IB/iser: Use beacon to indicate all completions were consumed

Avoid post_send counting (atomic) in the IO path just to keep track of
how many completions we need to consume.  Use a beacon post to indicate
that all prior posts completed.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Sagi Grimberg 2014-10-01 14:02:10 +03:00 committed by Roland Dreier
parent 6aabfa76f5
commit ff3dd52d26
3 changed files with 23 additions and 22 deletions

View File

@ -150,6 +150,7 @@
#define ISER_RSV 0x04
#define ISER_FASTREG_LI_WRID 0xffffffffffffffffULL
#define ISER_BEACON_WRID 0xfffffffffffffffeULL
struct iser_hdr {
u8 flags;
@ -335,11 +336,11 @@ struct fast_reg_descriptor {
* @cma_id: rdma_cm connection maneger handle
* @qp: Connection Queue-pair
* @post_recv_buf_count: post receive counter
* @post_send_buf_count: post send counter
* @rx_wr: receive work request for batch posts
* @device: reference to iser device
* @comp: iser completion context
* @pi_support: Indicate device T10-PI support
* @beacon: beacon send wr to signal all flush errors were drained
* @flush_comp: completes when all connection completions consumed
* @lock: protects fmr/fastreg pool
* @union.fmr:
@ -355,11 +356,11 @@ struct ib_conn {
struct rdma_cm_id *cma_id;
struct ib_qp *qp;
int post_recv_buf_count;
atomic_t post_send_buf_count;
struct ib_recv_wr rx_wr[ISER_MIN_POSTED_RX];
struct iser_device *device;
struct iser_comp *comp;
bool pi_support;
struct ib_send_wr beacon;
struct completion flush_comp;
spinlock_t lock;
union {

View File

@ -350,12 +350,10 @@ static int iser_post_rx_bufs(struct iscsi_conn *conn, struct iscsi_hdr *req)
return 0;
/*
* Check that there is one posted recv buffer (for the last login
* response) and no posted send buffers left - they must have been
* consumed during previous login phases.
* Check that there is one posted recv buffer
* (for the last login response).
*/
WARN_ON(ib_conn->post_recv_buf_count != 1);
WARN_ON(atomic_read(&ib_conn->post_send_buf_count) != 0);
if (session->discovery_sess) {
iser_info("Discovery session, re-using login RX buffer\n");
@ -634,8 +632,6 @@ void iser_snd_completion(struct iser_tx_desc *tx_desc,
tx_desc = NULL;
}
atomic_dec(&ib_conn->post_send_buf_count);
if (tx_desc && tx_desc->type == ISCSI_TX_CONTROL) {
/* this arithmetic is legal by libiscsi dd_data allocation */
task = (void *) ((long)(void *)tx_desc -

