When resuming with dpms off, the following warn can happen:

[  118.334082] ------------[ cut here ]------------
[  118.334105] WARNING: CPU: 2 PID: 2274 at drivers/gpu/drm/i915/intel_display.c:6319 __intel_set_mode+0xae5/0xb90 [i915]()
[  118.334106] WARN_ON(!crtc->state->enable)
[  118.334137] Modules linked in: i915
[  118.334139] CPU: 2 PID: 2274 Comm: kworker/u16:117 Not tainted 4.2.0-rc2-fixes+ #4148
[  118.334140] Hardware name: LENOVO 2349AV8/2349AV8, BIOS G1ETA5WW (2.65 ) 04/15/2014
[  118.334144] Workqueue: events_unbound async_run_entry_fn
[  118.334147]  ffffffffc017eef0 ffff8800ada93998 ffffffff817aa62a 0000000080000001
[  118.334149]  ffff8800ada939e8 ffff8800ada939d8 ffffffff810807e1 ffff8800ada939c8
[  118.334151]  ffff8800cea3b3d8 0000000000000000 ffff8800ad86b008 ffff880117705668
[  118.334151] Call Trace:
[  118.334155]  [<ffffffff817aa62a>] dump_stack+0x4f/0x7b
[  118.334157]  [<ffffffff810807e1>] warn_slowpath_common+0x81/0xc0
[  118.334158]  [<ffffffff81080861>] warn_slowpath_fmt+0x41/0x50
[  118.334173]  [<ffffffffc0120375>] __intel_set_mode+0xae5/0xb90 [i915]
[  118.334188]  [<ffffffffc0121312>] ? intel_modeset_compute_config+0x52/0xb40 [i915]
[  118.334191]  [<ffffffff8144de53>] ? drm_atomic_set_fb_for_plane+0x63/0x80
[  118.334205]  [<ffffffffc01269d9>] intel_set_mode+0x29/0x60 [i915]
[  118.334219]  [<ffffffffc012730a>] intel_crtc_restore_mode+0x13a/0x1f0 [i915]
[  118.334232]  [<ffffffffc0101160>] ? gen6_write16+0x250/0x250 [i915]
[  118.334246]  [<ffffffffc01283ec>] intel_modeset_setup_hw_state+0x89c/0xcd0 [i915]
[  118.334248]  [<ffffffff8137d260>] ? pci_pm_thaw+0x90/0x90
[  118.334255]  [<ffffffffc00ac11b>] i915_drm_resume+0xcb/0x160 [i915]
[  118.334262]  [<ffffffffc00ac1d2>] i915_pm_resume+0x22/0x30 [i915]
[  118.334263]  [<ffffffff8137d2c3>] pci_pm_resume+0x63/0xa0
[  118.334266]  [<ffffffff81467550>] dpm_run_callback+0x70/0x420
[  118.334267]  [<ffffffff81467cbd>] device_resume+0x9d/0x1c0
[  118.334269]  [<ffffffff814673d0>] ? initcall_debug_start+0x60/0x60
[  118.334270]  [<ffffffff81467dfc>] async_resume+0x1c/0x50
[  118.334271]  [<ffffffff810a6a94>] async_run_entry_fn+0x34/0xd0
[  118.334273]  [<ffffffff8109d4ad>] process_one_work+0x1dd/0x7e0
[  118.334275]  [<ffffffff8109d41a>] ? process_one_work+0x14a/0x7e0
[  118.334276]  [<ffffffff8109daf9>] worker_thread+0x49/0x450
[  118.334278]  [<ffffffff8109dab0>] ? process_one_work+0x7e0/0x7e0
[  118.334280]  [<ffffffff810a3cb9>] kthread+0xf9/0x110
[  118.334282]  [<ffffffff810a3bc0>] ? insert_kthread_work+0x90/0x90
[  118.334284]  [<ffffffff817b414f>] ret_from_fork+0x3f/0x70
[  118.334286]  [<ffffffff810a3bc0>] ? insert_kthread_work+0x90/0x90
[  118.334287] ---[ end trace 01f2cf6371b82d7a ]---

This warn is harmless, and can be fixed by not calling intel_crtc_disable when
the crtc is already disabled.
Reported-and-Tested-by: Jörg Otte <jrg.otte@gmail.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This reverts commit 19ee835c.

