Squashfs: Make ZLIB compression support optional
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>
diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index 7797218..1360d4f 100644
--- a/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@ -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 @@
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
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index cecf2be..110b047 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -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
diff --git a/fs/squashfs/decompressor.c b/fs/squashfs/decompressor.c
index 9f1b0bb..3f6271d 100644
--- a/fs/squashfs/decompressor.c
+++ b/fs/squashfs/decompressor.c
@@ -52,6 +52,12 @@
};
#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
};
diff --git a/fs/squashfs/decompressor.h b/fs/squashfs/decompressor.h
index 8ba70cf..330073e 100644
--- a/fs/squashfs/decompressor.h
+++ b/fs/squashfs/decompressor.h
@@ -56,4 +56,8 @@
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
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index e3be6a7..d126651 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -97,6 +97,3 @@
/* xattr.c */
extern const struct xattr_handler *squashfs_xattr_handlers[];
-
-/* zlib_wrapper.c */
-extern const struct squashfs_decompressor squashfs_zlib_comp_ops;