To avoid forking usermode thread when creating an idle task, move fork_idle
to a work queue.

If kernel starts with maxcpus= option which does not bring all available
cpus online at boot time, idle tasks for offline cpus are not created. If
later offline cpus are hotplugged through sysfs, __cpu_up is called in
the context of the user task, and fork_idle copies its non-zero mm
pointer.  This causes BUG() in per_cpu_trap_init.

This also avoids issues with resource limits of the CPU writing to sysfs,
containers, maybe others.
Signed-off-by: NMaksim Rayskiy <mrayskiy@broadcom.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2070/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Leverage the commit for ARM by Will Deacon:

- 446a5a8b
    ARM: 6205/1: perf: ensure counter delta is treated as unsigned

    Hardware performance counters on ARM are 32-bits wide but atomic64_t
    variables are used to represent counter data in the hw_perf_event structure.

    The armpmu_event_update function right-shifts a signed 64-bit delta variable
    and adds the result to the event count. This can lead to shifting in sign-bits
    if the MSB of the 32-bit counter value is set. This results in perf output
    such as:

     Performance counter stats for 'sleep 20':

     18446744073460670464  cycles             <-- 0xFFFFFFFFF12A6000
            7783773  instructions             #      0.000 IPC
                465  context-switches
                161  page-faults
            1172393  branches

       20.154242147  seconds time elapsed

    This patch ensures that the delta value is treated as unsigned so that the
    right shift sets the upper bits to zero.
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: a.p.zijlstra@chello.nl
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: wuzhangjin@gmail.com
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Patchwork: http://patchwork.linux-mips.org/patch/2015/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This is the MIPS part of the following commits by Frederic Weisbecker:

- f72c1a93
    perf: Factorize callchain context handling

    Store the kernel and user contexts from the generic layer instead
    of archs, this gathers some repetitive code.

- 56962b44
    perf: Generalize some arch callchain code

    - Most archs use one callchain buffer per cpu, except x86 that needs
      to deal with NMIs. Provide a default perf_callchain_buffer()
      implementation that x86 overrides.

    - Centralize all the kernel/user regs handling and invoke new arch
      handlers from there: perf_callchain_user() / perf_callchain_kernel()
      That avoid all the user_mode(), current->mm checks and so...

    - Invert some parameters in perf_callchain_*() helpers: entry to the
      left, regs to the right, following the traditional (dst, src).

- 70791ce9
    perf: Generalize callchain_store()

    callchain_store() is the same on every archs, inline it in
    perf_event.h and rename it to perf_callchain_store() to avoid
    any collision.

    This removes repetitive code.

- c1a65932
    perf: Drop unappropriate tests on arch callchains

    Drop the TASK_RUNNING test on user tasks for callchains as
    this check doesn't seem to make any sense.

    Also remove the tests for !current that is not supposed to
    happen and current->pid as this should be handled at the
    generic level, with exclude_idle attribute.
Reported-by: NWu Zhangjin <wuzhangjin@gmail.com>
Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: a.p.zijlstra@chello.nl
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: dengcheng.zhu@gmail.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Patchwork: http://patchwork.linux-mips.org/patch/2014/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Ignore events that are in off/error state or belong to a different PMU.

This patch originates from the following commit for ARM by Will Deacon:

- 65b4711f
    ARM: 6352/1: perf: fix event validation

    The validate_event function in the ARM perf events backend has the
    following problems:

    1.) Events that are disabled count towards the cost.
    2.) Events associated with other PMUs [for example, software events or
        breakpoints] do not count towards the cost, but do fail validation,
        causing the group to fail.

    This patch changes validate_event so that it ignores events in the
    PERF_EVENT_STATE_OFF state or that are scheduled for other PMUs.
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: a.p.zijlstra@chello.nl
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: wuzhangjin@gmail.com
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: dengcheng.zhu@gmail.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Cc: ddaney@caviumnetworks.com
Patchwork: http://patchwork.linux-mips.org/patch/2013/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This is the MIPS part of the following commits by Peter Zijlstra:

- a4eaf7f1
    perf: Rework the PMU methods

    Replace pmu::{enable,disable,start,stop,unthrottle} with
    pmu::{add,del,start,stop}, all of which take a flags argument.

