As can be seen in function uart_insert_char (serial_core) the element
buf_overrun of struct uart_icount is used to count overruns of
tty-buffer.
Added support for counting of overruns in imx driver analogue to
serial_core.
Signed-off-by: Manfred Schlaegl <manfred.schlaegl@gmx.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Disable interrupts before requesting them in order to fix a kernel oops
after lauching a kernel via kexec.

Tested on a imx6sl-evk board.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Being a soft core, it can be located not only on PPC or Microblaze
platforms.

Since the driver already does endianness detection we only need to
change the Kconfig to use it in other arches.

This is also done in other softcores as xilinx-spi.
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

SysRq support activation depends on CONFIG_SERIAL_STM32_USART_CONSOLE, but
this config flag does not exists.

This patch fix this by depending on the valid config flag, which is
SERIAL_STM32_CONSOLE.
Reported-by: Andreas Ruprecht <andreas.ruprecht@fau.de>
Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

While UART work in DMA mode, function start_rx will request descriptor
from DMA engine, if there is no left descriptor UART, driver will give
err logs "DMA slave single fail".

currently start_rx is called in set_termios function, so everytime, port
setting will call start_rx once.

Now put start_rx in startup, it will be called once while open the port.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

when UART works in DMA mode and left bytes in rx fifo less than
a dma transfer unit, DMA engine can't transfer the bytes out
to rx DMA buffer. so it need a way to fetch them out and
flush them into tty buffer in time.

in the above case, we want UART switch from DMA mode to PIO mode and
fetch && flush bytes into tty layer buffer until rxfifo become empty,
after that done let UART switch from PIO mode back to DMA mode.
(record as method1)

method1 result in the next receive result wrong. for example in PIO part
of method1, we fetched && pushed X1...X3 bytes, when UART rxfifo newly
received Y1...Y4 bytes, UART trigger a DMA unit transfer, the DMA unit's
content is X1...X3Y1 and rxfifo fifo status is empty, so X1X2X3 pushed
twice by PIO way and DMA way also the bytes Y2Y3Y4 missed. add rxfifo
reset operation before UART switch back to DMA mode would resolve the
issue. ([method1 + do fifo reset] record as method2)

before the commit, UART driver use method2. but methd2 have a risk of
data loss, as if UART's shift register receive a complete byte and
transfer it into rxfifo before rxfifo reset operation the byte will
loss.

UART and USP have the similar bits CLEAR_RX_ADDR_EN(uart)/FRADDR_CLR_EN(usp),
When found UART controller changing I/O to DMA mode, UART controller
clears the two low bits of read point (rx_fifo_addr[1:0]).
when enable the bit + method1(record as method3), in above example
the DMA unit's content is X1...X3Y1 and there are Y2Y3Y4 in rxfifo by
experiment, we just push bytes in rx DMA buffer.

BTW, the workaround works only for UART receive DMA channel use SINGLE
DMA mode.
Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The implementation of cris_console_device() is exactly the same as
uart_console_device(), so let's switch to use uart_console_device().
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Niklas Cassel <nks@flawful.org>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

OMAP h/w-assisted IXON flow control is borked. The transmitter becomes
stuck if XON is never received; clearing the fifos or resetting the
rx flow control bits has no effect.

Remove auto-IXANY as well, since without auto-IXON, it has no purpose.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Due to Advisory 21 as documented in AM437x errata document,
UART module cannot be disabled once DMA is used. The only
workaround is to softreset the module before disabling it.

DRA7x UARTs are compatible to AM437x UARTs in terms of
this errata and prescribed workaround.

Enable usage of workaround for this errata on DRA7x SoCs.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

AM335x, AM437x and DRA7x SoCs have an errata[1] due to which UART
cannot be idled after it has been used with DMA.

OMAP3 has a similar sounding errata which has been worked around
in a2fc3661 ("ARM: OMAP3: Use manual idle for UARTs
because of DMA errata"). But the workaround used there does not
apply to AM335x, AM437x SoCs.

After using DMA, the UART module on these SoCs must be soft reset
to go to idle.

This patch implements that errata workaround. It is expected that
UART will be used with DMA so no explicit check for DMA usage
has been added for errata applicability.

