Squashfs: Make ZLIB compression support optional

cc6d3497 · Phillip Lougher <[email protected]> · 2011-07-22 03:01:28 +01:00

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 <[email protected]>

Commit: cc6d3497141adedb71de8ddce62bf4cd4817832d
Parents: 812753d6

Changes

5 files changed · +25 −5

File	Status	Add	Del	Content
fs/squashfs/Kconfig	modified	+13	−1	View file
fs/squashfs/Makefile	modified	+2	−1	View file
fs/squashfs/decompressor.c	modified	+6	−0	View file
fs/squashfs/decompressor.h	modified	+4	−0	View file
fs/squashfs/squashfs.h	modified	+0	−3	View file

fs/squashfs/Kconfig

View file

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 @@ 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

fs/squashfs/Makefile

View file

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

fs/squashfs/decompressor.c

View file

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 @@ 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
 };

fs/squashfs/decompressor.h

View file

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_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

fs/squashfs/squashfs.h

View file

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 @@ 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;