In situations such as bond failover, The new session establishment
implicitly invokes the termination of the old connection.
So, we don't want to wait for the old connection wait_conn to completely
terminate before we accept the new connection and post a login response.
The solution is to deffer the comp_wait completion and the conn_put to
a work so wait_conn will effectively be non-blocking (flush errors are
assumed to come very fast).
We allocate isert_release_wq with WQ_UNBOUND and WQ_UNBOUND_MAX_ACTIVE
to spread the concurrency of release works.
Cc: <stable@xxxxxxxxxxxxxxx> # 3.10+
Reported-by: Slava Shwartsman <valyushash@xxxxxxxxx>
Signed-off-by: Sagi Grimberg <sagig@xxxxxxxxxxxx>
---
drivers/infiniband/ulp/isert/ib_isert.c | 42 +++++++++++++++++++++++++------
drivers/infiniband/ulp/isert/ib_isert.h | 1 +
2 files changed, 35 insertions(+), 8 deletions(-)
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index ef97197..13dd729 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -41,6 +41,7 @@ static DEFINE_MUTEX(device_list_mutex);
static LIST_HEAD(device_list);
static struct workqueue_struct *isert_rx_wq;
static struct workqueue_struct *isert_comp_wq;
+static struct workqueue_struct *isert_release_wq;
static void
isert_unmap_cmd(struct isert_cmd *isert_cmd, struct isert_conn *isert_conn);
@@ -3318,6 +3319,24 @@ isert_free_np(struct iscsi_np *np)
kfree(isert_np);
}
+static void isert_release_work(struct work_struct *work)
+{
+ struct isert_conn *isert_conn = container_of(work,
+ struct isert_conn,
+ release_work);
+
+ pr_info("Starting release conn %p\n", isert_conn);
+
+ wait_for_completion(&isert_conn->conn_wait);
+
+ mutex_lock(&isert_conn->conn_mutex);
+ isert_conn->state = ISER_CONN_DOWN;
+ mutex_unlock(&isert_conn->conn_mutex);
+
+ pr_info("Destroying conn %p\n", isert_conn);
+ isert_put_conn(isert_conn);
+}
+
static void isert_wait_conn(struct iscsi_conn *conn)
{
struct isert_conn *isert_conn = conn->context;
@@ -3337,14 +3356,9 @@ static void isert_wait_conn(struct iscsi_conn *conn)
mutex_unlock(&isert_conn->conn_mutex);
wait_for_completion(&isert_conn->conn_wait_comp_err);
- wait_for_completion(&isert_conn->conn_wait);
-
- mutex_lock(&isert_conn->conn_mutex);
- isert_conn->state = ISER_CONN_DOWN;
- mutex_unlock(&isert_conn->conn_mutex);
- pr_info("Destroying conn %p\n", isert_conn);
- isert_put_conn(isert_conn);
+ INIT_WORK(&isert_conn->release_work, isert_release_work);
+ queue_work(isert_release_wq, &isert_conn->release_work);
}
static void isert_free_conn(struct iscsi_conn *conn)
@@ -3392,10 +3406,21 @@ static int __init isert_init(void)
goto destroy_rx_wq;
}
+ isert_release_wq = alloc_workqueue("isert_release_wq", WQ_UNBOUND,
+ WQ_UNBOUND_MAX_ACTIVE);
+ if (!isert_release_wq) {
+ pr_err("Unable to allocate isert_release_wq\n");
+ ret = -ENOMEM;
+ goto destroy_comp_wq;
+ }
+
iscsit_register_transport(&iser_target_transport);
- pr_debug("iSER_TARGET[0] - Loaded iser_target_transport\n");
+ pr_info("iSER_TARGET[0] - Loaded iser_target_transport\n");
+
return 0;
+destroy_comp_wq:
+ destroy_workqueue(isert_comp_wq);
destroy_rx_wq:
destroy_workqueue(isert_rx_wq);
return ret;
@@ -3404,6 +3429,7 @@ destroy_rx_wq:
static void __exit isert_exit(void)
{
flush_scheduled_work();
+ destroy_workqueue(isert_release_wq);
destroy_workqueue(isert_comp_wq);
destroy_workqueue(isert_rx_wq);
iscsit_unregister_transport(&iser_target_transport);
diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
index 5e9148d..f8b4208 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -150,6 +150,7 @@ struct isert_conn {
int conn_fr_pool_size;
/* lock to protect fastreg pool */
spinlock_t conn_lock;
+ struct work_struct release_work;
#define ISERT_COMP_BATCH_COUNT 8
int conn_comp_batch;
struct llist_head conn_comp_llist;
--
1.7.1
--
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