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From:   Piotr Gorski <lucjan.lucjanov@gmail.com>
To:     linux-kernel@vger.kernel.org
Cc:     linux-kbuild@vger.kernel.org,
        Oleksandr Natalenko <oleksandr@natalenko.name>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Piotr Gorski <lucjan.lucjanov@gmail.com>
Subject: [PATCH] init: add support for zstd compressed modules
Date:   Tue, 30 Mar 2021 13:32:35 +0200
Message-Id: <20210330113235.2767216-1-lucjan.lucjanov@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

kmod 28 supports modules compressed in zstd format so let's add this possibility to kernel.

Signed-off-by: Piotr Gorski <lucjan.lucjanov@gmail.com>
---
 Makefile     | 7 +++++--
 init/Kconfig | 9 ++++++---
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 5160ff8903c1..82f4f4cc2955 100644
--- a/Makefile
+++ b/Makefile
@@ -1156,8 +1156,8 @@ endif # INSTALL_MOD_STRIP
 export mod_strip_cmd
 
 # CONFIG_MODULE_COMPRESS, if defined, will cause module to be compressed
-# after they are installed in agreement with CONFIG_MODULE_COMPRESS_GZIP
-# or CONFIG_MODULE_COMPRESS_XZ.
+# after they are installed in agreement with CONFIG_MODULE_COMPRESS_GZIP,
+# CONFIG_MODULE_COMPRESS_XZ, or CONFIG_MODULE_COMPRESS_ZSTD.
 
 mod_compress_cmd = true
 ifdef CONFIG_MODULE_COMPRESS
@@ -1167,6 +1167,9 @@ ifdef CONFIG_MODULE_COMPRESS
   ifdef CONFIG_MODULE_COMPRESS_XZ
     mod_compress_cmd = $(XZ) --lzma2=dict=2MiB -f
   endif # CONFIG_MODULE_COMPRESS_XZ
+  ifdef CONFIG_MODULE_COMPRESS_ZSTD
+    mod_compress_cmd = $(ZSTD) -T0 --rm -f -q
+  endif # CONFIG_MODULE_COMPRESS_ZSTD
 endif # CONFIG_MODULE_COMPRESS
 export mod_compress_cmd
 
diff --git a/init/Kconfig b/init/Kconfig
index 8c2cfd88f6ef..86a452bc2747 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2250,8 +2250,8 @@ config MODULE_COMPRESS
 	bool "Compress modules on installation"
 	help
 
-	  Compresses kernel modules when 'make modules_install' is run; gzip or
-	  xz depending on "Compression algorithm" below.
+	  Compresses kernel modules when 'make modules_install' is run; gzip,
+	  xz, or zstd depending on "Compression algorithm" below.
 
 	  module-init-tools MAY support gzip, and kmod MAY support gzip and xz.
 
@@ -2273,7 +2273,7 @@ choice
 	  This determines which sort of compression will be used during
 	  'make modules_install'.
 
-	  GZIP (default) and XZ are supported.
+	  GZIP (default), XZ, and ZSTD are supported.
 
 config MODULE_COMPRESS_GZIP
 	bool "GZIP"
@@ -2281,6 +2281,9 @@ config MODULE_COMPRESS_GZIP
 config MODULE_COMPRESS_XZ
 	bool "XZ"
 
+config MODULE_COMPRESS_ZSTD
+	bool "ZSTD"
+
 endchoice
 
 config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
-- 
2.31.0.97.g1424303384