zram: use 3.10 version of zram

commit 25eeb667599b192ea850a062d69383ee864c06ab
Author: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Date:   Wed Mar 13 15:06:16 2013 +0800

    zram: fix zram_bvec_read duplicate dump failure message and stat accumulation

    When zram decompress fails, the code unnecessarily dumps failure messages and
    does stat accumulation in function zram_decompress_page(), this work is already
    done in function zram_decompress_page, the patch skips the redundant work.

    Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 78110bb8dc4a7ff331bfa3cfe7d4e287cfb3f22b
Author: Joe Perches <joe@perches.com>
Date:   Mon Feb 11 09:41:29 2013 -0800

    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>

commit 1e927711c5ecabe76010ed9249f8f3747829f04f
Author: Fengguang Wu <fengguang.wu@intel.com>
Date:   Fri Feb 8 10:15:10 2013 +0800

    staging: zram: __zram_reset_device() can be static

    Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
    Cc: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 8b3cc3edb745cbc131560d19e3f32d81c07454b1
Author: Minchan Kim <minchan@kernel.org>
Date:   Wed Feb 6 08:48:53 2013 +0900

    zram: get rid of lockdep warning

    Lockdep complains about recursive deadlock of zram->init_lock.
    [1] made it false positive because we can't request IO to zram
    before setting disksize. Anyway, we should shut lockdep up to
    avoid many reporting from user.

    [1] : zram: force disksize setting before using zram

    Acked-by: Jerome Marchand <jmarchan@redhat.com>
    Acked-by: Nitin Gupta <ngupta@vflare.org>
    Signed-off-by: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 152bce6bdd6e6866ff83166ac75177d001c4360d
Author: Minchan Kim <minchan@kernel.org>
Date:   Wed Feb 6 08:45:22 2013 +0900

    zram: fix warning of print format

    kbuild bot whinges due to print format mistmatch caused by
    zram: force disksize setting before using zram.

    This patch fixes it.

    Reported-by: Wu Fengguang <fengguang.wu@intel.com>
    Signed-off-by: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 3de738cd30306f754ea35d35b5dad29fdbec84c9
Author: Minchan Kim <minchan@kernel.org>
Date:   Wed Jan 30 11:41:41 2013 +0900

    zram: give up lazy initialization of zram metadata

    1) User of zram normally do mkfs.xxx or mkswap before using
       the zram block device(ex, normally, do it at booting time)
       It ends up allocating such metadata of zram before real usage so
       benefit of lazy initialzation would be mitigated.

    2) Some user want to use zram when memory pressure is high.(ie, load zram
       dynamically, NOT booting time). It does make sense because people don't
       want to waste memory until memory pressure is high(ie, where zram is really
       helpful time). In this case, lazy initialzation could be failed easily
       because we will use GFP_NOIO instead of GFP_KERNEL for avoiding deadlock.
       So the benefit of lazy initialzation would be mitigated, too.

    3) Metadata overhead is not critical and Nitin has a plan to diet it.
       4K : 12 byte(64bit machine) -> 64G : 192M so 0.3% isn't big overhead
       If insane user use such big zram device up to 20, it could consume 6% of ram
       but efficieny of zram will cover the waste.

    So this patch gives up lazy initialization and instead we initialize metadata
    at disksize setting time.

    Acked-by: Jerome Marchand <jmarchand@redhat.com>
    Acked-by: Nitin Gupta <ngupta@vflare.org>
    Signed-off-by: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 0231c403bb065307493fe997ad170487b4d55eb8
Author: Minchan Kim <minchan@kernel.org>
Date:   Wed Jan 30 11:41:40 2013 +0900

    zram: force disksize setting before using zram

    Now zram document syas "set disksize is optional"
    but partly it's wrong. When you try to use zram firstly after
    booting, you must set disksize, otherwise zram can't work because
    zram gendisk's size is 0. But once you do it, you can use zram freely
    after reset because reset doesn't reset to zero paradoxically.
    So in this time, disksize setting is optional.:(
    It's inconsitent for user behavior and not straightforward.

    This patch forces always setting disksize firstly before using zram.
    Yes. It changes current behavior so someone could complain when
    he upgrades zram. Apparently it could be a problem if zram is mainline
    but it still lives in staging so behavior could be changed for right
    way to go. Let them excuse.

    Acked-by: Jerome Marchand <jmarchand@redhat.com>
    Acked-by: Nitin Gupta <ngupta@vflare.org>
    Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
    Signed-off-by: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 7e5a5104c6af709a8d97d5f4711e7c917761d464
Author: Minchan Kim <minchan@kernel.org>
Date:   Wed Jan 30 11:41:39 2013 +0900

    zram: Fix deadlock bug in partial read/write

    Now zram allocates new page with GFP_KERNEL in zram I/O path
    if IO is partial. Unfortunately, It may cause deadlock with
    reclaim path like below.

    write_page from fs
    fs_lock
    allocation(GFP_KERNEL)
    reclaim
    pageout
    				write_page from fs
    				fs_lock <-- deadlock

    This patch fixes it by using GFP_NOIO.  In read path, we
    reorganize code flow so that kmap_atomic is called after the
    GFP_NOIO allocation.

    Cc: stable@vger.kernel.org
    Acked-by: Jerome Marchand <jmarchand@redhat.com>
    Acked-by: Nitin Gupta <ngupta@vflare.org>
    [ penberg@kernel.org: don't use GFP_ATOMIC ]
    Signed-off-by: Pekka Enberg <penberg@kernel.org>
    Signed-off-by: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 0d145a501778042d0411c843ed5b468b41f8a171
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Wed Jan 30 09:36:52 2013 -0600

    staging: zsmalloc: remove unused pool name

    zs_create_pool() currently takes a name argument which is
    never used in any useful way.

    This patch removes it.

    Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
    Acked-by: Nitin Gupta <ngupta@vflare.org>
    Acked-by: Rik van Riel <riel@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 8f5f90a872c38b4e78f3cc95e8a25434b98e4db2
Merge: c0cd2da 949db15
Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date:   Fri Jan 25 21:25:02 2013 -0800

    Merge 3.8-rc5 into staging-next

    This resolves a merge issue with a iio driver, and the zram code.

    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit d178a07c4bd380492b6aca9e5d3985c19ca88fdb
Author: Davidlohr Bueso <davidlohr.bueso@hp.com>
Date:   Tue Jan 1 21:24:29 2013 -0800

    staging: zram: drop zram_stat_dec/inc functions

    It seems like an overkill to have adding and subtracting
    1 functions from the 32bit counters. Just do it directly.

    Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit cad683fb9d53fa2cbcf82660e663fa1180f86797
Author: Davidlohr Bueso <davidlohr.bueso@hp.com>
Date:   Tue Jan 1 21:24:22 2013 -0800

    staging: zram: show correct disksize

    The ->disksize variable stores values in units of bytes,
    print the correct size in Kb

    Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ca3d70bd68455133eabcb8a0ae1b40254d87188b
Author: Davidlohr Bueso <davidlohr.bueso@hp.com>
Date:   Tue Jan 1 21:24:13 2013 -0800

    staging: zram: simplify num_devices paramater

    Simplify dealing with num_devices when initializing zram.
    Also cleanup some of the output messages.

    Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 397c60668aa5ae7130b5ad4e73870d7b8a787085
Author: Nitin Gupta <ngupta@vflare.org>
Date:   Wed Jan 2 08:53:41 2013 -0800

    staging: zram: fix invalid memory references during disk write

    Fixes a bug introduced by commit c8f2f0db1 ("zram: Fix handling
    of incompressible pages") which caused invalid memory references
    during disk write. Invalid references could occur in two cases:
     - Incoming data expands on compression: In this case, reference was
    made to kunmap()'ed bio page.
     - Partial (non PAGE_SIZE) write with incompressible data: In this
    case, reference was made to a kfree()'ed buffer.

    Fixes bug 50081:
    https://bugzilla.kernel.org/show_bug.cgi?id=50081

    Signed-off-by: Nitin Gupta <ngupta@vflare.org>
    Cc: stable <stable@vger.kernel.org>
    Reported-by: Mihail Kasadjikov <hamer.mk@gmail.com>
    Reported-by: Tomas M <tomas@slax.org>
    Reviewed-by: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit dbc320f7490933eb6a073d82aceac75d5e7ce82b
Author: Masanari Iida <standby24x7@gmail.com>
Date:   Mon Jan 7 23:28:10 2013 +0900

    staging: Add angle bracket before and after the URL

    Add missing angle bracket before and after the URL.

    Signed-off-by: Masanari Iida <standby24x7@gmail.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 26907840e63b3187266db1865e76ea9e98b01b19
Author: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Date:   Tue Oct 30 22:42:31 2012 +0300

    staging: zram: handle mem suffixes in disk size zram_sysfs parameter

    Use memparse() to allow mem suffixes in disksize sysfs number.
    Examples:
        echo 256K > /sys/block/zram0/disksize
        echo 512M > /sys/block/zram0/disksize
        echo 1G > /sys/block/zram0/disksize

    Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
    Reviewed-by: Nitin Gupta <ngupta@vflare.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 37b51fdddf64e7ba0971d070428655f8d6f36578
Author: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Date:   Tue Oct 30 22:40:23 2012 +0300

    staging: zram: factor-out zram_decompress_page() function

    zram_bvec_read() shared decompress functionality with zram_read_before_write() function.
    Factor-out and make commonly used zram_decompress_page() function, which also simplified
    error handling in zram_bvec_read().

    Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
    Reviewed-by: Nitin Gupta <ngupta@vflare.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit cb1f6268acd7f1bca7153fa9ca187ffb73f60ab8
Merge: d9ff393 8f0d816
Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date:   Mon Oct 29 08:37:12 2012 -0700

    Merge 3.7-rc3 into staging-next

    This resolves the conflict with:
    	drivers/staging/comedi/drivers/amplc_dio200.c
    and syncs up the changes that happened in the staging directory for
    3.7-rc3.

    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit c8f2f0db1d0294aaf37e8a85bea9bbc4aaf5c0fe
Author: Nitin Gupta <ngupta@vflare.org>
Date:   Wed Oct 10 17:42:18 2012 -0700

    staging: zram: Fix handling of incompressible pages

    Change 130f315a (staging: zram: remove special handle of uncompressed page)
    introduced a bug in the handling of incompressible pages which resulted in
    memory allocation failure for such pages.

    When a page expands on compression, say from 4K to 4K+30, we were trying to
    do zsmalloc(pool, 4K+30). However, the maximum size which zsmalloc can
    allocate is PAGE_SIZE (for obvious reasons), so such allocation requests
    always return failure (0).

    For a page that has compressed size larger than the original size (this may
    happen with already compressed or random data), there is no point storing
    the compressed version as that would take more space and would also require
    time for decompression when needed again. So, the fix is to store any page,
    whose compressed size exceeds a threshold (max_zpage_size), as-it-is i.e.
    without compression.  Memory required for storing this uncompressed page can
    then be requested from zsmalloc which supports PAGE_SIZE sized allocations.

    Lastly, the fix checks that we do not attempt to "decompress" the page which
    we stored in the uncompressed form -- we just memcpy() out such pages.

    Signed-off-by: Nitin Gupta <ngupta@vflare.org>
    Reported-by: viechweg@gmail.com
    Reported-by: paerley@gmail.com
    Reported-by: wu.tommy@gmail.com
    Acked-by: Minchan Kim <minchan@kernel.org>
    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 55dcbbb1bf7eef83bcd3e0ba8de0b359a45804ed
Author: Minchan Kim <minchan@kernel.org>
Date:   Wed Oct 10 08:49:52 2012 +0900

    staging: zram: correct obsolete comment on max_zpage_size

    Zram doesn't use xv_malloc any more so it doesn't have
    limitation about zobj_header.

    Signed-off-by: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit b74185108668ef966e663878adbad65e03bfcb43
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Mon Jul 2 16:15:52 2012 -0500

    staging: zsmalloc: add mapping modes

    This patch improves mapping performance in zsmalloc by getting
    usage information from the user in the form of a "mapping mode"
    and using it to avoid unnecessary copying for objects that span
    pages.

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

commit 6e2361720b9da9ec830d407da058ca1827e62b12
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Mon Jun 25 11:14:36 2012 -0500

    staging: zram/zcache: swtich Kconfig dependency from X86 to ZSMALLOC

    This patch switches zcache and zram dependency to ZSMALLOC
    rather than X86.  There is no net change since ZSMALLOC
    depends on X86, however, this prevent further changes to
    these files as zsmalloc dependencies change.

