vmscan: fix initial shrinker size handling

A shrinker function can return -1, means that it cannot do anything
without a risk of deadlock.  For example prune_super() does this if it
cannot grab a superblock refrence, even if nr_to_scan=0.  Currently we
interpret this -1 as a ULONG_MAX size shrinker and evaluate `total_scan'
according to this.  So the next time around this shrinker can cause really
big pressure.  Let's skip such shrinkers instead.

Also make total_scan signed, otherwise the check (total_scan < 0) below
never works.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Merge remote-tracking branch 'kvmtool/master'

Conflicts:
include/net/9p/9p.h
scripts/kconfig/Makefile

Merge remote-tracking branch 'pinctrl/for-next'

Merge remote-tracking branch 'writeback/writeback-for-next'

Merge remote-tracking branch 'tmem/tmem'

Conflicts:
mm/swapfile.c

Merge remote-tracking branch 'usb/usb-next'

Merge remote-tracking branch 'tty/tty-next'

Conflicts:
drivers/tty/serial/Kconfig
drivers/tty/serial/Makefile
drivers/tty/tty_ldisc.c

Merge remote-tracking branch 'driver-core/driver-core-next'

Merge remote-tracking branch 'regmap/for-next'

Merge remote-tracking branch 'namespace/master'

Merge remote-tracking branch 'sysctl/master'

Merge remote-tracking branch 'percpu/for-next'

Merge remote-tracking branch 'xen-two/linux-next'

Merge remote-tracking branch 'xen/upstream/xen'

Conflicts:
arch/x86/xen/Kconfig

Merge remote-tracking branch 'kmemleak/kmemleak'

Merge remote-tracking branch 'tip/auto-latest'

Merge remote-tracking branch 'fsnotify/for-next'

Merge remote-tracking branch 'pm/linux-next'

Merge remote-tracking branch 'trivial/for-next'

Merge remote-tracking branch 'osd/linux-next'

Merge remote-tracking branch 'cputime/cputime'

Merge remote-tracking branch 'iommu/next'

Merge remote-tracking branch 'watchdog/linux-next'

Merge remote-tracking branch 'security/next'

Merge remote-tracking branch 'regulator/for-next'

Merge remote-tracking branch 'fbdev/fbdev-next'

Merge remote-tracking branch 'md/for-next'

Merge remote-tracking branch 'slab/for-next'

Merge remote-tracking branch 'kgdb/kgdb-next'

Merge remote-tracking branch 'mmc/mmc-next'

Merge remote-tracking branch 'battery/master'

Merge remote-tracking branch 'block/for-next'

Merge remote-tracking branch 'input/next'

Conflicts:
drivers/input/keyboard/samsung-keypad.c

Merge branch 'quilt/rr'

Merge remote-tracking branch 'cpufreq/next'

Merge remote-tracking branch 'sound-asoc/for-next'

Merge remote-tracking branch 'sound/for-next'

Merge remote-tracking branch 'crypto/master'

Merge remote-tracking branch 'l2-mtd/master'

Merge remote-tracking branch 'bluetooth/master'

Merge remote-tracking branch 'wireless-next/master'

Merge remote-tracking branch 'net-next/master'

Conflicts:
drivers/net/ethernet/nvidia/forcedeth.c
drivers/net/wireless/libertas/cfg.c

Merge remote-tracking branch 'slave-dma/next'

Conflicts:
drivers/dma/pl330.c

Merge remote-tracking branch 'target-merge/for-next-merge'

Merge remote-tracking branch 'infiniband/for-next'

Merge remote-tracking branch 'libata/NEXT'

Merge remote-tracking branch 'kconfig/for-next'

Merge remote-tracking branch 'kbuild/for-next'

Merge remote-tracking branch 'v4l-dvb/master'

Conflicts:
drivers/staging/media/as102/as102_drv.h

Merge remote-tracking branch 'hwmon-staging/hwmon-next'

Merge remote-tracking branch 'bjdooks-i2c/next-i2c'

Conflicts:
drivers/i2c/busses/i2c-designware-platdrv.c

Merge branch 'quilt/i2c'

Merge remote-tracking branch 'hid/for-next'

Merge remote-tracking branch 'pci/linux-next'

Merge remote-tracking branch 'xfs/master'

Merge remote-tracking branch 'ocfs2/linux-next'

Merge remote-tracking branch 'nfsd/nfsd-next'

Merge remote-tracking branch 'nfs/linux-next'

Merge remote-tracking branch 'logfs/master'

Conflicts:
fs/logfs/file.c

Merge remote-tracking branch 'gfs2/master'

Merge remote-tracking branch 'cifs/master'

