IB/iser: Fix connection teardown race condition

[sfrench/cifs-2.6.git] / drivers / infiniband / ulp / iser / iscsi_iser.c

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index 5a887efb4bdf1b6405d3fc4342918084ae420b57..37b33d708c2dd5aecfa9bcc0328fb60876e9c310 100644 (file)
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -83,6 +83,7 @@ static struct scsi_host_template iscsi_iser_sht;
 static struct iscsi_transport iscsi_iser_transport;
 static struct scsi_transport_template *iscsi_iser_scsi_transport;
 static struct workqueue_struct *release_wq;
+static DEFINE_MUTEX(unbind_iser_conn_mutex);
 struct iser_global ig;
 
 int iser_debug_level = 0;
@@ -550,12 +551,14 @@ iscsi_iser_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
         */
        if (iser_conn) {
                mutex_lock(&iser_conn->state_mutex);
+               mutex_lock(&unbind_iser_conn_mutex);
                iser_conn_terminate(iser_conn);
                iscsi_conn_stop(cls_conn, flag);
 
                /* unbind */
                iser_conn->iscsi_conn = NULL;
                conn->dd_data = NULL;
+               mutex_unlock(&unbind_iser_conn_mutex);
 
                complete(&iser_conn->stop_completion);
                mutex_unlock(&iser_conn->state_mutex);
@@ -977,13 +980,21 @@ static int iscsi_iser_slave_alloc(struct scsi_device *sdev)
        struct iser_conn *iser_conn;
        struct ib_device *ib_dev;
 
+       mutex_lock(&unbind_iser_conn_mutex);
+
        session = starget_to_session(scsi_target(sdev))->dd_data;
        iser_conn = session->leadconn->dd_data;
+       if (!iser_conn) {
+               mutex_unlock(&unbind_iser_conn_mutex);
+               return -ENOTCONN;
+       }
        ib_dev = iser_conn->ib_conn.device->ib_device;
 
        if (!(ib_dev->attrs.device_cap_flags & IB_DEVICE_SG_GAPS_REG))
                blk_queue_virt_boundary(sdev->request_queue, ~MASK_4K);
 
+       mutex_unlock(&unbind_iser_conn_mutex);
+
        return 0;
 }