It breaks existing old userspace which doesn't handle UNKNOWN
swizzling correct. Yes UNKNOWN was a thing back in 2009 and probably
still is on some other platforms, but it still pretty clearly broke
the testers machine. If we want this we need to extend the ioctl with
new paramters that only new userspace looks at.

Cc: Harald Arnesen <harald@skogtun.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reported-by: Harald Arnesen <harald@skogtun.org>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Previously only core DRM ioctls under the DRM_COMMAND_BASE were being
forwarded, but the drm.h header suggests (and reality confirms) ones
after (and including) DRM_COMMAND_END should be forwarded as well.

We need this to correctly forward the compat ioctl for the botched-up
addfb2.1 extension.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: stable@vger.kernel.org # 4.1+
[danvet: Explain why this is suddenly needed and add cc: stable.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

On Sun, Jul 12, 2015 at 09:52:51AM -0700, Linus Torvalds wrote:
> On Sun, Jul 12, 2015 at 1:03 AM, Jörg Otte <jrg.otte@gmail.com> wrote:
> > BUG: unable to handle kernel NULL pointer dereference at 0000000000000009
> > IP: [<ffffffffbd3447bb>] 0xffffffffbd3447bb
>
> Ugh. Please enable KALLSYMS to get sane symbols.
>
> But yes, "crtc_state->base.active" is at offset 9 from "crtc_state",
> so it's pretty clearly just that change frm
>
> -       if (intel_crtc->active) {
> +       if (crtc_state->base.active) {
>
> and "crtc_state" is NULL.
>
> And the code very much knows that crtc_state can be NULL, since it's
> initialized with
>
>         crtc_state = state->base.state ?
>                 intel_atomic_get_crtc_state(state->base.state,
> intel_crtc) : NULL;
>
> Tssk. Daniel? Should I just revert that commit dec4f799
> ("drm/i915: Use crtc_state->active in primary check_plane func") for
> now, or is there a better fix? Like just checking crtc_state for NULL?

Indeed embarrassing. I've missed that we still have 1 caller left that's
using the transitional helpers, and those don't fill out
plane_state->state backpointers to the global atomic update since there is
no global atomic update for transitional helpers. Below diff should fix
this - we need to preferentially check crts_state->active and if that's
not set intel_crtc->active should yield the right result for the one
remaining caller (it's in the crtc_disable paths).

This fixes a regression introduced in

commit dec4f799
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Jul 7 11:15:47 2015 +0200

    drm/i915: Use crtc_state->active in primary check_plane func

which was quickly reverted in

commit 01e2d062
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun Jul 12 15:00:20 2015 -0700

    Revert "drm/i915: Use crtc_state->active in primary check_plane func"

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jörg Otte <jrg.otte@gmail.com>
Reported-and-tested-by: Jörg Otte <jrg.otte@gmail.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

After the previous patch this flag will check always clear, as it's
never set for shmem backed and userptr objects, so we can remove it.
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Yeah this isn't really fixes but it's a nice cleanup to
clarify the code but not really worth the hassle of backmerging. So
just add to -fixes, we're still early in -rc.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This broken code was introduced in

commit aa7471d2
Author: Jani Nikula <jani.nikula@intel.com>
Date:   Wed Apr 1 11:15:21 2015 +0300

    drm/i915: add i915 specific connector debugfs file for DPCD

v2: Drop hunk that accidentally crept in.

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Bob Paauwe <bob.j.paauwe@intel.com>
Cc: François Valenduc <francoisvalenduc@gmail.com>
Reported-by: François Valenduc <francoisvalenduc@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

We have 3 types of DMA mappings for GEM objects:
1. physically contiguous for stolen and for objects needing contiguous
   memory
2. DMA-buf mappings imported via a DMA-buf attach operation
3. SG DMA mappings for shmem backed and userptr objects

For 1. and 2. the lifetime of the DMA mapping matches the lifetime of the
corresponding backing pages and so in practice we create/release the
mapping in the object's get_pages/put_pages callback.

For 3. the lifetime of the mapping matches that of any existing GPU binding
of the object, so we'll create the mapping when the object is bound to
the first vma and release the mapping when the object is unbound from its
last vma.

Since the object can be bound to multiple vmas, we can end up creating a
new DMA mapping in the 3. case even if the object already had one. This
is not allowed by the DMA API and can lead to leaked mapping data and
IOMMU memory space starvation in certain cases. For example HW IOMMU
drivers (intel_iommu) allocate a new range from their memory space
whenever a mapping is created, silently overriding a pre-existing
mapping.

Fix this by moving the creation/removal of DMA mappings to the object's
get_pages/put_pages callbacks. These callbacks already check for and do
an early return in case of any nested calls. This way objects of the 3.
case also become more like the other object types.

I noticed this issue by enabling DMA debugging, which got disabled after
a while due to its internal mapping tables getting full. It also reported
errors in connection to random other drivers that did a DMA mapping for
an address that was previously mapped by i915 but was never released.
Besides these diagnostic messages and the memory space starvation
problem for IOMMUs, I'm not aware of this causing a real issue.

The fix is based on a patch from Chris.

v2:
- move the DMA mapping create/remove calls to the get_pages/put_pages
  callbacks instead of adding new callbacks for these (Chris)
v3:
- also fix the get_page cache logic on the userptr async path (Chris)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The hang checker needs to inspect whether or not the ring request list is empty
as well as if the given engine has reached or passed the most recently
submitted request. The problem with this is that the hang checker cannot grab
the struct_mutex, which is required in order to safely inspect requests since
requests might be deallocated during inspection. In the past we've had kernel
panics due to this very unsynchronized access in the hang checker.

One solution to this problem is to not inspect the requests directly since
we're only interested in the seqno of the most recently submitted request - not
the request itself. Instead the seqno of the most recently submitted request is
stored separately, which the hang checker then inspects, circumventing the
issue of synchronization from the hang checker entirely.

This fixes a regression introduced in

commit 44cdd6d2
Author: John Harrison <John.C.Harrison@Intel.com>
Date:   Mon Nov 24 18:49:40 2014 +0000

    drm/i915: Convert 'ring_idle()' to use requests not seqnos

v2 (Chris Wilson):
- Pass current engine seqno to ring_idle() from i915_hangcheck_elapsed() rather
than compute it over again.
- Remove extra whitespace.

Issue: VIZ-5998
Signed-off-by: Tomas Elf <tomas.elf@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[danvet: Add regressing commit citation provided by Chris.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

