Re: [PATCH] lib/halfmd4: make build optional

[josh@joshtriplett.org]

On Thu, Nov 06, 2014 at 04:27:33PM -0500, Aristeu Rozanski wrote:
> From: Aristeu Rozanski <arozansk@redhat.com>
> 
> halfmd4 currently is built unconditionally:
> 	text    data     bss     dec     hex filename
> 	 801     176       8     985     3d9 lib/halfmd4.o
> 	 801     176       8     985     3d9 (TOTALS)
> 
> and it's used by ext3 and ext4. This patch is useful for situations
> in which memory footprint is a concern and those filesystems aren't
> used.
> 
> Cc: Jan Kara <jack@suse.cz>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Andreas Dilger <adilger.kernel@dilger.ca>
> Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
> Cc: Josh Triplett <josh@joshtriplett.org>
> Signed-off-by: Aristeu Rozanski <arozansk@redhat.com>

I already have a patch for this in the tiny tree, branch
tiny/no-halfmd4, and it uses an internal hidden Kconfig symbol.

- Josh Triplett

>  fs/ext3/Kconfig | 1 +
>  fs/ext4/Kconfig | 1 +
>  lib/Kconfig     | 7 +++++++
>  lib/Makefile    | 3 ++-
>  4 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ext3/Kconfig b/fs/ext3/Kconfig
> index e8c6ba0..a6ab4e8 100644
> --- a/fs/ext3/Kconfig
> +++ b/fs/ext3/Kconfig
> @@ -1,6 +1,7 @@
>  config EXT3_FS
>  	tristate "Ext3 journalling file system support"
>  	select JBD
> +	select HALF_MD4
>  	help
>  	  This is the journalling version of the Second extended file system
>  	  (often called ext3), the de facto standard Linux file system
> diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
> index efea5d5..cbb56ee 100644
> --- a/fs/ext4/Kconfig
> +++ b/fs/ext4/Kconfig
> @@ -4,6 +4,7 @@ config EXT4_FS
>  	select CRC16
>  	select CRYPTO
>  	select CRYPTO_CRC32C
> +	select HALF_MD4
>  	help
>  	  This is the next generation of the ext3 filesystem.
>  
> diff --git a/lib/Kconfig b/lib/Kconfig
> index 675920b..108196c 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -180,6 +180,13 @@ config CRC8
>  	  when they need to do cyclic redundancy check according CRC8
>  	  algorithm. Module will be called crc8.
>  
> +config HALF_MD4
> +	bool "Half MD4 transform"
> +	default y
> +	help
> +	  This option enables a reduced (32 bit output) version of MD4
> +	  transform.
> +
>  config AUDIT_GENERIC
>  	bool
>  	depends on AUDIT && !AUDIT_ARCH
> diff --git a/lib/Makefile b/lib/Makefile
> index 9c12cbc..53fd120 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -22,7 +22,7 @@ lib-$(CONFIG_SMP) += cpumask.o
>  lib-y	+= kobject.o klist.o
>  obj-y	+= lockref.o
>  
> -obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
> +obj-y += bcd.o div64.o sort.o parser.o debug_locks.o random32.o \
>  	 bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \
>  	 gcd.o lcm.o list_sort.o uuid.o iovec.o clz_ctz.o \
>  	 bsearch.o find_last_bit.o find_next_bit.o llist.o memweight.o kfifo.o \
> @@ -74,6 +74,7 @@ obj-$(CONFIG_CRC7)	+= crc7.o
>  obj-$(CONFIG_LIBCRC32C)	+= libcrc32c.o
>  obj-$(CONFIG_CRC8)	+= crc8.o
>  obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o
> +obj-$(CONFIG_HALF_MD4) += halfmd4.o
>  
>  obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/
>  obj-$(CONFIG_ZLIB_DEFLATE) += zlib_deflate/
> -- 
> 1.8.3.1
>