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iser-target: Remove an atomic operation from the IO path

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In order to know that we consumed all the connection completions
we maintain atomic post_send_buf_count for each IO post send. But
we can know that if we post a "beacon" (zero length RECV work request)
after we move the QP into error state and the target does not serve
any new IO. When we consume it, we know we finished all the connection
completion and we can go ahead and destroy stuff.

In error completion handler we now just need to check for ISERT_BEACON_WRID
to arrive and then wait for session commands to cleanup and complete
conn_wait_comp_err.

We reserve another CQ and QP entries to fit the zero length post recv.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Sagi Grimberg 2014-12-02 16:57:43 +02:00 committed by Nicholas Bellinger
parent 377d8f5c3e
commit bdf20e7254
2 changed files with 40 additions and 63 deletions
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100
drivers/infiniband/ulp/isert/ib_isert.c
View File

@ -35,7 +35,8 @@
#define ISERT_MAX_CONN 8
#define ISER_MAX_RX_CQ_LEN (ISERT_QP_MAX_RECV_DTOS * ISERT_MAX_CONN)
#define ISER_MAX_TX_CQ_LEN (ISERT_QP_MAX_REQ_DTOS * ISERT_MAX_CONN)
#define ISER_MAX_CQ_LEN (ISER_MAX_RX_CQ_LEN + ISER_MAX_TX_CQ_LEN)
#define ISER_MAX_CQ_LEN (ISER_MAX_RX_CQ_LEN + ISER_MAX_TX_CQ_LEN + \
ISERT_MAX_CONN)
static DEFINE_MUTEX(device_list_mutex);
static LIST_HEAD(device_list);
@ -127,7 +128,7 @@ isert_conn_setup_qp(struct isert_conn *isert_conn, struct rdma_cm_id *cma_id)
attr.send_cq = comp->cq;
attr.recv_cq = comp->cq;
attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS;
attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS;
attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS + 1;
/*
* FIXME: Use devattr.max_sge - 2 for max_send_sge as
* work-around for RDMA_READs with ConnectX-2.
@ -593,7 +594,6 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
init_completion(&isert_conn->conn_login_comp);
init_completion(&isert_conn->login_req_comp);
init_completion(&isert_conn->conn_wait);
init_completion(&isert_conn->conn_wait_comp_err);
kref_init(&isert_conn->conn_kref);
mutex_init(&isert_conn->conn_mutex);
spin_lock_init(&isert_conn->conn_lock);
@ -811,12 +811,6 @@ isert_conn_terminate(struct isert_conn *isert_conn)
case ISER_CONN_TERMINATING:
break;
case ISER_CONN_UP:
/*
* No flush completions will occur as we didn't
* get to ISER_CONN_FULL_FEATURE yet, complete
* to allow teardown progress.
*/
complete(&isert_conn->conn_wait_comp_err);
case ISER_CONN_FULL_FEATURE: /* FALLTHRU */
pr_info("Terminating conn %p state %d\n",
isert_conn, isert_conn->state);
@ -975,13 +969,9 @@ isert_post_send(struct isert_conn *isert_conn, struct iser_tx_desc *tx_desc)
send_wr.opcode = IB_WR_SEND;
send_wr.send_flags = IB_SEND_SIGNALED;
atomic_inc(&isert_conn->post_send_buf_count);
ret = ib_post_send(isert_conn->conn_qp, &send_wr, &send_wr_failed);
if (ret) {
if (ret)
pr_err("ib_post_send() failed, ret: %d\n", ret);
atomic_dec(&isert_conn->post_send_buf_count);
}
return ret;
}
@ -1877,7 +1867,6 @@ isert_do_control_comp(struct work_struct *work)
case ISTATE_SEND_TASKMGTRSP:
pr_debug("Calling iscsit_tmr_post_handler >>>>>>>>>>>>>>>>>\n");
atomic_dec(&isert_conn->post_send_buf_count);
