The davinci rtc driver uses the module_platform_driver_probe()
helper to call the probe function and mark it as __init, but
it also puts a reference into its davinci_rtc_driver function.

This will crash if we ever get a deferred probe and the probe
function is called again after the init section has been removed.
kbuild warns about this:

WARNING: vmlinux.o(.data+0x1aa2b4): Section mismatch in reference from the variable davinci_rtc_driver to the function .init.text:davinci_rtc_probe()
The variable davinci_rtc_driver references
the function __init davinci_rtc_probe()

This patch removes the .probe callback from the platform driver,
which avoids those problems.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

As said in the SAMA5D2 datasheet, "Prior to instructing the device
to enter ULP mode 1, ... and the internal sources of wake-up must
be cleared."

This patch is to clear the RTC alarm status flag prior to suspending
to avoid the erroneous wake-up activity, as it is often used as
the wake-up source for the ULP mode 1.
Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

A driver version is only really sensible for oot drivers. Also the
dev_info about having found a chip only signals that allocating the
driver data succeeded and so isn't worth much.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The flag reported on the RTC_READ_VL ioctl is only initialized when the
date is read out. So the voltage low value doesn't represent reality but
the status at the time the date was read (or 0 if the date was not read
yet).

Moreover when userspace requests a value via an ioctl there is no added
benefit to also make a prosa representation of this (and other) values
appear in the kernel log so remove the calls to dev_info and the driver
data members to track their state.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Use STMP_OFFSET_REG_(SET|CLR) instead of defining _SET and _CLR for
STMP3XXX_RTC_CTRL and STMP3XXX_RTC_PERSISTENT0 - no functional changes.
Signed-off-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Fix misleading and inconsistent copyright header wording.

Alter the copyright header text and MODULE_LICENSE macro to ensure the
GPL v2 licence description is correctly represented.

It will remove the incorrectly LGPL worded text. Words such as "Library"
from the line "GNU Library General Public License"; and replace the word
"library" with "program" in several other places.

The copyright should match the GPL v2 description as specified in the GNU
license found here: http://www.gnu.org/licenses/gpl-2.0.html

It should also match this copyright text with the correct MODULE_LICENSE
macro text as found in the kernel: include/linux/module.h
In this case "GNU Public License v2 or later" is linked with "GPL".
Signed-off-by: Steve Twiss <stwiss.opensource@diasemi.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Return an error when the date is invalid as the policy should be
implemented there.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

braces {} are not necessary for single statement blocks
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The IRQF_NO_SUSPEND flag is used to identify the interrupts that should
be left enabled so as to allow them to work as expected during the
suspend-resume cycle, but doesn't guarantee that it will wake the system
from a suspended state, enable_irq_wake is recommended to be used for
the wakeup.

This patch removes the use of IRQF_NO_SUSPEND flags and uses newly
introduce PM wakeup APIs dev_pm_{set,clear}_wake_irq.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: rtc-linux@googlegroups.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The IRQF_NO_SUSPEND flag is used to identify the interrupts that should
be left enabled so as to allow them to work as expected during the
suspend-resume cycle, but doesn't guarantee that it will wake the system
from a suspended state, enable_irq_wake is recommended to be used for
the wakeup.

This patch removes the use of IRQF_NO_SUSPEND flags and uses newly
introduce PM wakeup APIs dev_pm_{set,clear}_wake_irq.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: rtc-linux@googlegroups.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The IRQF_NO_SUSPEND flag is used to identify the interrupts that should
be left enabled so as to allow them to work as expected during the
suspend-resume cycle, but doesn't guarantee that it will wake the system
from a suspended state, enable_irq_wake is recommended to be used for
the wakeup.

This patch removes the use of IRQF_NO_SUSPEND flags and uses newly
introduce PM wakeup APIs dev_pm_{set,clear}_wake_irq.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: rtc-linux@googlegroups.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The variable can take signed values.

The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2038576Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Introduce a device tree binding for specifying the trickle charger
configuration for ds1390.
Signed-off-by: Ivan Grimaldi <grimaldi.ivan@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

spi_write_then_read puts in rx_buf the received data starting from
the first byte of the rx_buf
Signed-off-by: Ivan Grimaldi <grimaldi.ivan@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Calling ioctl(..., RTC_UIE_ON, ...) without CONFIG_RTC_INTF_DEV_UIE_EMUL
either ends in rtc_update_irq_enable if rtc->uie_unsupported is true
or in __rtc_set_alarm in the if (!rtc->ops->set_alarm) branch. In both
cases the return value is -EINVAL. So check for that one instead of
ENOTTY.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

The header of the pcf2127 driver specifies GPL v2 only as license, so
use "GPL v2" as module license specifier instead of "GPL" as the latter
means "GNU Public License v2 or later".
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Pull memremap fix from Dan Williams:
 "The new memremap() api introduced in the 4.3 cycle to unify/replace
  ioremap_cache() and ioremap_wt() is mishandling the highmem case.
  This patch has received a build success notification from a
  0day-kbuild-robot run and has received an ack from Ard"

From the commit message:
 "The impact of this bug is low for now since the pmem driver is the
  only user of memremap(), but this is important to fix before more
  conversions to memremap arrive in 4.4"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  memremap: fix highmem support

Pull x86 fixes from Thomas Gleixner:
 "This set of updates contains:

   - Another bugfix for the pathologic vm86 machinery.  Clear
     thread.vm86 on fork to prevent corrupting the parent state.  This
     comes along with an update to the vm86 selftest case

   - Fix another corner case in the ioapic setup code which causes a
     boot crash on some oddball systems

   - Fix the fallout from the dma allocation consolidation work, which
     leads to a NULL pointer dereference when the allocation code is
     called with a NULL device"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/vm86: Set thread.vm86 to NULL on fork/clone
  selftests/x86: Add a fork() to entry_from_vm86 to catch fork bugs
  x86/ioapic: Prevent NULL pointer dereference in setup_ioapic_dest()
  x86/dma-mapping: Fix arch_dma_alloc_attrs() oops with NULL dev

Pull timer fixes from Thomas Gleixner:
 "The last round of minimalistic fixes for clocksource drivers:

   - Prevent multiple shutdown of the sh_mtu2 clocksource

   - Annotate a bunch of clocksource/schedclock functions with notrace
     to prevent an annoying ftrace recursion issue"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clocksource/drivers/sh_mtu2: Fix multiple shutdown call issue
  clocksource/drivers/digicolor: Prevent ftrace recursion
  clocksource/drivers/fsl_ftm_timer: Prevent ftrace recursion
  clocksource/drivers/vf_pit_timer: Prevent ftrace recursion
  clocksource/drivers/prima2: Prevent ftrace recursion
  clocksource/drivers/samsung_pwm_timer: Prevent ftrace recursion
  clocksource/drivers/pistachio: Prevent ftrace recursion
  clocksource/drivers/arm_global_timer: Prevent ftrace recursion

Pull irq fixes from Thomas Gleixner:
 "The last two one-liners for 4.3 from the irqchip space:

   - Regression fix for armada SoC which addresses the fallout from the
     set_irq_flags() cleanup

   - Add the missing propagation of the irq_set_type() callback to the
     parent interrupt controller of the tegra interrupt chip"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/tegra: Propagate IRQ type setting to parent
  irqchip/armada-370-xp: Fix regression by clearing IRQ_NOAUTOEN

Pull ARM SoC fixes from Olof Johansson:
 "This should be our final batch of fixes for 4.3:

   - A patch from Sudeep Holla that fixes annotation of wakeup sources
     properly, old unused format seems to have spread through copying.

   - Two patches from Tony for OMAP.  One dealing with MUSB setup
     problems due to runtime PM being enabled too early on the parent
     device.  The other fixes IRQ numbering for OMAP1"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  usb: musb: omap2430: Fix regression caused by driver core change
  ARM: OMAP1: fix incorrect INT_DMA_LCD
  ARM: dts: fix gpio-keys wakeup-source property

Pull SCSI fixes from James Bottomley:
 "This is three essential bug fixes for various SCSI parts.

  The only affected users are SCSI multi-path via device handler
  (basically all the enterprise) and mvsas users.  The dh bugs are an
  async entanglement in boot resulting in a serious WARN_ON trip and a
  use after free on remove leading to a crash with strict memory
  accounting.  The mvsas bug manifests as a null deref oops but only on
  abort sequences; however, these can commonly occur with SATA attached
  devices, hence the fix"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi_dh: don't try to load a device handler during async probing
  scsi_dh: fix use-after-free when removing scsi device
  mvsas: Fix NULL pointer dereference in mvs_slot_task_free

Pull md bug fixes from Neil Brown:
 "Two more bug fixes for md.