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

commit 80677c2538283678c7b2ef7ebbd653a3fa54d086
Author: Sam Hansen <solid.se7en@gmail.com>
Date:   Thu Jun 7 16:03:48 2012 -0700

    staging: zram: conventions, __aligned() attribute

    Using the __aligned() attribute in favor of __attribute__((aligned(size)))

    Signed-off-by: Sam Hansen <solid.se7en@gmail.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 94b8435ff4d46dde75173da45564b0d65889dc64
Author: Sam Hansen <solid.se7en@gmail.com>
Date:   Thu Jun 7 16:03:47 2012 -0700

    staging: zram: conventions pr_warning -> pr_warn()

    Porting zram to use the pr_warn() function instead of the deprecated
    pr_warning().

    Signed-off-by: Sam Hansen <solid.se7en@gmail.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 130f315a174d127cbb90d4d1a4a7088dbcf930b5
Author: Minchan Kim <minchan@kernel.org>
Date:   Fri Jun 8 15:39:27 2012 +0900

    staging: zram: remove special handle of uncompressed page

    xvmalloc can't handle PAGE_SIZE page so that zram have to
    handle it specially but zsmalloc can do it so let's remove
    unnecessary special handling code.

    Quote from Nitin
    "I think page vs handle distinction was added since xvmalloc could not
    handle full page allocation. Now that zsmalloc allows full page
    allocation, we can just use it for both cases. This would also allow
    removing the ZRAM_UNCOMPRESSED flag. The only downside will be slightly
    slower code path for full page allocation but this event is anyways
    supposed to be rare, so should be fine."

    1. This patch reduces code very much.

     drivers/staging/zram/zram_drv.c   |  104 +++++--------------------------------
     drivers/staging/zram/zram_drv.h   |   17 +-----
     drivers/staging/zram/zram_sysfs.c |    6 +--
     3 files changed, 15 insertions(+), 112 deletions(-)

    2. change pages_expand with bad_compress so it can count
       bad compression(above 75%) ratio.

    3. remove zobj_header which is for back-reference for defragmentation
       because firstly, it's not used at the moment and zsmalloc can't handle
       bigger size than PAGE_SIZE so zram can't do it any more without redesign.

    Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
    Signed-off-by: Minchan Kim <minchan@kernel.org>
    Acked-by: Nitin Gupta <ngupta@vflare.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 374a69191d12a0525b7ffe1197abc30c4795a230
Author: Minchan Kim <minchan@kernel.org>
Date:   Fri Jun 8 15:39:26 2012 +0900

    staging: zram: fix random data read

    fd1a30de makes a bug that it uses (struct page *) as zsmalloc's handle
    although it's a uncompressed page so that it can access random page,
    return random data or even crashed by get_first_page in zs_map_object.

    Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
    Cc: Jerome Marchand <jmarchan@redhat.com>
    Signed-off-by: Minchan Kim <minchan@kernel.org>
    Acked-by: Nitin Gupta <ngupta@vflare.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit c234434835b1f4bad9bdbae6710044cba387c9e5
Author: Minchan Kim <minchan@kernel.org>
Date:   Fri Jun 8 15:39:25 2012 +0900

    staging: zsmalloc: zsmalloc: use unsigned long instead of void *

    We should use unsigned long as handle instead of void * to avoid any
    confusion. Without this, users may just treat zs_malloc return value as
    a pointer and try to deference it.

    This patch passed compile test(zram, zcache and ramster) and zram is
    tested on qemu.

    changelog
      * from v2
    	- remove hval pointed out by Nitin
    	- based on next-20120607
      * from v1
    	- change zcache's zv_create return value
    	- baesd on next-20120604

    Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
    Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
    Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    Signed-off-by: Minchan Kim <minchan@kernel.org>
    Acked-by: Nitin Gupta <ngupta@vflare.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Change-Id: I5157794e120bbae7ba1e5d0f122dae4fba4a079b
Signed-off-by: Larry Bassel <lbassel@codeaurora.org>

5 files changed, 245 insertions, 372 deletions

diff --git a/drivers/staging/zram/Kconfig b/drivers/staging/zram/Kconfig
index be5abe8e794..983314c4134 100644
--- a/drivers/staging/zram/Kconfig
+++ b/drivers/staging/zram/Kconfig
@@ -14,7 +14,7 @@ config ZRAM
 	  disks and maybe many more.
 
 	  See zram.txt for more information.
-	  Project home: http://compcache.googlecode.com/
+	  Project home: <https://compcache.googlecode.com/>
 
 config ZRAM_DEBUG
 	bool "Compressed RAM block device debug support"
diff --git a/drivers/staging/zram/zram.txt b/drivers/staging/zram/zram.txt
index 5f75d298756..765d790ae83 100644
--- a/drivers/staging/zram/zram.txt
+++ b/drivers/staging/zram/zram.txt
@@ -23,17 +23,17 @@ Following shows a typical sequence of steps for using zram.
 	This creates 4 devices: /dev/zram{0,1,2,3}
 	(num_devices parameter is optional. Default: 1)
 
-2) Set Disksize (Optional):
-	Set disk size by writing the value to sysfs node 'disksize'
-	(in bytes). If disksize is not given, default value of 25%
-	of RAM is used.
-
-	# Initialize /dev/zram0 with 50MB disksize
-	echo $((50*1024*1024)) > /sys/block/zram0/disksize
-
-	NOTE: disksize cannot be changed if the disk contains any
-	data. So, for such a disk, you need to issue 'reset' (see below)
-	before you can change its disksize.
+2) Set Disksize
+        Set disk size by writing the value to sysfs node 'disksize'.
+        The value can be either in bytes or you can use mem suffixes.
+        Examples:
+            # Initialize /dev/zram0 with 50MB disksize
+            echo $((50*1024*1024)) > /sys/block/zram0/disksize
+
+            # Using mem suffixes
+            echo 256K > /sys/block/zram0/disksize
+            echo 512M > /sys/block/zram0/disksize
+            echo 1G > /sys/block/zram0/disksize
 
 3) Activate:
 	mkswap /dev/zram0
@@ -65,8 +65,9 @@ Following shows a typical sequence of steps for using zram.
 	echo 1 > /sys/block/zram0/reset
 	echo 1 > /sys/block/zram1/reset
 
-	(This frees all the memory allocated for the given device).
-
+	This frees all the memory allocated for the given device and
+	resets the disksize to zero. You must set the disksize again
+	before reusing the device.
 
