v4.19.13 snapshot.
diff --git a/tools/lib/api/fd/array.h b/tools/lib/api/fd/array.h
new file mode 100644
index 0000000..b39557d
--- /dev/null
+++ b/tools/lib/api/fd/array.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __API_FD_ARRAY__
+#define __API_FD_ARRAY__
+
+#include <stdio.h>
+
+struct pollfd;
+
+/**
+ * struct fdarray: Array of file descriptors
+ *
+ * @priv: Per array entry priv area, users should access just its contents,
+ * not set it to anything, as it is kept in synch with @entries, being
+ * realloc'ed, * for instance, in fdarray__{grow,filter}.
+ *
+ * I.e. using 'fda->priv[N].idx = * value' where N < fda->nr is ok,
+ * but doing 'fda->priv = malloc(M)' is not allowed.
+ */
+struct fdarray {
+ int nr;
+ int nr_alloc;
+ int nr_autogrow;
+ struct pollfd *entries;
+ union {
+ int idx;
+ void *ptr;
+ } *priv;
+};
+
+void fdarray__init(struct fdarray *fda, int nr_autogrow);
+void fdarray__exit(struct fdarray *fda);
+
+struct fdarray *fdarray__new(int nr_alloc, int nr_autogrow);
+void fdarray__delete(struct fdarray *fda);
+
+int fdarray__add(struct fdarray *fda, int fd, short revents);
+int fdarray__poll(struct fdarray *fda, int timeout);
+int fdarray__filter(struct fdarray *fda, short revents,
+ void (*entry_destructor)(struct fdarray *fda, int fd, void *arg),
+ void *arg);
+int fdarray__grow(struct fdarray *fda, int extra);
+int fdarray__fprintf(struct fdarray *fda, FILE *fp);
+
+static inline int fdarray__available_entries(struct fdarray *fda)
+{
+ return fda->nr_alloc - fda->nr;
+}
+
+#endif /* __API_FD_ARRAY__ */