MDR1 register needs to be restored right after soft-reset because
"UART mode" must be set in that register for module wake-up on AM335x
to work. As a result, SCR register is now used to determine if
context was lost during sleep.

[1] See Advisory 21 in AM437x errata SPRZ408B, updated April 2015.
    http://www.ti.com/lit/er/sprz408b/sprz408b.pdfSigned-off-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use of of_machine_is_compatible() for handling AM335x specific
"DMA kick" quirk in 8250_omap driver makes it ugly to extend the
quirk for other platforms. Instead use a new compatible.

The new compatible will also make it easier to take care of
other quirks on AM335x and like SoCs.

In order to not break backward DTB compatibility for users of
8250_omap driver on AM335x based boards, existing use of
of_machine_is_compatible() has not been removed.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The silicon errata[1] workaround implemented in a follow-on
patch, "serial: 8250_omap: workaround errata on disabling
UART after using DMA", requires MDR1 register programming.

Extract MDR1 register update into helper function,
omap8250_update_mdr1() to help with that.

[1] Advisory 21 in http://www.ti.com/lit/er/sprz408b/sprz408b.pdfSigned-off-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The compatible "ti,am4372-uart" is used in arch/arm/boot/dts/am4372.dtsi
but not documented. Add necessary documentation.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

omap_device infrastructure has a suspend_noirq hook which
runtime suspends all devices late in the suspend cycle (see
_od_suspend_noirq() in arch/arm/mach-omap2/omap_device.c)

This leads to a NULL pointer exception in 8250_omap driver
since by the time omap8250_runtime_suspend() is called, 8250_dma
driver has already set rxchan to NULL via serial8250_release_dma().

Make an explicit check to see if rxchan is NULL in
runtime_{suspend|resume} hooks to fix this.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fintek chip can be configured for io addresses different than the standard.

Query the chip for the configured addresses and try to match it with the
pnp address.
Reported-by: Peter Hong <peter_hong@fintek.com.tw>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Chip can be configured to use entry key different than 0x77. Try all the
valid keys until one gives out the right chip id.
Reported-by: Peter Hong <peter_hong@fintek.com.tw>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There are some chips with the same interface but different chip ip.
Reported-by: Peter Hong <peter_hong@fintek.com.tw>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fintek chip can be connected at address 0x4e and also 0x2e.
Add some logic to find out the address of the chip.
Reported-by: Peter Hong <peter_hong@fintek.com.tw>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Save the port index and the line id in a private structure.
Reported-by: Peter Hong <peter_hong@fintek.com.tw>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In little endian cases, macro htons unfolds to __swab16 which
provides special case for constants. In big endian cases,
__constant_htons and htons expand directly to the same expression.
So, replace __constant_htons with htons with the goal of getting
rid of the definition of __constant_htons completely.

The semantic patch that performs this transformation is as follows:

@@expression x;@@

- __constant_htons(x)
+ htons(x)
Signed-off-by: Vaishali Thakkar <vthakkar1994@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull SCSI fixes from James Bottomley:
 "Two fairly simple fixes: one is a change that causes us to have a very
  low queue depth leading to performance issues and the other is a null
  deref occasionally in tapes thanks to use after put"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: fix host max depth checking for the 'queue_depth' sysfs interface
  st: null pointer dereference panic caused by use after kref_put by st_open

Pull MIPS fixes from Ralf Baechle:
 "Another round of MIPS fixes for 4.2.

  Things are looking quite decent at this stage but the recent work on
  the FPU support took its toll:

   - fix an incorrect overly restrictive ifdef

   - select O32 64-bit FP support for O32 binary compatibility

   - remove workarounds for Sibyte SB1250 Pass1 parts.  There are rare
     fixing the workarounds is not worth the effort.

   - patch up an outdated and now incorrect comment"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: fpu.h: Allow 64-bit FPU on a 64-bit MIPS R6 CPU
  MIPS: SB1: Remove support for Pass 1 parts.
  MIPS: Require O32 FP64 support for MIPS64 with O32 compat
  MIPS: asm-offset.c: Patch up various comments refering to the old filename.