 Please report any problems at:
  - Mailing list: linux-mm-cc at laptop dot org
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index df26f6c6353..e34e3fe0ae2 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -40,17 +40,7 @@ static int zram_major;
 struct zram *zram_devices;
 
 /* Module params (documentation at end) */
-static unsigned int num_devices;
-
-static void zram_stat_inc(u32 *v)
-{
-	*v = *v + 1;
-}
-
-static void zram_stat_dec(u32 *v)
-{
-	*v = *v - 1;
-}
+static unsigned int num_devices = 1;
 
 static void zram_stat64_add(struct zram *zram, u64 *v, u64 inc)
 {
@@ -71,22 +61,22 @@ static void zram_stat64_inc(struct zram *zram, u64 *v)
 	zram_stat64_add(zram, v, 1);
 }
 
-static int zram_test_flag(struct zram *zram, u32 index,
+static int zram_test_flag(struct zram_meta *meta, u32 index,
 			enum zram_pageflags flag)
 {
-	return zram->table[index].flags & BIT(flag);
+	return meta->table[index].flags & BIT(flag);
 }
 
-static void zram_set_flag(struct zram *zram, u32 index,
+static void zram_set_flag(struct zram_meta *meta, u32 index,
 			enum zram_pageflags flag)
 {
-	zram->table[index].flags |= BIT(flag);
+	meta->table[index].flags |= BIT(flag);
 }
 
-static void zram_clear_flag(struct zram *zram, u32 index,
+static void zram_clear_flag(struct zram_meta *meta, u32 index,
 			enum zram_pageflags flag)
 {
-	zram->table[index].flags &= ~BIT(flag);
+	meta->table[index].flags &= ~BIT(flag);
 }
 
 static int page_zero_filled(void *ptr)
@@ -104,70 +94,38 @@ static int page_zero_filled(void *ptr)
 	return 1;
 }
 
-static void zram_set_disksize(struct zram *zram, size_t totalram_bytes)
-{
-	if (!zram->disksize) {
-		pr_info(
-		"disk size not provided. You can use disksize_kb module "
-		"param to specify size.\nUsing default: (%u%% of RAM).\n",
-		default_disksize_perc_ram
-		);
-		zram->disksize = default_disksize_perc_ram *
-					(totalram_bytes / 100);
-	}
-
-	if (zram->disksize > 2 * (totalram_bytes)) {
-		pr_info(
-		"There is little point creating a zram of greater than "
-		"twice the size of memory since we expect a 2:1 compression "
-		"ratio. Note that zram uses about 0.1%% of the size of "
-		"the disk when not in use so a huge zram is "
-		"wasteful.\n"
-		"\tMemory Size: %zu kB\n"
-		"\tSize you selected: %llu kB\n"
-		"Continuing anyway ...\n",
-		totalram_bytes >> 10, zram->disksize
-		);
-	}
-
-	zram->disksize &= PAGE_MASK;
-}
-
 static void zram_free_page(struct zram *zram, size_t index)
 {
-	void *handle = zram->table[index].handle;
+	struct zram_meta *meta = zram->meta;
+	unsigned long handle = meta->table[index].handle;
+	u16 size = meta->table[index].size;
 
 	if (unlikely(!handle)) {
 		/*
 		 * No memory is allocated for zero filled pages.
 		 * Simply clear zero page flag.
 		 */
-		if (zram_test_flag(zram, index, ZRAM_ZERO)) {
-			zram_clear_flag(zram, index, ZRAM_ZERO);
-			zram_stat_dec(&zram->stats.pages_zero);
+		if (zram_test_flag(meta, index, ZRAM_ZERO)) {
+			zram_clear_flag(meta, index, ZRAM_ZERO);
+			zram->stats.pages_zero--;
 		}
 		return;
 	}
 
-	if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
-		__free_page(handle);
-		zram_clear_flag(zram, index, ZRAM_UNCOMPRESSED);
-		zram_stat_dec(&zram->stats.pages_expand);
-		goto out;
-	}
+	if (unlikely(size > max_zpage_size))
+		zram->stats.bad_compress--;
 
-	zs_free(zram->mem_pool, handle);
+	zs_free(meta->mem_pool, handle);
 
-	if (zram->table[index].size <= PAGE_SIZE / 2)
-		zram_stat_dec(&zram->stats.good_compress);
+	if (size <= PAGE_SIZE / 2)
+		zram->stats.good_compress--;
 
-out:
 	zram_stat64_sub(zram, &zram->stats.compr_size,
-			zram->table[index].size);
-	zram_stat_dec(&zram->stats.pages_stored);
+			meta->table[index].size);
+	zram->stats.pages_stored--;
 
-	zram->table[index].handle = NULL;
-	zram->table[index].size = 0;
+	meta->table[index].handle = 0;
+	meta->table[index].size = 0;
 }
 
 static void handle_zero_page(struct bio_vec *bvec)
@@ -175,25 +133,9 @@ static void handle_zero_page(struct bio_vec *bvec)
 	struct page *page = bvec->bv_page;
 	void *user_mem;
 
-	user_mem = kmap_atomic(page, KM_USER0);
+	user_mem = kmap_atomic(page);
 	memset(user_mem + bvec->bv_offset, 0, bvec->bv_len);
-	kunmap_atomic(user_mem, KM_USER0);
-
-	flush_dcache_page(page);
-}
-
-static void handle_uncompressed_page(struct zram *zram, struct bio_vec *bvec,
-				     u32 index, int offset)
-{
-	struct page *page = bvec->bv_page;
-	unsigned char *user_mem, *cmem;
-
-	user_mem = kmap_atomic(page, KM_USER0);
-	cmem = kmap_atomic(zram->table[index].handle, KM_USER1);
-
-	memcpy(user_mem + bvec->bv_offset, cmem + offset, bvec->bv_len);
-	kunmap_atomic(user_mem, KM_USER0);
-	kunmap_atomic(cmem, KM_USER1);
+	kunmap_atomic(user_mem);
 
 	flush_dcache_page(page);
 }
@@ -203,64 +145,26 @@ static inline int is_partial_io(struct bio_vec *bvec)
 	return bvec->bv_len != PAGE_SIZE;
 }
 
