Avoid warnings like those:

drivers/media/pci/ddbridge/ddbridge-core.c: In function 'dvb_input_detach':
drivers/media/pci/ddbridge/ddbridge-core.c:787:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (input->fe) {
      ^
drivers/media/pci/ddbridge/ddbridge-core.c:792:2: note: here
  case 4:
  ^~~~
...

On several cases, it is just that gcc 7.1 is not capable of
understanding the comment, but on other places, we need an
annotation.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

When a REMOTE_KEY_PRESSED event happens, it does the right
thing. However, if debug is enabled, it will print a bogus
message warning that "key repeated".

Fix it.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

The logic that handles CA_SET_PID is clearly missing a
break: it prints that the command succeeded, but, due to the
missing break, it would be returning -EOPNOTSUPP, as if the
driver weren't supporting such ioctl.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Right now, the driver is doing the right thing for
PVC_ERRORCODE_UNKNOWN and PVC_ERRORCODE_INVALID_CONTROL:
for both, it returns an error code (SAA_ERR_NOT_SUPPORTED).

However, it is printing two error messages instead of one
on those cases.

Fix the logic.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

There's a missing break for VSB16 modulation logic, with would
cause it to return -EINVAL, instead of handling it.

Fix it.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

gcc-7 suggests that an expression using a bitwise not and a bitmask
on a 'bool' variable is better written using boolean logic:

drivers/media/rc/imon.c: In function 'imon_incoming_scancode':
drivers/media/rc/imon.c:1725:22: error: '~' on a boolean expression [-Werror=bool-operation]
    ictx->pad_mouse = ~(ictx->pad_mouse) & 0x1;
                      ^
drivers/media/rc/imon.c:1725:22: note: did you mean to use logical not?

I agree.

Fixes: 21677cfc ("V4L/DVB: ir-core: add imon driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

This is a patch to the atomisp_tpg.c file that fixes up a missing
blank line warning found by the checkpatch.pl tool
Signed-off-by: Manny Vindiola <mannyv@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

We're putting the NUL terminators one space beyond where they belong.
This doesn't show up in testing because all but the callers put a NUL in
the correct place themselves.  LOL.  It causes a static checker warning
about buffer overflows.

Fixes: a49d2536 ("staging/atomisp: Add support for the Intel IPU v2")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

We should verify that "ix < max_len" before we test whether we have
reached the NUL terminator.

Fixes: a49d2536 ("staging/atomisp: Add support for the Intel IPU v2")
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

With gcc-7.1.1 I was getting the following compile error:

error: ‘*’ in boolean context, suggest ‘&&’ instead

The problem is the definition of CEIL_DIV:
 #define CEIL_DIV(a, b)       ((b) ? ((a) + (b) - 1) / (b) : 0)

Which when called as: CEIL_DIV(x, y * z) triggers this error, note
we cannot do as the error suggests since b is evaluated multiple times.

This commit fixes these compile errors.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Fix sparse warnings: "symbol not declared; should it be static?"
Signed-off-by: Guru Das Srinagesh <gurooodas@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Fix for warnings reported by checkpatch.pl:
 - Multiline comment style
 - Bare "unsigned"
 - Missing blank line after declarations
 - Un-needed braces around single-statement branch
Signed-off-by: Avraham Shukron <avraham.shukron@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Fix for error (not warnings) reported by checkpatch.pl
Specifically:
 - missing whitespace around "=" and after ","
 - indentation with spaces instead of tabs
 - lines starting with a whitespace

This patch does not affect the compiled code in any way.
Signed-off-by: Avraham Shukron <avraham.shukron@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Fixes a sparse warning:

drivers/staging/media/atomisp/platform/intel-mid/intel_mid_pcihelpers.c:35:5: warning: symbol 'qos' was not declared. Should it be static?
Signed-off-by: Valentin Vidic <Valentin.Vidic@CARNet.hr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Added "static" storage class to 4 not-declared functions
Signed-off-by: Avraham Shukron <avraham.shukron@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix checkpatch warning: removed unnecessary initialization of
static variable "skip_fwload" to 0 in source atomisp_v4l2.c
Signed-off-by: Fabrizio Perria <fabrizio.perria@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Fixes sparse warning "dubious: x & !y" in logical expression.
Signed-off-by: Guru Das Srinagesh <gurooodas@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

__printf validation adds format and argument validation.

Fix the various broken format/argument mismatches.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

The below mentioned fix contains a small but severe bug,
fix it to make the driver work again.

Fixes: 3538aa6e ("[media] tc358743: fix register i2c_rd/wr functions")

Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Fix a link error in this specific combination of config options:

CONFIG_MEDIA_CEC_SUPPORT=y
CONFIG_CEC_CORE=m
CONFIG_MEDIA_CEC_NOTIFIER=y
CONFIG_VIDEO_STI_HDMI_CEC=m
CONFIG_DRM_STI=y

drivers/gpu/drm/sti/sti_hdmi.o: In function `sti_hdmi_remove':
sti_hdmi.c:(.text.sti_hdmi_remove+0x10): undefined reference to
`cec_notifier_set_phys_addr'
sti_hdmi.c:(.text.sti_hdmi_remove+0x34): undefined reference to
`cec_notifier_put'
drivers/gpu/drm/sti/sti_hdmi.o: In function `sti_hdmi_connector_get_modes':
sti_hdmi.c:(.text.sti_hdmi_connector_get_modes+0x4a): undefined
reference to `cec_notifier_set_phys_addr_from_edid'
drivers/gpu/drm/sti/sti_hdmi.o: In function `sti_hdmi_probe':
sti_hdmi.c:(.text.sti_hdmi_probe+0x204): undefined reference to
`cec_notifier_get'
drivers/gpu/drm/sti/sti_hdmi.o: In function `sti_hdmi_connector_detect':
sti_hdmi.c:(.text.sti_hdmi_connector_detect+0x36): undefined reference
to `cec_notifier_set_phys_addr'
drivers/gpu/drm/sti/sti_hdmi.o: In function `sti_hdmi_disable':
sti_hdmi.c:(.text.sti_hdmi_disable+0xc0): undefined reference to
`cec_notifier_set_phys_addr'

The version below seems to work, though I don't particularly
like the IS_REACHABLE() addition since that can be confusing
to users.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

We should ensure that 'plane_no' is '< vb->num_planes' as done in
'vb2_plane_cookie' just a few lines below.

Fixes: e23ccc0a ("[media] v4l: add videobuf2 Video for Linux 2 driver framework")

Cc: stable@vger.kernel.org
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Remove including <linux/version.h> that is not needed.
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

The driver allocates the spinlock but not initialize it.
Use spin_lock_init() on it to initialize it correctly.

This is detected by Coccinelle semantic patch.

Fixes: 0f314f6c ("[media] rainshadow-cec: new RainShadow Tech HDMI
CEC driver")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

The conversion from soc_camera omitted a correct handling of the clock
gating for a sensor. When the pxa_camera driver module was removed it
tried to unregister clk, but this caused a similar warning:

  WARNING: CPU: 0 PID: 6740 at drivers/media/v4l2-core/v4l2-clk.c:278
  v4l2_clk_unregister(): Refusing to unregister ref-counted 0-0030 clock!

The clock was at time still refcounted by the sensor driver. Before
the removing of the pxa_camera the clock must be dropped by the sensor
driver. This should be triggered by v4l2_async_notifier_unregister() call
which removes sensor driver module too, calls unbind() function and then
tries to probe sensor driver again. Inside unbind() we can safely
unregister the v4l2 clock as the sensor driver got removed. The original
v4l2_clk_unregister() should be put inside test as the clock can be
already unregistered from unbind(). If there was not any bound sensor
the clock is still present.

The codepath is practically a copy from the old soc_camera. The bug was
tested with a pxa_camera+ov9640 combination during the conversion
of the ov9640 from the soc_camera.
Signed-off-by: Petr Cvek <petr.cvek@tul.cz>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Changing the IS_REACHABLE() into a plain #ifdef broke the case of
CONFIG_MEDIA_RC=m && CONFIG_MEDIA_CEC=y:

drivers/media/cec/cec-core.o: In function `cec_unregister_adapter':
cec-core.c:(.text.cec_unregister_adapter+0x18): undefined reference to `rc_unregister_device'
drivers/media/cec/cec-core.o: In function `cec_delete_adapter':
cec-core.c:(.text.cec_delete_adapter+0x54): undefined reference to `rc_free_device'
drivers/media/cec/cec-core.o: In function `cec_register_adapter':
cec-core.c:(.text.cec_register_adapter+0x94): undefined reference to `rc_register_device'
cec-core.c:(.text.cec_register_adapter+0xa4): undefined reference to `rc_free_device'
cec-core.c:(.text.cec_register_adapter+0x110): undefined reference to `rc_unregister_device'
drivers/media/cec/cec-core.o: In function `cec_allocate_adapter':
cec-core.c:(.text.cec_allocate_adapter+0x234): undefined reference to `rc_allocate_device'
drivers/media/cec/cec-adap.o: In function `cec_received_msg':
cec-adap.c:(.text.cec_received_msg+0x734): undefined reference to `rc_keydown'
cec-adap.c:(.text.cec_received_msg+0x768): undefined reference to `rc_keyup'

This adds an additional dependency to explicitly forbid this combination.

Fixes: 5f2c467c ("[media] cec: add MEDIA_CEC_RC config option")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

The barrier implied by spin_unlock() in rain_irq_work_handler makes it hard
for gcc to figure out the state of the variables, leading to a false-positive
warning:

drivers/media/usb/rainshadow-cec/rainshadow-cec.c: In function 'rain_irq_work_handler':
drivers/media/usb/rainshadow-cec/rainshadow-cec.c:171:31: error: 'data' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Slightly rearranging the code makes it easier for the compiler to see that the
code is correct, and gets rid of the warning.

Fixes: 0f314f6c ("[media] rainshadow-cec: new RainShadow Tech HDMI CEC driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

gcc warns about an obviously incorrect use of strncat():

drivers/media/usb/rainshadow-cec/rainshadow-cec.c: In function 'rain_cec_adap_transmit':
drivers/media/usb/rainshadow-cec/rainshadow-cec.c:299:4: error: specified bound 48 equals the size of the destination [-Werror=stringop-overflow=]

It seems that strlcat was intended here, and using that makes the
code correct.

Fixes: 0f314f6c ("[media] rainshadow-cec: new RainShadow Tech HDMI CEC driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

ir_lirc_register() currently creates its own lirc_buffer before
passing the lirc_driver to lirc_register_driver().

When a module is later unloaded, ir_lirc_unregister() gets called
which performs a call to lirc_unregister_driver() and then free():s
the lirc_buffer.

The problem is that:

a) there can still be a userspace app holding an open lirc fd
   when lirc_unregister_driver() returns; and

b) the lirc_buffer contains "wait_queue_head_t wait_poll" which
   is potentially used as long as any userspace app is still around.

The result is an oops which can be triggered quite easily by a
userspace app monitoring its lirc fd using epoll() and not closing
the fd promptly on device removal.

The minimalistic fix is to let lirc_dev create the lirc_buffer since
lirc_dev will then also free the buffer once it believes it is safe to
do so.
Signed-off-by: David Härdeman <david@hardeman.nu>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

The call to input_register_device() needs to take place
before the repeat parameters are set or the input subsystem
repeat handling will be disabled (as was already noted in
the comments in that function).

Cc: stable <stable@vger.kernel.org> # v4.11
Signed-off-by: David Härdeman <david@hardeman.nu>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Since this driver does no detection of hardware, it might be used with
a non-sir port. Escape out if we are spinning.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Several atomisp files use:
	 ccflags-y += -Werror

As, on media, our usual procedure is to use W=1, and atomisp
has *a lot* of warnings with such flag enabled,like:

./drivers/staging/media/atomisp/pci/atomisp2/css2400/hive_isp_css_common/host/system_local.h:62:26: warning: 'DDR_BASE' defined but not used [-Wunused-const-variable=]

At the end, it causes our build to fail, impacting our workflow.

So, remove this crap. If one wants to force -Werror, he
can still build with it enabled by passing a parameter to
make.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Linux 4.12-rc1

* tag 'v4.12-rc1': (13212 commits)
  Linux 4.12-rc1
  mm, docs: update memory.stat description with workingset* entries
  mm: vmscan: scan until it finds eligible pages
  mm, thp: copying user pages must schedule on collapse
  dax: fix PMD data corruption when fault races with write
  dax: fix data corruption when fault races with write
  ext4: return to starting transaction in ext4_dax_huge_fault()
  mm: fix data corruption due to stale mmap reads
  dax: prevent invalidation of mapped DAX entries
  Tigran has moved
  mm, vmalloc: fix vmalloc users tracking properly
  mm/khugepaged: add missed tracepoint for collapse_huge_page_swapin
  gcov: support GCC 7.1
  mm, vmstat: Remove spurious WARN() during zoneinfo print
  time: delete current_fs_time()
  hwpoison, memcg: forcibly uncharge LRU pages
  sound: Disable the build of OSS drivers
  drm/i915: Make vblank evade warnings optional
  Input: cros_ec_keyb - remove extraneous 'const'
  drm/nouveau/therm: remove ineffective workarounds for alarm bugs
  ...

Pull some more input subsystem updates from Dmitry Torokhov:
 "An updated xpad driver with a few more recognized device IDs, and a
  new psxpad-spi driver, allowing connecting Playstation 1 and 2 joypads
  via SPI bus"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: cros_ec_keyb - remove extraneous 'const'
  Input: add support for PlayStation 1/2 joypads connected via SPI
  Input: xpad - add USB IDs for Mad Catz Brawlstick and Razer Sabertooth
  Input: xpad - sync supported devices with xboxdrv
  Input: xpad - sort supported devices by USB ID

Pull UBI/UBIFS updates from Richard Weinberger:

 - new config option CONFIG_UBIFS_FS_SECURITY

 - minor improvements

 - random fixes

* tag 'upstream-4.12-rc1' of git://git.infradead.org/linux-ubifs:
  ubi: Add debugfs file for tracking PEB state
  ubifs: Fix a typo in comment of ioctl2ubifs & ubifs2ioctl
  ubifs: Remove unnecessary assignment
  ubifs: Fix cut and paste error on sb type comparisons
  ubi: fastmap: Fix slab corruption
  ubifs: Add CONFIG_UBIFS_FS_SECURITY to disable/enable security labels
  ubi: Make mtd parameter readable
  ubi: Fix section mismatch

Pull UML fixes from Richard Weinberger:
 "No new stuff, just fixes"

* 'for-linus-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: Add missing NR_CPUS include
  um: Fix to call read_initrd after init_bootmem
  um: Include kbuild.h instead of duplicating its macros
  um: Fix PTRACE_POKEUSER on x86_64
  um: Set number of CPUs
  um: Fix _print_addr()

Merge misc fixes from Andrew Morton:
 "15 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm, docs: update memory.stat description with workingset* entries
  mm: vmscan: scan until it finds eligible pages
  mm, thp: copying user pages must schedule on collapse
  dax: fix PMD data corruption when fault races with write
  dax: fix data corruption when fault races with write
  ext4: return to starting transaction in ext4_dax_huge_fault()
  mm: fix data corruption due to stale mmap reads
  dax: prevent invalidation of mapped DAX entries
  Tigran has moved
  mm, vmalloc: fix vmalloc users tracking properly
  mm/khugepaged: add missed tracepoint for collapse_huge_page_swapin
  gcov: support GCC 7.1
  mm, vmstat: Remove spurious WARN() during zoneinfo print
  time: delete current_fs_time()
  hwpoison, memcg: forcibly uncharge LRU pages

Commit 4b4cea91691d ("mm: vmscan: fix IO/refault regression in cache
workingset transition") introduced three new entries in memory stat
file:

 - workingset_refault
 - workingset_activate
 - workingset_nodereclaim

This commit adds a corresponding description to the cgroup v2 docs.

Link: http://lkml.kernel.org/r/1494530293-31236-1-git-send-email-guro@fb.comSigned-off-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Although there are a ton of free swap and anonymous LRU page in elgible
zones, OOM happened.

