PM: wakelocks: Replace variable and constants names with CAF version
ashmem: fix deadlock when system is low on memory

When system is low on memory, allocating memory while holding the
ashmem_mutex may try to directly reclaim memory. Then ashmem_shrink()
is called in same thread. It will deadlock at acquiring ashmem_mutex.
This change lets ashmem_shrink() return failure if ashmem_mutex is not
available. Memory will be reclaimed from others.

Change-Id: I3b6024d5477d37245f4ebde6d7069fb77af789ee
Signed-off-by: Yuanyuan Zhong <yuanyuan.zhong@gmail.com>
vmscan: move referenced VM_EXEC pages to active list

In commit 64574746, "vmscan: detect mapped file pages used only once",
Johannes Weiner, added logic to page_check_reference to cycle again
used once pages.

In commit 8cab4754, "vmscan: make mapped executable pages the first
class citizen", Wu Fengguang, added logic to shrink_active_list which
protects file-backed VM_EXEC pages by keeping them in the active_list if
they are referenced.

This patch adds logic to move such pages from the inactive list to the
active list immediately if they have been referenced. If a VM_EXEC page
is seen as referenced during an inactive list scan, that reference must
have occurred after the page was put on the inactive list. There is no
need to wait for the page to be referenced again.

Change-Id: I17c312e916377e93e5a92c52518b6c829f9ab30b
Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
fs: mark_inode_dirty barrier fix

Filesystems appear to be using ->dirty_inode, expecting that the dirtying
operating is done and visible to all CPUs (eg. setting private inode dirty
bits, without any barriers themselves). So release the dirty "critical
section" with a barrier before calling ->dirty_inode.

Cost is not significantly changed, because we're just moving the barrier.
Those filesystems that do use ->dirty_inode should have to care slightly
less about barriers, which is a good thing.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
fs: add sync_inode_metadata

Add a new helper to write out the inode using the writeback code,
that is including the correct dirty bit and list manipulation.  A few
of filesystems already opencode this, and a lot of others should be
using it instead of using write_inode_now which also writes out the
data.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
sync_inode_metadata: fix comment

Use correct function name, remove incorrect apostrophe

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs: simple fsync race fix

It is incorrect to test inode dirty bits without participating in the inode
writeback protocol. Inode writeback sets I_SYNC and clears I_DIRTY_?, then
writes out the particular bits, then clears I_SYNC when it is done. BTW. it
may not completely write all pages out, so I_DIRTY_PAGES would get set
again.

This is a standard pattern used throughout the kernel's writeback caches
(I_SYNC ~= I_WRITEBACK, if that makes it clearer).

And so it is not possible to determine an inode's dirty status just by
checking I_DIRTY bits. Especially not for the purpose of data integrity
syncs.

Missing the check for these bits means that fsync can complete while
writeback to the inode is underway. Inode writeback functions get this
right, so call into them rather than try to shortcut things by testing
dirty state improperly.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
fs: ext2 inode sync fix

There is a big fuckup with inode metadata writeback (I suspect in a lot
of filesystems, but I've only dared to look at a couple as yet).

ext2 relies on ->write_inode being called from sync_inode_metadata in
fsync in order to sync the inode. However I_DIRTY_SYNC gets cleared
after a call to this guy, and it doesn't actually write back and wait
on the inode block unless it is called for sync. This means that write_inode
from background writeback can kill the inode dirty bits without the data
getting to disk. Fsync will subsequently miss it.

The fix is for ->write_inode to dirty the buffers/cache, and then ->fsync to
write back the dirty data. In the full filesystem sync case, buffercache
writeback in the generic code will write back the dirty data. Other
filesystems could use ->sync_fs for this.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
staging: zram: import zram from CAF's jb_chocolate (kernel 3.0.8)

This is the version right before the first zcache import.
(Change ID: 80ae3fa5d6712ef3625eff617f72e190645d6361)
staging: zcache: in-kernel tmem code

[PATCH V2 1/3] drivers/staging: zcache: in-kernel tmem code

Transcendent memory ("tmem") is a clean API/ABI that provides
for an efficient address translation and a set of highly
concurrent access methods to copy data between a page-oriented
data source (e.g. cleancache or frontswap) and a page-addressable
memory ("PAM") data store.  Of critical importance, the PAM data
store is of unknown (and possibly varying) size so any individual
access may succeed or fail as defined by the API/ABI.

Tmem exports a basic set of access methods (e.g. put, get,
flush, flush object, new pool, and destroy pool) which are
normally called from a "host" (e.g. zcache).

To be functional, two sets of "ops" must be registered by the
host, one to provide "host services" (memory allocation) and
one to provide page-addressable memory ("PAM") hooks.

Tmem supports one or more "clients", each which can provide
a set of "pools" to partition pages.  Each pool contains
a set of "objects"; each object holds pointers to some number
of PAM page descriptors ("pampd"), indexed by an "index" number.
This triple <pool id, object id, index> is sometimes referred
to as a "handle".  Tmem's primary function is to essentially
provide address translation of handles into pampds and move
data appropriately.

As an example, for cleancache, a pool maps to a filesystem,
an object maps to a file, and the index is the page offset
into the file.  And in this patch, zcache is the host and
each PAM descriptor points to a compressed page of data.

Tmem supports two kinds of pages: "ephemeral" and "persistent".
Ephemeral pages may be asynchronously reclaimed "bottoms up"
so the data structures and concurrency model must allow for
this.  For example, each pampd must retain sufficient information
to invalidate tmem's handle-to-pampd translation.
its containing object so that, on reclaim, all tmem data
structures can be made consistent.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
staging: zcache: host services and PAM services

[PATCH V2 2/3] drivers/staging: zcache: host services and PAM services

Zcache provides host services (memory allocation) for tmem,
a "shim" to interface cleancache and frontswap to tmem, and
two different page-addressable memory implemenations using
lzo1x compression.  The first, "compression buddies" ("zbud")
compresses pairs of pages and supplies a shrinker interface
that allows entire pages to be reclaimed.  The second is
a shim to xvMalloc which is more space-efficient but
less receptive to page reclamation.  The first is used
for ephemeral pools and the second for persistent pools.
All ephemeral pools share the same memory, that is, even
pages from different pools can share the same page.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
staging: zcache: misc build/config

[PATCH V2 3/3] drivers/staging: zcache: misc build/config

Makefiles and Kconfigs to build zcache in drivers/staging

There is a dependency on xvmalloc.* which in 2.6.37 resides
in drivers/staging/zram.  Should this move or disappear,
some Makefile/Kconfig changes will be required.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
staging: zcache: fix memory leak

obj is not freed if __get_free_page() failed.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
staging: zram: merge newer zram code
Staging: zram: initialize device on first read

Currently the device is initialized when first write is done to the
device. Any read attempt before the first write would fail, including
"hidden" read the user may not know about (as for example if he tries
to write a partial block).

This patch initializes the device on first request, whether read or
write.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
staging: Allow sharing xvmalloc for zram and zcache

Both zram and zcache use xvmalloc allocator. If xvmalloc
is compiled separately for both of them, we will get linker
error if they are both selected as "built-in". We can also
get linker error regarding missing xvmalloc symbols if zram
is not built.

So, we now compile xvmalloc separately and export its symbols
which are then used by both of zram and zcache.

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
msm: htcleo: update defconfig for zram changes