[PATCH 3.10 84/85] iscsi/iser-target: Fix isert_conn->state hung shutdown issues

Greg Kroah-Hartman
2014-03-21T00:22:11Z

From: Nicholas Bellinger <nab@linux-iscsi.org>

commit defd884845297fd5690594bfe89656b01f16d87e upstream.

This patch addresses a couple of different hug shutdown issues
related to wait_event() + isert_conn->state. First, it changes
isert_conn->conn_wait + isert_conn->conn_wait_comp_err from
waitqueues to completions, and sets ISER_CONN_TERMINATING from
within isert_disconnect_work().

Second, it splits isert_free_conn() into isert_wait_conn() that
is called earlier in iscsit_close_connection() to ensure that
all outstanding commands have completed before continuing.

Finally, it breaks isert_cq_comp_err() into seperate TX / RX
related code, and adds logic in isert_cq_rx_comp_err() to wait
for outstanding commands to complete before setting ISER_CONN_DOWN
and calling complete(&isert_conn->conn_wait_comp_err).

Acked-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/ulp/isert/ib_isert.c | 104 ++++++++++++++------------------
drivers/infiniband/ulp/isert/ib_isert.h | 4 -
drivers/target/iscsi/iscsi_target.c | 4 +
include/target/iscsi/iscsi_transport.h | 1
4 files changed, 53 insertions(+), 60 deletions(-)

--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -392,8 +392,8 @@ isert_connect_request(struct rdma_cm_id
isert_conn->state = ISER_CONN_INIT;
INIT_LIST_HEAD(&isert_conn->conn_accept_node);
init_completion(&isert_conn->conn_login_comp);
- init_waitqueue_head(&isert_conn->conn_wait);
- init_waitqueue_head(&isert_conn->conn_wait_comp_err);
+ init_completion(&isert_conn->conn_wait);
+ init_completion(&isert_conn->conn_wait_comp_err);
kref_init(&isert_conn->conn_kref);
kref_get(&isert_conn->conn_kref);
mutex_init(&isert_conn->conn_mutex);
@@ -550,11 +550,11 @@ isert_disconnect_work(struct work_struct

pr_debug("isert_disconnect_work(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
mutex_lock(&isert_conn->conn_mutex);
- isert_conn->state = ISER_CONN_DOWN;
+ if (isert_conn->state == ISER_CONN_UP)
+ isert_conn->state = ISER_CONN_TERMINATING;

if (isert_conn->post_recv_buf_count == 0 &&
atomic_read(&isert_conn->post_send_buf_count) == 0) {
- pr_debug("Calling wake_up(&isert_conn->conn_wait);\n");
mutex_unlock(&isert_conn->conn_mutex);
goto wake_up;
}
@@ -574,7 +574,7 @@ isert_disconnect_work(struct work_struct
mutex_unlock(&isert_conn->conn_mutex);

wake_up:
- wake_up(&isert_conn->conn_wait);
+ complete(&isert_conn->conn_wait);
isert_put_conn(isert_conn);
}

@@ -1348,7 +1348,7 @@ isert_do_control_comp(struct work_struct
pr_debug("Calling iscsit_logout_post_handler >>>>>>>>>>>>>>\n");
/*
* Call atomic_dec(&isert_conn->post_send_buf_count)
- * from isert_free_conn()
+ * from isert_wait_conn()
*/
isert_conn->logout_posted = true;
iscsit_logout_post_handler(cmd, cmd->conn);
@@ -1426,31 +1426,38 @@ isert_send_completion(struct iser_tx_des
}

static void
-isert_cq_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn)
+isert_cq_tx_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn)
{
struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
+ struct isert_cmd *isert_cmd = tx_desc->isert_cmd;

- if (tx_desc) {
- struct isert_cmd *isert_cmd = tx_desc->isert_cmd;
+ if (!isert_cmd)
+ isert_unmap_tx_desc(tx_desc, ib_dev);
+ else
+ isert_completion_put(tx_desc, isert_cmd, ib_dev);
+}

- if (!isert_cmd)
- isert_unmap_tx_desc(tx_desc, ib_dev);
- else
- isert_completion_put(tx_desc, isert_cmd, ib_dev);
+static void
+isert_cq_rx_comp_err(struct isert_conn *isert_conn)
+{
+ struct iscsi_conn *conn = isert_conn->conn;
+
+ if (isert_conn->post_recv_buf_count)
+ return;
+
+ if (conn->sess) {
+ target_sess_cmd_list_set_waiting(conn->sess->se_sess);
+ target_wait_for_sess_cmds(conn->sess->se_sess);
}

- if (isert_conn->post_recv_buf_count == 0 &&
- atomic_read(&isert_conn->post_send_buf_count) == 0) {
- pr_debug("isert_cq_comp_err >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
- pr_debug("Calling wake_up from isert_cq_comp_err\n");
+ while (atomic_read(&isert_conn->post_send_buf_count))
+ msleep(3000);

- mutex_lock(&isert_conn->conn_mutex);
- if (isert_conn->state != ISER_CONN_DOWN)
- isert_conn->state = ISER_CONN_TERMINATING;
- mutex_unlock(&isert_conn->conn_mutex);
+ mutex_lock(&isert_conn->conn_mutex);
+ isert_conn->state = ISER_CONN_DOWN;
+ mutex_unlock(&isert_conn->conn_mutex);

