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iscsi/iser-target: Fix isert_conn->state hung shutdown issues
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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 <[email protected]>
Cc: Or Gerlitz <[email protected]>
Cc: <[email protected]> #3.10+
Signed-off-by: Nicholas Bellinger <[email protected]>
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Nicholas Bellinger committed Mar 5, 2014
1 parent 5159d76 commit defd884
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Showing 4 changed files with 55 additions and 60 deletions.
106 changes: 48 additions & 58 deletions drivers/infiniband/ulp/isert/ib_isert.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -492,8 +492,8 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
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);
Expand Down Expand Up @@ -688,11 +688,11 @@ isert_disconnect_work(struct work_struct *work)

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;
}
Expand All @@ -712,7 +712,7 @@ isert_disconnect_work(struct work_struct *work)
mutex_unlock(&isert_conn->conn_mutex);

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

Expand Down Expand Up @@ -1589,7 +1589,7 @@ isert_do_control_comp(struct work_struct *work)
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);
Expand Down Expand Up @@ -1691,31 +1691,39 @@ isert_send_completion(struct iser_tx_desc *tx_desc,
}

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 (!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 ib_device *ib_dev = isert_conn->conn_cm_id->device;
struct iscsi_conn *conn = isert_conn->conn;

if (tx_desc) {
struct isert_cmd *isert_cmd = tx_desc->isert_cmd;
if (isert_conn->post_recv_buf_count)
return;

if (!isert_cmd)
isert_unmap_tx_desc(tx_desc, ib_dev);
else
isert_completion_put(tx_desc, isert_cmd, ib_dev);
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
Expand All @@ -1740,8 +1748,9 @@ isert_cq_tx_work(struct work_struct *work)
pr_debug("TX wc.status != IB_WC_SUCCESS >>>>>>>>>>>>>>\n");
pr_debug("TX wc.status: 0x%08x\n", wc.status);
pr_debug("TX wc.vendor_err: 0x%08x\n", wc.vendor_err);

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);
}
}

Expand Down Expand Up @@ -1784,7 +1793,7 @@ isert_cq_rx_work(struct work_struct *work)
wc.vendor_err);
}
isert_conn->post_recv_buf_count--;
isert_cq_comp_err(NULL, isert_conn);
isert_cq_rx_comp_err(isert_conn);
}
}

Expand Down Expand Up @@ -2702,22 +2711,11 @@ 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()
Expand All @@ -2727,38 +2725,29 @@ static void isert_free_conn(struct iscsi_conn *conn)
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);
}
Expand All @@ -2771,6 +2760,7 @@ static struct iscsit_transport iser_target_transport = {
.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_get_login_rx = isert_get_login_rx,
.iscsit_put_login_tx = isert_put_login_tx,
Expand Down
4 changes: 2 additions & 2 deletions drivers/infiniband/ulp/isert/ib_isert.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -116,8 +116,8 @@ 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;
struct list_head conn_fr_pool;
int conn_fr_pool_size;
Expand Down
4 changes: 4 additions & 0 deletions drivers/target/iscsi/iscsi_target.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4196,6 +4196,10 @@ 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);

/*
Expand Down
1 change: 1 addition & 0 deletions include/target/iscsi/iscsi_transport.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@ 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 *);
int (*iscsit_get_login_rx)(struct iscsi_conn *, struct iscsi_login *);
int (*iscsit_put_login_tx)(struct iscsi_conn *, struct iscsi_login *, u32);
Expand Down

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