staging: zcache: fix cleancache race condition with shrinker

commit 6d7d9798ad5c97ee4e911dd070dc12dc5ae55bd0 upstream.

This patch fixes a race condition that results in memory
corruption when using cleancache.

The race exists between the zcache shrinker handler,
shrink_zcache_memory() and cleancache_get_page().

In most cases, the shrinker will both evict a zbpg
from its buddy list and flush it from tmem before a
cleancache_get_page() occurs on that page. A subsequent
cleancache_get_page() will fail in the tmem layer.

In the rare case that two occur together and the
cleancache_get_page() path gets through the tmem
layer before the shrinker path can flush tmem,
zbud_decompress() does a check to see if the zbpg is a
"zombie", i.e. not on a buddy list, which means the shrinker
is in the process of reclaiming it. If the zbpg is a zombie,
zbud_decompress() returns -EINVAL.

However, this return code is being ignored by the caller,
zcache_pampd_get_data_and_free(), which results in the
caller of cleancache_get_page() thinking that the page has
been properly retrieved when it has not.

This patch modifies zcache_pampd_get_data_and_free() to
convey the failure up the stack so that the caller of
cleancache_get_page() knows the page retrieval failed.

This needs to be applied to stable trees as well.
zcache-main.c was named zcache.c before v3.1, so
I'm not sure how you want to handle trees earlier
than that.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CHROMIUM: UPSTREAM: staging: zram/zcache: swtich Kconfig dependency from X86 to ZSMALLOC

upstream: commit 6e2361720b9da9ec830d407da058ca1827e62b12

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>

BUG=chromium-os:36829
TEST=compile, verify that zram module is updated and /boot/config is correct

Change-Id: I91f6ed46549fe62a9fe3035063d98beb2f5d966a
Signed-off-by: Luigi Semenzato <semenzato@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/39289
Tested-by: Luigi Semenzato <semenzato@google.com>
Reviewed-by: Sonny Rao <sonnyrao@chromium.org>
Commit-Ready: Luigi Semenzato <semenzato@google.com>
staging: zcache: don't limit number of pools per client

Currently the amount of pools each client can use is limited to 16, this is
and arbitrary limit which isn't really required by current implementation.

This places and arbitrary limit on the number of mounted filesystems that
can use cleancache.

This patch removes that limit and uses IDR to do sparse mapping of pools
in each client.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Conflicts:
	drivers/staging/zcache/zcache-main.c

Change-Id: Iecac1793dd0eb2b37ed265160cc159de65c2dca1
staging: zcache: fix refcount leak

In zcache_get_pool_by_id, the refcount of zcache_host is not increased, but
it is always decreased in zcache_put_pool

Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: fix a compile warning

Fix:

drivers/staging/zcache/zcache-main.c: In function ‘zcache_comp_op’:
drivers/staging/zcache/zcache-main.c:112:2: warning: ‘ret’ may be used uninitial

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: mark zbud_init/zcache_comp_init as __init

These functions are called only when system is initializing, so mark __init
for them to free memory

Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: cleanup zbud_init

Need not set global parameters to 0

Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: optimize zcache_do_preload

zcache_do_preload is called in zcache_put_page where IRQ is disabled, so, need
not care preempt

Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: cleanup zcache_do_preload and zcache_put_page

Cleanup the code for zcache_do_preload and zcache_put_page

Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: introduce get_zcache_client

Introduce get_zcache_client to remove the common code

Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
staging: zcache: cleanup the code between tmem_obj_init and tmem_obj_find

tmem_obj_find and insertion tmem-obj have the some logic, we can integrate
the code

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Conflicts:
	drivers/staging/zcache/tmem.c

Change-Id: I0d75d354b3db4c0e6902e375b5d8d4292fc6002a
defconfig: m8: enable zcache

Change-Id: I6854e563bc94f6830183bd2cddf6eff0bf9a4dec
drivers: staging: Fix Zcache

 * Remove dependency on obsolete qcache
 * Fix args for updated zsmalloc

Change-Id: I47835fbacee862917736e0e2164f40e9320a7b06
cpufreq: interactive: turn boost_pulse off on boost off

Change-Id: I36fe217fa047d68ea90e78b12c7db4537ea8010b
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
cpufreq: Persist cpufreq time in state data across hotplug

Cpufreq time_in_state data for all CPUs is made persistent across
hotplug and exposed to userspace via sysfs file
/sys/devices/system/cpu/cpufreq/all_time_in_state

Change-Id: I97cb5de24b6de16189bf8b5df9592d0a6e6ddf32
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>
cpufreq: fix sleeping in atomic context when realloc freq_table for all_time_in_state

Commit 40cf2f8 (cpufreq: Persist cpufreq time in state data across hotplug)
causes the following call trace to be spit on boot:

BUG: sleeping function called from invalid context at mm/slub.c:936
in_atomic(): 1, irqs_disabled(): 0, pid: 1, name: swapper/0
CPU: 6 PID: 1 Comm: swapper/0 Not tainted 3.10.9-20140624.172707-eng-gd6c0f69-dirty #50
Backtrace:
[<c0012270>] (dump_backtrace+0x0/0x10c) from [<c001256c>] (show_stack+0x18/0x1c)
 r6:ffff1788 r5:c0c020c0 r4:e609c000 r3:00000000
[<c0012554>] (show_stack+0x0/0x1c) from [<c07a2970>] (dump_stack+0x20/0x28)
[<c07a2950>] (dump_stack+0x0/0x28) from [<c0057678>] (__might_sleep+0x104/0x120)
[<c0057574>] (__might_sleep+0x0/0x120) from [<c00ff000>] (__kmalloc_track_caller+0x144/0x274)
 r6:00000000 r5:e609c000 r4:e6802140
[<c00feebc>] (__kmalloc_track_caller+0x0/0x274) from [<c00da098>] (krealloc+0x58/0xb0)
[<c00da040>] (krealloc+0x0/0xb0) from [<c050266c>] (cpufreq_allstats_create+0x120/0x204)
 r8:e4c4ff00 r7:c0d266b8 r6:0013d620 r5:e4c4e600 r4:00000001
r3:e535d6d0
[<c050254c>] (cpufreq_allstats_create+0x0/0x204) from [<c0502e38>] (cpufreq_stat_notifier_policy+0xb8/0xd0)
[<c0502d80>] (cpufreq_stat_notifier_policy+0x0/0xd0) from [<c00517cc>] (notifier_call_chain+0x4c/0x8c)
 r5:00000000 r4:fffffffe
[<c0051780>] (notifier_call_chain+0x0/0x8c) from [<c00519fc>] (__blocking_notifier_call_chain+0x50/0x68)
 r8:c0cd4d00 r7:00000002 r6:e609dd7c r5:ffffffff r4:c0d25a4c
r3:ffffffff
[<c00519ac>] (__blocking_notifier_call_chain+0x0/0x68) from [<c0051a34>] (blocking_notifier_call_chain+0x20/0x28)
 r7:c0e24f30 r6:00000000 r5:e53e1e00 r4:e609dd7c
[<c0051a14>] (blocking_notifier_call_chain+0x0/0x28) from [<c0500fec>] (__cpufreq_set_policy+0xc0/0x1d0)
[<c0500f2c>] (__cpufreq_set_policy+0x0/0x1d0) from [<c0501308>] (cpufreq_add_dev_interface+0x20c/0x270)
 r7:00000008 r6:00000000 r5:e53e1e00 r4:e53e1e58
[<c05010fc>] (cpufreq_add_dev_interface+0x0/0x270) from [<c05016a8>] (cpufreq_add_dev+0x33c/0x420)
[<c050136c>] (cpufreq_add_dev+0x0/0x420) from [<c03604a4>] (subsys_interface_register+0x80/0xbc)
[<c0360424>] (subsys_interface_register+0x0/0xbc) from [<c050035c>] (cpufreq_register_driver+0x8c/0x194)

Change-Id: If77a656d0ea60a8fc4083283d104509fa6c07f8f
Signed-off-by: Minsung Kim <ms925.kim@samsung.com>
cpufreq: interactive: Remove unnecessary cpu_online() check

Cpufreq no longer calls governor callback for offlined cpus. i.e. All
policy->cpus are guaranteed to be online. Hence we don't need explicit check to
see if cpu is online or not.

Change-Id: I9ad85ea4addd5b4a40952e59ed730dd15e328690
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
cpufreq: interactive: Add target_loads_down freq selection

Using a single set of target loads causes an excessive number
of frequency changes.  Reduce by having a mode that allows
for separate load factos for "up" frequency selection and
"down" frequency selection.

If user-space specifies target_loads_down then the new
duel mode frequency selection will be used and frequencies
will be scaled up to meet the load requirements but they
will only be scaled down if the can be scaled down without
violating the down target loads.

If user-space does not store a value in target_loads_down
then this change makes no functional difference in the
governor.

Conflicts:
	drivers/cpufreq/cpufreq_interactive.c

Change-Id: If19cd1d2b48e18ab4f0baf0576f89b765b96a3ee
Merge branch 'cm-11.0' of github.com:CyanogenMod/android_kernel_htc_msm8974 into kitkat
Revert "cpufreq: interactive: Add target_loads_down freq selection"

This was providing a small improvement but not enough to justify
diverging so much from everyone else.

This reverts commit ebbc58964f8b261176f217ab3a6184e1875acf4e.

Change-Id: I64319ed4451eb37721314eb760a2631c0e1a2387