Staging: zcache: delete it
Dan Magenheimer says that it is now safe to delete zcache, so quick,
before he changes his mind, drop the thing on the floor and run
screaming away.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: rename ramster to zcache

[V2: no code changes, patchset now generated via git format-patch -M]

In staging, rename ramster to zcache

The original zcache in staging was a "demo" version, and this new zcache
is a significant rewrite.  While certain disagreements were being resolved,
both "old zcache" and "new zcache" needed to reside in the staging tree
simultaneously.  In order to minimize code change and churn, the newer
version of zcache was temporarily merged into the "ramster" staging driver
which, prior to that, had at one time heavily leveraged the older version
of zcache.  So, recently, "new zcache" resided in the ramster directory.

Got that? No? Sorry, temporary political compromises are rarely pretty.

The older version of zcache is no longer being maintained and has now
been removed from the staging tree.  So now the newer version of zcache
can rightfully reclaim sole possession of the name "zcache".

FYI, this [PATCH 2/5] is simply a "git mv" generated by "git format-patch -M".

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: adjustments to config/build files due to renaming

[V2: no code changes, patchset now generated via git format-patch -M]

In staging/zcache, adjust config/build due to ramster->zcache renaming

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: fix uninitialized variable compile warning

[V2: no code changes, patchset now generated via git format-patch -M]

Fix unitialized variable in zcache which generates warning during build

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: fix ppc64 and other arches where PAGE_SIZE!=4K

Replace raw constant 12 with PAGE_SHIFT to fix non-x86 arches and
provoke build failure if PAGE_SHIFT is too big

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Staging: zcache: remove unnecessary braces in zcache-main.c

This fixes a checkpatch.pl issue of
'braces {} are not necessary for single statement blocks'

Signed-off-by: Ryo Munakata <ryomnktml@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: Remove unnecessary OOM messages

alloc failures already get standardized OOM
messages and a dump_stack.

For the affected mallocs around these OOM messages:

Converted kzallocs with multiplies to kcalloc.
Converted kmallocs with multiplies to kmalloc_array.
Converted a kmalloc/strlen/strncpy to kstrdup.
Moved a spin_lock below a removed OOM message and
removed a now unnecessary spin_unlock.
Neatened alignment and whitespace.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging/zcache: Fix/improve zcache writeback code, tie to a config option

It was observed by Andrea Arcangeli in 2011 that zcache can get "full"
and there must be some way for compressed swap pages to be (uncompressed
and then) sent through to the backing swap disk.  A prototype of this
functionality, called "unuse", was added in 2012 as part of a major update
to zcache (aka "zcache2"), but was left unfinished due to the unfortunate
temporary fork of zcache.

This earlier version of the code had an unresolved memory leak
and was anyway dependent on not-yet-upstream frontswap and mm changes.
The code was meanwhile adapted by Seth Jennings for similar
functionality in zswap (which he calls "flush").  Seth also made some
clever simplifications which are herein ported back to zcache.  As a
result of those simplifications, the frontswap changes are no longer
necessary, but a slightly different (and simpler) set of mm changes are
still required [1].  The memory leak is also fixed.

Due to feedback from akpm in a zswap thread, this functionality in zcache
has now been renamed from "unuse" to "writeback".

Although this zcache writeback code now works, there are open questions
as how best to handle the policy that drives it.  As a result, this
patch also ties writeback to a new config option.  And, since the
code still depends on not-yet-upstreamed mm patches, to avoid build
problems, the config option added by this patch temporarily depends
on "BROKEN"; this config dependency can be removed in trees that
contain the necessary mm patches.

[1] https://lkml.org/lkml/2013/1/29/540/ https://lkml.org/lkml/2013/1/29/539/

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zcache: Fix compile warnings due to usage of debugfs_create_size_t

When we compile we get tons of:
include/linux/debugfs.h:80:16: note: expected ‘size_t *’ but argument is
of type ‘long int *’
drivers/staging/zcache/zcache-main.c:279:2: warning: passing argument 4
of ‘debugfs_create_size_t’ from incompatible pointer type [enabled by d
efault]

which is b/c we end up using 'unsigned' or 'unsigned long' instead
of 'ssize_t'. So lets fix this up and use the proper type.

[v2: Rebased directly on staging]
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ramster: Fix compile warnings due to usage of debugfs_create_size_t

We get tons of "note: expected ‘size_t *’ but argument is of type ‘long
int *’" warnings. This fixes it.

Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zbud: Fix compile warnings due to usage of debugfs_create_size_t

.
drivers/staging/zcache/zbud.c:336: warning: passing argument 4 of ‘debugfs_create_size_t’ from incompatible pointer type
include/linux/debugfs.h:80: note: expected ‘size_t *’ but argument is of type ‘long unsigned int *’
..

which is b/c we end up using 'unsigned' or 'unsigned long' instead
of 'ssize_t'. So lets fix this up and use the proper type.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zcache/zbud: Fix __init mismatch

We get:
WARNING: drivers/staging/zcache/zcache.o(.text+0x13a1): Section mismatch
in reference from the function zcache_init() to the function
.init.text:zbud_init()
The function zcache_init() references
the function __init zbud_init().
This is often because zcache_init lacks a __init
annotation or the annotation of zbud_init is wrong.

And this fixes it.

Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging/zache checkpatch ERROR: spaces prohibited around that

zbud.c:106: ERROR: spaces prohibited around that ':' (ctx:VxW)
zbud.c:107: ERROR: spaces prohibited around that ':' (ctx:VxW)

Signed-off-by: Robert Berger <rber.git@ReliableEmbeddedSystems.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zcache: s/int/bool/ on the various options.

There are so many, but this allows us to at least have them
right in as bool.

Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
[v1: Rebase on ramster->zcache move]
[v2: Rebase on staging/zcache: Fix/improve zcache writeback code, tie to a config option]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zcache: Provide accessory functions for counter increase

This is the first step in moving the debugfs code out of the
main file in-to another file. And also allow the code to run
without CONFIG_DEBUG_FS defined.

Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
[v2: Rebase on top staging/zcache: Fix/improve zcache writeback code, tie to a config option]
[v3: Rebase on top of zcache: Fix compile warnings due to usage of debugfs_create_size_t]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zcache: Provide accessory functions for counter decrease.

This way we can have all wrapped with these functions and
can disable/enable this with CONFIG_DEBUG_FS.

Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
[v2: Rebase on top of staging/zcache: Fix/improve zcache writeback code, tie to a config option]
[v3: Rebase on top of zcache: Fix compile warnings due to usage of debugfs_create_size_t]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zcache: The last of the atomic reads has now an accessory function.

And now we can move the code ([inc|dec]_zcache_[*]) to their own file
with a header to make them nops or feed in debugfs.

Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zcache: Make the debug code use pr_debug

as if you are debugging this driver you would be using 'debug'
on the command line anyhow - and this would dump the debug
data on the proper loglevel.

While at it also remove the unconditional #define ZCACHE_DEBUG.

Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zcache: Move debugfs code out of zcache-main.c file.

Note that at this point there is no CONFIG_ZCACHE_DEBUG
option in the Kconfig. So in effect all of the counters
are nop until that option gets re-introduced in:
zcache/debug: Coalesce all debug under CONFIG_ZCACHE_DEBUG

Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
[v1: Fixed conflicts due to rebase]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zcache/debug: Use an array to initialize/use debugfs attributes.

It makes it neater and also allows us to piggyback on that
in the zcache_dump function.

Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>