[SCSI] libiscsi: fix logout pdu processing

According to the iscsi RFC, we cannot send other requests if
we have sent a logout pdu. This patch enforces this requirement
by blocking the session and suspending the send thread. Userspace
decides if we restart the connection or if we just free everything.

Signed-off-by: Mike Christie <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/libiscsi.c

···
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_failure);
 
+static int iscsi_xmit_imm_task(struct iscsi_conn *conn)
+{
+	struct iscsi_hdr *hdr = conn->mtask->hdr;
+	int rc, was_logout = 0;
+
+	if ((hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGOUT) {
+		conn->session->state = ISCSI_STATE_IN_RECOVERY;
+		iscsi_block_session(session_to_cls(conn->session));
+		was_logout = 1;
+	}
+	rc = conn->session->tt->xmit_mgmt_task(conn, conn->mtask);
+	if (rc)
+		return rc;
+
+	if (was_logout) {
+		set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
+		return -ENODATA;
+	}
+	return 0;
+}
+
 /**
  * iscsi_data_xmit - xmit any command into the scheduled connection
  * @conn: iscsi connection
···
 		conn->ctask = NULL;
 	}
 	if (conn->mtask) {
-		rc = tt->xmit_mgmt_task(conn, conn->mtask);
+		rc = iscsi_xmit_imm_task(conn);
 	        if (rc)
 		        goto again;
 		/* done with this in-progress mtask */
···
 			list_add_tail(&conn->mtask->running,
 				      &conn->mgmt_run_list);
 			spin_unlock_bh(&conn->session->lock);
-			rc = tt->xmit_mgmt_task(conn, conn->mtask);
+			rc = iscsi_xmit_imm_task(conn);
 		        if (rc)
 			        goto again;
 	        }