[ 1572.417121] BUG: unable to handle kernel NULL pointer dereference at           (null)
[ 1572.421010] IP: [<ffffffffa00b2514>] ftrace_raw_event_i915_context+0x5d/0x70 [i915]
[ 1572.424970] PGD 1766a3067 PUD 1767a2067 PMD 0
[ 1572.428892] Oops: 0000 [#1] SMP
[ 1572.432787] Modules linked in: ipv6 dm_mod iTCO_wdt iTCO_vendor_support snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_controller snd_hda_codec snd_hda_core snd_hwdep snd_pcm snd_timer snd soundcore serio_raw pcspkr lpc_ich i2c_i801 mfd_core battery ac acpi_cpufreq i915 button video drm_kms_helper drm
[ 1572.441720] CPU: 2 PID: 18853 Comm: kworker/u8:0 Not tainted 4.0.0_kcloud_3f0360_20150429+ #588
[ 1572.446298] Workqueue: i915 i915_gem_retire_work_handler [i915]
[ 1572.450876] task: ffff880002f428f0 ti: ffff880035724000 task.ti: ffff880035724000
[ 1572.455557] RIP: 0010:[<ffffffffa00b2514>]  [<ffffffffa00b2514>] ftrace_raw_event_i915_context+0x5d/0x70 [i915]
[ 1572.460423] RSP: 0018:ffff880035727ce8  EFLAGS: 00010286
[ 1572.465262] RAX: ffff880073f1643c RBX: ffff880002da9058 RCX: ffff880073e5db40
[ 1572.470179] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880035727ce8
[ 1572.475107] RBP: ffff88007bb11a00 R08: 0000000000000000 R09: 0000000000000000
[ 1572.480034] R10: 0000000000362200 R11: 0000000000000008 R12: 0000000000000000
[ 1572.484952] R13: ffff880035727d78 R14: ffff880002dc1c98 R15: ffff880002dc1dc8
[ 1572.489886] FS:  0000000000000000(0000) GS:ffff88017fd00000(0000) knlGS:0000000000000000
[ 1572.494883] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1572.499859] CR2: 0000000000000000 CR3: 000000017572a000 CR4: 00000000001006e0
[ 1572.504842] Stack:
[ 1572.509834]  ffff88017b0090c0 ffff880073f16438 ffff880002da9058 ffff880073f1643c
[ 1572.514904]  0000000000000246 ffff880100000000 ffff88007bb11a00 ffff880002ddeb10
[ 1572.519985]  ffff8801759f79c0 ffffffffa0092ff0 0000000000000000 ffff88007bb11a00
[ 1572.525049] Call Trace:
[ 1572.530093]  [<ffffffffa0092ff0>] ? i915_gem_context_free+0xa8/0xc1 [i915]
[ 1572.535227]  [<ffffffffa009b969>] ? i915_gem_request_free+0x4e/0x50 [i915]
[ 1572.540347]  [<ffffffffa00b5533>] ? intel_execlists_retire_requests+0x14c/0x159 [i915]
[ 1572.545500]  [<ffffffffa009d9ea>] ? i915_gem_retire_requests+0x9d/0xeb [i915]
[ 1572.550664]  [<ffffffffa009dd8c>] ? i915_gem_retire_work_handler+0x4c/0x61 [i915]
[ 1572.555825]  [<ffffffff8104ca7f>] ? process_one_work+0x1b2/0x31d
[ 1572.560951]  [<ffffffff8104d278>] ? worker_thread+0x24d/0x339
[ 1572.566033]  [<ffffffff8104d02b>] ? cancel_delayed_work_sync+0xa/0xa
[ 1572.571140]  [<ffffffff81050b25>] ? kthread+0xce/0xd6
[ 1572.576191]  [<ffffffff81050a57>] ? kthread_create_on_node+0x162/0x162
[ 1572.581228]  [<ffffffff8179b3c8>] ? ret_from_fork+0x58/0x90
[ 1572.586259]  [<ffffffff81050a57>] ? kthread_create_on_node+0x162/0x162
[ 1572.591318] Code: de 48 89 e7 e8 09 4d 00 e1 48 85 c0 74 27 48 89 68 10 48 8b 55 38 48 89 e7 48 89 50 18 48 8b 55 10 48 8b 12 48 8b 12 48 8b 52 38 <8b> 12 89 50 08 e8 95 4d 00 e1 48 83 c4 30 5b 5d 41 5c c3 41 55
[ 1572.596981] RIP  [<ffffffffa00b2514>] ftrace_raw_event_i915_context+0x5d/0x70 [i915]
[ 1572.602464]  RSP <ffff880035727ce8>
[ 1572.607911] CR2: 0000000000000000

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90112#c23Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This reverts commit dec4f799.

Jörg Otte reports a NULL pointder dereference due to this commit, as
'crtc_state' very much can be NULL:

        crtc_state = state->base.state ?
                intel_atomic_get_crtc_state(state->base.state, intel_crtc) : NULL;

So the change to test 'crtc_state->base.active' cannot possibly be
correct as-is.

There may be some other minimal fix (like just checking crtc_state for
NULL), but I'm just reverting it now for the rc2 release, and people
like Daniel Vetter who actually know this code will figure out what the
right solution is in the longer term.
Reported-and-bisected-by: Jörg Otte <jrg.otte@gmail.com>
Cc: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
CC: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull VFS fixes from Al Viro:
 "Fixes for this cycle regression in overlayfs and a couple of
  long-standing (== all the way back to 2.6.12, at least) bugs"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  freeing unlinked file indefinitely delayed
  fix a braino in ovl_d_select_inode()
  9p: don't leave a half-initialized inode sitting around

Pull MIPS fixes from Ralf Baechle:
 "A fair number of 4.2 fixes also because Markos opened the flood gates.

   - Patch up the math used calculate the location for the page bitmap.

   - The FDC (Not what you think, FDC stands for Fast Debug Channel) IRQ
     around was causing issues on non-Malta platforms, so move the code
     to a Malta specific location.

   - A spelling fix replicated through several files.

   - Fix to the emulation of an R2 instruction for R6 cores.

   - Fix the JR emulation for R6.

   - Further patching of mindless 64 bit issues.

   - Ensure the kernel won't crash on CPUs with L2 caches with >= 8
     ways.

