ACPI / scan: always register memory hotplug scan handler

Prevent platform devices from being created for ACPI memory device
objects if CONFIG_ACPI_HOTPLUG_MEMORY is unset by compiling out the
memory hotplug scan handler's callbacks only in that case and still
compiling its device ID list in and registering the scan handler in
either case.

Also unset the memory hotplug scan handler's .attach() callback
if acpi_no_memhotplug is set, but still register the scan handler to
avoid creating platform devices for ACPI memory devices in that case
too.

This change is based on a prototype from Zhang Rui.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
ACPI / scan: always register ACPI LPSS scan handler

Prevent platform devices from being created for ACPI LPSS devices
if CONFIG_X86_INTEL_LPSS is unset by compiling out the LPSS scan
handler's callbacks only in that case and still compiling its device
ID list in and registering the scan handler in either case.

This change is based on a prototype from Zhang Rui.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
ACPI / scan: use platform bus type by default for _HID enumeration

Because of the growing demand for enumerating ACPI devices to
platform bus, change the code to enumerate ACPI device objects to
platform bus by default.  Namely, create platform devices for the
ACPI device objects that
 1. Have pnp.type.platform_id set (device objects with _HID currently).
 2. Do not have a scan handler attached.
 3. Are not SPI/I2C slave devices (that should be enumerated to the
    appropriate buses bus by their parent).

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
[rjw: Subject and changelog, rebase and code cleanup]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
blk-mq: blk_mq_tag_to_rq should handle flush request

flush request is special, which borrows the tag from the parent
request. Hence blk_mq_tag_to_rq needs special handling to return
the flush request from the tag.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Merge branch 'for-3.16/core' into for-3.16/drivers

Pulled in for the blk_mq_tag_to_rq() change, which impacts
mtip32xx.

Signed-off-by: Jens Axboe <axboe@fb.com>
block: virtio_blk: don't hold spin lock during world switch

Firstly, it isn't necessary to hold lock of vblk->vq_lock
when notifying hypervisor about queued I/O.

Secondly, virtqueue_notify() will cause world switch and
it may take long time on some hypervisors(such as, qemu-arm),
so it isn't good to hold the lock and block other vCPUs.

On arm64 quad core VM(qemu-kvm), the patch can increase I/O
performance a lot with VIRTIO_RING_F_EVENT_IDX enabled:
	- without the patch: 14K IOPS
	- with the patch: 34K IOPS

fio script:
	[global]
	direct=1
	bsrange=4k-4k
	timeout=10
	numjobs=4
	ioengine=libaio
	iodepth=64

	filename=/dev/vdc
	group_reporting=1

	[f1]
	rw=randread

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org # 3.13+
Signed-off-by: Jens Axboe <axboe@fb.com>
blk-mq: make the sysfs mq/ layout reflect current mappings

Currently blk-mq registers all the hardware queues in sysfs,
regardless of whether it uses them (e.g. they have CPU mappings)
or not. The unused hardware queues lack the cpux/ directories,
and the other sysfs entries (like active, pending, etc) are all
zeroes.

Change this so that sysfs correctly reflects the current mappings
of the hardware queues.

Signed-off-by: Jens Axboe <axboe@fb.com>
shrink_dentry_list(): take parent's ->d_lock earlier

The cause of livelocks there is that we are taking ->d_lock on
dentry and its parent in the wrong order, forcing us to use
trylock on the parent's one.  d_walk() takes them in the right
order, and unfortunately it's not hard to create a situation
when shrink_dentry_list() can't make progress since trylock
keeps failing, and shrink_dcache_parent() or check_submounts_and_drop()
keeps calling d_walk() disrupting the very shrink_dentry_list() it's
waiting for.

Solution is straightforward - if that trylock fails, let's unlock
the dentry itself and take locks in the right order.  We need to
stabilize ->d_parent without holding ->d_lock, but that's doable
using RCU.  And we'd better do that in the very beginning of the
loop in shrink_dentry_list(), since the checks on refcount, etc.
would need to be redone anyway.

That deals with a half of the problem - killing dentries on the
shrink list itself.  Another one (dropping their parents) is
in the next commit.

locking parent is interesting - it would be easy to do rcu_read_lock(),
lock whatever we think is a parent, lock dentry itself and check
if the parent is still the right one.  Except that we need to check
that *before* locking the dentry, or we are risking taking ->d_lock
out of order.  Fortunately, once the D1 is locked, we can check if
D2->d_parent is equal to D1 without the need to lock D2; D2->d_parent
can start or stop pointing to D1 only under D1->d_lock, so taking
D1->d_lock is enough.  In other words, the right solution is
rcu_read_lock/lock what looks like parent right now/check if it's
still our parent/rcu_read_unlock/lock the child.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
dealing with the rest of shrink_dentry_list() livelock

We have the same problem with ->d_lock order in the inner loop, where
we are dropping references to ancestors.  Same solution, basically -
instead of using dentry_kill() we use lock_parent() (introduced in the
previous commit) to get that lock in a safe way, recheck ->d_count
(in case if lock_parent() has ended up dropping and retaking ->d_lock
and somebody managed to grab a reference during that window), trylock
the inode->i_lock and use __dentry_kill() to do the rest.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
dentry_kill() doesn't need the second argument now

it's 1 in the only remaining caller.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
PCI: Make pci_bus_add_device() void

pci_bus_add_device() always returns 0, so there's no point in returning
anything at all.  Make it a void function and remove the tests of the
return value from the callers.