Merge remote-tracking branch 'xtensa/master'

Merge remote-tracking branch 'unicore32/unicore32'

Merge remote-tracking branch 's390/features'

Merge remote-tracking branch '52xx-and-virtex/powerpc/next'

Merge remote-tracking branch 'parisc/for-next'

Merge remote-tracking branch 'mips/mips-for-linux-next'

Merge remote-tracking branch 'm68knommu/for-next'

Conflicts:
arch/m68k/Kconfig.debug

Merge remote-tracking branch 'm68k/for-next'

Merge remote-tracking branch 'ia64/next'

Merge remote-tracking branch 'cris/for-next'

Merge remote-tracking branch 'c6x/for-linux-next'

Merge remote-tracking branch 'tegra/for-next'

Merge remote-tracking branch 's5p/for-next'

Merge remote-tracking branch 'i.MX/for-next'

Conflicts:
arch/arm/mach-mx5/clock-mx51-mx53.c
arch/arm/mach-mx5/devices-imx53.h
arch/arm/mach-mx5/mm.c
arch/arm/plat-mxc/include/mach/hardware.h

Merge remote-tracking branch 'at91/at91-next'

Merge remote-tracking branch 'arm-lpae/for-next'

Conflicts:
arch/arm/include/asm/pgalloc.h
arch/arm/include/asm/pgtable.h
arch/arm/include/asm/tlb.h

Merge remote-tracking branch 'arm/for-next'

Merge remote-tracking branch 'ide/master'

Merge remote-tracking branch 'input-current/for-linus'

Merge remote-tracking branch 'char-misc.current/char-misc-linus'

Merge remote-tracking branch 'usb.current/usb-linus'

Merge remote-tracking branch 'tty.current/tty-linus'

Merge remote-tracking branch 'driver-core.current/driver-core-linus'

Merge remote-tracking branch 'wireless/master'

Merge remote-tracking branch 'pci-current/for-linus'

Merge remote-tracking branch 'net/master'

Merge remote-tracking branch 'sparc/master'

Merge remote-tracking branch 'arm-current/fixes'

Merge branches 'ar7-for-next', 'ath79-for-next', 'bcm63xx-for-next', 'bmips', 'cavium-for-next', 'kprobes-for-next' and 'raza-for-next' into mips-for-linux-next

MIPS: ath79: Rename dev-ar913x-wmac.c to dev-wmac.c

Rename the file as a last step of the 'ar913x' removal changes.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3034/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: ath79: Rename dev-ar913x-wmac.h to dev-wmac.h

The 'ar913x' part was removed from the common variable and function names,
so remove that from the relevant header file name as well.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3033/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS Kprobes: Support branch instructions probing

This patch provides support for kprobes on branch instructions. The branch
instruction at the probed address is actually emulated and not executed
out-of-line like other normal instructions. Instead the delay-slot instruction
is copied and single stepped out of line.

At the time of probe hit, the original branch instruction is evaluated
and the target cp0_epc is computed similar to compute_retrun_epc(). It
is also checked if the delay slot instruction can be skipped, which is
true if there is a NOP in delay slot or branch is taken in case of
branch likely instructions. Once the delay slot instruction is single
stepped the normal execution resume with the cp0_epc updated the earlier
computed cp0_epc as per the branch instructions.

Signed-off-by: Maneesh Soni <manesoni@cisco.com>
Signed-off-by: Victor Kamensky <kamensky@cisco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: ananth@in.ibm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2914/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS Kprobes: Refactor branch emulation

This patch refactors MIPS branch emulation code so as to allow skipping
delay slot instruction in case of branch likely instructions when branch is
not taken. This is useful for keeping the code common for use cases like
kprobes where one would like to handle the branch instructions keeping the
delay slot instuction also in picture for branch likely instructions. Also
allow emulation when instruction to be decoded is not at pt_regs->cp0_epc
as in case of kprobes where pt_regs->cp0_epc points to the breakpoint
instruction.

The patch also exports the function for modules.

Signed-off-by: Maneesh Soni <manesoni@cisco.com>
Signed-off-by: Victor Kamensky <kamensky@cisco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: ananth@in.ibm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2913/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS Kprobes: Deny probes on ll/sc instructions

As ll/sc instruction are for atomic read-modify-write operations, allowing
probes on top of these insturctions is a bad idea.

Signed-off-by: Victor Kamensky <kamensky@cisco.com>
Signed-off-by: Maneesh Soni <manesoni@cisco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: ananth@in.ibm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2912/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS Kprobes: Fix OOPS in arch_prepare_kprobe()

This patch fixes the arch_prepare_kprobe() on MIPS when it tries to find the
instruction at the previous address to the probed address. The oops happens
when the probed address is the first address in a kernel module and there is
no previous address. The patch uses probe_kernel_read() to safely read the
previous instruction.

