zsmalloc: use PageFlag macro instead of [set|test]_bit

MM code always uses PageXXX to handle page flags.
Let's keep the consistency.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: rename zspage_order with zspage_pages

zspage_order defines how many pages are needed to make a zspage.
So _order_ is rather awkward naming. It already deceive Jonathan
- http://lwn.net/Articles/477067/
" For each size, the code calculates an optimum number of pages (up to 16)"

Let's change from _order_ to _pages_ and some function names.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: add/fix function comment

Add/fix the comment.

Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: fix uninit'ed variable warning

This patch fixes an uninitialized variable warning in
alloc_zspage().  It also fixes the secondary issue of
prev_page leaving scope on each loop iteration.  The only
reason this ever worked was because prev_page was occupying
the same space on the stack on each iteration.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc documentation

Documentation of various struct page fields
used by zsmalloc.

Changes for v2:
	- Regroup descriptions as suggested by Konrad

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: Finish conversion to a separate module

ZSMALLOC is tristate, but the code has no MODULE_LICENSE and since it
depends on GPL-only symbols it cannot be loaded as a module.  This in
turn breaks zram which now depends on it.  I assume it's meant to be
Dual BSD/GPL like the other z-stuff.

There is also no module_exit, which will make it impossible to unload.
Add the appropriate module_init and module_exit declarations suggested
by comments.

Reported-by: Christian Ohm <chr.ohm@gmx.net>
References: http://bugs.debian.org/677273
Cc: stable@vger.kernel.org # v3.4
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zsmalloc: add details to zs_map_object boiler plate

Add information on the usage limits of zs_map_object()

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>