drivers/staging: Configurable android log buffer sizes

Purpose is reduce the buffer size accordingly and observe savings
in the total kernel static size, which is useful for
memory constrained devices.

Signed-off-by: Bhargav Upperla <bhargavuln@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
scsi: ufs: long sequential read/write tests

This test adds the ability to test the UFS task management feature
in the driver. It loads the queue with requests in order to allow
the task management to operate in full capacity.

Modify test-iosched infrastructure to support the new tests:
- expose  check_test_completion()

Note: we submit 16-bio requests since the current HW is very slow
and we don't want to exceed the timeout duration.

Signed-off-by: Dolev Raviv <draviv@codeaurora.org>
Signed-off-by: Lee Susman <lsusman@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
slim_msm: Report flow-error and mask apps slimbus port interrupts

Apps side slimbus ports may overflow/underflow if BAM pipes connected
to those ports don't have descriptors scheduled.
Report such errors and mask the port interrupts until BAM pipes have
descriptors scheduled to avoid interrupts firing multiple times.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
slim_msm: Signal client's completion for per transfer notification

Slimbus ports are connected to BAM pipes and ports inform the pipe
when descriptor's data transfer is done. Clients queue a completion
per descrptor when that descriptor is processed. This completion will
get overwritten if client queues multiple descriptors. Use
per-transfer user-data as client's completion to avoid this problem.
This also reduces controller-driver involvement in data transfer.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
slim_msm: Optimize slimbus data port's connection with BAM pipe

Slimbus data port on apps side can be connected in any diretion (as
source, or as destination). BAM pipe connected to that port should
only be disconnected/reconnected if this port direction changes.
This helps with reducing calls to connect/disconnect BAM pipes.
Allocate descriptors to avoid getting descriptor-space from the
common pool and free them only when the port is deallocated.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
slimbus: Fix port allocation and deallocation for manager's ports

Since Manager's ports don't have any direction when allocated, make
sure the direction is not checked when connect-port is called on a
manager port. Ensure that controller's port resourced are freed-up
when dealloc_mgrports is called.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
slim_msm: Get platform-specific information from platform-data

Number of pipes available to application processor for data channels,
and product-code field of enumeration address needed for setting
these pipes can be different for different platforms.
Store this platform-specific information in platform-data, and get
it from Device-Tree if applicable.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
msm8974: Increase allowed constraint for regulator voltage

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zsmalloc: use 3.10 version of zsmalloc

Author: Arnd Bergmann <arnd@arndb.de>
Date:   Tue Apr 23 18:30:48 2013 +0200

    staging/zsmalloc: don't use pgtable-mapping from modules

    Building zsmalloc as a module does not work on ARM because it uses
    an interface that is not exported:

    ERROR: "flush_tlb_kernel_range" [drivers/staging/zsmalloc/zsmalloc.ko] undefined!

    Since this is only used as a performance optimization and only on ARM,
    we can avoid the problem simply by not using that optimization when
    building zsmalloc it is a loadable module.

    flush_tlb_kernel_range is often an inline function, but out of the
    architectures that use an extern function, only powerpc exports
    it.

    Signed-off-by: Arnd Bergmann <arnd@arndb.de>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
    Cc: Nitin Gupta <ngupta@vflare.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit d95abbbb291bf5bce078148f53603ce9c0aa1d44
Author: Joerg Roedel <joro@8bytes.org>
Date:   Wed Mar 27 01:43:14 2013 +0100

    staging: zsmalloc: Fix link error on ARM

    Testing the arm chromebook config against the upstream
    kernel produces a linker error for the zsmalloc module from
    staging. The symbol flush_tlb_kernel_range is not available
    there. Fix this by removing the reimplementation of
    unmap_kernel_range in the zsmalloc module and using the
    function directly. The unmap_kernel_range function is not
    usable by modules, so also disallow building the driver as a
    module for now.

    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: Joerg Roedel <joro@8bytes.org>
    Acked-by: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 22b751c3d0376e86a377e3a0aa2ddbbe9d2eefc1
Author: Mel Gorman <mgorman@suse.de>
Date:   Fri Feb 22 16:34:59 2013 -0800

    mm: rename page struct field helpers

    The function names page_xchg_last_nid(), page_last_nid() and
    reset_page_last_nid() were judged to be inconsistent so rename them to a
    struct_field_op style pattern.  As it looked jarring to have
    reset_page_mapcount() and page_nid_reset_last() beside each other in
    memmap_init_zone(), this patch also renames reset_page_mapcount() to
    page_mapcount_reset().  There are others like init_page_count() but as
    it is used throughout the arch code a rename would likely cause more
    conflicts than it is worth.

    [akpm@linux-foundation.org: fix zcache]
    Signed-off-by: Mel Gorman <mgorman@suse.de>
    Suggested-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.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 9915518887e83764269d5b617d01782893877ed3
Author: Minchan Kim <minchan@kernel.org>
Date:   Mon Jan 28 10:00:08 2013 +0900

    staging: zsmalloc: Fix TLB coherency and build problem

    Recently, Matt Sealey reported he fail to build zsmalloc caused by
    using of local_flush_tlb_kernel_range which are architecture dependent
    function so !CONFIG_SMP in ARM couldn't implement it so it ends up
    build error following as.

      MODPOST 216 modules
      LZMA    arch/arm/boot/compressed/piggy.lzma
      AS      arch/arm/boot/compressed/lib1funcs.o
    ERROR: "v7wbi_flush_kern_tlb_range"
    [drivers/staging/zsmalloc/zsmalloc.ko] undefined!
    make[1]: *** [__modpost] Error 1
    make: *** [modules] Error 2
    make: *** Waiting for unfinished jobs....

    The reason we used that function is copy method by [1]
    was really slow in ARM but at that time.

    More severe problem is ARM can prefetch speculatively on other CPUs
    so under us, other TLBs can have an entry only if we do flush local
    CPU. Russell King pointed that. Thanks!
    We don't have many choices except using flush_tlb_kernel_range.

    My experiment in ARMv7 processor 4 core didn't make any difference with
    zsmapbench[2] between local_flush_tlb_kernel_range and flush_tlb_kernel_range
    but still page-table based is much better than copy-based.

    * bigger is better.

    1. local_flush_tlb_kernel_range: 3918795 mappings
    2. flush_tlb_kernel_range : 3989538 mappings
    3. copy-based: 635158 mappings

    This patch replace local_flush_tlb_kernel_range with
    flush_tlb_kernel_range which are avaialbe in all architectures
    because we already have used it in vmalloc allocator which are
    generic one so build problem should go away and performane loss
    shoud be void.

    [1] f553646, zsmalloc: add page table mapping method
    [2] https://github.com/spartacus06/zsmapbench

    Cc: stable@vger.kernel.org
    Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
    Cc: Russell King <linux@arm.linux.org.uk>
    Cc: Konrad Rzeszutek Wilk <konrad@darnok.org>
    Cc: Nitin Gupta <ngupta@vflare.org>
    Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
    Reported-by: Matt Sealey <matt@genesi-usa.com>
    Signed-off-by: Minchan Kim <minchan@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit d662b8eba94e9f6d4c036719dbf629ef0c9309cf
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Fri Jan 25 11:46:18 2013 -0600

    staging: zsmalloc: make CLASS_DELTA relative to PAGE_SIZE

    Right now ZS_SIZE_CLASS_DELTA is hardcoded to be 16.  This
    creates 254 classes for systems with 4k pages. However, on
    PPC64 with 64k pages, it creates 4095 classes which is far
    too many.

    This patch makes ZS_SIZE_CLASS_DELTA relative to PAGE_SIZE
    so that regardless of the page size, there will be the same
    number of classes.

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

commit 4bbc0bc06b8b0cced31ee17beb753ad51a2e47e7
Author: Davidlohr Bueso <davidlohr.bueso@hp.com>
Date:   Fri Jan 4 12:14:00 2013 -0800

    staging: zsmalloc: comment zs_create_pool function

    Just as with zs_malloc() and zs_map_object(), it is worth
    formally commenting the zs_create_pool() function.

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

commit 0959c63f11c3bbef0a7d6c5011be8d25503f547c
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Wed Aug 8 15:12:17 2012 +0900

    zsmalloc: collapse internal .h into .c

    The patch collapses in the internal zsmalloc_int.h into
    the zsmalloc-main.c file.

    This is done in preparation for the promotion to mm/ where
    separate internal headers are discouraged.

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

commit f553646a67cb215577402cb702b67c8cf8fdb46f
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Wed Jul 18 11:55:56 2012 -0500

    staging: zsmalloc: add page table mapping method

    This patchset provides page mapping via the page table.
    On some archs, most notably ARM, this method has been
    demonstrated to be faster than copying.

    The logic controlling the method selection (copy vs page table)
    is controlled by the definition of USE_PGTABLE_MAPPING which
    is/can be defined for any arch that performs better with page
    table mapping.

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

commit c60369f011251c60de506994aab088f1afb90bf4
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Wed Jul 18 11:55:55 2012 -0500

    staging: zsmalloc: prevent mappping in interrupt context

    Because we use per-cpu mapping areas shared among the
    pools/users, we can't allow mapping in interrupt context
    because it can corrupt another users mappings.

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

commit 6539a36c0cb9ec7f1c1633b535ac83b2bdf0ae6d
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Wed Jul 18 11:55:54 2012 -0500

    staging: zsmalloc: s/firstpage/page in new copy map funcs

    firstpage already has precedent and meaning the first page
    of a zspage.  In the case of the copy mapping functions,
    it is the first of a pair of pages needing to be mapped.

    This patch just renames the firstpage argument to "page" to
    avoid confusion.

    Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
    Acked-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 166cfda752ca22eb6912614993b85f9a997dbd8f
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Mon Jul 2 16:15:51 2012 -0500

    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>

commit 103123305c4f695cbb11555d51a32ea14d6bed05
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Mon Jul 2 16:15:50 2012 -0500

    staging: zsmalloc: add single-page object fastpath in unmap

    Improve zs_unmap_object() performance by adding a fast path for
    objects that don't span pages.