[bhelgaas: changelog, remove unused "err" from i82875p_setup_overfl_dev()]
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
PCI: imx6: Fix imx6_add_pcie_port() section mismatch warning

imx6_add_pcie_port() is called only from from imx6_pcie_probe() which is
annotated with __init.  Thus it makes sense to annotate
imx6_add_pcie_port() with __init to avoid section mismatch warnings.

[bhelgaas: changelog]
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sean Cross <xobs@kosagi.com>
Merge tag 'renesas-fixes-for-v3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas into next/fixes-non-critical

Merge "Renesas ARM Based SoC Fixes for v3.16" from Simon Horman:

This corrects a bug that will be introduced in v3.15.
The bug causes audio playback to fail on the Armadillo800 EVA board.

* tag 'renesas-fixes-for-v3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas:
  ARM: shmobile: armadillo800eva: fixup HDMI sound flags setting

Signed-off-by: Olof Johansson <olof@lixom.net>
blk-mq: blk_mq_unregister_hctx() can be static

CC: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
arm64: kernel: initialize broadcast hrtimer based clock event device

On platforms implementing CPU power management, the CPUidle subsystem
can allow CPUs to enter idle states where local timers logic is lost on power
down. To keep the software timers functional the kernel relies on an
always-on broadcast timer to be present in the platform to relay the
interrupt signalling the timer expiries.

For platforms implementing CPU core gating that do not implement an always-on
HW timer or implement it in a broken way, this patch adds code to initialize
the kernel hrtimer based clock event device upon boot (which can be chosen as
tick broadcast device by the kernel).
It relies on a dynamically chosen CPU to be always powered-up. This CPU then
relays the timer interrupt to CPUs in deep-idle states through its HW local
timer device.

Having a CPU always-on has implications on power management platform
capabilities and makes CPUidle suboptimal, since at least a CPU is kept
always in a shallow idle state by the kernel to relay timer interrupts,
but at least leaves the kernel with a functional system with some working
power management capabilities.

The hrtimer based clock event device is unconditionally registered, but
has the lowest possible rating such that any broadcast-capable HW clock
event device present will be chosen in preference as the tick broadcast
device.

Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
vfio/pci: Fix sizing of DPA and THP express capabilities

When sizing the TPH capability we store the register containing the
table size into the 'dword' variable, but then use the uninitialized
'byte' variable to analyze the size.  The table size is also actually
reported as an N-1 value, so correct sizing to account for this.

The round_up() for both TPH and DPA is unnecessary, remove it.

Detected by Coverity: CID 714665 & 715156

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
ARM/PCI: Call pcie_bus_configure_settings() to set MPS

Call pcie_bus_configure_settings() on ARM, like for other platforms.
pcie_bus_configure_settings() makes sure the MPS across the bus is uniform
and provides the ability to tune the MRSS and MPS to higher performance
values.  This is particularly important for embedded where there is no
firmware to program these PCIe settings for the OS.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
CC: Santosh Shilimkar <santosh.shilimkar@ti.com>
Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs dcache livelock fix from Al Viro:
 "Fixes for livelocks in shrink_dentry_list() introduced by fixes to
  shrink list corruption; the root cause was that trylock of parent's
  ->d_lock could be disrupted by d_walk() happening on other CPUs,
  resulting in shrink_dentry_list() making no progress *and* the same
  d_walk() being called again and again for as long as
  shrink_dentry_list() doesn't get past that mess.

  The solution is to have shrink_dentry_list() treat that trylock
  failure not as 'try to do the same thing again', but 'lock them in the
  right order'"

* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  dentry_kill() doesn't need the second argument now
  dealing with the rest of shrink_dentry_list() livelock
  shrink_dentry_list(): take parent's ->d_lock earlier
  expand dentry_kill(dentry, 0) in shrink_dentry_list()
  split dentry_kill()
  lift the "already marked killed" case into shrink_dentry_list()
i82875p_edac: Assign PCI resources before adding device

Assign PCI resources before pci_bus_add_device().  The resources must be
assigned before a driver can claim the device.

[bhelgaas: changelog]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
ARM: dts: enable RTC and WDT nodes on Origen boards

Enabled RTC and WDT nodes on exynos4210-origen and
exynos4412-origen boards.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
[kgene.kim@samsung.com: squashed similar two patches]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>