iscsit_tmr_post_handler(cmd, cmd->conn);
cmd->i_state = ISTATE_SENT_STATUS;
@ -1885,7 +1874,6 @@ isert_do_control_comp(struct work_struct *work)
break;
case ISTATE_SEND_REJECT:
pr_debug("Got isert_do_control_comp ISTATE_SEND_REJECT: >>>\n");
atomic_dec(&isert_conn->post_send_buf_count);
cmd->i_state = ISTATE_SENT_STATUS;
isert_completion_put(&isert_cmd->tx_desc, isert_cmd, ib_dev, false);
@ -1893,11 +1881,9 @@ isert_do_control_comp(struct work_struct *work)
case ISTATE_SEND_LOGOUTRSP:
pr_debug("Calling iscsit_logout_post_handler >>>>>>>>>>>>>>\n");
atomic_dec(&isert_conn->post_send_buf_count);
iscsit_logout_post_handler(cmd, cmd->conn);
break;
case ISTATE_SEND_TEXTRSP:
atomic_dec(&isert_conn->post_send_buf_count);
cmd->i_state = ISTATE_SENT_STATUS;
isert_completion_put(&isert_cmd->tx_desc, isert_cmd, ib_dev, false);
break;
@ -1915,7 +1901,6 @@ isert_response_completion(struct iser_tx_desc *tx_desc,
struct ib_device *ib_dev)
{
struct iscsi_cmd *cmd = isert_cmd->iscsi_cmd;
struct isert_rdma_wr *wr = &isert_cmd->rdma_wr;
if (cmd->i_state == ISTATE_SEND_TASKMGTRSP ||
cmd->i_state == ISTATE_SEND_LOGOUTRSP ||
@ -1928,18 +1913,6 @@ isert_response_completion(struct iser_tx_desc *tx_desc,
return;
}
/**
* If send_wr_num is 0 this means that we got
* RDMA completion and we cleared it and we should
* simply decrement the response post. else the
* response is incorporated in send_wr_num, just
* sub it.
**/
if (wr->send_wr_num)
atomic_sub(wr->send_wr_num, &isert_conn->post_send_buf_count);
else
atomic_dec(&isert_conn->post_send_buf_count);
cmd->i_state = ISTATE_SENT_STATUS;
isert_completion_put(tx_desc, isert_cmd, ib_dev, false);
}
@ -1953,7 +1926,6 @@ isert_send_completion(struct iser_tx_desc *tx_desc,
struct isert_rdma_wr *wr;
if (!isert_cmd) {
atomic_dec(&isert_conn->post_send_buf_count);
isert_unmap_tx_desc(tx_desc, ib_dev);
return;
}
@ -1971,13 +1943,11 @@ isert_send_completion(struct iser_tx_desc *tx_desc,
break;
case ISER_IB_RDMA_WRITE:
pr_debug("isert_send_completion: Got ISER_IB_RDMA_WRITE\n");
atomic_sub(wr->send_wr_num, &isert_conn->post_send_buf_count);
isert_completion_rdma_write(tx_desc, isert_cmd);
break;
case ISER_IB_RDMA_READ:
pr_debug("isert_send_completion: Got ISER_IB_RDMA_READ:\n");
atomic_sub(wr->send_wr_num, &isert_conn->post_send_buf_count);
isert_completion_rdma_read(tx_desc, isert_cmd);
break;
default:
@ -2013,6 +1983,18 @@ is_isert_tx_desc(struct isert_conn *isert_conn, void *wr_id)
static void
isert_cq_comp_err(struct isert_conn *isert_conn, struct ib_wc *wc)
{
if (wc->wr_id == ISER_BEACON_WRID) {
struct iscsi_conn *conn = isert_conn->conn;
if (conn->sess) {
target_sess_cmd_list_set_waiting(conn->sess->se_sess);
target_wait_for_sess_cmds(conn->sess->se_sess);
}
pr_info("conn %p completing conn_wait_comp_err\n",
isert_conn);
complete(&isert_conn->conn_wait_comp_err);
} else
if (is_isert_tx_desc(isert_conn, (void *)wc->wr_id)) {
struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
struct isert_cmd *isert_cmd;
@ -2024,22 +2006,10 @@ isert_cq_comp_err(struct isert_conn *isert_conn, struct ib_wc *wc)
isert_unmap_tx_desc(desc, ib_dev);
else
isert_completion_put(desc, isert_cmd, ib_dev, true);
atomic_dec(&isert_conn->post_send_buf_count);
} else {
isert_conn->post_recv_buf_count--;
}
if (isert_conn->post_recv_buf_count == 0 &&
atomic_read(&isert_conn->post_send_buf_count) == 0) {
