From 9bc18b25d1a5a5c08b01c40fbf0624f3107d04d3 Mon Sep 17 00:00:00 2001
From: Flatcar Buildbot <buildbot@flatcar-linux.org>
Date: Mon, 2 Mar 2026 07:25:44 +0000
Subject: [PATCH] eclass/dist-kernel-utils: Sync with Gentoo

It's from Gentoo commit 5d417624a82991d4786b59dff1213e10ee641a12.

Signed-off-by: Flatcar Buildbot <buildbot@flatcar-linux.org>
---
 .../eclass/dist-kernel-utils.eclass           | 39 ++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/sdk_container/src/third_party/portage-stable/eclass/dist-kernel-utils.eclass b/sdk_container/src/third_party/portage-stable/eclass/dist-kernel-utils.eclass
index 975efd2d63..1ebf17092b 100644
--- a/sdk_container/src/third_party/portage-stable/eclass/dist-kernel-utils.eclass
+++ b/sdk_container/src/third_party/portage-stable/eclass/dist-kernel-utils.eclass
@@ -1,4 +1,4 @@
-# Copyright 2020-2025 Gentoo Authors
+# Copyright 2020-2026 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 # @ECLASS: dist-kernel-utils.eclass
@@ -215,6 +215,43 @@ dist-kernel_PV_to_KV() {
 	echo "${kv}"
 }
 
+# @FUNCTION: dist-kernel_get_compressor
+# @USAGE: <kernel_config>
+# @DESCRIPTION:
+# Returns the compressor with arguments for compressing kernel modules
+# based on the CONFIG_MODULES_COMPESS_* setting in the kernel config.
+dist-kernel_get_compressor() {
+	debug-print-function ${FUNCNAME} "$@"
+
+	[[ ${#} -eq 1 ]] || die "${FUNCNAME}: invalid arguments"
+
+	local suffix=$(dist-kernel_get_module_suffix "${1}")
+	local compress=()
+	# Options taken from linux-mod-r1.eclass.
+	# We don't instruct the compressor to parallelize because it applies
+	# multithreading per file, so it works only for big files, and we have
+	# lots of small files instead.
+	case ${suffix} in
+		.ko)
+			return
+			;;
+		.ko.gz)
+			compress+=( gzip )
+			;;
+		.ko.xz)
+			compress+=( xz --check=crc32 --lzma2=dict=1MiB )
+			;;
+		.ko.zst)
+			compress+=( zstd -q --rm )
+			;;
+		*)
+			die "Unknown compressor: ${suffix}"
+			;;
+	esac
+
+	echo "${compress[@]}"
+}
+
 # @FUNCTION: dist-kernel_get_module_suffix
 # @USAGE: <kernel_config>
 # @DESCRIPTION: