staging: zcache: support multiple clients, prep for KVM and RAMster

This is version 3 of an update to zcache, incorporating feedback from the list.
This patch adds support to the in-kernel transcendent memory ("tmem") code
and the zcache driver for multiple clients, which will be needed for both
RAMster and KVM support.  It also adds additional tmem callbacks to support
RAMster and corresponding no-op stubs in the zcache driver.  In v2, I've
also taken the liberty of adding some additional sysfs variables to
both surface information and allow policy control.  Those experimenting
with zcache should find them useful.  V3 clarifies some code walking
and declaring arrays.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>

[v3: error27@gmail.com: fix array bounds/walking]
[v2: konrad.wilk@oracle.com: fix bools, add check for NULL, fix a comment]
[v2: sjenning@linux.vnet.ibm.com: add info/tunables for poor compression]
[v2: marcusklemm@googlemail.com: add tunable for max persistent pages]
Acked-by: Dan Carpenter <error27@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: linux-mm@kvack.org
Cc: kvm@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

staging: fix zcache building

zcache is only building tmem.c and not building zcache.c. To keep the
module name, zcache.c must be renamed if symbols from tmem.c are to
remain unexported.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

staging: zcache: module is GPL

This avoids tainting the kernel as if a proprietary module was loaded.
The kernel will still be tainted because this is a staging driver.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

staging: zcache: include module.h for MODULE_LICENSE

The oncoming cleanup of module.h usage requires the explicit inclusion
of module.h when it was otherwise being included indirectly. Otherwise,
building zcache will fail.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

zcache: Use div_u64 for 64-bit division

xv_get_total_size_bytes returns a u64 value and it's used in a division.
This causes build failures in 32-bit architectures, as reported by Randy
Dunlap.

Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

zcache: Fix build error when sysfs is not defined

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

staging: zcache: fix possible sleep under lock

zcache_new_pool() calls kmalloc() with GFP_KERNEL which has
__GFP_WAIT set.  However, zcache_new_pool() gets called on
a stack that holds the swap_lock spinlock, leading to a
possible sleep-with-lock situation. The lock is obtained
in enable_swap_info().

The patch replaces GFP_KERNEL with GFP_ATOMIC.

v2: replace with GFP_ATOMIC, not GFP_IOFS

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@suse.de>

staging: zcache: fix typos

The patch fixes two typos in zcache-main.c

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@suse.de>

staging: zcache: fix crash on high memory swap

zcache_put_page() was modified to pass page_address(page) instead of the
actual page structure. In combination with the function signature changes
to tmem_put() and zcache_pampd_create(), zcache_pampd_create() tries to
(re)derive the page structure from the virtual address.  However, if the
original page is a high memory page (or any unmapped page), this
virt_to_page() fails because the page_address() in zcache_put_page()
returned NULL.

This patch changes zcache_put_page() and zcache_get_page() to pass
the page structure instead of the page's virtual address, which
may or may not exist.

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@suse.de>

Staging: zcache: signedness bug in tmem_get()

"ret" needs to be signed for the error handling to work properly.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

staging: zcache: fix cleancache crash

After commit c5f5c4db3938 ("staging: zcache: fix crash on high memory
swap") cleancache crashes on the first successful get.  This was caused
by a remaining virt_to_page() call in zcache_pampd_get_data_and_free()
that only gets run in the cleancache path.

The patch converts the virt_to_page() to struct page casting like was
done for other instances in c5f5c4db3938.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Tested-By: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

staging: zcache: fix crash on cpu remove

In the case that a cpu is taken offline before zcache_do_preload() is
ever called on the cpu, the per-cpu zcache_preloads structure will
be uninitialized.  In the CPU_DEAD case for zcache_cpu_notifier(),
kp->obj is not checked before calling kmem_cache_free() on it.
If it is NULL, a crash results.

This patch ensures that both kp->obj and kp->page are not NULL before
calling the respective free functions. In practice, just checking
one or the other should be sufficient since they are assigned together
in zcache_do_preload(), but I check both for safety.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Acked-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

staging: zcache: reduce tmem bucket lock contention

tmem uses hash buckets each with their own rbtree and lock to
quickly lookup tmem objects.  tmem has TMEM_HASH_BUCKETS (256)
buckets per pool.  However, because of the way the tmem_oid is
generated for frontswap pages, only 16 unique tmem_oids are being
generated, resulting in only 16 of the 256 buckets being used.
This cause high lock contention for the per bucket locks.

This patch changes SWIZ_BITS to include more bits of the offset.
The result is that all 256 hash buckets are potentially used resulting in a
95% drop in hash bucket lock contention.