-static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
-			  u32 index, int offset, struct bio *bio)
+static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
 {
-	int ret;
-	size_t clen;
-	struct page *page;
-	struct zobj_header *zheader;
-	unsigned char *user_mem, *cmem, *uncmem = NULL;
-
-	page = bvec->bv_page;
-
-	if (zram_test_flag(zram, index, ZRAM_ZERO)) {
-		handle_zero_page(bvec);
-		return 0;
-	}
-
-	/* Requested page is not present in compressed area */
-	if (unlikely(!zram->table[index].handle)) {
-		pr_debug("Read before write: sector=%lu, size=%u",
-			 (ulong)(bio->bi_sector), bio->bi_size);
-		handle_zero_page(bvec);
-		return 0;
-	}
+	int ret = LZO_E_OK;
+	size_t clen = PAGE_SIZE;
+	unsigned char *cmem;
+	struct zram_meta *meta = zram->meta;
+	unsigned long handle = meta->table[index].handle;
 
-	/* Page is stored uncompressed since it's incompressible */
-	if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
-		handle_uncompressed_page(zram, bvec, index, offset);
+	if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) {
+		memset(mem, 0, PAGE_SIZE);
 		return 0;
 	}
 
-	if (is_partial_io(bvec)) {
-		/* Use  a temporary buffer to decompress the page */
-		uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL);
-		if (!uncmem) {
-			pr_info("Error allocating temp memory!\n");
-			return -ENOMEM;
-		}
-	}
-
-	user_mem = kmap_atomic(page, KM_USER0);
-	if (!is_partial_io(bvec))
-		uncmem = user_mem;
-	clen = PAGE_SIZE;
-
-	cmem = zs_map_object(zram->mem_pool, zram->table[index].handle);
-
-	ret = lzo1x_decompress_safe(cmem + sizeof(*zheader),
-				    zram->table[index].size,
-				    uncmem, &clen);
-
-	if (is_partial_io(bvec)) {
-		memcpy(user_mem + bvec->bv_offset, uncmem + offset,
-		       bvec->bv_len);
-		kfree(uncmem);
-	}
-
-	zs_unmap_object(zram->mem_pool, zram->table[index].handle);
-	kunmap_atomic(user_mem, KM_USER0);
+	cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
+	if (meta->table[index].size == PAGE_SIZE)
+		memcpy(mem, cmem, PAGE_SIZE);
+	else
+		ret = lzo1x_decompress_safe(cmem, meta->table[index].size,
+						mem, &clen);
+	zs_unmap_object(meta->mem_pool, handle);
 
 	/* Should NEVER happen. Return bio error if it does. */
 	if (unlikely(ret != LZO_E_OK)) {
@@ -269,182 +173,165 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 		return ret;
 	}
 
-	flush_dcache_page(page);
-
 	return 0;
 }
 
-static int zram_read_before_write(struct zram *zram, char *mem, u32 index)
+static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
+			  u32 index, int offset, struct bio *bio)
 {
 	int ret;
-	size_t clen = PAGE_SIZE;
-	struct zobj_header *zheader;
-	unsigned char *cmem;
+	struct page *page;
+	unsigned char *user_mem, *uncmem = NULL;
+	struct zram_meta *meta = zram->meta;
+	page = bvec->bv_page;
 
-	if (zram_test_flag(zram, index, ZRAM_ZERO) ||
-	    !zram->table[index].handle) {
-		memset(mem, 0, PAGE_SIZE);
+	if (unlikely(!meta->table[index].handle) ||
+			zram_test_flag(meta, index, ZRAM_ZERO)) {
+		handle_zero_page(bvec);
 		return 0;
 	}
 
-	cmem = zs_map_object(zram->mem_pool, zram->table[index].handle);
+	if (is_partial_io(bvec))
+		/* Use  a temporary buffer to decompress the page */
+		uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
 
-	/* Page is stored uncompressed since it's incompressible */
-	if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
-		memcpy(mem, cmem, PAGE_SIZE);
-		kunmap_atomic(cmem, KM_USER0);
-		return 0;
-	}
+	user_mem = kmap_atomic(page);
+	if (!is_partial_io(bvec))
+		uncmem = user_mem;
 
-	ret = lzo1x_decompress_safe(cmem + sizeof(*zheader),
-				    zram->table[index].size,
-				    mem, &clen);
-	zs_unmap_object(zram->mem_pool, zram->table[index].handle);
+	if (!uncmem) {
+		pr_info("Unable to allocate temp memory\n");
+		ret = -ENOMEM;
+		goto out_cleanup;
+	}
 
+	ret = zram_decompress_page(zram, uncmem, index);
 	/* Should NEVER happen. Return bio error if it does. */
-	if (unlikely(ret != LZO_E_OK)) {
-		pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
-		zram_stat64_inc(zram, &zram->stats.failed_reads);
-		return ret;
-	}
+	if (unlikely(ret != LZO_E_OK))
+		goto out_cleanup;
 
-	return 0;
+	if (is_partial_io(bvec))
+		memcpy(user_mem + bvec->bv_offset, uncmem + offset,
+				bvec->bv_len);
+
+	flush_dcache_page(page);
+	ret = 0;
+out_cleanup:
+	kunmap_atomic(user_mem);
+	if (is_partial_io(bvec))
+		kfree(uncmem);
+	return ret;
 }
 
 static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 			   int offset)
 {
-	int ret;
-	u32 store_offset;
+	int ret = 0;
 	size_t clen;
-	void *handle;
-	struct zobj_header *zheader;
-	struct page *page, *page_store;
+	unsigned long handle;
+	struct page *page;
 	unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
+	struct zram_meta *meta = zram->meta;
 
 	page = bvec->bv_page;
-	src = zram->compress_buffer;
+	src = meta->compress_buffer;
 
 	if (is_partial_io(bvec)) {
 		/*
 		 * This is a partial IO. We need to read the full page
 		 * before to write the changes.
 		 */
-		uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL);
+		uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
 		if (!uncmem) {
-			pr_info("Error allocating temp memory!\n");
 			ret = -ENOMEM;
 			goto out;
 		}
-		ret = zram_read_before_write(zram, uncmem, index);
-		if (ret) {
-			kfree(uncmem);
+		ret = zram_decompress_page(zram, uncmem, index);
+		if (ret)
 			goto out;
-		}
 	}
 
 	/*
 	 * System overwrites unused sectors. Free memory associated
 	 * with this sector now.
 	 */
-	if (zram->table[index].handle ||
-	    zram_test_flag(zram, index, ZRAM_ZERO))
+	if (meta->table[index].handle ||
+	    zram_test_flag(meta, index, ZRAM_ZERO))
 		zram_free_page(zram, index);
 
-	user_mem = kmap_atomic(page, KM_USER0);
+	user_mem = kmap_atomic(page);
 
