[SCSI] iser: fix handling of scsi cmnds during recovery.

After the stop_conn callback has returned the LLD should not
touch the scsi cmds. iscsi_tcp and libiscsi use the
conn->recv_lock and suspend_rx field to halt recv path
processing, but iser does not have any protection.

This patch modifies iser so that userspace can just
call the ep_disconnect callback, which will halt
all recv IO, before calling the stop_conn callback so
we do not have to worry about the conn->recv_lock and
suspend rx field. iser just needs to stop the send side
from accessing the ib conn.

Fixup to handle when the ep poll fails and ep disconnect
is called from Erez.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.h b/drivers/infiniband/ulp/iser/iscsi_iser.h
index 66a2f30..bd5c1a5 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.h
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.h
@@ -242,6 +242,7 @@
 struct iser_conn {
 	struct iscsi_iser_conn       *iser_conn; /* iser conn for upcalls  */
 	enum iser_ib_conn_state	     state;	    /* rdma connection state   */
+	atomic_t		     refcount;
 	spinlock_t		     lock;	    /* used for state changes  */
 	struct iser_device           *device;       /* device context          */
 	struct rdma_cm_id            *cma_id;       /* CMA ID		       */
@@ -314,6 +315,10 @@
 
 int  iser_conn_init(struct iser_conn **ib_conn);
 
+void iser_conn_get(struct iser_conn *ib_conn);
+
+void iser_conn_put(struct iser_conn *ib_conn);
+
 void iser_conn_terminate(struct iser_conn *ib_conn);
 
 void iser_rcv_completion(struct iser_desc *desc,