When the connection reinstatement is performed, the target driver
executes a complex scheme of complete()/wait_for_completion() that is not
really needed.
Considering that:
1) The callers of iscsit_connection_reinstatement_rcfr() and
iscsit_cause_connection_reinstatement() hold a reference
to the conn structure.
2) iscsit_close_connection() will sleep when calling
iscsit_check_conn_usage_count() until the conn structure's refcount
reaches zero.
we can optimize the driver the following way:
* The threads that must sleep until the connection is closed
will all wait for the "conn_wait_comp" completion,
iscsit_close_connection() will then call complete_all() to wake them up.
No need to have multiple completion structures.
* The conn_post_wait_comp completion is not necessary and can be removed
because iscsit_close_connection() sleeps until all the other threads
release the conn structure.
(see the iscsit_check_conn_usage_count() function)
V2: do not set connection_reinstatement to 1 in iscsit_close_connection(),
leave iscsit_cause_connection_reinstatement() deal with reentrancy.
Signed-off-by: Maurizio Lombardi <mlombard@xxxxxxxxxx>
---
drivers/target/iscsi/iscsi_target.c | 27 +++--------------------
drivers/target/iscsi/iscsi_target_erl0.c | 6 +----
drivers/target/iscsi/iscsi_target_login.c | 2 --
drivers/target/iscsi/iscsi_target_util.c | 3 ---
include/target/iscsi/iscsi_target_core.h | 4 ----
5 files changed, 4 insertions(+), 38 deletions(-)
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 2c54c5d8412d..d558c4c064cb 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -4226,31 +4226,10 @@ int iscsit_close_connection(
/*
* If connection reinstatement is being performed on this connection,
* up the connection reinstatement semaphore that is being blocked on
- * in iscsit_cause_connection_reinstatement().
+ * in iscsit_cause_connection_reinstatement() or
+ * in iscsit_connection_reinstatement_rcfr()
*/
- spin_lock_bh(&conn->state_lock);
- if (atomic_read(&conn->sleep_on_conn_wait_comp)) {
- spin_unlock_bh(&conn->state_lock);
- complete(&conn->conn_wait_comp);
- wait_for_completion(&conn->conn_post_wait_comp);
- spin_lock_bh(&conn->state_lock);
- }
-
- /*
- * If connection reinstatement is being performed on this connection
- * by receiving a REMOVECONNFORRECOVERY logout request, up the
- * connection wait rcfr semaphore that is being blocked on
- * an iscsit_connection_reinstatement_rcfr().
- */
- if (atomic_read(&conn->connection_wait_rcfr)) {
- spin_unlock_bh(&conn->state_lock);
- complete(&conn->conn_wait_rcfr_comp);
- wait_for_completion(&conn->conn_post_wait_comp);
- spin_lock_bh(&conn->state_lock);
- }
- atomic_set(&conn->connection_reinstatement, 1);
- spin_unlock_bh(&conn->state_lock);
-
+ complete_all(&conn->conn_wait_comp);
/*
* If any other processes are accessing this connection pointer we
* must wait until they have completed.
diff --git a/drivers/target/iscsi/iscsi_target_erl0.c b/drivers/target/iscsi/iscsi_target_erl0.c
index 102c9cbf59f3..584e0a0b517d 100644
--- a/drivers/target/iscsi/iscsi_target_erl0.c
+++ b/drivers/target/iscsi/iscsi_target_erl0.c
@@ -839,8 +839,7 @@ void iscsit_connection_reinstatement_rcfr(struct iscsi_conn *conn)
send_sig(SIGINT, conn->rx_thread, 1);
sleep:
- wait_for_completion(&conn->conn_wait_rcfr_comp);
- complete(&conn->conn_post_wait_comp);
+ wait_for_completion(&conn->conn_wait_comp);
}
void iscsit_cause_connection_reinstatement(struct iscsi_conn *conn, int sleep)
@@ -871,12 +870,9 @@ void iscsit_cause_connection_reinstatement(struct iscsi_conn *conn, int sleep)
spin_unlock_bh(&conn->state_lock);
return;
}
-
- atomic_set(&conn->sleep_on_conn_wait_comp, 1);
spin_unlock_bh(&conn->state_lock);
wait_for_completion(&conn->conn_wait_comp);
- complete(&conn->conn_post_wait_comp);
}
EXPORT_SYMBOL(iscsit_cause_connection_reinstatement);
diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index 1a9c50401bdb..982c23459272 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -1096,9 +1096,7 @@ static struct iscsi_conn *iscsit_alloc_conn(struct iscsi_np *np)
INIT_LIST_HEAD(&conn->conn_cmd_list);
INIT_LIST_HEAD(&conn->immed_queue_list);
INIT_LIST_HEAD(&conn->response_queue_list);
- init_completion(&conn->conn_post_wait_comp);
init_completion(&conn->conn_wait_comp);
- init_completion(&conn->conn_wait_rcfr_comp);
init_completion(&conn->conn_waiting_on_uc_comp);
init_completion(&conn->conn_logout_comp);
init_completion(&conn->rx_half_close_comp);
diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 6dd5810e2af1..d7b1f9110d49 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -824,9 +824,6 @@ struct iscsi_conn *iscsit_get_conn_from_cid_rcfr(struct iscsi_session *sess, u16
list_for_each_entry(conn, &sess->sess_conn_list, conn_list) {
if (conn->cid == cid) {
iscsit_inc_conn_usage_count(conn);
- spin_lock(&conn->state_lock);
- atomic_set(&conn->connection_wait_rcfr, 1);
- spin_unlock(&conn->state_lock);
spin_unlock_bh(&sess->conn_lock);
return conn;
}
diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h
index 1eccb2ac7d02..aeb8932507c2 100644
--- a/include/target/iscsi/iscsi_target_core.h
+++ b/include/target/iscsi/iscsi_target_core.h
@@ -542,12 +542,8 @@ struct iscsi_conn {
atomic_t connection_exit;
atomic_t connection_recovery;
atomic_t connection_reinstatement;
- atomic_t connection_wait_rcfr;
- atomic_t sleep_on_conn_wait_comp;
atomic_t transport_failed;
- struct completion conn_post_wait_comp;
struct completion conn_wait_comp;
- struct completion conn_wait_rcfr_comp;
struct completion conn_waiting_on_uc_comp;
struct completion conn_logout_comp;
struct completion tx_half_close_comp;
--
2.27.0
