd_disabled) {
cmd->queue->snd_cmd = NULL;
nvmet_tcp_put_cmd(cmd);
} else {
nvmet_setup_response_pdu(cmd);
}
return 1;
}