  balloon invoked oom-killer: gfp_mask=0x17080c0(GFP_KERNEL_ACCOUNT|__GFP_ZERO|__GFP_NOTRACK), nodemask=(null),  order=0, oom_score_adj=0
  CPU: 7 PID: 1138 Comm: balloon Not tainted 4.11.0-rc6-mm1-zram-00289-ge228d67e9677-dirty #17
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
  Call Trace:
   oom_kill_process+0x21d/0x3f0
   out_of_memory+0xd8/0x390
   __alloc_pages_slowpath+0xbc1/0xc50
   __alloc_pages_nodemask+0x1a5/0x1c0
   pte_alloc_one+0x20/0x50
   __pte_alloc+0x1e/0x110
   __handle_mm_fault+0x919/0x960
   handle_mm_fault+0x77/0x120
   __do_page_fault+0x27a/0x550
   trace_do_page_fault+0x43/0x150
   do_async_page_fault+0x2c/0x90
   async_page_fault+0x28/0x30
  Mem-Info:
  active_anon:424716 inactive_anon:65314 isolated_anon:0
   active_file:52 inactive_file:46 isolated_file:0
   unevictable:0 dirty:27 writeback:0 unstable:0
   slab_reclaimable:3967 slab_unreclaimable:4125
   mapped:133 shmem:43 pagetables:1674 bounce:0
   free:4637 free_pcp:225 free_cma:0
  Node 0 active_anon:1698864kB inactive_anon:261256kB active_file:208kB inactive_file:184kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:532kB dirty:108kB writeback:0kB shmem:172kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
  DMA free:7316kB min:32kB low:44kB high:56kB active_anon:8064kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB slab_reclaimable:464kB slab_unreclaimable:40kB kernel_stack:0kB pagetables:24kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
  lowmem_reserve[]: 0 992 992 1952
  DMA32 free:9088kB min:2048kB low:3064kB high:4080kB active_anon:952176kB inactive_anon:0kB active_file:36kB inactive_file:0kB unevictable:0kB writepending:88kB present:1032192kB managed:1019388kB mlocked:0kB slab_reclaimable:13532kB slab_unreclaimable:16460kB kernel_stack:3552kB pagetables:6672kB bounce:0kB free_pcp:56kB local_pcp:24kB free_cma:0kB
  lowmem_reserve[]: 0 0 0 959
  Movable free:3644kB min:1980kB low:2960kB high:3940kB active_anon:738560kB inactive_anon:261340kB active_file:188kB inactive_file:640kB unevictable:0kB writepending:20kB present:1048444kB managed:1010816kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:832kB local_pcp:60kB free_cma:0kB
  lowmem_reserve[]: 0 0 0 0
  DMA: 1*4kB (E) 0*8kB 18*16kB (E) 10*32kB (E) 10*64kB (E) 9*128kB (ME) 8*256kB (E) 2*512kB (E) 2*1024kB (E) 0*2048kB 0*4096kB = 7524kB
  DMA32: 417*4kB (UMEH) 181*8kB (UMEH) 68*16kB (UMEH) 48*32kB (UMEH) 14*64kB (MH) 3*128kB (M) 1*256kB (H) 1*512kB (M) 2*1024kB (M) 0*2048kB 0*4096kB = 9836kB
  Movable: 1*4kB (M) 1*8kB (M) 1*16kB (M) 1*32kB (M) 0*64kB 1*128kB (M) 2*256kB (M) 4*512kB (M) 1*1024kB (M) 0*2048kB 0*4096kB = 3772kB
  378 total pagecache pages
  17 pages in swap cache
  Swap cache stats: add 17325, delete 17302, find 0/27
  Free swap  = 978940kB
  Total swap = 1048572kB
  524157 pages RAM
  0 pages HighMem/MovableOnly
  12629 pages reserved
  0 pages cma reserved
  0 pages hwpoisoned
  [ pid ]   uid  tgid total_vm      rss nr_ptes nr_pmds swapents oom_score_adj name
  [  433]     0   433     4904        5      14       3       82             0 upstart-udev-br
  [  438]     0   438    12371        5      27       3      191         -1000 systemd-udevd

With investigation, skipping page of isolate_lru_pages makes reclaim
void because it returns zero nr_taken easily so LRU shrinking is
effectively nothing and just increases priority aggressively.  Finally,
OOM happens.

The problem is that get_scan_count determines nr_to_scan with eligible
zones so although priority drops to zero, it couldn't reclaim any pages
if the LRU contains mostly ineligible pages.

get_scan_count:

        size = lruvec_lru_size(lruvec, lru, sc->reclaim_idx);
	size = size >> sc->priority;

Assumes sc->priority is 0 and LRU list is as follows.

	N-N-N-N-H-H-H-H-H-H-H-H-H-H-H-H-H-H-H-H

(Ie, small eligible pages are in the head of LRU but others are
 almost ineligible pages)

In that case, size becomes 4 so VM want to scan 4 pages but 4 pages from
tail of the LRU are not eligible pages.  If get_scan_count counts
skipped pages, it doesn't reclaim any pages remained after scanning 4
pages so it ends up OOM happening.

This patch makes isolate_lru_pages try to scan pages until it encounters
eligible zones's pages.

[akpm@linux-foundation.org: clean up mind-bending `for' statement.  Tweak comment text]
Fixes: 3db65812 ("Revert "mm, vmscan: account for skipped pages as a partial scan"")
Link: http://lkml.kernel.org/r/1494457232-27401-1-git-send-email-minchan@kernel.orgSigned-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We have encountered need_resched warnings in __collapse_huge_page_copy()
while doing {clear,copy}_user_highpage() over HPAGE_PMD_NR source pages.

mm->mmap_sem is held for write, but the iteration is well bounded.

Reschedule as needed.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705101426380.109808@chino.kir.corp.google.comSigned-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>