    The new interface extends the capability to stop a counter while
    keeping it scheduled on the PMU. We replace the throttled state with
    the generic stopped state.

    This also allows us to efficiently stop/start counters over certain
    code paths (like IRQ handlers).

    It also allows scheduling a counter without it starting, allowing for
    a generic frozen state (useful for rotating stopped counters).

    The stopped state is implemented in two different ways, depending on
    how the architecture implemented the throttled state:

     1) We disable the counter:
        a) the pmu has per-counter enable bits, we flip that
        b) we program a NOP event, preserving the counter state

     2) We store the counter state and ignore all read/overflow events

For MIPSXX, the stopped state is implemented in the way of 1.b as above.

- 33696fc0
    perf: Per PMU disable

    Changes perf_disable() into perf_pmu_disable().

- 24cd7f54
    perf: Reduce perf_disable() usage

    Since the current perf_disable() usage is only an optimization,
    remove it for now. This eases the removal of the __weak
    hw_perf_enable() interface.

- b0a873eb
    perf: Register PMU implementations

    Simple registration interface for struct pmu, this provides the
    infrastructure for removing all the weak functions.

- 51b0fe39
    perf: Deconstify struct pmu

    sed -ie 's/const struct pmu\>/struct pmu/g' `git grep -l "const struct pmu\>"`
Reported-by: NWu Zhangjin <wuzhangjin@gmail.com>
Acked-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: a.p.zijlstra@chello.nl
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: wuzhangjin@gmail.com
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: dengcheng.zhu@gmail.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com
Cc: ddaney@caviumnetworks.com
Patchwork: http://patchwork.linux-mips.org/patch/2012/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This is the MIPS part of the following commit by Peter Zijlstra:

- e360adbe
    irq_work: Add generic hardirq context callbacks

    Provide a mechanism that allows running code in IRQ context. It is
    most useful for NMI code that needs to interact with the rest of the
    system -- like wakeup a task to drain buffers.

    Perf currently has such a mechanism, so extract that and provide it as
    a generic feature, independent of perf so that others may also
    benefit.

    The IRQ context callback is generated through self-IPIs where
    possible, or on architectures like powerpc the decrementer (the
    built-in timer facility) is set to generate an interrupt immediately.

    Architectures that don't have anything like this get to do with a
    callback from the timer tick. These architectures can call
    irq_work_run() at the tail of any IRQ handlers that might enqueue such
    work (like the perf IRQ handler) to avoid undue latencies in
    processing the work.

For MIPSXX, we need to call irq_work_run() at the tail of the perf IRQ
handler as described above.
Reported-by: NWu Zhangjin <wuzhangjin@gmail.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@gmail.com>
To: fweisbec@gmail.com
To: will.deacon@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: matt@console-pimps.org
Cc: sshtylyov@mvista.com,
Patchwork: http://patchwork.linux-mips.org/patch/2011/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NYoichi Yuasa <yuasa@linux-mips.org>
Cc: linux-mips <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/2055/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This error was reported by cppcheck:
arch/mips/loongson/common/machtype.c:56: error: Dangerous usage of 'str' (strncpy doesn't always 0-terminate it)

If strncpy copied MACHTYPE_LEN bytes, the destination string str
was not terminated.

The patch adds one more byte to str and makes sure that this byte is
always 0.
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Arnaud Patard <apatard@mandriva.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/2053/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Under some combinations of CONFIG_*, lastpfn in page_is_ram is 'set
but not used'.  Mark it as __maybe_unused to quiet the warning/error.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2033/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

GCC-4.6 can find more unused code than previous versions could.

In the case of arch/mips/math-emu/ieee754int.h, the COMPXSP and
COMPXDP macros are used in several places, but a couple of them leave
xs unused.  The easiest thing to do is mark it as __maybe_unused to
quiet the warning.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2032/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The variable arg3 in _sys_sysmips() is unused.  Remove it.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2034/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

GCC-4.6 can find more unused code than previous versions could.

