v4.19.13 snapshot.
diff --git a/include/linux/errseq.h b/include/linux/errseq.h
new file mode 100644
index 0000000..fc27777
--- /dev/null
+++ b/include/linux/errseq.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * See Documentation/core-api/errseq.rst and lib/errseq.c
+ */
+#ifndef _LINUX_ERRSEQ_H
+#define _LINUX_ERRSEQ_H
+
+typedef u32 errseq_t;
+
+errseq_t errseq_set(errseq_t *eseq, int err);
+errseq_t errseq_sample(errseq_t *eseq);
+int errseq_check(errseq_t *eseq, errseq_t since);
+int errseq_check_and_advance(errseq_t *eseq, errseq_t *since);
+#endif