  One bugfix for a list corruption in raid5 because of incorrect
  locking.

  Other for possible data corruption when a recovering device is failed,
  removed, and re-added.

  Both tagged for -stable"

* tag 'md/4.3-rc7-fixes' of git://neil.brown.name/md:
  Revert "md: allow a partially recovered device to be hot-added to an array."
  md/raid5: fix locking in handle_stripe_clean_event()

Pull drm fixes from Dave Airlie:
 "Two drm atomic core fixes.

  And two radeon patches needed to fix a backlight regression on some
  older hardware"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm: Correct arguments to list_tail_add in create blob ioctl
  drm: crtc: integer overflow in drm_property_create_blob()
  drm/radeon: fix dpms when driver backlight control is disabled
  drm/radeon: move bl encoder assignment into bl init

Pull Ceph fix from Sage Weil:
 "This sets the stable pages flag on the RBD block device when we have
  CRCs enabled.  (This is necessary since the default assumption for
  block devices changed in 3.9)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  rbd: require stable pages if message data CRCs are enabled

Pull overlayfs bug fixes from Miklos Szeredi:
 "This contains fixes for bugs that appeared in earlier kernels (all are
  marked for -stable)"

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: free lower_mnt array in ovl_put_super
  ovl: free stack of paths in ovl_fill_super
  ovl: fix open in stacked overlay
  ovl: fix dentry reference leak
  ovl: use O_LARGEFILE in ovl_copy_up()

Pull networking fixes from David Miller:

 1) Fix two regressions in ipv6 route lookups, particularly wrt output
    interface specifications in the lookup key.  From David Ahern.

 2) Fix checks in ipv6 IPSEC tunnel pre-encap fragmentation, from
    Herbert Xu.

 3) Fix mis-advertisement of 1000BASE-T on bcm63xx_enet, from Simon
    Arlott.

 4) Some smsc phys misbehave with energy detect mode enabled, so add a
    DT property and disable it on such switches.  From Heiko Schocher.

 5) Fix TSO corruption on TX in mv643xx_eth, from Philipp Kirchhofer.

 6) Fix regression added by removal of openvswitch vport stats, from
    James Morse.

 7) Vendor Kconfig options should be bool, not tristate, from Andreas
    Schwab.

 8) Use non-_BH() net stats bump in tcp_xmit_probe_skb(), otherwise we
    barf during TCP REPAIR operations.

 9) Fix various bugs in openvswitch conntrack support, from Joe
    Stringer.

10) Fix NETLINK_LIST_MEMBERSHIPS locking, from David Herrmann.

11) Don't have VSOCK do sock_put() in interrupt context, from Jorgen
    Hansen.

12) Fix skb_realloc_headroom() failures properly in ISDN, from Karsten
    Keil.

13) Add some device IDs to qmi_wwan, from Bjorn Mork.

14) Fix ovs egress tunnel information when using lwtunnel devices, from
    Pravin B Shelar.

15) Add missing NETIF_F_FRAGLIST to macvtab feature list, from Jason
    Wang.

16) Fix incorrect handling of throw routes when the result of the throw
    cannot find a match, from Xin Long.

17) Protect ipv6 MTU calculations from wrap-around, from Hannes Frederic
    Sowa.

18) Fix failed autonegotiation on KSZ9031 micrel PHYs, from Nathan
    Sullivan.

19) Add missing memory barries in descriptor accesses or xgbe driver,
    from Thomas Lendacky.

20) Fix release conditon test in pppoe_release(), from Guillaume Nault.

21) Fix gianfar bugs wrt filter configuration, from Claudiu Manoil.

22) Fix violations of RX buffer alignment in sh_eth driver, from Sergei
    Shtylyov.

23) Fixing missing of_node_put() calls in various places around the
    networking, from Julia Lawall.

24) Fix incorrect leaf now walking in ipv4 routing tree, from Alexander
    Duyck.

25) RDS doesn't check pskb_pull()/pskb_trim() return values, from
    Sowmini Varadhan.

