[PATCH 3/5] fs: squashfs: port zlib compression support from kernel

[Sascha Hauer]

On Fri, Oct 21, 2016 at 08:04:35AM +0200, Yegor Yefremov wrote:
> Hi Enrico,
> 
> On Tue, Oct 4, 2016 at 9:40 PM, Sascha Hauer <s.hauer at pengutronix.de> wrote:
> > On Tue, Oct 04, 2016 at 12:10:46PM +0200, Enrico Jorns wrote:
> >> As this is the default compression method for squashfs, make this the
> >> default in kconfig selection, too
> >>
> >> Signed-off-by: Enrico Jorns <ejo at pengutronix.de>
> >> ---
> >>  fs/squashfs/Kconfig        |  20 ++++++-
> >>  fs/squashfs/Makefile       |   1 +
> >>  fs/squashfs/zlib_wrapper.c | 132 +++++++++++++++++++++++++++++++++++++++++++++
> >>  3 files changed, 152 insertions(+), 1 deletion(-)
> >>  create mode 100644 fs/squashfs/zlib_wrapper.c
> >>
> >> diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
> >> index d2de168..1cb1ac5 100644
> >> --- a/fs/squashfs/Kconfig
> >> +++ b/fs/squashfs/Kconfig
> >> @@ -17,6 +17,19 @@ menuconfig FS_SQUASHFS
> >>         embedded systems where low overhead is needed.  Further information
> >>         and tools are available from http://squashfs.sourceforge.net.
> >>
> >> +config SQUASHFS_ZLIB
> >> +     bool "Include support for ZLIB compressed file systems"
> >> +     depends on FS_SQUASHFS
> >> +     select ZLIB
> >> +     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_LZ4
> >>       bool "Include support for LZ4 compressed file systems"
> >>       depends on FS_SQUASHFS
> >> @@ -30,9 +43,10 @@ config SQUASHFS_LZ4
> >>         LZ4 is not the standard compression used in Squashfs and so most
> >>         file systems will be readable without selecting this option.
> >>
> >> +       If unsure, say N.
> >> +
> >>  config SQUASHFS_LZO
> >>       bool "Include support for LZO compressed file systems"
> >> -     default y
> >>       depends on FS_SQUASHFS
> >>       select LZO_DECOMPRESS
> >>       help
> >> @@ -44,6 +58,8 @@ config SQUASHFS_LZO
> >>         LZO is not the standard compression used in Squashfs and so most
> >>         file systems will be readable without selecting this option.
> >>
> >> +       If unsure, say N.
> >> +
> >>  config SQUASHFS_XZ
> >>       bool "Include support for XZ compressed file systems"
> >>       default y
> >> @@ -57,3 +73,5 @@ config SQUASHFS_XZ
> >>
> >>         XZ is not the standard compression used in Squashfs and so most
> >>         file systems will be readable without selecting this option.
> >> +
> >> +       If unsure, say N.
> >
> > Here unrelated Kconfig entries are changed. Also in the end we get
> > "default y" for SQUASHFS_XZ along with the help "If unsure, say N."
> > which seems inconsistent.
> 
> Care to send v2?

Enrico is on holiday, so I just did.

> 
> @Sascha what is the plan as to the default compression selection?
> Leave XZ or set it to ZLIB? I'm open for both options.

In the new series I enabled zlib as default since this is what the
kconfig help text says. For the others I chose a "Enable it when the
algorithm is enabled anyway"

Sascha

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