[PATCH 04/12] iser-target: Rework connection termination

Sagi Grimberg
2016-02-24T17:24:01Z

From: Jenny Derzhavetz <jennyf@mellanox.com>

When we receive an event that triggers connection termination,
we have a a couple of things we may want to do:
1. In case we are already terminating, bailout early
2. In case we are connected but not bound, disconnect and schedule
a connection cleanup silently (don't reinstate)
3. In case we are connected and bound, disconnect and reinstate the connection

This rework fixes a bug that was detected against a mis-behaved
initiator which rejected our rdma_cm accept, in this stage the
isert_conn is no bound and reinstate caused a bogus dereference.

What's great about this is that we don't need the
post_recv_buf_count anymore, so get rid of it.

Signed-off-by: Jenny Derzhavetz <jennyf@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
---
drivers/infiniband/ulp/isert/ib_isert.c | 107 ++++++++++++++++----------------
drivers/infiniband/ulp/isert/ib_isert.h | 1 -
2 files changed, 52 insertions(+), 56 deletions(-)

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 73b2233edcff..0e1a802c3618 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -65,6 +65,7 @@ isert_rdma_accept(struct isert_conn *isert_conn);
struct rdma_cm_id *isert_setup_id(struct isert_np *isert_np);

static void isert_release_work(struct work_struct *work);
+static void isert_wait4flush(struct isert_conn *isert_conn);

static inline bool
isert_prot_cmd(struct isert_conn *conn, struct se_cmd *cmd)
@@ -820,6 +821,25 @@ isert_put_conn(struct isert_conn *isert_conn)
kref_put(&isert_conn->kref, isert_release_kref);
}

+static void
+isert_handle_unbound_conn(struct isert_conn *isert_conn)
+{
+ struct isert_np *isert_np = isert_conn->cm_id->context;
+
+ mutex_lock(&isert_np->mutex);
+ if (!list_empty(&isert_conn->node)) {
+ /*
+ * This means iscsi doesn't know this connection
+ * so schedule a cleanup ourselves
+ */
+ list_del_init(&isert_conn->node);
+ isert_put_conn(isert_conn);
+ complete(&isert_conn->wait);
+ queue_work(isert_release_wq, &isert_conn->release_work);
+ }
+ mutex_unlock(&isert_np->mutex);
+}
+
/**
* isert_conn_terminate() - Initiate connection termination
* @isert_conn: isert connection struct
@@ -837,24 +857,19 @@ isert_conn_terminate(struct isert_conn *isert_conn)
{
int err;

- switch (isert_conn->state) {
- case ISER_CONN_TERMINATING:
- break;
- case ISER_CONN_UP:
- case ISER_CONN_BOUND:
- case ISER_CONN_FULL_FEATURE: /* FALLTHRU */
- isert_info("Terminating conn %p state %d\n",
- isert_conn, isert_conn->state);
- isert_conn->state = ISER_CONN_TERMINATING;
- err = rdma_disconnect(isert_conn->cm_id);
- if (err)
- isert_warn("Failed rdma_disconnect isert_conn %p\n",
- isert_conn);
- break;
- default:
- isert_warn("conn %p teminating in state %d\n",
- isert_conn, isert_conn->state);
- }
+ if (isert_conn->state >= ISER_CONN_TERMINATING)
+ return;
+
+ isert_info("Terminating conn %p state %d\n",
+ isert_conn, isert_conn->state);
+ isert_conn->state = ISER_CONN_TERMINATING;
+ err = rdma_disconnect(isert_conn->cm_id);
+ if (err)
+ isert_warn("Failed rdma_disconnect isert_conn %p\n",
+ isert_conn);
+
+ isert_info("conn %p completing wait\n", isert_conn);
+ complete(&isert_conn->wait);
}

static int
@@ -888,30 +903,27 @@ static int
isert_disconnected_handler(struct rdma_cm_id *cma_id,
enum rdma_cm_event_type event)
{
- struct isert_np *isert_np = cma_id->context;
struct isert_conn *isert_conn = cma_id->qp->qp_context;
- bool terminating = false;