26) Fix VLAN configuration in mlx4 driver, from Jack Morgenstein.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (79 commits)
  ipv6: protect mtu calculation of wrap-around and infinite loop by rounding issues
  Revert "Merge branch 'ipv6-overflow-arith'"
  net/mlx4: Copy/set only sizeof struct mlx4_eqe bytes
  net/mlx4_en: Explicitly set no vlan tags in WQE ctrl segment when no vlan is present
  vhost: fix performance on LE hosts
  bpf: sample: define aarch64 specific registers
  amd-xgbe: Fix race between access of desc and desc index
  RDS-TCP: Recover correctly from pskb_pull()/pksb_trim() failure in rds_tcp_data_recv
  forcedeth: fix unilateral interrupt disabling in netpoll path
  openvswitch: Fix skb leak using IPv6 defrag
  ipv6: Export nf_ct_frag6_consume_orig()
  openvswitch: Fix double-free on ip_defrag() errors
  fib_trie: leaf_walk_rcu should not compute key if key is less than pn->key
  net: mv643xx_eth: add missing of_node_put
  ath6kl: add missing of_node_put
  net: phy: mdio: add missing of_node_put
  netdev/phy: add missing of_node_put
  net: netcp: add missing of_node_put
  net: thunderx: add missing of_node_put
  ipv6: gre: support SIT encapsulation
  ...

thread.vm86 points to per-task information -- the pointer should not
be copied on clone.

Fixes: d4ce0f26 ("x86/vm86: Move fields from 'struct kernel_vm86_struct' to 'struct vm86'")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Stas Sergeev <stsp@list.ru>
Link: http://lkml.kernel.org/r/71c5d6985d70ec8197c8d72f003823c81b7dcf99.1446270067.git.luto@kernel.orgSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

Mere possession of vm86 state is strange.  Make sure that nothing
gets corrupted if we fork after calling vm86().
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Stas Sergeev <stsp@list.ru>
Link: http://lkml.kernel.org/r/08f83295460a80e41dc5e3e81ec40d6844d316f5.1446270067.git.luto@kernel.orgSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

Pull input layer fixes from Dmitry Torokhov:

 - a change to the ALPS driver where we had limit the quirk for
   trackstick handling from being active on all Dells to just a few
   models

 - a fix for a build dependency issue in the sur40 driver

 - a small clock handling fixup in the LPC32xx touchscreen driver

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: alps - only the Dell Latitude D420/430/620/630 have separate stick button bits
  Input: sur40 - add dependency on VIDEO_V4L2
  Input: lpc32xx_ts - fix warnings caused by enabling unprepared clock

Pull PCI fix from Bjorn Helgaas:
 "Sorry for this last-minute update; it's been in -next for quite a
  while, but I forgot about it until I started getting ready for the
  merge window.

  It's small and fixes a way a user could cause a panic via sysfs, so I
  think it's worth getting it in v4.3.

  NUMA:
    - Prevent out of bounds access in sysfs numa_node override (Sasha Levin)"

* tag 'pci-v4.3-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: Prevent out of bounds access in numa_node override

Merge tag 'omap-for-v4.3/fixes-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into fixes

Two omap regression fixes:

- Fix omap3 MUSB with DMA caused by driver core changes

- Fix LCD DMA interrupt number for omap1 that did not
  get changed for sparse IRQ changes

* tag 'omap-for-v4.3/fixes-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
  usb: musb: omap2430: Fix regression caused by driver core change
  ARM: OMAP1: fix incorrect INT_DMA_LCD
Signed-off-by: Olof Johansson <olof@lixom.net>

Arguments passed to list_add_tail were reversed resulting in deletion
of old blob property everytime the new one is added.

Fixes

commit e2f5d2ea
Author: Daniel Stone <daniels@collabora.com>
Date:   Fri May 22 13:34:51 2015 +0100

    drm/mode: Add user blob-creation ioctl
Signed-off-by: Maneet Singh <mmaneetsingh@nvidia.com>
[seanpaul tweaked commit subject a little]
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Cc: stable@kernel.org # v4.2
Reviewed-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>

This reverts commit 7eb41885.

This commit is poorly justified, I can find not discusison in email,
and it clearly causes a problem.

