+LU_KEY_INIT_GENERIC(tgt);
+
+/* context key constructor/destructor: tgt_ses_key_init, tgt_ses_key_fini */
+LU_KEY_INIT_FINI(tgt_ses, struct tgt_session_info);
+
+/* context key: tgt_session_key */
+struct lu_context_key tgt_session_key = {
+ .lct_tags = LCT_SERVER_SESSION,
+ .lct_init = tgt_ses_key_init,
+ .lct_fini = tgt_ses_key_fini,
+};
+EXPORT_SYMBOL(tgt_session_key);
+
+LU_KEY_INIT_GENERIC(tgt_ses);
+
+/*
+ * this page is allocated statically when module is initializing
+ * it is used to simulate data corruptions, see ost_checksum_bulk()
+ * for details. as the original pages provided by the layers below
+ * can be remain in the internal cache, we do not want to modify
+ * them.
+ */
+struct page *tgt_page_to_corrupt;