Pull parisc fix from Helge Deller:
 "A memory leak fix from Christophe Jaillet which was introduced with
  kernel 4.0 and which leads to kernel crashes on parisc after 1-3 days"

* 'parisc-4.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: mm: Fix a memory leak related to pmd not attached to the pgd

Pull ARM SoC fixes from Olof Johansson:
 "By far most of the fixes here are updates to DTS files to deal with
  some mostly minor bugs.

  There's also a fix to deal with non-PM kernel configs on i.MX, a
  regression fix for ethernet on PXA platforms and a dependency fix for
  OMAP"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  ARM: keystone: dts: rename pcie nodes to help override status
  ARM: keystone: dts: fix dt bindings for PCIe
  ARM: pxa: fix dm9000 platform data regression
  ARM: dts: Correct audio input route & set mic bias for am335x-pepper
  ARM: OMAP2+: Add HAVE_ARM_SCU for AM43XX
  MAINTAINERS: digicolor: add dts files
  ARM: ux500: fix MMC/SD card regression
  ARM: ux500: define serial port aliases
  ARM: dts: OMAP5: Add #iommu-cells property to IOMMUs
  ARM: dts: OMAP4: Add #iommu-cells property to IOMMUs
  ARM: dts: Fix frequency scaling on Gumstix Pepper
  ARM: dts: configure regulators for Gumstix Pepper
  ARM: dts: omap3: overo: Update LCD panel names
  ARM: dts: cros-ec-keyboard: Add support for some Japanese keys
  ARM: imx6: gpc: always enable PU domain if CONFIG_PM is not set
  ARM: dts: imx53-qsb: fix TVE entry
  ARM: dts: mx23: fix iio-hwmon support
  ARM: dts: imx27: Adjust the GPT compatible string
  ARM: socfpga: dts: Fix entries order
  ARM: socfpga: dts: Fix adxl34x formating and compatible string

Commit 6134d949 ("MIPS: asm: fpu: Allow 64-bit FPU on MIPS32 R6")
added support for 64-bit FPU on a 32-bit MIPS R6 processor but it missed
the 64-bit CPU case leading to FPU failures when requesting FR=1 mode
(which is always the case for MIPS R6 userland) when running a 32-bit
kernel on a 64-bit CPU. We also fix the MIPS R2 case.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Fixes: 6134d949 ("MIPS: asm: fpu: Allow 64-bit FPU on MIPS32 R6")
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: <stable@vger.kernel.org> # 4.0+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10734/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

Commit 0e0da48d ("parisc: mm: don't count preallocated pmds")
introduced a memory leak.

After this commit, the 'return' statement in pmd_free is executed in all
cases. Even for pmd that are not attached to the pgd.  So 'free_pages'
can never be called anymore, leading to a memory leak.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org  # v4.0+
Signed-off-by: Helge Deller <deller@gmx.de>

Merge "pxa fixes for v4.2" from Robert Jarzmik:

ARM: pxa: fixes for v4.2-rc2

This single fix reenables ethernet cards for several pxa boards,
broken by regulator addition to dm9000 driver.

* tag 'pxa-fixes-v4.2-rc2' of https://github.com/rjarzmik/linux:
  ARM: pxa: fix dm9000 platform data regression

Pull ARM fixes from Russell King:
 "A small set of ARM fixes for -rc3, most of them not far off
  one-liners, with the exception of fixing the V7 cache invalidation for
  incoming SMP processors which was causing problems for SoCFPGA
  devices"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: fix __virt_to_idmap build error on !MMU
  ARM: invalidate L1 before enabling coherency
  ARM: 8404/1: dma-mapping: fix off-by-one error in bitmap size check
  ARM: 8402/1: perf: Don't use of_node after putting it
  ARM: 8400/1: use virt_to_idmap to get phys_reset address

Pull x86 fixes from Ingo Molnar:
 "Two families of fixes:

   - Fix an FPU context related boot crash on newer x86 hardware with
     larger context sizes than what most people test.  To fix this
     without ugly kludges or extensive reverts we had to touch core task
     allocator, to allow x86 to determine the task size dynamically, at
     boot time.

