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IB/iser: Protect iser state machine with a mutex

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The iser connection state lookups and transitions are not fully protected.

Some transitions are protected with a spinlock, and in some cases the
state is accessed unprotected due to specific assumptions of the flow.

Introduce a new mutex to protect the connection state access. We use a
mutex since we need to also include a scheduling operations executed
under the state lock.

Each state transition/condition and its corresponding action will be
protected with the state mutex.

The rdma_cm events handler acquires the mutex when handling connection
events. Since iser connection state can transition to DOWN
concurrently during connection establishment, we bailout from
addr/route resolution events when the state is not PENDING.

This addresses a scenario where ep_poll retries expire during CMA
connection establishment. In this case ep_disconnect is invoked while
CMA events keep coming (address/route resolution, connected, etc...).

Signed-off-by: Ariel Nahum <arieln@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Ariel Nahum
2014-07-31 13:27:49 +03:00
committed by Roland Dreier
parent f1a8bf0983
commit 504130c039
3 changed files with 65 additions and 14 deletions
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15
drivers/infiniband/ulp/iser/iscsi_iser.c
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@@ -632,10 +632,13 @@ iscsi_iser_ep_poll(struct iscsi_endpoint *ep, int timeout_ms)
msecs_to_jiffies(timeout_ms));
/* if conn establishment failed, return error code to iscsi */
if (!rc &&
(ib_conn->state == ISER_CONN_TERMINATING ||
ib_conn->state == ISER_CONN_DOWN))
rc = -1;
if (rc == 0) {
mutex_lock(&ib_conn->state_mutex);
if (ib_conn->state == ISER_CONN_TERMINATING ||
ib_conn->state == ISER_CONN_DOWN)
rc = -1;
mutex_unlock(&ib_conn->state_mutex);
}
iser_info("ib conn %p rc = %d\n", ib_conn, rc);
@@ -654,6 +657,7 @@ iscsi_iser_ep_disconnect(struct iscsi_endpoint *ep)
ib_conn = ep->dd_data;
iser_info("ep %p ib conn %p state %d\n", ep, ib_conn, ib_conn->state);
mutex_lock(&ib_conn->state_mutex);
iser_conn_terminate(ib_conn);
/*
@@ -664,7 +668,10 @@ iscsi_iser_ep_disconnect(struct iscsi_endpoint *ep)
if (ib_conn->iscsi_conn) {
INIT_WORK(&ib_conn->release_work, iser_release_work);
queue_work(release_wq, &ib_conn->release_work);
mutex_unlock(&ib_conn->state_mutex);
} else {
ib_conn->state = ISER_CONN_DOWN;
mutex_unlock(&ib_conn->state_mutex);
iser_conn_release(ib_conn);
}
iscsi_destroy_endpoint(ep);