Index: sys/compat/linuxkpi/common/include/linux/devcoredump.h
===================================================================
--- /dev/null
+++ sys/compat/linuxkpi/common/include/linux/devcoredump.h
@@ -0,0 +1,76 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 The FreeBSD Foundation
+ *
+ * This software was developed by Björn Zeeb under sponsorship from
+ * the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef	__LKPI_LINUX_DEVCOREDUMP_H
+#define	__LKPI_LINUX_DEVCOREDUMP_H
+
+#include <linux/slab.h>
+#include <linux/scatterlist.h>
+#include <linux/device.h>
+
+static inline void
+_lkpi_dev_coredumpsg_free(struct scatterlist *table)
+{
+	struct scatterlist *iter;
+	struct page *p;
+	int i;
+
+	iter = table;
+	for_each_sg(table, iter, sg_nents(table), i) {
+		p = sg_page(iter);
+		if (p)
+			__free_page(p);
+	}
+
+	/* XXX what about chained tables? */
+	kfree(table);
+}
+
+static inline void
+dev_coredumpv(struct device *dev __unused, void *data, size_t datalen __unused,
+    gfp_t gfp __unused)
+{
+
+	/* UNIMPLEMENTED */
+	vfree(data);
+}
+
+static inline void
+dev_coredumpsg(struct device *dev __unused, struct scatterlist *table,
+    size_t datalen __unused, gfp_t gfp __unused)
+{
+
+	/* UNIMPLEMENTED */
+	_lkpi_dev_coredumpsg_free(table);
+}
+
+#endif	/* __LKPI_LINUX_DEVCOREDUMP_H */