If we configure a kernel with CONFIG_NOCB_CPU=y, CONFIG_RCU_NOCB_CPU_NONE=y and
CONFIG_CPUMASK_OFFSTACK=n and do not pass in a rcu_nocb= boot parameter, the
cpumask rcu_nocb_mask can be garbage instead of NULL.

Hence this commit replaces checks for rcu_nocb_mask == NULL with a check for
have_rcu_nocb_mask.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

RCU currently uses for_each_possible_cpu() to spawn rcuo kthreads,
which can result in more rcuo kthreads than one would expect, for
example, derRichard reported 64 CPUs worth of rcuo kthreads on an
8-CPU image.  This commit therefore creates rcuo kthreads only for
those CPUs that actually come online.

This was reported by derRichard on the OFTC IRC network.
Reported-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

Currently, RCU spawns kthreads from several different early_initcall()
functions.  Although this has served RCU well for quite some time,
as more kthreads are added a more deterministic approach is required.
This commit therefore causes all of RCU's early-boot kthreads to be
spawned from a single early_initcall() function.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

Return false instead of 0 in rcu_nocb_adopt_orphan_cbs() as this has
bool as return type.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

Return false instead of 0 in __call_rcu_nocb() as this has bool as
return type.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

Return true/false in rcu_nocb_adopt_orphan_cbs() instead of 0/1 as
this function has return type of bool.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

Return true/false instead of 0/1 in __call_rcu_nocb() as this returns a
bool type.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

This commit checks the return value of the zalloc_cpumask_var() used for
allocating cpumask for rcu_nocb_mask.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

Commit b58cc46c (rcu: Don't offload callbacks unless specifically
requested) failed to adjust the callback lists of the CPUs that are
known to be no-CBs CPUs only because they are also nohz_full= CPUs.
This failure can result in callbacks that are posted during early boot
getting stranded on nxtlist for CPUs whose no-CBs property becomes
apparent late, and there can also be spurious warnings about offline
CPUs posting callbacks.

This commit fixes these problems by adding an early-boot rcu_init_nohz()
that properly initializes the no-CBs CPUs.

Note that kernels built with CONFIG_RCU_NOCB_CPU_ALL=y or with
CONFIG_RCU_NOCB_CPU=n do not exhibit this bug.  Neither do kernels
booted without the nohz_full= boot parameter.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>

The nocb callbacks generated before the nocb kthreads are spawned are
enqueued in the nocb queue for later processing. Commit fbce7497 ("rcu:
Parallelize and economize NOCB kthread wakeups") introduced nocb leader kthreads
which checked the nocb_leader_wake flag to see if there were any such pending
callbacks. A case was reported in which newly spawned leader kthreads were not
processing the pending callbacks as this flag was not set, which led to a boot
hang.

The following commit ensures that the newly spawned nocb kthreads process the
pending callbacks by allowing the kthreads to run immediately after spawning
instead of waiting. This is done by inverting the logic of nocb_leader_wake
tests to nocb_leader_sleep which allows us to use the default initialization of
this flag to 0 to let the kthreads run.
Reported-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Link: http://www.spinics.net/lists/kernel/msg1802899.html
[ paulmck: Backported to v3.17-rc2. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Amit Shah <amit.shah@redhat.com>

Pull NFS client fixes from Trond Myklebust:
 "Highlights:

   - more fixes for read/write codepath regressions
     * sleeping while holding the inode lock
     * stricter enforcement of page contiguity when coalescing requests
     * fix up error handling in the page coalescing code

   - don't busy wait on SIGKILL in the file locking code"

* tag 'nfs-for-3.17-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  nfs: Don't busy-wait on SIGKILL in __nfs_iocounter_wait
  nfs: can_coalesce_requests must enforce contiguity
  nfs: disallow duplicate pages in pgio page vectors
  nfs: don't sleep with inode lock in lock_and_join_requests
  nfs: fix error handling in lock_and_join_requests
  nfs: use blocking page_group_lock in add_request
  nfs: fix nonblocking calls to nfs_page_group_lock
  nfs: change nfs_page_group_lock argument

Merge tag 'renesas-sh-drivers-for-v3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas

Pull SH driver fix from Simon Horman:
 "Confine SH_INTC to platforms that need it"

* tag 'renesas-sh-drivers-for-v3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas:
  sh: intc: Confine SH_INTC to platforms that need it