View File

@ -41,7 +41,8 @@
#define ISCSI_ISER_MAX_CONN 8
#define ISER_MAX_RX_LEN (ISER_QP_MAX_RECV_DTOS * ISCSI_ISER_MAX_CONN)
#define ISER_MAX_TX_LEN (ISER_QP_MAX_REQ_DTOS * ISCSI_ISER_MAX_CONN)
#define ISER_MAX_CQ_LEN (ISER_MAX_RX_LEN + ISER_MAX_TX_LEN)
#define ISER_MAX_CQ_LEN (ISER_MAX_RX_LEN + ISER_MAX_TX_LEN + \
ISCSI_ISER_MAX_CONN)
static int iser_cq_poll_limit = 512;
@ -457,10 +458,10 @@ static int iser_create_ib_conn_res(struct ib_conn *ib_conn)
init_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
init_attr.qp_type = IB_QPT_RC;
if (ib_conn->pi_support) {
init_attr.cap.max_send_wr = ISER_QP_SIG_MAX_REQ_DTOS;
init_attr.cap.max_send_wr = ISER_QP_SIG_MAX_REQ_DTOS + 1;
init_attr.create_flags |= IB_QP_CREATE_SIGNATURE_EN;
} else {
init_attr.cap.max_send_wr = ISER_QP_MAX_REQ_DTOS;
init_attr.cap.max_send_wr = ISER_QP_MAX_REQ_DTOS + 1;
}
ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);
@ -634,6 +635,7 @@ void iser_conn_release(struct iser_conn *iser_conn)
int iser_conn_terminate(struct iser_conn *iser_conn)
{
struct ib_conn *ib_conn = &iser_conn->ib_conn;
struct ib_send_wr *bad_wr;
int err = 0;
/* terminate the iser conn only if the conn state is UP */
@ -658,6 +660,11 @@ int iser_conn_terminate(struct iser_conn *iser_conn)
iser_err("Failed to disconnect, conn: 0x%p err %d\n",
iser_conn, err);
/* post an indication that all flush errors were consumed */
err = ib_post_send(ib_conn->qp, &ib_conn->beacon, &bad_wr);
if (err)
iser_err("conn %p failed to post beacon", ib_conn);
wait_for_completion(&ib_conn->flush_comp);
}
@ -867,7 +874,6 @@ void iser_conn_init(struct iser_conn *iser_conn)
{
iser_conn->state = ISER_CONN_INIT;
iser_conn->ib_conn.post_recv_buf_count = 0;
atomic_set(&iser_conn->ib_conn.post_send_buf_count, 0);
init_completion(&iser_conn->ib_conn.flush_comp);
init_completion(&iser_conn->stop_completion);
init_completion(&iser_conn->ib_completion);
@ -900,6 +906,9 @@ int iser_connect(struct iser_conn *iser_conn,
iser_conn->state = ISER_CONN_PENDING;
ib_conn->beacon.wr_id = ISER_BEACON_WRID;
ib_conn->beacon.opcode = IB_WR_SEND;
ib_conn->cma_id = rdma_create_id(iser_cma_handler,
(void *)iser_conn,
RDMA_PS_TCP, IB_QPT_RC);
@ -1106,13 +1115,10 @@ int iser_post_send(struct ib_conn *ib_conn, struct iser_tx_desc *tx_desc)
send_wr.opcode = IB_WR_SEND;
send_wr.send_flags = IB_SEND_SIGNALED;
atomic_inc(&ib_conn->post_send_buf_count);
ib_ret = ib_post_send(ib_conn->qp, &send_wr, &send_wr_failed);
if (ib_ret) {
if (ib_ret)
iser_err("ib_post_send failed, ret:%d\n", ib_ret);
atomic_dec(&ib_conn->post_send_buf_count);
}
return ib_ret;
}
@ -1164,7 +1170,6 @@ iser_handle_comp_error(struct ib_conn *ib_conn,
if (is_iser_tx_desc(iser_conn, (void *)wc->wr_id)) {
struct iser_tx_desc *desc = (struct iser_tx_desc *)wc->wr_id;
atomic_dec(&ib_conn->post_send_buf_count);
if (desc->type == ISCSI_TX_DATAOUT)
kmem_cache_free(ig.desc_cache, desc);
} else {
@ -1196,7 +1201,6 @@ static void iser_handle_wc(struct ib_wc *wc)
if (wc->opcode == IB_WC_SEND) {
tx_desc = (struct iser_tx_desc *)wc->wr_id;
iser_snd_completion(tx_desc, ib_conn);
atomic_dec(&ib_conn->post_send_buf_count);
} else {
iser_err("Unknown wc opcode %d\n", wc->opcode);
}
@ -1207,12 +1211,12 @@ static void iser_handle_wc(struct ib_wc *wc)
else
iser_dbg("flush error: wr id %llx\n", wc->wr_id);
if (wc->wr_id != ISER_FASTREG_LI_WRID)
if (wc->wr_id != ISER_FASTREG_LI_WRID &&
wc->wr_id != ISER_BEACON_WRID)
iser_handle_comp_error(ib_conn, wc);
/* complete in case all flush errors were consumed */
if (ib_conn->post_recv_buf_count == 0 &&
atomic_read(&ib_conn->post_send_buf_count) == 0)
if (wc->wr_id == ISER_BEACON_WRID)
complete(&ib_conn->flush_comp);
}
}