CPU 3 Unable to handle kernel paging request at virtual address ffffffffc0211ffc, epc == ffffffff81113204, ra == ffffffff8111511c
Oops[#1]:
Cpu 3
$ 0   : 0000000000000000 0000000000000001 ffffffffc0212000 0000000000000000
$ 4   : ffffffffc0220030 0000000000000000 0000000000000adf ffffffff81a3f898
$ 8   : ffffffffc0220030 ffffffffffffffff 000000000000ffff 0000000000004821
$12   : 000000000000000a ffffffff81105ddc ffffffff812927d0 0000000000000000
$16   : ffffffff81a40000 ffffffffc0220030 ffffffffc0220030 ffffffffc0212660
$20   : 0000000000000000 0000000000000008 efffffffffffffff ffffffffc0220000
$24   : 0000000000000002 ffffffff8139f5b0
$28   : a800000072adc000 a800000072adfca0 ffffffffc0220000 ffffffff8111511c
Hi    : 0000000000000000
Lo    : 0000000000000000
epc   : ffffffff81113204 arch_prepare_kprobe+0x1c/0xe8
    Tainted: P
ra    : ffffffff8111511c register_kprobe+0x33c/0x730
Status: 10008ce3    KX SX UX KERNEL EXL IE
Cause : 00800008
BadVA : ffffffffc0211ffc
PrId  : 000d9008 (Cavium Octeon II)
Modules linked in: bpa_mem crashinfo pds tun cpumem ipv6 exportfs nfsd OOBnd(P) OOBhal(P) cvmx_mdio cvmx_gpio aipcmod(P) mtsmod procfs(P) utaker_mod dplr_pci hello atomicm_foo [last unloaded: sysmgr_hb]
Process stapio (pid: 5603, threadinfo=a800000072adc000, task=a8000000722e0438, tls=000000002b4bcda0)
Stack : ffffffff81a40000 ffffffff81a40000 ffffffffc0220030 ffffffff8111511c
        ffffffffc0218008 0000000000000001 ffffffffc0218008 0000000000000001
        ffffffffc0220000 ffffffffc021efe8 1000000000000000 0000000000000008
        efffffffffffffff ffffffffc0220000 ffffffffc0220000 ffffffffc021d500
        0000000000000022 0000000000000002 1111000072be02b8 0000000000000000
        00000000000015e6 00000000000015e6 00000000007d0f00 a800000072be02b8
        0000000000000000 ffffffff811d16c8 a80000000382e3b0 ffffffff811d5ba0
        ffffffff81b0a270 ffffffff81b0a270 ffffffffc0212000 0000000000000013
        ffffffffc0220030 ffffffffc021ed00 a800000089114c80 000000007f90d590
        a800000072adfe38 a800000089114c80 0000000010020000 0000000010020000
        ...
Call Trace:
[<ffffffff81113204>] arch_prepare_kprobe+0x1c/0xe8
[<ffffffff8111511c>] register_kprobe+0x33c/0x730
[<ffffffffc021d500>] _stp_ctl_write_cmd+0x8e8/0xa88 [atomicm_foo]
[<ffffffff812925cc>] vfs_write+0xb4/0x178
[<ffffffff81292828>] SyS_write+0x58/0x148
[<ffffffff81103844>] handle_sysn32+0x44/0x84

Code: ffb20010  ffb00000  dc820028 <8c44fffc> 8c500000  0c4449e0  0004203c  14400029  3c048199

Signed-off-by: Maneesh Soni <manesoni@cisco.com>
Signed-off-by: Victor Kamensky <kamensky@cisco.com>
Cc: David Daney <david.daney@cavium.com>
Cc: ananth@in.ibm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2915/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: ath79: Register the wireless MAC device on the AP121 board

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3032/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: ath79: Rename ATH79_DEV_AR913X_WMAC option to ATH79_DEV_WMAC

The ATH79_DEV_AR913X_WMAC option was used to select the AR913x specific
wireless MAC registration code.  The registration code now supports the
AR933X SoCs as well. Rename the option to reflect the changes.

Also make the new option depends on SOC_AR933X.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3031/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: ath79: Add AR933x specific WMAC setup code

The wireless MAC of the AR933x SoCs uses different base address, and
requires different setup code.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3030/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MIPS: ath79: Separate AR913x SoC specific WMAC setup code

The device registration code can be shared between the different SoCs, but
the required setup code varies Move AR913x specific setup code into a
separate function in order to make adding support for another SoCs easier.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3029/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>