mutex_lock(&isert_conn->mutex);
- terminating = (isert_conn->state == ISER_CONN_TERMINATING);
- isert_conn_terminate(isert_conn);
- mutex_unlock(&isert_conn->mutex);
-
- isert_info("conn %p completing wait\n", isert_conn);
- complete(&isert_conn->wait);
-
- if (terminating)
- goto out;
-
- mutex_lock(&isert_np->mutex);
- if (!list_empty(&isert_conn->node)) {
- list_del_init(&isert_conn->node);
- isert_put_conn(isert_conn);
- queue_work(isert_release_wq, &isert_conn->release_work);
+ switch (isert_conn->state) {
+ case ISER_CONN_TERMINATING:
+ break;
+ case ISER_CONN_UP:
+ isert_conn_terminate(isert_conn);
+ isert_wait4flush(isert_conn);
+ isert_handle_unbound_conn(isert_conn);
+ break;
+ case ISER_CONN_BOUND:
+ case ISER_CONN_FULL_FEATURE: /* FALLTHRU */
+ iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
+ break;
+ default:
+ isert_warn("conn %p teminating in state %d\n",
+ isert_conn, isert_conn->state);
}
- mutex_unlock(&isert_np->mutex);
+ mutex_unlock(&isert_conn->mutex);

-out:
return 0;
}

@@ -985,13 +997,10 @@ isert_post_recvm(struct isert_conn *isert_conn, u32 count)
rx_wr--;
rx_wr->next = NULL; /* mark end of work requests list */

- isert_conn->post_recv_buf_count += count;
ret = ib_post_recv(isert_conn->qp, isert_conn->rx_wr,
&rx_wr_failed);
- if (ret) {
+ if (ret)
isert_err("ib_post_recv() failed with ret: %d\n", ret);
- isert_conn->post_recv_buf_count -= count;
- }

return ret;
}
@@ -1007,12 +1016,9 @@ isert_post_recv(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc)
rx_wr.num_sge = 1;
rx_wr.next = NULL;

- isert_conn->post_recv_buf_count++;
ret = ib_post_recv(isert_conn->qp, &rx_wr, &rx_wr_failed);
- if (ret) {
+ if (ret)
isert_err("ib_post_recv() failed with ret: %d\n", ret);
- isert_conn->post_recv_buf_count--;
- }

return ret;
}
@@ -1132,12 +1138,9 @@ isert_rdma_post_recvl(struct isert_conn *isert_conn)
rx_wr.sg_list = &sge;
rx_wr.num_sge = 1;

- isert_conn->post_recv_buf_count++;
ret = ib_post_recv(isert_conn->qp, &rx_wr, &rx_wr_fail);
- if (ret) {
+ if (ret)
isert_err("ib_post_recv() failed: %d\n", ret);
- isert_conn->post_recv_buf_count--;
- }

return ret;
}
@@ -1633,7 +1636,6 @@ isert_rcv_completion(struct iser_rx_desc *desc,
ib_dma_sync_single_for_device(ib_dev, rx_dma, rx_buflen,
DMA_FROM_DEVICE);

- isert_conn->post_recv_buf_count--;
}

static int
@@ -2073,11 +2075,6 @@ isert_cq_comp_err(struct isert_conn *isert_conn, struct ib_wc *wc)
isert_unmap_tx_desc(desc, ib_dev);
else
isert_completion_put(desc, isert_cmd, ib_dev, true);
- } else {
- isert_conn->post_recv_buf_count--;
- if (!isert_conn->post_recv_buf_count &&
- isert_conn->state >= ISER_CONN_BOUND)
- iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
}
}

diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
index b80ec44fb4e1..1aa019ab9d78 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -180,7 +180,6 @@ struct isert_device;

struct isert_conn {
enum iser_conn_state state;
- int post_recv_buf_count;
u32 responder_resources;
u32 initiator_depth;
bool pi_support;
--
1.8.4.3