struct iscsi_conn *conn = isert_conn->conn;
if (conn->sess) {
target_sess_cmd_list_set_waiting(conn->sess->se_sess);
target_wait_for_sess_cmds(conn->sess->se_sess);
}
iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
complete(&isert_conn->conn_wait_comp_err);
if (!isert_conn->post_recv_buf_count)
iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
}
}
@ -2098,13 +2068,10 @@ isert_post_response(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd)
struct ib_send_wr *wr_failed;
int ret;
atomic_inc(&isert_conn->post_send_buf_count);
ret = ib_post_send(isert_conn->conn_qp, &isert_cmd->tx_desc.send_wr,
&wr_failed);
if (ret) {
pr_err("ib_post_send failed with %d\n", ret);
atomic_dec(&isert_conn->post_send_buf_count);
return ret;
}
return ret;
@ -2889,13 +2856,9 @@ isert_put_datain(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
wr->send_wr_num += 1;
}
atomic_add(wr->send_wr_num, &isert_conn->post_send_buf_count);
rc = ib_post_send(isert_conn->conn_qp, wr->send_wr, &wr_failed);
if (rc) {
if (rc)
pr_warn("ib_post_send() failed for IB_WR_RDMA_WRITE\n");
atomic_sub(wr->send_wr_num, &isert_conn->post_send_buf_count);
}
if (!isert_prot_cmd(isert_conn, se_cmd))
pr_debug("Cmd: %p posted RDMA_WRITE + Response for iSER Data "
@ -2927,13 +2890,10 @@ isert_get_dataout(struct iscsi_conn *conn, struct iscsi_cmd *cmd, bool recovery)
return rc;
}
atomic_add(wr->send_wr_num, &isert_conn->post_send_buf_count);
rc = ib_post_send(isert_conn->conn_qp, wr->send_wr, &wr_failed);
if (rc) {
if (rc)
pr_warn("ib_post_send() failed for IB_WR_RDMA_READ\n");
atomic_sub(wr->send_wr_num, &isert_conn->post_send_buf_count);
}
pr_debug("Cmd: %p posted RDMA_READ memory for ISER Data WRITE\n",
isert_cmd);
@ -3274,6 +3234,22 @@ static void isert_release_work(struct work_struct *work)
isert_put_conn(isert_conn);
}
static void
isert_wait4flush(struct isert_conn *isert_conn)
{
struct ib_recv_wr *bad_wr;
init_completion(&isert_conn->conn_wait_comp_err);
isert_conn->beacon.wr_id = ISER_BEACON_WRID;
/* post an indication that all flush errors were consumed */
if (ib_post_recv(isert_conn->conn_qp, &isert_conn->beacon, &bad_wr)) {
pr_err("conn %p failed to post beacon", isert_conn);
return;
}
wait_for_completion(&isert_conn->conn_wait_comp_err);
}
static void isert_wait_conn(struct iscsi_conn *conn)
{
struct isert_conn *isert_conn = conn->context;
@ -3292,7 +3268,7 @@ static void isert_wait_conn(struct iscsi_conn *conn)
isert_conn_terminate(isert_conn);
mutex_unlock(&isert_conn->conn_mutex);
wait_for_completion(&isert_conn->conn_wait_comp_err);
isert_wait4flush(isert_conn);
INIT_WORK(&isert_conn->release_work, isert_release_work);
queue_work(isert_release_wq, &isert_conn->release_work);

3
drivers/infiniband/ulp/isert/ib_isert.h
View File

@ -7,6 +7,7 @@
#define ISERT_RDMA_LISTEN_BACKLOG 10
#define ISCSI_ISER_SG_TABLESIZE 256
#define ISER_FASTREG_LI_WRID 0xffffffffffffffffULL
#define ISER_BEACON_WRID 0xfffffffffffffffeULL
enum isert_desc_type {
ISCSI_TX_CONTROL,
@ -122,7 +123,6 @@ struct isert_device;
struct isert_conn {
enum iser_conn_state state;
int post_recv_buf_count;
atomic_t post_send_buf_count;
u32 responder_resources;
u32 initiator_depth;
bool pi_support;
@ -155,6 +155,7 @@ struct isert_conn {
/* lock to protect fastreg pool */
spinlock_t conn_lock;
struct work_struct release_work;
struct ib_recv_wr beacon;
};
#define ISERT_MAX_CQ 64