- wake_up(&isert_conn->conn_wait_comp_err);
- }
+ complete(&isert_conn->conn_wait_comp_err);
}

static void
@@ -1475,7 +1482,7 @@ isert_cq_tx_work(struct work_struct *wor
pr_debug("TX wc.status != IB_WC_SUCCESS >>>>>>>>>>>>>>\n");
pr_debug("TX wc.status: 0x%08x\n", wc.status);
atomic_dec(&isert_conn->post_send_buf_count);
- isert_cq_comp_err(tx_desc, isert_conn);
+ isert_cq_tx_comp_err(tx_desc, isert_conn);
}
}

@@ -1517,7 +1524,7 @@ isert_cq_rx_work(struct work_struct *wor
pr_debug("RX wc.status: 0x%08x\n", wc.status);

isert_conn->post_recv_buf_count--;
- isert_cq_comp_err(NULL, isert_conn);
+ isert_cq_rx_comp_err(isert_conn);
}
}

@@ -2218,22 +2225,11 @@ isert_free_np(struct iscsi_np *np)
kfree(isert_np);
}

-static int isert_check_state(struct isert_conn *isert_conn, int state)
-{
- int ret;
-
- mutex_lock(&isert_conn->conn_mutex);
- ret = (isert_conn->state == state);
- mutex_unlock(&isert_conn->conn_mutex);
-
- return ret;
-}
-
-static void isert_free_conn(struct iscsi_conn *conn)
+static void isert_wait_conn(struct iscsi_conn *conn)
{
struct isert_conn *isert_conn = conn->context;

- pr_debug("isert_free_conn: Starting \n");
+ pr_debug("isert_wait_conn: Starting \n");
/*
* Decrement post_send_buf_count for special case when called
* from isert_do_control_comp() -> iscsit_logout_post_handler()
@@ -2243,38 +2239,29 @@ static void isert_free_conn(struct iscsi
atomic_dec(&isert_conn->post_send_buf_count);

if (isert_conn->conn_cm_id && isert_conn->state != ISER_CONN_DOWN) {
- pr_debug("Calling rdma_disconnect from isert_free_conn\n");
+ pr_debug("Calling rdma_disconnect from isert_wait_conn\n");
rdma_disconnect(isert_conn->conn_cm_id);
}
/*
* Only wait for conn_wait_comp_err if the isert_conn made it
* into full feature phase..
*/
- if (isert_conn->state == ISER_CONN_UP) {
- pr_debug("isert_free_conn: Before wait_event comp_err %d\n",
- isert_conn->state);
- mutex_unlock(&isert_conn->conn_mutex);
-
- wait_event(isert_conn->conn_wait_comp_err,
- (isert_check_state(isert_conn, ISER_CONN_TERMINATING)));
-
- wait_event(isert_conn->conn_wait,
- (isert_check_state(isert_conn, ISER_CONN_DOWN)));
-
- isert_put_conn(isert_conn);
- return;
- }
if (isert_conn->state == ISER_CONN_INIT) {
mutex_unlock(&isert_conn->conn_mutex);
- isert_put_conn(isert_conn);
return;
}
- pr_debug("isert_free_conn: wait_event conn_wait %d\n",
- isert_conn->state);
+ if (isert_conn->state == ISER_CONN_UP)
+ isert_conn->state = ISER_CONN_TERMINATING;
mutex_unlock(&isert_conn->conn_mutex);

- wait_event(isert_conn->conn_wait,
- (isert_check_state(isert_conn, ISER_CONN_DOWN)));
+ wait_for_completion(&isert_conn->conn_wait_comp_err);
+
+ wait_for_completion(&isert_conn->conn_wait);
+}
+
+static void isert_free_conn(struct iscsi_conn *conn)
+{
+ struct isert_conn *isert_conn = conn->context;

isert_put_conn(isert_conn);
}
@@ -2286,6 +2273,7 @@ static struct iscsit_transport iser_targ
.iscsit_setup_np = isert_setup_np,
.iscsit_accept_np = isert_accept_np,
.iscsit_free_np = isert_free_np,
+ .iscsit_wait_conn = isert_wait_conn,
.iscsit_free_conn = isert_free_conn,
.iscsit_alloc_cmd = isert_alloc_cmd,
.iscsit_get_login_rx = isert_get_login_rx,
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -103,8 +103,8 @@ struct isert_conn {
struct isert_device *conn_device;
struct work_struct conn_logout_work;
struct mutex conn_mutex;
- wait_queue_head_t conn_wait;
- wait_queue_head_t conn_wait_comp_err;
+ struct completion conn_wait;
+ struct completion conn_wait_comp_err;
struct kref conn_kref;
};

--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -4144,6 +4144,10 @@ int iscsit_close_connection(
iscsit_stop_timers_for_cmds(conn);
iscsit_stop_nopin_response_timer(conn);
iscsit_stop_nopin_timer(conn);
+
+ if (conn->conn_transport->iscsit_wait_conn)
+ conn->conn_transport->iscsit_wait_conn(conn);
+
iscsit_free_queue_reqs_for_conn(conn);

/*
--- a/include/target/iscsi/iscsi_transport.h
+++ b/include/target/iscsi/iscsi_transport.h
@@ -11,6 +11,7 @@ struct iscsit_transport {
int (*iscsit_setup_np)(struct iscsi_np *, struct __kernel_sockaddr_storage *);
int (*iscsit_accept_np)(struct iscsi_np *, struct iscsi_conn *);
void (*iscsit_free_np)(struct iscsi_np *);
+ void (*iscsit_wait_conn)(struct iscsi_conn *);
void (*iscsit_free_conn)(struct iscsi_conn *);
struct iscsi_cmd *(*iscsit_alloc_cmd)(struct iscsi_conn *, gfp_t);
int (*iscsit_get_login_rx)(struct iscsi_conn *, struct iscsi_login *);