-	if (is_partial_io(bvec))
+	if (is_partial_io(bvec)) {
 		memcpy(uncmem + offset, user_mem + bvec->bv_offset,
 		       bvec->bv_len);
-	else
+		kunmap_atomic(user_mem);
+		user_mem = NULL;
+	} else {
 		uncmem = user_mem;
+	}
 
 	if (page_zero_filled(uncmem)) {
-		kunmap_atomic(user_mem, KM_USER0);
+		kunmap_atomic(user_mem);
 		if (is_partial_io(bvec))
 			kfree(uncmem);
-		zram_stat_inc(&zram->stats.pages_zero);
-		zram_set_flag(zram, index, ZRAM_ZERO);
+		zram->stats.pages_zero++;
+		zram_set_flag(meta, index, ZRAM_ZERO);
 		ret = 0;
 		goto out;
 	}
 
 	ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen,
-			       zram->compress_workmem);
+			       meta->compress_workmem);
 
-	kunmap_atomic(user_mem, KM_USER0);
-	if (is_partial_io(bvec))
-			kfree(uncmem);
+	if (!is_partial_io(bvec)) {
+		kunmap_atomic(user_mem);
+		user_mem = NULL;
+		uncmem = NULL;
+	}
 
 	if (unlikely(ret != LZO_E_OK)) {
 		pr_err("Compression failed! err=%d\n", ret);
 		goto out;
 	}
 
-	/*
-	 * Page is incompressible. Store it as-is (uncompressed)
-	 * since we do not want to return too many disk write
-	 * errors which has side effect of hanging the system.
-	 */
 	if (unlikely(clen > max_zpage_size)) {
+		zram->stats.bad_compress++;
 		clen = PAGE_SIZE;
-		page_store = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
-		if (unlikely(!page_store)) {
-			pr_info("Error allocating memory for "
-				"incompressible page: %u\n", index);
-			ret = -ENOMEM;
-			goto out;
-		}
-
-		store_offset = 0;
-		zram_set_flag(zram, index, ZRAM_UNCOMPRESSED);
-		zram_stat_inc(&zram->stats.pages_expand);
-		handle = page_store;
-		src = kmap_atomic(page, KM_USER0);
-		cmem = kmap_atomic(page_store, KM_USER1);
-		goto memstore;
+		src = NULL;
+		if (is_partial_io(bvec))
+			src = uncmem;
 	}
 
-	handle = zs_malloc(zram->mem_pool, clen + sizeof(*zheader));
+	handle = zs_malloc(meta->mem_pool, clen);
 	if (!handle) {
 		pr_info("Error allocating memory for compressed "
 			"page: %u, size=%zu\n", index, clen);
 		ret = -ENOMEM;
 		goto out;
 	}
-	cmem = zs_map_object(zram->mem_pool, handle);
-
-memstore:
-#if 0
-	/* Back-reference needed for memory defragmentation */
-	if (!zram_test_flag(zram, index, ZRAM_UNCOMPRESSED)) {
-		zheader = (struct zobj_header *)cmem;
-		zheader->table_idx = index;
-		cmem += sizeof(*zheader);
-	}
-#endif
+	cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
 
+	if ((clen == PAGE_SIZE) && !is_partial_io(bvec))
+		src = kmap_atomic(page);
 	memcpy(cmem, src, clen);
+	if ((clen == PAGE_SIZE) && !is_partial_io(bvec))
+		kunmap_atomic(src);
 
-	if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
-		kunmap_atomic(cmem, KM_USER1);
-		kunmap_atomic(src, KM_USER0);
-	} else {
-		zs_unmap_object(zram->mem_pool, handle);
-	}
+	zs_unmap_object(meta->mem_pool, handle);
 
-	zram->table[index].handle = handle;
-	zram->table[index].size = clen;
+	meta->table[index].handle = handle;
+	meta->table[index].size = clen;
 
 	/* Update stats */
 	zram_stat64_add(zram, &zram->stats.compr_size, clen);
-	zram_stat_inc(&zram->stats.pages_stored);
+	zram->stats.pages_stored++;
 	if (clen <= PAGE_SIZE / 2)
-		zram_stat_inc(&zram->stats.good_compress);
-
-	return 0;
+		zram->stats.good_compress++;
 
 out:
+	if (is_partial_io(bvec))
+		kfree(uncmem);
+
 	if (ret)
 		zram_stat64_inc(zram, &zram->stats.failed_writes);
 	return ret;
@@ -550,69 +437,56 @@ static inline int valid_io_request(struct zram *zram, struct bio *bio)
 /*
  * Handler function for all zram I/O requests.
  */
-static int zram_make_request(struct request_queue *queue, struct bio *bio)
+static void zram_make_request(struct request_queue *queue, struct bio *bio)
 {
 	struct zram *zram = queue->queuedata;
 
-	if (unlikely(!zram->init_done) && zram_init_device(zram))
-		goto error;
-
 	down_read(&zram->init_lock);
 	if (unlikely(!zram->init_done))
-		goto error_unlock;
+		goto error;
 
 	if (!valid_io_request(zram, bio)) {
 		zram_stat64_inc(zram, &zram->stats.invalid_io);
-		goto error_unlock;
+		goto error;
 	}
 
 	__zram_make_request(zram, bio, bio_data_dir(bio));
 	up_read(&zram->init_lock);
 
-	return 0;
+	return;
 
-error_unlock:
-	up_read(&zram->init_lock);
 error:
+	up_read(&zram->init_lock);
 	bio_io_error(bio);
-	return 0;
 }
 
-void __zram_reset_device(struct zram *zram)
+static void __zram_reset_device(struct zram *zram)
 {
 	size_t index;
+	struct zram_meta *meta;
 
-	zram->init_done = 0;
-
-	/* Free various per-device buffers */
-	kfree(zram->compress_workmem);
-	free_pages((unsigned long)zram->compress_buffer, 1);
+	if (!zram->init_done)
+		return;
 
-	zram->compress_workmem = NULL;
-	zram->compress_buffer = NULL;
+	meta = zram->meta;
+	zram->init_done = 0;
 
 	/* Free all pages that are still in this zram device */
 	for (index = 0; index < zram->disksize >> PAGE_SHIFT; index++) {
-		void *handle = zram->table[index].handle;
+		unsigned long handle = meta->table[index].handle;
 		if (!handle)
 			continue;
 
-		if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED)))
-			__free_page(handle);
-		else
-			zs_free(zram->mem_pool, handle);
+		zs_free(meta->mem_pool, handle);
 	}
 