     I've tested it on a number of x86 platforms, and I cross-built it
     to a handful of architectures:

                                        (warns)               (warns)
       testing     x86-64:  -git:  pass (    0),  -tip:  pass (    0)
       testing     x86-32:  -git:  pass (    0),  -tip:  pass (    0)
       testing        arm:  -git:  pass ( 1359),  -tip:  pass ( 1359)
       testing       cris:  -git:  pass ( 1031),  -tip:  pass ( 1031)
       testing       m32r:  -git:  pass ( 1135),  -tip:  pass ( 1135)
       testing       m68k:  -git:  pass ( 1471),  -tip:  pass ( 1471)
       testing       mips:  -git:  pass ( 1162),  -tip:  pass ( 1162)
       testing    mn10300:  -git:  pass ( 1058),  -tip:  pass ( 1058)
       testing     parisc:  -git:  pass ( 1846),  -tip:  pass ( 1846)
       testing      sparc:  -git:  pass ( 1185),  -tip:  pass ( 1185)

     ... so I hope the cross-arch impact 'none', as intended.

     (by Dave Hansen)

   - Fix various NMI handling related bugs unearthed by the big asm code
     rewrite and generally make the NMI code more robust and more
     maintainable while at it.  These changes are a bit late in the
     cycle, I hope they are still acceptable.

     (by Andy Lutomirski)"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86
  x86/fpu, sched: Dynamically allocate 'struct fpu'
  x86/entry/64, x86/nmi/64: Add CONFIG_DEBUG_ENTRY NMI testing code
  x86/nmi/64: Make the "NMI executing" variable more consistent
  x86/nmi/64: Minor asm simplification
  x86/nmi/64: Use DF to avoid userspace RSP confusing nested NMI detection
  x86/nmi/64: Reorder nested NMI checks
  x86/nmi/64: Improve nested NMI comments
  x86/nmi/64: Switch stacks on userspace NMI entry
  x86/nmi/64: Remove asm code that saves CR2
  x86/nmi: Enable nested do_nmi() handling for 64-bit kernels

Pull timer fix from Ingo Molnar:
 "Fix for a misplaced export that can cause build failures in certain
  (rare) Kconfig situations"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick: Move the export of tick_broadcast_oneshot_control to the proper place

Pull scheduler fix from Ingo Molnar:
 "A oneliner rq throttling fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Test list head instead of list entry in throttle_cfs_rq()

Pull perf fixes from Ingo Molnar:
 "Mostly tooling fixes, plus a static key fix fixing /sys/devices/cpu/rdpmc"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf tools: Really allow to specify custom CC, AR or LD
  perf auxtrace: Fix misplaced check for HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT
  perf hists browser: Take the --comm, --dsos, etc filters into account
  perf symbols: Store if there is a filter in place
  x86, perf: Fix static_key bug in load_mm_cr4()
  tools: Copy lib/hweight.c from the kernel sources
  perf tools: Fix the detached tarball wrt rbtree copy
  perf thread_map: Fix the sizeof() calculation for map entries
  tools lib: Improve clean target
  perf stat: Fix shadow declaration of close
  perf tools: Fix lockup using 32-bit compat vdso

Pull irq fixes from Ingo Molnar:
 "Misc irq fixes:

   - two driver fixes
   - a Xen regression fix
   - a nested irq thread crash fix"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gicv3-its: Fix mapping of LPIs to collections
  genirq: Prevent resend to interrupts marked IRQ_NESTED_THREAD
  genirq: Revert sparse irq locking around __cpu_up() and move it to x86 for now
  gpio/davinci: Fix race in installing chained irq handler

