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iser-target: Fix session reset bug with RDMA_CM_EVENT_DISCONNECTED

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This patch addresses a bug where RDMA_CM_EVENT_DISCONNECTED may occur
before the connection shutdown has been completed by rx/tx threads,
that causes isert_free_conn() to wait indefinately on ->conn_wait.

This patch allows isert_disconnect_work code to invoke rdma_disconnect
when isert_disconnect_work() process context is started by client
session reset before isert_free_conn() code has been reached.

It also adds isert_conn->conn_mutex protection for ->state within
isert_disconnect_work(), isert_cq_comp_err() and isert_free_conn()
code, along with isert_check_state() for wait_event usage.

(v2: Add explicit iscsit_cause_connection_reinstatement call
     during isert_disconnect_work() to force conn reset)

Cc: [email protected]  # 3.10+
Cc: Or Gerlitz <[email protected]>
Signed-off-by: Nicholas Bellinger <[email protected]>
This commit is contained in:
Nicholas Bellinger 2013-07-03 03:05:37 -07:00
commit b2cb96494d
4 changed files with 66 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

74
drivers/infiniband/ulp/isert/ib_isert.c
View file

@ -388,6 +388,7 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
init_waitqueue_head(&isert_conn->conn_wait_comp_err);
kref_init(&isert_conn->conn_kref);
kref_get(&isert_conn->conn_kref);
mutex_init(&isert_conn->conn_mutex);
cma_id->context = isert_conn;
isert_conn->conn_cm_id = cma_id;
@ -540,15 +541,32 @@ isert_disconnect_work(struct work_struct *work)
struct isert_conn, conn_logout_work);
pr_debug("isert_disconnect_work(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
mutex_lock(&isert_conn->conn_mutex);
isert_conn->state = ISER_CONN_DOWN;
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");
wake_up(&isert_conn->conn_wait);
mutex_unlock(&isert_conn->conn_mutex);
goto wake_up;
}
if (!isert_conn->conn_cm_id) {
mutex_unlock(&isert_conn->conn_mutex);
isert_put_conn(isert_conn);
return;
}
if (!isert_conn->logout_posted) {
pr_debug("Calling rdma_disconnect for !logout_posted from"
" isert_disconnect_work\n");
rdma_disconnect(isert_conn->conn_cm_id);
mutex_unlock(&isert_conn->conn_mutex);
iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
goto wake_up;
}
mutex_unlock(&isert_conn->conn_mutex);
wake_up:
wake_up(&isert_conn->conn_wait);
isert_put_conn(isert_conn);
}
@ -1439,7 +1457,11 @@ isert_cq_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn)
pr_debug("isert_cq_comp_err >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
pr_debug("Calling wake_up from isert_cq_comp_err\n");
isert_conn->state = ISER_CONN_TERMINATING;
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);
wake_up(&isert_conn->conn_wait_comp_err);
}
}
@ -2209,6 +2231,17 @@ 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)
{
struct isert_conn *isert_conn = conn->context;
@ -2218,26 +2251,43 @@ static void isert_free_conn(struct iscsi_conn *conn)
* Decrement post_send_buf_count for special case when called
* from isert_do_control_comp() -> iscsit_logout_post_handler()
*/
mutex_lock(&isert_conn->conn_mutex);
if (isert_conn->logout_posted)
atomic_dec(&isert_conn->post_send_buf_count);
if (isert_conn->conn_cm_id)
if (isert_conn->conn_cm_id && isert_conn->state != ISER_CONN_DOWN) {
pr_debug("Calling rdma_disconnect from isert_free_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_INIT) {
if (isert_conn->state == ISER_CONN_UP) {
pr_debug("isert_free_conn: Before wait_event comp_err %d\n",
isert_conn->state);
wait_event(isert_conn->conn_wait_comp_err,
isert_conn->state == ISER_CONN_TERMINATING);
pr_debug("isert_free_conn: After wait_event #1 >>>>>>>>>>>>\n");
}
mutex_unlock(&isert_conn->conn_mutex);
pr_debug("isert_free_conn: wait_event conn_wait %d\n", isert_conn->state);
wait_event(isert_conn->conn_wait, isert_conn->state == ISER_CONN_DOWN);
pr_debug("isert_free_conn: After wait_event #2 >>>>>>>>>>>>>>>>>>>>\n");
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);
mutex_unlock(&isert_conn->conn_mutex);
wait_event(isert_conn->conn_wait,
(isert_check_state(isert_conn, ISER_CONN_DOWN)));
isert_put_conn(isert_conn);
}

1
drivers/infiniband/ulp/isert/ib_isert.h
View file

@ -102,6 +102,7 @@ struct isert_conn {
struct ib_qp *conn_qp;
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 kref conn_kref;