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Squashfs: Make ZLIB compression support optional

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Squashfs now supports XZ and LZO compression in addition to ZLIB.
As such it no longer makes sense to always include ZLIB support.
In particular embedded systems may only use LZO or XZ compression, and
the ability to exclude ZLIB support will reduce kernel size.

Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
This commit is contained in:
Phillip Lougher 2011-07-22 03:01:28 +01:00
parent 812753d66f
commit cc6d349714
5 changed files with 25 additions and 5 deletions
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14
fs/squashfs/Kconfig
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@ -1,7 +1,6 @@
config SQUASHFS
tristate "SquashFS 4.0 - Squashed file system support"
depends on BLOCK
select ZLIB_INFLATE
help
Saying Y here includes support for SquashFS 4.0 (a Compressed
Read-Only File System). Squashfs is a highly compressed read-only
@ -36,6 +35,19 @@ config SQUASHFS_XATTR
If unsure, say N.
config SQUASHFS_ZLIB
bool "Include support for ZLIB compressed file systems"
depends on SQUASHFS
select ZLIB_INFLATE
default y
help
ZLIB compression is the standard compression used by Squashfs
file systems. It offers a good trade-off between compression
achieved and the amount of CPU time and memory necessary to
compress and decompress.
If unsure, say Y.
config SQUASHFS_LZO
bool "Include support for LZO compressed file systems"
depends on SQUASHFS

3
fs/squashfs/Makefile
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@ -4,7 +4,8 @@
obj-$(CONFIG_SQUASHFS) += squashfs.o
squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o
squashfs-y += namei.o super.o symlink.o decompressor.o
squashfs-$(CONFIG_SQUASHFS_XATTR) += xattr.o xattr_id.o
squashfs-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o
squashfs-$(CONFIG_SQUASHFS_XZ) += xz_wrapper.o
squashfs-$(CONFIG_SQUASHFS_ZLIB) += zlib_wrapper.o

6
fs/squashfs/decompressor.c
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@ -52,6 +52,12 @@ static const struct squashfs_decompressor squashfs_xz_comp_ops = {
};
#endif
#ifndef CONFIG_SQUASHFS_ZLIB
static const struct squashfs_decompressor squashfs_zlib_comp_ops = {
NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0
};
#endif
static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
NULL, NULL, NULL, 0, "unknown", 0
};

4
fs/squashfs/decompressor.h
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@ -56,4 +56,8 @@ extern const struct squashfs_decompressor squashfs_xz_comp_ops;
extern const struct squashfs_decompressor squashfs_lzo_comp_ops;
#endif
#ifdef CONFIG_SQUASHFS_ZLIB
extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
#endif
#endif

3
fs/squashfs/squashfs.h
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@ -97,6 +97,3 @@ extern const struct inode_operations squashfs_symlink_inode_ops;
/* xattr.c */
extern const struct xattr_handler *squashfs_xattr_handlers[];
/* zlib_wrapper.c */
extern const struct squashfs_decompressor squashfs_zlib_comp_ops;