Pull MIPS fixes from Ralf Baechle:
 "Pretty much all across the field so with this we should be in
  reasonable shape for the upcoming -rc2"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: OCTEON: make get_system_type() thread-safe
  MIPS: CPS: Initialize EVA before bringing up VPEs from secondary cores
  MIPS: Malta: EVA: Rename 'eva_entry' to 'platform_eva_init'
  MIPS: EVA: Add new EVA header
  MIPS: scall64-o32: Fix indirect syscall detection
  MIPS: syscall: Fix AUDIT value for O32 processes on MIPS64
  MIPS: Loongson: Fix COP2 usage for preemptible kernel
  MIPS: NL: Fix nlm_xlp_defconfig build error
  MIPS: Remove race window in page fault handling
  MIPS: Malta: Improve system memory detection for '{e, }memsize' >= 2G
  MIPS: Alchemy: Fix db1200 PSC clock enablement
  MIPS: BCM47XX: Fix reboot problem on BCM4705/BCM4785
  MIPS: Remove duplicated include from numa.c
  MIPS: Add common plat_irq_dispatch declaration
  MIPS: MSP71xx: remove unused plat_irq_dispatch() argument
  MIPS: GIC: Remove useless parens from GICBIS().
  MIPS: perf: Mark pmu interupt IRQF_NO_THREAD

Merge tag 'trace-fixes-v3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull fix for ftrace function tracer/profiler conflict from Steven Rostedt:
 "The rewrite of the ftrace code that makes it possible to allow for
  separate trampolines had a design flaw with the interaction between
  the function and function_graph tracers.

  The main flaw was the simplification of the use of multiple tracers
  having the same filter (like function and function_graph, that use the
  set_ftrace_filter file to filter their code).  The design assumed that
  the two tracers could never run simultaneously as only one tracer can
  be used at a time.  The problem with this assumption was that the
  function profiler could be implemented on top of the function graph
  tracer, and the function profiler could run at the same time as the
  function tracer.  This caused the assumption to be broken and when
  ftrace detected this failed assumpiton it would spit out a nasty
  warning and shut itself down.

  Instead of using a single ftrace_ops that switches between the
  function and function_graph callbacks, the two tracers can again use
  their own ftrace_ops.  But instead of having a complex hierarchy of
  ftrace_ops, the filter fields are placed in its own structure and the
  ftrace_ops can carefully use the same filter.  This change took a bit
  to be able to allow for this and currently only the global_ops can
  share the same filter, but this new design can easily be modified to
  allow for any ftrace_ops to share its filter with another ftrace_ops.

  The first four patches deal with the change of allowing the ftrace_ops
  to share the filter (and this needs to go to 3.16 as well).

  The fifth patch fixes a bug that was also caused by the new changes
  but only for archs other than x86, and only if those archs implement a
  direct call to the function_graph tracer which they do not do yet but
  will in the future.  It does not need to go to stable, but needs to be
  fixed before the other archs update their code to allow direct calls
  to the function_graph trampoline"

* tag 'trace-fixes-v3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Use current addr when converting to nop in __ftrace_replace_code()
  ftrace: Fix function_profiler and function tracer together
  ftrace: Fix up trampoline accounting with looping on hash ops
  ftrace: Update all ftrace_ops for a ftrace_hash_ops update
  ftrace: Allow ftrace_ops to use the hashes from other ops

Pull x86 fixes from Ingo Molnar:
 "A couple of EFI fixes, plus misc fixes all around the map"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi/arm64: Store Runtime Services revision
  firmware: Do not use WARN_ON(!spin_is_locked())
  x86_32, entry: Clean up sysenter_badsys declaration
  x86/doc: Fix the 'tlb_single_page_flush_ceiling' sysconfig path
  x86/mm: Fix sparse 'tlb_single_page_flush_ceiling' warning and make the variable read-mostly
  x86/mm: Fix RCU splat from new TLB tracepoints

Pull perf fixes from Ingo Molnar:
 "A kprobes and a perf compat ioctl fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Handle compat ioctl
  kprobes: Skip kretprobe hit in NMI context to avoid deadlock

Pull ARM SoC fixes from Olof Johansson:
 "A collection of fixes from this week, it's been pretty quiet and
  nothing really stands out as particularly noteworthy here -- mostly
  minor fixes across the field:

   - ODROID booting was fixed due to PMIC interrupts missing in DT
   - a collection of i.MX fixes
   - minor Tegra fix for regulators
   - Rockchip fix and addition of SoC-specific mailing list to make it
     easier to find posted patches"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  bus: arm-ccn: Fix warning message
  ARM: shmobile: koelsch: Remove non-existent i2c6 pinmux
  ARM: tegra: apalis/colibri t30: fix on-module 5v0 supplies
  MAINTAINERS: add new Rockchip SoC list
  ARM: dts: rockchip: readd missing mmc0 pinctrl settings
  ARM: dts: ODROID i2c improvements
  ARM: dts: Enable PMIC interrupts on ODROID
  ARM: dts: imx6sx: fix the pad setting for uart CTS_B
  ARM: dts: i.MX53: fix apparent bug in VPU clks
  ARM: imx: correct gpu2d_axi and gpu3d_axi clock setting
  ARM: dts: imx6: edmqmx6: change enet reset pin
  ARM: dts: vf610-twr: Fix pinctrl_esdhc1 pin definitions.
  ARM: imx: remove unnecessary ARCH_HAS_OPP select
  ARM: imx: fix TLB missing of IOMUXC base address during suspend
  ARM: imx6: fix SMP compilation again
  ARM: dt: sun6i: Add #address-cells and #size-cells to i2c controller nodes

Pull gpio fixes from Linus Walleij:

 - a largeish fix for the IRQ handling in the new Zynq driver.  The
   quite verbose commit message gives the exact details.
 - move some defines for gpiod flags outside an ifdef to make stub
   functions work again.
 - various minor fixes that we can accept for -rc1.

* tag 'gpio-v3.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpio-lynxpoint: enable input sensing in resume
  gpio: move GPIOD flags outside #ifdef
  gpio: delete unneeded test before of_node_put
  gpio: zynq: Fix IRQ handlers
  gpiolib: devres: use correct structure type name in sizeof
  MAINTAINERS: Change maintainer for gpio-bcm-kona.c

Pull drm fixes from Dave Airlie:
 "Intel and radeon fixes.

  Post KS/LC git requests from i915 and radeon stacked up.  They are all
  fixes along with some new pci ids for radeon, and one maintainers file
  entry.

   - i915: display fixes and irq fixes
   - radeon: pci ids, and misc gpuvm, dpm and hdp cache"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (29 commits)
  MAINTAINERS: Add entry for Renesas DRM drivers
  drm/radeon: add additional SI pci ids
  drm/radeon: add new bonaire pci ids
  drm/radeon: add new KV pci id
  Revert "drm/radeon: Use write-combined CPU mappings of ring buffers with PCIe"
  drm/radeon: fix active_cu mask on SI and CIK after re-init (v3)
  drm/radeon: fix active cu count for SI and CIK
  drm/radeon: re-enable selective GPUVM flushing
  drm/radeon: Sync ME and PFP after CP semaphore waits v4
  drm/radeon: fix display handling in radeon_gpu_reset
  drm/radeon: fix pm handling in radeon_gpu_reset
  drm/radeon: Only flush HDP cache for indirect buffers from userspace
  drm/radeon: properly document reloc priority mask
  drm/i915: don't try to retrain a DP link on an inactive CRTC
  drm/i915: make sure VDD is turned off during system suspend
  drm/i915: cancel hotplug and dig_port work during suspend and unload
  drm/i915: fix HPD IRQ reenable work cancelation
  drm/i915: take display port power domain in DP HPD handler
  drm/i915: Don't try to enable cursor from setplane when crtc is disabled
  drm/i915: Skip load detect when intel_crtc->new_enable==true
  ...

As reported by Dan Aloni, commit f8567a38 ("aio: fix aio request
leak when events are reaped by userspace") introduces a regression when
user code attempts to perform io_submit() with more events than are
available in the ring buffer.  Reverting that commit would reintroduce a
regression when user space event reaping is used.

Fixing this bug is a bit more involved than the previous attempts to fix
this regression.  Since we do not have a single point at which we can
count events as being reaped by user space and io_getevents(), we have
to track event completion by looking at the number of events left in the
event ring.  So long as there are as many events in the ring buffer as
there have been completion events generate, we cannot call
put_reqs_available().  The code to check for this is now placed in
refill_reqs_available().

A test program from Dan and modified by me for verifying this bug is available
at http://www.kvack.org/~bcrl/20140824-aio_bug.c .
Reported-by: Dan Aloni <dan@kernelim.com>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Acked-by: Dan Aloni <dan@kernelim.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: stable@vger.kernel.org      # v3.16 and anything that f8567a38 was backported to
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

A message warning a user about wrong vc value was printing
out port instead.
Reported-by: Drew Richardson <drew.richardson@arm.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

On r8a7791, i2c6 (aka iic3) doesn't need pinmux, but the koelsch dts
refers to non-existent pinmux configuration data:

pinmux core: sh-pfc does not support function i2c6
sh-pfc e6060000.pfc: invalid function i2c6 in map table

Remove it to fix this.

Fixes: commit 1d41f36a ("ARM: shmobile:
       koelsch dts: Add VDD MPU regulator for DVFS")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Olof Johansson <olof@lixom.net>

Working on Gigabit/PCIe support in U-Boot for Apalis T30 I realised
that the current device tree source includes for our modules only
happen to work due to referencing the on-carrier 5v0 supply from USB
which is not at all available on-module. The modules actually contain
TPS60150 charge pumps to generate the PMIC required 5 volts from the
one and only 3.3 volt module supply. This patch fixes this.

(Note: When back-porting this to v3.16 stable releases, simply drop the
change to tegra30-apalis.dtsi; that file was added in v3.17)

Cc: <stable@vger.kernel.org> #v3.16+
Signed-off-by: Marcel Ziswiler <marcel@ziswiler.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'v3.17-rockchip-fixes1' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip into fixes

Merge "ARM: rockchip: fix for 3.17" from Heiko Stubner:

Pinctrl that got accidentially dropped when reorganizing the
dts files and addition of the new Rockchip list to MAINTAINERS.

* tag 'v3.17-rockchip-fixes1' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip:
  MAINTAINERS: add new Rockchip SoC list
  ARM: dts: rockchip: readd missing mmc0 pinctrl settings
Signed-off-by: Olof Johansson <olof@lixom.net>

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>

This pull just contains some new pci ids.

* 'drm-fixes-3.17' of git://people.freedesktop.org/~agd5f/linux:
  drm/radeon: add additional SI pci ids
  drm/radeon: add new bonaire pci ids
  drm/radeon: add new KV pci id

Add the new list that Rockchip-specific patches should also be directed to.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

During the restructuring of the Rockchip Cortex-A9 dtsi files it seems
like the pinctrl settings vanished at some point from the mmc0 support.

This of course renders them unusable, so readd the necessary pinctrl
properties.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Merge tag 'sunxi-dt-for-3.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux into fixes

Merge "Allwinner DT changes, take 2" from Maxime Ripard:

Only a single patch in here that fixes a DTC warning.

* tag 'sunxi-dt-for-3.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux:
  ARM: dt: sun6i: Add #address-cells and #size-cells to i2c controller nodes
Signed-off-by: Olof Johansson <olof@lixom.net>

In __ftrace_replace_code(), when converting the call to a nop in a function
it needs to compare against the "curr" (current) value of the ftrace ops, and
not the "new" one. It currently does not affect x86 which is the only arch
to do the trampolines with function graph tracer, but when other archs that do
depend on this code implement the function graph trampoline, it can crash.

Here's an example when ARM uses the trampolines (in the future):

 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 9 at kernel/trace/ftrace.c:1716 ftrace_bug+0x17c/0x1f4()
 Modules linked in: omap_rng rng_core ipv6
 CPU: 0 PID: 9 Comm: migration/0 Not tainted 3.16.0-test-10959-gf0094b28-dirty #52
 [<c02188f4>] (unwind_backtrace) from [<c021343c>] (show_stack+0x20/0x24)
 [<c021343c>] (show_stack) from [<c095a674>] (dump_stack+0x78/0x94)
 [<c095a674>] (dump_stack) from [<c02532a0>] (warn_slowpath_common+0x7c/0x9c)
 [<c02532a0>] (warn_slowpath_common) from [<c02532ec>] (warn_slowpath_null+0x2c/0x34)
 [<c02532ec>] (warn_slowpath_null) from [<c02cbac4>] (ftrace_bug+0x17c/0x1f4)
 [<c02cbac4>] (ftrace_bug) from [<c02cc44c>] (ftrace_replace_code+0x80/0x9c)
 [<c02cc44c>] (ftrace_replace_code) from [<c02cc658>] (ftrace_modify_all_code+0xb8/0x164)
 [<c02cc658>] (ftrace_modify_all_code) from [<c02cc718>] (__ftrace_modify_code+0x14/0x1c)
 [<c02cc718>] (__ftrace_modify_code) from [<c02c7244>] (multi_cpu_stop+0xf4/0x134)
 [<c02c7244>] (multi_cpu_stop) from [<c02c6e90>] (cpu_stopper_thread+0x54/0x130)
 [<c02c6e90>] (cpu_stopper_thread) from [<c0271cd4>] (smpboot_thread_fn+0x1ac/0x1bc)
 [<c0271cd4>] (smpboot_thread_fn) from [<c026ddf0>] (kthread+0xe0/0xfc)
 [<c026ddf0>] (kthread) from [<c020f318>] (ret_from_fork+0x14/0x20)
 ---[ end trace dc9ce72c5b617d8f ]---
[   65.047264] ftrace failed to modify [<c0208580>] asm_do_IRQ+0x10/0x1c
[   65.054070]  actual: 85:1b:00:eb