-	vfree(zram->table);
-	zram->table = NULL;
-
-	zs_destroy_pool(zram->mem_pool);
-	zram->mem_pool = NULL;
-
+	zram_meta_free(zram->meta);
+	zram->meta = NULL;
 	/* Reset stats */
 	memset(&zram->stats, 0, sizeof(zram->stats));
 
 	zram->disksize = 0;
+	set_capacity(zram->disk, 0);
 }
 
 void zram_reset_device(struct zram *zram)
@@ -622,69 +496,84 @@ void zram_reset_device(struct zram *zram)
 	up_write(&zram->init_lock);
 }
 
-int zram_init_device(struct zram *zram)
+void zram_meta_free(struct zram_meta *meta)
 {
-	int ret;
-	size_t num_pages;
-
-	down_write(&zram->init_lock);
+	zs_destroy_pool(meta->mem_pool);
+	kfree(meta->compress_workmem);
+	free_pages((unsigned long)meta->compress_buffer, 1);
+	vfree(meta->table);
+	kfree(meta);
+}
 
-	if (zram->init_done) {
-		up_write(&zram->init_lock);
-		return 0;
-	}
+struct zram_meta *zram_meta_alloc(u64 disksize)
+{
+	size_t num_pages;
+	struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
+	if (!meta)
+		goto out;
 
-	zram_set_disksize(zram, totalram_pages << PAGE_SHIFT);
+	meta->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
+	if (!meta->compress_workmem)
+		goto free_meta;
 
-	zram->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
-	if (!zram->compress_workmem) {
-		pr_err("Error allocating compressor working memory!\n");
-		ret = -ENOMEM;
-		goto fail_no_table;
-	}
-
-	zram->compress_buffer =
+	meta->compress_buffer =
 		(void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
-	if (!zram->compress_buffer) {
+	if (!meta->compress_buffer) {
 		pr_err("Error allocating compressor buffer space\n");
-		ret = -ENOMEM;
-		goto fail_no_table;
+		goto free_workmem;
 	}
 
-	num_pages = zram->disksize >> PAGE_SHIFT;
-	zram->table = vzalloc(num_pages * sizeof(*zram->table));
-	if (!zram->table) {
+	num_pages = disksize >> PAGE_SHIFT;
+	meta->table = vzalloc(num_pages * sizeof(*meta->table));
+	if (!meta->table) {
 		pr_err("Error allocating zram address table\n");
-		ret = -ENOMEM;
-		goto fail_no_table;
+		goto free_buffer;
 	}
 
-	set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
+	meta->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM);
+	if (!meta->mem_pool) {
+		pr_err("Error creating memory pool\n");
+		goto free_table;
+	}
 
-	/* zram devices sort of resembles non-rotational disks */
-	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
+	return meta;
 
-	zram->mem_pool = zs_create_pool("zram", GFP_NOIO | __GFP_HIGHMEM);
-	if (!zram->mem_pool) {
-		pr_err("Error creating memory pool\n");
-		ret = -ENOMEM;
-		goto fail;
+free_table:
+	vfree(meta->table);
+free_buffer:
+	free_pages((unsigned long)meta->compress_buffer, 1);
+free_workmem:
+	kfree(meta->compress_workmem);
+free_meta:
+	kfree(meta);
+	meta = NULL;
+out:
+	return meta;
+}
+
+void zram_init_device(struct zram *zram, struct zram_meta *meta)
+{
+	if (zram->disksize > 2 * (totalram_pages << PAGE_SHIFT)) {
+		pr_info(
+		"There is little point creating a zram of greater than "
+		"twice the size of memory since we expect a 2:1 compression "
+		"ratio. Note that zram uses about 0.1%% of the size of "
+		"the disk when not in use so a huge zram is "
+		"wasteful.\n"
+		"\tMemory Size: %lu kB\n"
+		"\tSize you selected: %llu kB\n"
+		"Continuing anyway ...\n",
+		(totalram_pages << PAGE_SHIFT) >> 10, zram->disksize >> 10
+		);
 	}
 
+	/* zram devices sort of resembles non-rotational disks */
+	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
+
+	zram->meta = meta;
 	zram->init_done = 1;
-	up_write(&zram->init_lock);
 
 	pr_debug("Initialization done!\n");
-	return 0;
-
-fail_no_table:
-	/* To prevent accessing table entries during cleanup */
-	zram->disksize = 0;
-fail:
-	__zram_reset_device(zram);
-	up_write(&zram->init_lock);
-	pr_err("Initialization failed: err=%d\n", ret);
-	return ret;
 }
 
 static void zram_slot_free_notify(struct block_device *bdev,
@@ -725,7 +614,7 @@ static int create_device(struct zram *zram, int device_id)
 	zram->disk = alloc_disk(1);
 	if (!zram->disk) {
 		blk_cleanup_queue(zram->queue);
-		pr_warning("Error allocating disk structure for device %d\n",
+		pr_warn("Error allocating disk structure for device %d\n",
 			device_id);
 		ret = -ENOMEM;
 		goto out;
@@ -756,7 +645,7 @@ static int create_device(struct zram *zram, int device_id)
 	ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj,
 				&zram_disk_attr_group);
 	if (ret < 0) {
-		pr_warning("Error creating sysfs group");
+		pr_warn("Error creating sysfs group");
 		goto out;
 	}
 
@@ -790,7 +679,7 @@ static int __init zram_init(void)
 	int ret, dev_id;
 
 	if (num_devices > max_num_devices) {
-		pr_warning("Invalid value for num_devices: %u\n",
+		pr_warn("Invalid value for num_devices: %u\n",
 				num_devices);
 		ret = -EINVAL;
 		goto out;
@@ -798,18 +687,12 @@ static int __init zram_init(void)
 
 	zram_major = register_blkdev(0, "zram");
 	if (zram_major <= 0) {
-		pr_warning("Unable to get major number\n");
+		pr_warn("Unable to get major number\n");
 		ret = -EBUSY;
 		goto out;
 	}
 
-	if (!num_devices) {
-		pr_info("num_devices not specified. Using default: 1\n");
-		num_devices = 1;
-	}
-
 	/* Allocate the device array and initialize each one */
-	pr_info("Creating %u devices ...\n", num_devices);
 	zram_devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL);
 	if (!zram_devices) {
 		ret = -ENOMEM;
@@ -822,6 +705,8 @@ static int __init zram_init(void)
 			goto free_devices;
 	}
 
