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SubjectRe: fastboot: unpacking initramfs faster
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Date
Here is a quick and dirty patch that works for me. Applies to current
git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-x86.git

Work on monolithic-kernel decompression and multithreading is next.

>From 27d64e5fca08d695282da219eb71e5fca978a9d2 Mon Sep 17 00:00:00 2001
From: Andreas Robinson <andr345@gmail.com>
Date: Thu, 26 Mar 2009 16:44:14 +0100
Subject: [PATCH] lib: support lzo-compressed initramfs images

Impact: Allows faster unpacking of the initial ramdisk.

LZO files are marginally larger than gzip, about 7% for the
best compression method lzo1x_999, but decompress about 30%
faster on x86 hardware.

This patch supports a new stream format generated by a
userspace tool named blzo.

Patch content:
* necessary additions to Kconfig and makefiles
* a simple initramfs decompressor
---
include/linux/decompress/ublzo.h | 12 ++++++
lib/Kconfig | 4 ++
lib/Makefile | 1 +
lib/decompress.c | 5 +++
lib/decompress_ublzo.c | 75 ++++++++++++++++++++++++++++++++++++++
usr/Kconfig | 9 +++++
6 files changed, 106 insertions(+), 0 deletions(-)
create mode 100644 include/linux/decompress/ublzo.h
create mode 100644 lib/decompress_ublzo.c

diff --git a/include/linux/decompress/ublzo.h b/include/linux/decompress/ublzo.h
new file mode 100644
index 0000000..e453d07
--- /dev/null
+++ b/include/linux/decompress/ublzo.h
@@ -0,0 +1,12 @@
+#ifndef DECOMPRESS_UBLZO_H
+#define DECOMPRESS_UBLZO_H
+
+int ublzo(unsigned char *, int,
+ int(*fill)(void*, unsigned int),
+ int(*flush)(void*, unsigned int),
+ unsigned char *output,
+ int *posp,
+ void(*error)(char *x)
+ );
+
+#endif
diff --git a/lib/Kconfig b/lib/Kconfig
index e3b7d7a..9e5c7f1 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -104,6 +104,10 @@ config LZO_DECOMPRESS
# These all provide a common interface (hence the apparent duplication with
# ZLIB_INFLATE; DECOMPRESS_GZIP is just a wrapper.)
#
+config DECOMPRESS_BLZO
+ select LZO_DECOMPRESS
+ tristate
+
config DECOMPRESS_GZIP
select ZLIB_INFLATE
tristate
diff --git a/lib/Makefile b/lib/Makefile
index b24222c..9ee48e8 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -65,6 +65,7 @@ obj-$(CONFIG_REED_SOLOMON) += reed_solomon/
obj-$(CONFIG_LZO_COMPRESS) += lzo/
obj-$(CONFIG_LZO_DECOMPRESS) += lzo/

+lib-$(CONFIG_DECOMPRESS_BLZO) += decompress_ublzo.o
lib-$(CONFIG_DECOMPRESS_GZIP) += decompress_inflate.o
lib-$(CONFIG_DECOMPRESS_BZIP2) += decompress_bunzip2.o
lib-$(CONFIG_DECOMPRESS_LZMA) += decompress_unlzma.o
diff --git a/lib/decompress.c b/lib/decompress.c
index d2842f5..8c189a0 100644
--- a/lib/decompress.c
+++ b/lib/decompress.c
@@ -9,10 +9,14 @@
#include <linux/decompress/bunzip2.h>
#include <linux/decompress/unlzma.h>
#include <linux/decompress/inflate.h>
+#include <linux/decompress/ublzo.h>

#include <linux/types.h>
#include <linux/string.h>

+#ifndef CONFIG_DECOMPRESS_BLZO
+# define ublzo NULL
+#endif
#ifndef CONFIG_DECOMPRESS_GZIP
# define gunzip NULL
#endif
@@ -28,6 +32,7 @@ static const struct compress_format {
const char *name;
decompress_fn decompressor;
} compressed_formats[] = {
+ { {'B', 'L'}, "blzo", ublzo },
{ {037, 0213}, "gzip", gunzip },
{ {037, 0236}, "gzip", gunzip },
{ {0x42, 0x5a}, "bzip2", bunzip2 },
diff --git a/lib/decompress_ublzo.c b/lib/decompress_ublzo.c
new file mode 100644
index 0000000..136f57f
--- /dev/null
+++ b/lib/decompress_ublzo.c
@@ -0,0 +1,75 @@
+/* Simple LZO file format decompressor.
+ *
+ * Copyright (C) 2009 Andreas Robinson <andr345@gmail.com>
+ *
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/types.h>
+#include <linux/lzo.h>
+
+#ifndef STATIC
+#include <linux/decompress/ublzo.h>
+#endif /* STATIC */
+#include <linux/decompress/mm.h>
+
+#define BLZO_BLOCK_SIZE 65536
+
+int INIT ublzo(unsigned char *inbuf, int len,
+ int(*fill)(void*, unsigned int),
+ int(*flush)(void*, unsigned int),
+ unsigned char *output,
+ int *posp,
+ void(*error)(char *x))
+{
+ int ret = LZO_E_OK;
+ size_t start_len, in_len, out_len;
+ void *out;
+
+ start_len = len;
+
+ if (fill) {
+ error("the decompress 'fill' feature is not yet implemented");
+ return LZO_E_ERROR;
+ } else {
+ out = malloc(BLZO_BLOCK_SIZE);
+ if (!out)
+ panic("Cannot allocate decompression buffers!");
+
+ if (memcmp("BLZO", inbuf, 4) != 0)
+ return LZO_E_ERROR;
+
+ inbuf += 4;
+ len -= 4;
+
+ while (len > 0) {
+ in_len = (inbuf[0] << 8) + inbuf[1];
+ inbuf += 2;
+ len -= 2;
+ if (in_len == 0)
+ goto done;
+
+ out_len = BLZO_BLOCK_SIZE;
+ ret = lzo1x_decompress_safe(inbuf, in_len, out, &out_len);
+ if (ret != LZO_E_OK) {
+ error("error in LZO archive");
+ goto done;
+ }
+
+ inbuf += in_len;
+ len -= in_len;
+ flush(out, out_len);
+ }
+ }
+
+done:
+ free(out);
+ *posp = start_len - len;
+ return ret;
+}
+
+#define decompress ublzo
diff --git a/usr/Kconfig b/usr/Kconfig
index 43a3a0f..ff2b15c 100644
--- a/usr/Kconfig
+++ b/usr/Kconfig
@@ -45,6 +45,15 @@ config INITRAMFS_ROOT_GID

If you are not sure, leave it set to "0".

+config RD_BLZO
+ bool "Initial ramdisk compressed using blzo"
+ default y
+ depends on BLK_DEV_INITRD=y
+ select DECOMPRESS_BLZO
+ help
+ Support loading of a blzo encoded initial ramdisk or cpio buffer.
+ If unsure, say Y.
+
config RD_GZIP
bool "Initial ramdisk compressed using gzip"
default y
--
1.5.6.3



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