Fixes: 7413af1f "ftrace: Make get_ftrace_addr() and get_ftrace_addr_old() global"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The latest rewrite of ftrace removed the separate ftrace_ops of
the function tracer and the function graph tracer and had them
share the same ftrace_ops. This simplified the accounting by removing
the multiple layers of functions called, where the global_ops func
would call a special list that would iterate over the other ops that
were registered within it (like function and function graph), which
itself was registered to the ftrace ops list of all functions
currently active. If that sounds confusing, the code that implemented
it was also confusing and its removal is a good thing.

The problem with this change was that it assumed that the function
and function graph tracer can never be used at the same time.
This is mostly true, but there is an exception. That is when the
function profiler uses the function graph tracer to profile.
The function profiler can be activated the same time as the function
tracer, and this breaks the assumption and the result is that ftrace
will crash (it detects the error and shuts itself down, it does not
cause a kernel oops).

To solve this issue, a previous change allowed the hash tables
for the functions traced by a ftrace_ops to be a pointer and let
multiple ftrace_ops share the same hash. This allows the function
and function_graph tracer to have separate ftrace_ops, but still
share the hash, which is what is done.

Now the function and function graph tracers have separate ftrace_ops
again, and the function tracer can be run while the function_profile
is active.

Cc: stable@vger.kernel.org # 3.16 (apply after 3.17-rc4 is out)
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

If a SIGKILL is sent to a task waiting in __nfs_iocounter_wait,
it will busy-wait or soft lockup in its while loop.
nfs_wait_bit_killable won't sleep, and the loop won't exit on
the error return.

Stop the busy-wait by breaking out of the loop when
nfs_wait_bit_killable returns an error.
Signed-off-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Commit 6094f838
"nfs: allow coalescing of subpage requests" got rid of the requirement
that requests cover whole pages, but it made some incorrect assumptions.

It turns out that callers of this interface can map adjacent requests
(by file position as seen by req_offset + req->wb_bytes) to different pages,
even when they could share a page. An example is the direct I/O interface -
iov_iter_get_pages_alloc may return one segment with a partial page filled
and the next segment (which is adjacent in the file position) starts with a
new page.
Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Adjacent requests that share the same page are allowed, but should only
use one entry in the page vector. This avoids overruning the page
vector - it is sized based on how many bytes there are, not by
request count.

This fixes issues that manifest as "Redzone overwritten" bugs (the
vector overrun) and hangs waiting on page read / write, as it waits on
the same page more than once.

This also adds bounds checking to the page vector with a graceful failure
(WARN_ON_ONCE and pgio error returned to application).
Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

This handles the 'nonblock=false' case in nfs_lock_and_join_requests.
If the group is already locked and blocking is allowed, drop the inode lock
and wait for the group lock to be cleared before trying it all again.
This should fix warnings found in peterz's tree (sched/wait branch), where
might_sleep() checks are added to wait.[ch].
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Reviewed-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

This fixes handling of errors from nfs_page_group_lock in
nfs_lock_and_join_requests.  It now releases the inode lock and the
reference to the head request.
Reported-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Reviewed-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

__nfs_pageio_add_request was calling nfs_page_group_lock nonblocking, but
this can return -EAGAIN which would end up passing -EIO to the application.

There is no reason not to block in this path, so change the two calls to
do so. Also, there is no need to check the return value of
nfs_page_group_lock when nonblock=false, so remove the error handling code.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Reviewed-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs_page_group_lock was calling wait_on_bit_lock even when told not to
block. Fix by first trying test_and_set_bit, followed by wait_on_bit_lock
if and only if blocking is allowed.  Return -EAGAIN if nonblocking and the
test_and_set of the bit was already locked.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Reviewed-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

Flip the meaning of the second argument from 'wait' to 'nonblock' to
match related functions. Update all five calls to reflect this change.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Reviewed-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>