If a device which is being recovered fails and is subsequently
re-added to an array, there could easily have been changes to the
array *before* the point where the recovery was up to.  So the
recovery must start again from the beginning.

If a spare is being recovered and fails, then when it is re-added we
really should do a bitmap-based recovery up to the recovery-offset,
and then a full recovery from there.  Before this reversion, we only
did the "full recovery from there" which is not corect.  After this
reversion with will do a full recovery from the start, which is safer
but not ideal.

It will be left to a future patch to arrange the two different styles
of recovery.
Reported-and-tested-by: Nate Dailey <nate.dailey@stratus.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Cc: stable@vger.kernel.org (3.14+)
Fixes: 7eb41885 ("md: allow a partially recovered device to be hot-added to an array.")

The size here comes from the user via the ioctl, it is a number between
1-u32max so the addition here could overflow on 32 bit systems.

Fixes: f453ba04 ('DRM: add mode setting support')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Cc: stable@kernel.org # v4.2
Signed-off-by: Dave Airlie <airlied@gmail.com>

Pull arm64 fixes from Will Deacon:
 "Apologies for this being so late, but we've uncovered a few nasty
  issues on arm64 which didn't settle down until yesterday and the fixes
  all look suitable for 4.3.  Of the four patches, three of them are
  Cc'd to stable, with the remaining patch fixing an issue that only
  took effect during the merge window.

  Summary:

   - Fix corruption in SWP emulation when STXR fails due to contention
   - Fix MMU re-initialisation when resuming from a low-power state
   - Fix stack unwinding code to match what ftrace expects
   - Fix relocation code in the EFI stub when DRAM base is not 2MB aligned"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64/efi: do not assume DRAM base is aligned to 2 MB
  Revert "ARM64: unwind: Fix PC calculation"
  arm64: kernel: fix tcr_el1.t0sz restore on systems with extended idmap
  arm64: compat: fix stxr failure case in SWP emulation

Pull ia64 kcmp syscall from Tony Luck:
 "Missed adding the kcmp() syscall a long time ago.  Now it seems that
  it is essential to build systemd"

* tag 'please-pull-syscalls' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  [IA64] Wire up kcmp syscall

After commit 566c09c5 ("raid5: relieve lock contention in get_active_stripe()")
__find_stripe() is called under conf->hash_locks + hash.
But handle_stripe_clean_event() calls remove_hash() under
conf->device_lock.

Under some cirscumstances the hash chain can be circuited,
and we get an infinite loop with disabled interrupts and locked hash
lock in __find_stripe(). This leads to hard lockup on multiple CPUs
and following system crash.

I was able to reproduce this behavior on raid6 over 6 ssd disks.
The devices_handle_discard_safely option should be set to enable trim
support. The following script was used:

for i in `seq 1 32`; do
    dd if=/dev/zero of=large$i bs=10M count=100 &
done

neilb: original was against a 3.x kernel.  I forward-ported
  to 4.3-rc.  This verison is suitable for any kernel since
  Commit: 59fc630b ("RAID5: batch adjacent full stripe write")
  (v4.1+).  I'll post a version for earlier kernels to stable.
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Fixes: 566c09c5 ("raid5: relieve lock contention in get_active_stripe()")
Signed-off-by: NeilBrown <neilb@suse.com>
Cc: Shaohua Li <shli@kernel.org>
Cc: <stable@vger.kernel.org> # 3.13 - 4.2

rbd requires stable pages, as it performs a crc of the page data before
they are send to the OSDs.

But since kernel 3.9 (patch 1d1d1a76
"mm: only enforce stable page writes if the backing device requires
it") it is not assumed anymore that block devices require stable pages.

This patch sets the necessary flag to get stable pages back for rbd.

In a ceph installation that provides multiple ext4 formatted rbd
devices "bad crc" messages appeared regularly (ca 1 message every 1-2
minutes on every OSD that provided the data for the rbd) in the
OSD-logs before this patch. After this patch this messages are pretty
much gone (only ca 1-2 / month / OSD).

Cc: stable@vger.kernel.org # 3.9+, needs backporting
Signed-off-by: Ronny Hegewald <Ronny.Hegewald@online.de>
[idryomov@gmail.com: require stable pages only in crc case, changelog]
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>