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>

1 files changed, 13 insertions, 1 deletions

diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index 7797218d0b30..1360d4f88f41 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