In the case of protected_restore_fp_context{,32}, the variable tmp is
really used.  Its use is tricky in that we really care about the side
effects of the __put_user() calls.  So we must mark tmp with
__maybe_unused to quiet the warning.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2035/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NAnoop P A <anoop.pa@gmail.com>
To: Ben Hutchings <ben@decadent.org.uk>
To: linux-mips@linux-mips.org
To: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1804/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NAnoop P A <anoop.pa@gmail.com>
To: linux-mips@linux-mips.org
To: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1803/Tested-by: NShane McDonald <mcdonald.shane@gmail.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Loongson builds have an ad-hoc cmdline default of "console=ttyS0,115200
root=/dev/hda1". These settings come from a vendor; I remember builds
from Lemote branch requiring a "console=tty" override in order to get a
working console.

At least on Yeeloong, they're particularly useless: there's no external
serial port, and the IDE drive is now recognised as /dev/sda.
Signed-off-by: NRobert Millan <rmh@gnu.org>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1759/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The sysmips(MIPS_FIXADE, ...) case contains an obvious copy-and-paste
error in the handling of the TIF_LOGADE flag. Fix that

Patchwork: https://patchwork.linux-mips.org/patch/1997/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

It was reported that GCC-4.3.3 (with CodeSourcery extensions) fails
without this.
Reported-by: NJonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2010/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

trace.func should be set to the recorded ip of the mcount calling site
in the __mcount_loc section to filter the function entries configured
through the tracing/set_graph_function interface, but before, this is
set to the self_ra(the return address of mcount), which has made
set_graph_function not work as expected.

This fixes it via calculating the right recorded ip in the __mcount_loc
section and assign it to trace.func.
Reported-by: NZhiping Zhong <xzhong86@163.com>
Signed-off-by: NWu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Sergei Shtylyov <sshtylyov@mvista.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2017/Signed-off-by: NRalf Baechle <ralf@duck.linux-mips.net>

This moves the comments out of ftrace_make_nop() and cleans it.  At the
same time, a macro MCOUNT_OFFSET_INSNS is defined for sharing with the
next patch.
Signed-off-by: NWu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2008/Signed-off-by: NRalf Baechle <ralf@duck.linux-mips.net>

The old prepare_ftrace_return() for MIPS is confused and have introduced
some problem. This patch cleans up the names of the arguments, variables
and related functions.

For MIPS, the 2nd argument of prepare_ftrace_return() is not really the
'selfpc' described in ftrace-design.txt but instead it is the self
return address. This did break the compatibility of the generic
interface but really reduced one unneeded calculation for to get the
current function name, the parent return address and the self return
address are enough, no need to tranform the self return address to the
self address.

But set_graph_function of function graph tracer is an exception, it does
need the 2nd argument of prepare_ftrace_return() as 'selfpc', for it
will use 'selfpc' to match user's configuration of function graph
entries, but in reality, it doesn't need the 'selfpc' but the recorded
ip address of the mcount calling site in the __mcount_loc section. So,
the 2nd argument of prepare_ftrace_return() is not important, the real
requirement is the right recorded ip address should be calculated and
assign to trace.func, this will be fixed in the next patches.
Reported-by: NZhiping Zhong <xzhong86@163.com>
Signed-off-by: NWu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2007/Signed-off-by: NRalf Baechle <ralf@duck.linux-mips.net>

The old in_module() may not work in some situations(e.g. when module &
kernel are in the same address space when CONFIG_MAPPED_KERNEL=y), The
in_kernel_space() is more generic and it is also easy to be implemented
via cloning the existing core_kernel_text(), so, replace the in_module()
with in_kernel_space().
Signed-off-by: NWu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2005/Signed-off-by: NRalf Baechle <ralf@duck.linux-mips.net>

This simply moves the "ip-=4" statement down to the end of the do { ...
} while (...); loop, which reduces one unneeded subtration and the
subsequent memory loading and comparison.
Signed-off-by: NWu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2006/Signed-off-by: NRalf Baechle <ralf@duck.linux-mips.net>

SPIN_LOCK_UNLOCK is deprecated. Use the lockdep capable variant instead.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2025/Signed-off-by: NRalf Baechle <ralf@duck.linux-mips.net>

Fix for a dumb preadv()/pwritev() compat bug - unlike the native
variants, the compat_...  ones forget to check FMODE_P{READ,WRITE}, so
e.g.  on pipe the native preadv() will fail with -ESPIPE and compat one
will act as readv() and succeed.

Not critical, but it's a clear bug with trivial fix, so IMO it's OK for
-final.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/staging:
  hwmon/f71882fg: Set platform drvdata to NULL later
  hwmon/f71882fg: Fix a typo in a comment

* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: break out of shrink_delalloc earlier
  btrfs: fix not enough reserved space
  btrfs: fix dip leak
  Btrfs: make sure not to return overlapping extents to fiemap
  Btrfs: deal with short returns from copy_from_user
  Btrfs: fix regressions in copy_from_user handling

* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6:
  [SCSI] target: Fix t_transport_aborted handling in LUN_RESET + active I/O shutdown

Recent change to fixdep:

    commit b7bd1821
    Author: Michal Marek <mmarek@suse.cz>
    Date:   Thu Feb 17 15:13:54 2011 +0100

    fixdep: Do not record dependency on the source file itself

changed the format of the *.cmd files without realizing that it is also
used by modpost. Put the path to the source file to the file back, in a
special variable, so that modpost sees all source files when calculating
srcversion for modules.
Reported-and-tested-by: NHenrik Rydberg <rydberg@euromail.se>
Signed-off-by: NMichal Marek <mmarek@suse.cz>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

* git://git.infradead.org/users/dwmw2/mtd-2.6.38:
  mtd: add "platform:" prefix for platform modalias
  mtd: mtd_blkdevs: fix double free on error path
  mtd: amd76xrom: fix oops at boot when resources are not available
  mtd: fix race in cfi_cmdset_0001 driver
  mtd: jedec_probe: initialise make sector erase command variable
  mtd: jedec_probe: Change variable name from cfi_p to cfi

* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
  drm/radeon: fix page flipping hangs on r300/r400
  drm/radeon: add pageflip hooks for fusion

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: fix mis-synchronisation in blkdev_issue_zeroout()

* 'fix/asoc' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ASoC: Ensure WM8958 gets all WM8994 late revision widgets
  ASoC: Fix typo in late revision WM8994 DAC2R name
  ASoC: Use the correct DAPM context when cleaning up final widget set
  ASoC: Fix broken bitfield definitions in WM8978
  ASoC: AM3517: Update codec name after multi-component update

The device table is required to load modules based on modaliases.

After adding MODULE_DEVICE_TABLE, below entries will be added to
modules.pcimap:

  pch_gpio             0x00008086 0x00008803 0xffffffff 0xffffffff 0x00000000 0x00000000 0x0
  ml_ioh_gpio          0x000010db 0x0000802e 0xffffffff 0xffffffff 0x00000000 0x00000000 0x0
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Cc: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When vmscan.c calls page_referenced(), if an anon page was created
before a process forked, rmap will search for it in both of the
processes, even though one of them might have since broken COW.

If the child process mlocks the vma where the COWed page belongs to,
page_referenced() running on the page mapped by the parent would lead to
*vm_flags getting VM_LOCKED set erroneously (leading to the references
on the parent page being ignored and evicting the parent page too
early).

*mapcount would also be decremented by page_referenced_one even if the
page wasn't found by page_check_address.

This also lets pmdp_clear_flush_young_notify() go ahead on a
pmd_trans_splitting() pmd.

We hold the page_table_lock so __split_huge_page_map() must wait the
pmdp_clear_flush_young_notify() to complete before it can modify the
pmd.  The pmd is also still mapped in userland so the young bit may
materialize through a tlb miss before split_huge_page_map runs.

This will provide a more accurate page_referenced() behavior during
split_huge_page().
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Reported-by: NMichel Lespinasse <walken@google.com>
Reviewed-by: NMichel Lespinasse <walken@google.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Reviewed-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel<riel@redhat.com>
Reviewed-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This avoids a possible race leading to trying to dereference NULL.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NJean Delvare <khali@linux-fr.org>
Cc: stable@kernel.org
Signed-off-by: NGuenter Roeck <guenter.roeck@ericsson.com>

Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Acked-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGuenter Roeck <guenter.roeck@ericsson.com>

We've been getting reports of complete system lockups with rv3xx hw on
AGP and PCIE when running gnome-shell or kwin with compositing.

It appears the hw really doesn't like setting these registers while
stuff is running, this moves the setting of the registers into the modeset
since they aren't required to be changed anywhere else.

fixes: https://bugs.freedesktop.org/show_bug.cgi?id=35183

Reported-and-tested-by: Álmos <aaalmosss@gmail.com
Signed-off-by: NDave Airlie <airlied@redhat.com>

Josef had changed shrink_delalloc to exit after three shrink
attempts, which wasn't quite enough because new writers could
race in and steal free space.

But it also fixed deadlocks and stalls as we tried to recover
delalloc reservations.  The code was tweaked to loop 1024
times, and would reset the counter any time a small amount
of progress was made.  This was too drastic, and with a
lot of writers we can end up stuck in shrink_delalloc forever.

The shrink_delalloc loop is fairly complex because the caller is looping
too, and the caller will go ahead and force a transaction commit to make
sure we reclaim space.

This reworks things to exit shrink_delalloc when we've forced some
writeback and the delalloc reservations have gone down.  This means
the writeback has not just started but has also finished at
least some of the metadata changes required to reclaim delalloc
space.

If we've got this wrong, we're returning ENOSPC too early, which
is a big improvement over the current behavior of hanging the machine.

Test 224 in xfstests hammers on this nicely, and with 1000 writers
trying to fill a 1GB drive we get our first ENOSPC at 93% full.  The
other writers are able to continue until we get 100%.

This is a worst case test for btrfs because the 1000 writers are doing
small IO, and the small FS size means we don't have a lot of room
for metadata chunks.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

BZ29402
https://bugzilla.kernel.org/show_bug.cgi?id=29402

We can hit serious mis-synchronization in bio completion path of
blkdev_issue_zeroout() leading to a panic.

The problem is that when we are going to wait_for_completion() in
blkdev_issue_zeroout() we check if the bb.done equals issued (number of
submitted bios). If it does, we can skip the wait_for_completition()
and just out of the function since there is nothing to wait for.
However, there is a ordering problem because bio_batch_end_io() is
calling atomic_inc(&bb->done) before complete(), hence it might seem to
blkdev_issue_zeroout() that all bios has been completed and exit. At
this point when bio_batch_end_io() is going to call complete(bb->wait),
bb and wait does not longer exist since it was allocated on stack in
blkdev_issue_zeroout() ==> panic!

(thread 1)                      (thread 2)
bio_batch_end_io()              blkdev_issue_zeroout()
  if(bb) {                      ...
    if (bb->end_io)             ...
      bb->end_io(bio, err);     ...
    atomic_inc(&bb->done);      ...
    ...                         while (issued != atomic_read(&bb.done))
    ...                         (let issued == bb.done)
    ...                         (do the rest of the function)
    ...                         return ret;
    complete(bb->wait);
    ^^^^^^^^
    panic

We can fix this easily by simplifying bio_batch and completion counting.

Also remove bio_end_io_t *end_io since it is not used.
Signed-off-by: NLukas Czerner <lczerner@redhat.com>
Reported-by: NEric Whitney <eric.whitney@hp.com>
Tested-by: NEric Whitney <eric.whitney@hp.com>
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
CC: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Since 43cc71ee (platform: prefix MODALIAS
with "platform:"), the platform modalias is prefixed with "platform:".
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org