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

commit 5f601902c61e6cda627ec71c10609021067ed0fa
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Mon Jul 2 16:15:49 2012 -0500

    staging: zsmalloc: remove x86 dependency

    This patch replaces the page table assisted object mapping
    method, which has x86 dependencies, with a arch-independent
    method that does a simple copy into a temporary per-cpu
    buffer.

    While a copy seems like it would be worse than mapping the pages,
    tests demonstrate the copying is always faster and, in the case of
    running inside a KVM guest, roughly 4x faster.

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

commit 069f101fa463351f528773d73b74e9b606b3f66a
Author: Ben Hutchings <ben@decadent.org.uk>
Date:   Wed Jun 20 02:31:11 2012 +0100

    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>

commit b4b700c5a61c6e6db976f60d4eb6ad369e838aa9
Author: Seth Jennings <sjenning@linux.vnet.ibm.com>
Date:   Wed Jun 13 16:03:42 2012 -0500

    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>

commit 2db51dae56240b52fe08ddbb1a2eb47fe7cfd044
Author: Nitin Gupta <ngupta@vflare.org>
Date:   Sat Jun 9 17:41:14 2012 -0700

    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>

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>

commit 00a61d8618bb7314113eb3ba27c12631cd85c298
Author: Minchan Kim <minchan@kernel.org>
Date:   Thu May 3 15:40:40 2012 +0900

    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>

commit 2e3b61547191a5934ff6c789aaa4d7e9a9e52f5a
Author: Minchan Kim <minchan@kernel.org>
Date:   Thu May 3 15:40:39 2012 +0900

    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>

commit d210267741fb2a8b6d741d9040703683a39087f4
Merge: 69964ea 5bb196a
Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date:   Wed May 2 11:48:07 2012 -0700

    Merge 3.4-rc5 into staging-next

    This resolves the conflict in:
    	drivers/staging/vt6656/ioctl.c

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

commit a27545bf0bab9027e5c040901b68956551d9f63e
Author: Minchan Kim <minchan@kernel.org>
Date:   Wed Apr 25 15:23:09 2012 +0900

    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>

Change-Id: I542f0b9eaf0264e1c9e38f9669fec8ea0debae7c
Signed-off-by: Larry Bassel <lbassel@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
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>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Staging: Fixes string split across lines in zram

Fixes the following checkpatch warning in zram_drv.c:
WARNING: quoted string split across lines

Signed-off-by: Marlies Ruck <marlies.ruck@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: avoid invalid memory access in zram_exit()

Memory for zram->disk object may have already been freed after returning
from destroy_device(zram), then it's unsafe for zram_reset_device(zram)
to access zram->disk again.

We can't solve this bug by flipping the order of destroy_device(zram)
and zram_reset_device(zram), that will cause deadlock issues to the
zram sysfs handler.

So fix it by holding an extra reference to zram->disk before calling
destroy_device(zram).

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: use zram->lock to protect zram_free_page() in swap free notify path

zram_slot_free_notify() is free-running without any protection from
concurrent operations. So there are race conditions between
zram_bvec_read()/zram_bvec_write() and zram_slot_free_notify(),
and possible consequences include:
1) Trigger BUG_ON(!handle) on zram_bvec_write() side.
2) Access to freed pages on zram_bvec_read() side.
3) Break some fields (bad_compress, good_compress, pages_stored)
   in zram->stats if the swap layer makes concurrently call to
   zram_slot_free_notify().

So enhance zram_slot_free_notify() to acquire writer lock on zram->lock
before calling zram_free_page().

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: destroy all devices on error recovery path in zram_init()

On error recovery path of zram_init(), it leaks the zram device object
causing the failure. So change create_device() to free allocated
resources on error path.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: avoid double free in function zram_bvec_write()

When doing a patial write and the whole page is filled with zero,
zram_bvec_write() will free uncmem twice.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: avoid access beyond the zram device

Function valid_io_request() should verify the entire request are within
the zram device address range. Otherwise it may cause invalid memory
access when accessing/modifying zram->meta->table[index] because the
'index' is out of range. Then it may access non-exist memory, randomly
modify memory belong to other subsystems, which is hard to track down.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: kill unused zram_get_num_devices()

Now there's no caller of zram_get_num_devices(), so kill it.
And change zram_devices to static because it's only used in zram_drv.c.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: optimize memory operations with clear_page()/copy_page()

Some architectures provides architecture-specific, optimized version of
clear_page()/copy_page(), which may have better performance than
memset()/memcpy(). So use clear_page()/copy_page() to optimize zram
performance if possible.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: protect sysfs handler from invalid memory access

Use zram->init_lock to protect access to zram->meta, otherwise it
may cause invalid memory access if zram->meta has been freed by
zram_reset_device().

This issue may be triggered by:
Thread 1:
while true; do cat mem_used_total; done
Thread 2:
while true; do echo 8M > disksize; echo 1 > reset; done

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
zram: simplify and optimize dev_to_zram()

Simplify and optimize dev_to_zram() without walking the zram_devices
array.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>