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@suse.de>

staging: zcache: remove zcache_direct_reclaim_lock

zcache_do_preload() currently does a spin_trylock() on the
zcache_direct_reclaim_lock. Holding this lock intends to prevent
shrink_zcache_memory() from evicting zbud pages as a result
of a preload.

However, it also prevents two threads from
executing zcache_do_preload() at the same time.  The first
thread will obtain the lock and the second thread's spin_trylock()
will fail (an aborted preload) causing the page to be either lost
(cleancache) or pushed out to the swap device (frontswap). It
also doesn't ensure that the call to shrink_zcache_memory() is
on the same thread as the call to zcache_do_preload().

Additional, there is no need for this mechanism because all
zcache_do_preload() calls that come down from cleancache already
have PF_MEMALLOC set in the process flags which prevents
direct reclaim in the memory manager. If the zcache_do_preload()
call is done from the frontswap path, we _want_ reclaim to be
done (which it isn't right now).

This patch removes the zcache_direct_reclaim_lock and related
statistics in zcache.

Based on v3.1-rc8

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Reviewed-by: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Staging: zcache: Fix calls to obsolete function

Function "strict_strtol" replaced by "kstrtol" as suggested by the checkpatch script

Signed-off-by: Bernhard Heinloth <bernhard@heinloth.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

zcache: fix deadlock condition

I discovered this deadlock condition awhile ago working on RAMster
but it affects zcache as well.  The list spinlock must be
locked prior to the page spinlock and released after.  As
a result, the page copy must also be done while the locks are held.

Applies to 3.2.  Konrad, please push (via GregKH?)...
this is definitely a bug fix so need not be pushed during
a -rc0 window.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

zcache: Set SWIZ_BITS to 8 to reduce tmem bucket lock contention.

SWIZ_BITS > 8 results in a much larger number of "tmem_obj"
allocations, likely one per page-placed-in-frontswap.  The
tmem_obj is not huge (roughly 100 bytes), but it is large
enough to add a not-insignificant memory overhead to zcache.

The SWIZ_BITS=8  will get roughly the same lock contention
without the space wastage.

The effect of SWIZ_BITS can be thought of as "2^SWIZ_BITS is
the number of unique oids that be generated" (This concept is
limited to frontswap's use of tmem).

Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

staging: zcache: fix serialization bug in zv stats

In a multithreaded workload, the zv_curr_dist_counts
and zv_cumul_dist_counts statistics are being corrupted
because the increments and decrements in zv_create
and zv_free are not atomic.

This patch converts these statistics and their corresponding
increments/decrements/reads to atomic operations.

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>

staging: zcache: crypto API support

This patch allow zcache to use the crypto API for page compression.
It replaces the direct LZO compress/decompress calls with calls
into the crypto compression API. The compressor to be used is
specified in the kernel boot line with the zcache parameter like:
zcache=lzo or zcache=deflate.  If the specified compressor can't
be loaded, zcache uses lzo as the default compressor.

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>

staging: zcache: avoid AB-BA deadlock condition

Commit 9256a47 fixed a deadlock condition, being sure that the buddy
list spinlock is always taken before the page spinlock.

However in zbud_free_and_delist() locking order is the opposite
(page lock -> list lock).

Possible unsafe locking scenario (reported by lockdep):

        CPU0                    CPU1
        ----                    ----
   lock(&(&zbpg->lock)->rlock);
                                lock(zbud_budlists_spinlock);
                                lock(&(&zbpg->lock)->rlock);
   lock(zbud_budlists_spinlock);

Fix by grabbing the locks in opposite order in zbud_free_and_delist().

Signed-off-by: Andrea Righi <andrea@betterlinux.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers: qcache: Port various fixes from zcache

 * Fix various lockups to improve stability

Change-Id: Ifeec71a934aa5f08b1b0b57bb05e22d0d7bf84e6
ion: Fix build with qcache disabled

 * Qcache is still unstable and buggy, but currently crashes if fully
   disabled on 8960.
 * Allow disabling of Qcache for 8960 and fix the dependency in msm_ion.

Change-Id: I3b2fc40ecce757530b64ddabb03081aaa425b603
zcache

Change-Id: If0e0f5826b48ef615f9182d25e6b73b6692a8619
msm_fb: Clear real pipe attributes in the pipe free

Clear original pipe attributes in the pipe free call.

Change-Id: I776869e7997e5b70e4c2b102e1a394034247bbcd
Signed-off-by: Kalyan Thota <kalyant@codeaurora.org>
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>

Conflicts:
	drivers/video/msm/mdp4_overlay.c
msm_fb: display: free base layer pipe at adb stop

Base layer pipe need to be freed at adb stop so that same
pipe can be allocated at adb start.

CRs-fixed: 390644
Change-Id: I948bb27687cfe1c96cc3b071b7bb9bb84b2c52c6
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Signed-off-by: Ajay Dudani <adudani@codeaurora.org>
msm_fb: display: empty pending queue during suspend

Overlay_play() adds a pipe into pending queue and pan_display()
will commit those pipes to hardware and empty queue. This patch
will make sure queue is empty at suspend so that no unexpected
pipes will be commited to hardware by pan_display() at resume.
Otherwise, iommu page fault may happen.

Change-Id: Ib35c247550bb8754f9bff68a6352022d58c55ff8
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>

Conflicts:
	drivers/video/msm/mdp4_overlay_dsi_video.c
	drivers/video/msm/mdp4_overlay_dtv.c
	drivers/video/msm/mdp4_overlay_lcdc.c
[ARM] msm: call video start function

Change-Id: Ib8ef8d2c0e0d550a2d100dd90334400f6761f6ac
Signed-off-by: Iliyan Malchev <malchev@google.com>

Conflicts:
	drivers/video/msm/mdp4_overlay_dsi_video.c
msm: mdp: Disable vsync in video off.

Change-Id: I69fa66e4b3110a5d996d9c91dea6e73bd5280f47
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>
msm_fb: display: check base layer pipe at irq handler

Change-Id: Ib188d575044f5479672503508042c8c1e9c759c4
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>
Revert "msm: display: fence fd releasing"

This reverts commit e221a8a6c352028e4ebf6de314cf1285a022ca77.
display: removed the code exhausts file descriptor in mdp overlay and rotator.

Fix the problem crashed while playing video clips and VT camera test.
ion_share_dma_buf is called in pr_debug.
So, it is called depends on build option and makes crash problem.

Change-Id: Ia96fdb7838eb2f3cdf979d8e0f886cb64eba6ca8
msm_fb: Display: Fix Dithering issue for rgb565 format

Using RGB888 as source format and rgb565 as destination pixel format,
will cause image corruption on the display. Fix this issue by
setting the destination format as RGB888 in MDP and DSI controller
pixel format as RGB565 for DSI specific panels.

CRs-Fixed: 377484
Change-Id: If58976ee9cd4825efb39437170e54796fa2213e0
Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>
video: msm_fb: Ensure backlight is scaled atomically.

Ensure that when backlight scaling ratio or backlight level is being
changed that the operation execute atomically. This prevents a backlight
level change from being overwritten when it interrupts a backlight scale
update.

CRs-Fixed: 404017
Signed-off-by: Carl Vanderlip <carlv@codeaurora.org>
(cherry picked from commit ce328861aa1f4fa489e9abfc9d1e02b13af2ba47)

Signed-off-by: Dhivya Subramanian <dthiru@codeaurora.org>
(cherry picked from commit 0584596f75f8f2b184b8be1a0479ee61e449acba)

Change-Id: Ifb4bd5e823815b51dae38f1b8647b80d21b8ee45
Signed-off-by: Sudhir Sharma <sudsha@codeaurora.org>
msm_fb: display: remove extra dmap irq disable

irq enable and disable need to be called symmetrically.
Remove an extra dmap irq disable call.

Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>
msm: display: display idle checking update

msm_fb_blank_sub might be called for UNBLANK from
display update work queue, which is at commit state.
Idle detection is invalid in this situation
Add detection for external snd earlyuspend/resume interface.

Change-Id: I1b08d10c9c494b9b3df5e95c4a54036877d5653f
Signed-off-by: Ken Zhang <kenz@codeaurora.org>
msm: dsi: use timeout for dma transfer

Use wait_for_completion_timeout instead of wait_for_completion
not to stuck in the kernel even when the DMA fails.

Change-Id: I29702c3c62f78399c173d660bbbc17a07ed27468
Signed-off-by: Iliyan Malchev <malchev@google.com>

Conflicts:
	drivers/video/msm/mipi_dsi_host.c
mdp: Do not start LUT for overlay0

The post processing daemon is not used currently.
Enabling the LUT without using it can potentially
cause display hangs.
msm: mdp: Remove mixer1 blt for external

BLT mode is not needed for external displays since
there is no extra downscaling needed for videos.
video: msm: Remove old post processing overlay integration

Remove old implementation of HSIC and QSEED smoothing/sharpening overlay
integration. Need to replace with new implementation that better integrates
the existing functions of the two APIs.

CRs-Fixed: 380750
Change-Id: Id3469fad16764ed88e74a8da75bb873f726ba366
Signed-off-by: Carl Vanderlip <carlv@codeaurora.org>
Signed-off-by: Pravin Tamkhane <pravint@codeaurora.org>

Conflicts:
	drivers/video/msm/Makefile