2 files changed, 21 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 67077ad6edbb..606a66cdcdb8 100644
--- a/Makefile
+++ b/Makefile
@@ -720,6 +720,22 @@ mod_strip_cmd = true
 endif # INSTALL_MOD_STRIP
 export mod_strip_cmd
 
+# Select initial ramdisk compression format, default is gzip(1).
+# This shall be used by the dracut(8) tool while creating an initramfs image.
+#
+INITRD_COMPRESS=gzip
+ifeq ($(CONFIG_RD_BZIP2), y)
+        INITRD_COMPRESS=bzip2
+else ifeq ($(CONFIG_RD_LZMA), y)
+        INITRD_COMPRESS=lzma
+else ifeq ($(CONFIG_RD_XZ), y)
+        INITRD_COMPRESS=xz
+else ifeq ($(CONFIG_RD_LZO), y)
+        INITRD_COMPRESS=lzo
+else ifeq ($(CONFIG_RD_LZ4), y)
+        INITRD_COMPRESS=lz4
+endif
+export INITRD_COMPRESS
 
 ifdef CONFIG_MODULE_SIG_ALL
 MODSECKEY = ./signing_key.priv
diff --git a/init/do_mounts_rd.c b/init/do_mounts_rd.c
index 143e98de6f29..7c098ac9068a 100644
--- a/init/do_mounts_rd.c
+++ b/init/do_mounts_rd.c
@@ -57,6 +57,11 @@ static int __init crd_load(int in_fd, int out_fd, decompress_fn deco);
  *      cramfs
  *      squashfs
  *      gzip
+ *      bzip2
+ *      lzma
+ *      xz
+ *      lzo
+ *      lz4
  */
 static int __init
 identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)