Merge fixes from Andrew Morton:
 "25 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (25 commits)
  lib/decompress: set the compressor name to NULL on error
  mm/cma_debug: correct size input to bitmap function
  mm/cma_debug: fix debugging alloc/free interface
  mm/page_owner: set correct gfp_mask on page_owner
  mm/page_owner: fix possible access violation
  fsnotify: fix oops in fsnotify_clear_marks_by_group_flags()
  /proc/$PID/cmdline: fixup empty ARGV case
  dma-debug: skip debug_dma_assert_idle() when disabled
  hexdump: fix for non-aligned buffers
  checkpatch: fix long line messages about patch context
  mm: clean up per architecture MM hook header files
  MAINTAINERS: uclinux-h8-devel is moderated for non-subscribers
  mailmap: update Sudeep Holla's email id
  Update Viresh Kumar's email address
  mm, meminit: suppress unused memory variable warning
  configfs: fix kernel infoleak through user-controlled format string
  include, lib: add __printf attributes to several function prototypes
  s390/hugetlb: add hugepages_supported define
  mm: hugetlb: allow hugepages_supported to be architecture specific
  revert "s390/mm: make hugepages_supported a boot time decision"
  ...

Pull btrfs fixes from Chris Mason:
 "These are all from Filipe, and cover a few problems we've had reported
  on the list recently (along with ones he found on his own)"

* 'for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix file corruption after cloning inline extents
  Btrfs: fix order by which delayed references are run
  Btrfs: fix list transaction->pending_ordered corruption
  Btrfs: fix memory leak in the extent_same ioctl
  Btrfs: fix shrinking truncate when the no_holes feature is enabled

Pull rtc fixes from Alexandre Belloni:
 "A few fixes for the RTC susbsystem for 4.2.

  The mt6397 driver was introduce in 4.2 so it is worth fixing before
  the final release.  I though the compilation warning for armada38x was
  fixed by akpm in commit f98b733e ("rtc-armada38x.c: remove unused
  local `flags'") but he actually missed some occurrences of the
  variables.  Since I received 4 patches for that, I think we can
  include it now.

  Summary:
   - fix mt6397 wakealarm creation
   - remove a compilation warning for armada38x that was forgotten"

* tag 'rtc-v4.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux:
  rtc: armada38x: Remove unused variable from armada38x_rtc_set_time()
  rtc: mt6397: enable wakeup before registering rtc device

Pull device mapper fixes from Mike Snitzer:

 - revert a request-based DM core change that caused IO latency to
   increase and adversely impact both throughput and system load

 - fix for a use after free bug in DM core's device cleanup

 - a couple DM btree removal fixes (used by dm-thinp)

 - a DM thinp fix for order-5 allocation failure

 - a DM thinp fix to not degrade to read-only metadata mode when in
   out-of-data-space mode for longer than the 'no_space_timeout'

 - fix a long-standing oversight in both dm-thinp and dm-cache by now
   exporting 'needs_check' in status if it was set in metadata

 - fix an embarrassing dm-cache busy-loop that caused worker threads to
   eat cpu even if no IO was actively being issued to the cache device

* tag 'dm-4.2-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache: avoid calls to prealloc_free_structs() if possible
  dm cache: avoid preallocation if no work in writeback_some_dirty_blocks()
  dm cache: do not wake_worker() in free_migration()
  dm cache: display 'needs_check' in status if it is set
  dm thin: display 'needs_check' in status if it is set
  dm thin: stay in out-of-data-space mode once no_space_timeout expires
  dm: fix use after free crash due to incorrect cleanup sequence
  Revert "dm: only run the queue on completion if congested or no requests pending"
  dm btree: silence lockdep lock inversion in dm_btree_del()
  dm thin: allocate the cell_sort_array dynamically
  dm btree remove: fix bug in redistribute3

Don't burden architectures without dynamic task_struct sizing
with the overhead of dynamic sizing.

Also optimize the x86 code a bit by caching task_struct_size.
Acked-and-Tested-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1437128892-9831-3-git-send-email-mingo@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

The FPU rewrite removed the dynamic allocations of 'struct fpu'.
But, this potentially wastes massive amounts of memory (2k per
task on systems that do not have AVX-512 for instance).

Instead of having a separate slab, this patch just appends the
space that we need to the 'task_struct' which we dynamically
allocate already.  This saves from doing an extra slab
allocation at fork().

The only real downside here is that we have to stick everything
and the end of the task_struct.  But, I think the
BUILD_BUG_ON()s I stuck in there should keep that from being too
fragile.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1437128892-9831-2-git-send-email-mingo@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>