+	pr_info("Created %u device(s) ...\n", num_devices);
+
 	return 0;
 
 free_devices:
@@ -843,8 +728,7 @@ static void __exit zram_exit(void)
 		zram = &zram_devices[i];
 
 		destroy_device(zram);
-		if (zram->init_done)
-			zram_reset_device(zram);
+		zram_reset_device(zram);
 	}
 
 	unregister_blkdev(zram_major, "zram");
diff --git a/drivers/staging/zram/zram_drv.h b/drivers/staging/zram/zram_drv.h
index 880f01388ed..2d1a3f1e8ed 100644
--- a/drivers/staging/zram/zram_drv.h
+++ b/drivers/staging/zram/zram_drv.h
@@ -26,23 +26,8 @@
  */
 static const unsigned max_num_devices = 32;
 
-/*
- * Stored at beginning of each compressed object.
- *
- * It stores back-reference to table entry which points to this
- * object. This is required to support memory defragmentation.
- */
-struct zobj_header {
-#if 0
-	u32 table_idx;
-#endif
-};
-
 /*-- Configurable parameters */
 
-/* Default zram disk size: 25% of total RAM */
-static const unsigned default_disksize_perc_ram = 25;
-
 /*
  * Pages that compress to size greater than this are stored
  * uncompressed in memory.
@@ -51,8 +36,8 @@ static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
 
 /*
  * NOTE: max_zpage_size must be less than or equal to:
- *   ZS_MAX_ALLOC_SIZE - sizeof(struct zobj_header)
- * otherwise, xv_malloc() would always return failure.
+ *   ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would
+ * always return failure.
  */
 
 /*-- End of configurable params */
@@ -68,9 +53,6 @@ static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
 
 /* Flags for zram pages (table[page_no].flags) */
 enum zram_pageflags {
-	/* Page is stored uncompressed */
-	ZRAM_UNCOMPRESSED,
-
 	/* Page consists entirely of zeros */
 	ZRAM_ZERO,
 
@@ -81,11 +63,11 @@ enum zram_pageflags {
 
 /* Allocated for each disk page */
 struct table {
-	void *handle;
+	unsigned long handle;
 	u16 size;	/* object size (excluding header) */
 	u8 count;	/* object ref count (not yet used) */
 	u8 flags;
-} __attribute__((aligned(4)));
+} __aligned(4);
 
 struct zram_stats {
 	u64 compr_size;		/* compressed size of pages stored */
@@ -98,17 +80,21 @@ struct zram_stats {
 	u32 pages_zero;		/* no. of zero filled pages */
 	u32 pages_stored;	/* no. of pages currently stored */
 	u32 good_compress;	/* % of pages with compression ratio<=50% */
-	u32 pages_expand;	/* % of incompressible pages */
+	u32 bad_compress;	/* % of pages with compression ratio>=75% */
 };
 
-struct zram {
-	struct zs_pool *mem_pool;
+struct zram_meta {
 	void *compress_workmem;
 	void *compress_buffer;
 	struct table *table;
+	struct zs_pool *mem_pool;
+};
+
+struct zram {
+	struct zram_meta *meta;
 	spinlock_t stat64_lock;	/* protect 64-bit stats */
-	struct rw_semaphore lock;	/* protect compression buffers against
-					 * concurrent writes */
+	struct rw_semaphore lock; /* protect compression buffers and table
+				   * against concurrent read and writes */
 	struct request_queue *queue;
 	struct gendisk *disk;
 	int init_done;
@@ -129,7 +115,9 @@ unsigned int zram_get_num_devices(void);
 extern struct attribute_group zram_disk_attr_group;
 #endif
 
-extern int zram_init_device(struct zram *zram);
-extern void __zram_reset_device(struct zram *zram);
+extern void zram_reset_device(struct zram *zram);
+extern struct zram_meta *zram_meta_alloc(u64 disksize);
+extern void zram_meta_free(struct zram_meta *meta);
+extern void zram_init_device(struct zram *zram, struct zram_meta *meta);
 
 #endif
diff --git a/drivers/staging/zram/zram_sysfs.c b/drivers/staging/zram/zram_sysfs.c
index 5142d074de8..68ccad121f3 100644
--- a/drivers/staging/zram/zram_sysfs.c
+++ b/drivers/staging/zram/zram_sysfs.c
@@ -15,6 +15,7 @@
 #include <linux/device.h>
 #include <linux/genhd.h>
 #include <linux/mm.h>
+#include <linux/kernel.h>
 
 #include "zram_drv.h"
 
@@ -54,23 +55,27 @@ static ssize_t disksize_show(struct device *dev,
 static ssize_t disksize_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
-	int ret;
 	u64 disksize;
+	struct zram_meta *meta;
 	struct zram *zram = dev_to_zram(dev);
 
-	ret = kstrtoull(buf, 10, &disksize);
-	if (ret)
-		return ret;
+	disksize = memparse(buf, NULL);
+	if (!disksize)
+		return -EINVAL;
 
+	disksize = PAGE_ALIGN(disksize);
+	meta = zram_meta_alloc(disksize);
 	down_write(&zram->init_lock);
 	if (zram->init_done) {
 		up_write(&zram->init_lock);
+		zram_meta_free(meta);
 		pr_info("Cannot change disksize for initialized device\n");
 		return -EBUSY;
 	}
 
-	zram->disksize = PAGE_ALIGN(disksize);
+	zram->disksize = disksize;
 	set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
+	zram_init_device(zram, meta);
 	up_write(&zram->init_lock);
 
 	return len;
@@ -117,11 +122,7 @@ static ssize_t reset_store(struct device *dev,
 	if (bdev)
 		fsync_bdev(bdev);
 
-	down_write(&zram->init_lock);
-	if (zram->init_done)
-		__zram_reset_device(zram);
-	up_write(&zram->init_lock);
-
+	zram_reset_device(zram);
 	return len;
 }
 
@@ -192,11 +193,10 @@ static ssize_t mem_used_total_show(struct device *dev,
 {
 	u64 val = 0;
 	struct zram *zram = dev_to_zram(dev);
+	struct zram_meta *meta = zram->meta;
 
-	if (zram->init_done) {
-		val = zs_get_total_size_bytes(zram->mem_pool) +
-			((u64)(zram->stats.pages_expand) << PAGE_SHIFT);
-	}
+	if (zram->init_done)
+		val = zs_get_total_size_bytes(meta->mem_pool);
 
 	return sprintf(buf, "%llu\n", val);
 }