   - Use compat_sys_getsockopt for O32 ABI on 64 bit kernels.

   - Fix cache flushing for multithreaded cores.

   - A build fix"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
  MIPS: O32: Use compat_sys_getsockopt.
  MIPS: c-r4k: Extend way_string array
  MIPS: Pistachio: Support CDMM & Fast Debug Channel
  MIPS: Malta: Make GIC FDC IRQ workaround Malta specific
  MIPS: c-r4k: Fix cache flushing for MT cores
  Revert "MIPS: Kconfig: Disable SMP/CPS for 64-bit"
  MIPS: cps-vec: Use macros for various arithmetics and memory operations
  MIPS: kernel: cps-vec: Replace KSEG0 with CKSEG0
  MIPS: kernel: cps-vec: Use ta0-ta3 pseudo-registers for 64-bit
  MIPS: kernel: cps-vec: Replace mips32r2 ISA level with mips64r2
  MIPS: kernel: cps-vec: Replace 'la' macro with PTR_LA
  MIPS: kernel: smp-cps: Fix 64-bit compatibility errors due to pointer casting
  MIPS: Fix erroneous JR emulation for MIPS R6
  MIPS: Fix branch emulation for BLTC and BGEC instructions
  MIPS: kernel: traps: Fix broken indentation
  MIPS: bootmem: Don't use memory holes for page bitmap
  MIPS: O32: Do not handle require 32 bytes from the stack to be readable.
  MIPS, CPUFREQ: Fix spelling of Institute.
  MIPS: Lemote 2F: Fix build caused by recent mass rename.

Pull x86 fixes from Thomas Gleixner:

 - the high latency PIT detection fix, which slipped through the cracks
   for rc1

 - a regression fix for the early printk mechanism

 - the x86 part to plug irq/vector related hotplug races

 - move the allocation of the espfix pages on cpu hotplug to non atomic
   context.  The current code triggers a might_sleep() warning.

 - a series of KASAN fixes addressing boot crashes and usability

 - a trivial typo fix for Kconfig help text

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kconfig: Fix typo in the CONFIG_CMDLINE_BOOL help text
  x86/irq: Retrieve irq data after locking irq_desc
  x86/irq: Use proper locking in check_irq_vectors_for_cpu_disable()
  x86/irq: Plug irq vector hotplug race
  x86/earlyprintk: Allow early_printk() to use console style parameters like '115200n8'
  x86/espfix: Init espfix on the boot CPU side
  x86/espfix: Add 'cpu' parameter to init_espfix_ap()
  x86/kasan: Move KASAN_SHADOW_OFFSET to the arch Kconfig
  x86/kasan: Add message about KASAN being initialized
  x86/kasan: Fix boot crash on AMD processors
  x86/kasan: Flush TLBs after switching CR3
  x86/kasan: Fix KASAN shadow region page tables
  x86/init: Clear 'init_level4_pgt' earlier
  x86/tsc: Let high latency PIT fail fast in quick_pit_calibrate()

Pull timer fixes from Thomas Gleixner:
 "This update from the timer departement contains:

   - A series of patches which address a shortcoming in the tick
     broadcast code.

     If the broadcast device is not available or an hrtimer emulated
     broadcast device, some of the original assumptions lead to boot
     failures.  I rather plugged all of the corner cases instead of only
     addressing the issue reported, so the change got a little larger.

     Has been extensivly tested on x86 and arm.

   - Get rid of the last holdouts using do_posix_clock_monotonic_gettime()

   - A regression fix for the imx clocksource driver

   - An update to the new state callbacks mechanism for clockevents.
     This is required to simplify the conversion, which will take place
     in 4.3"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick/broadcast: Prevent NULL pointer dereference
  time: Get rid of do_posix_clock_monotonic_gettime
  cris: Replace do_posix_clock_monotonic_gettime()
  tick/broadcast: Unbreak CONFIG_GENERIC_CLOCKEVENTS=n build
  tick/broadcast: Handle spurious interrupts gracefully
  tick/broadcast: Check for hrtimer broadcast active early
  tick/broadcast: Return busy when IPI is pending
  tick/broadcast: Return busy if periodic mode and hrtimer broadcast
  tick/broadcast: Move the check for periodic mode inside state handling
  tick/broadcast: Prevent deep idle if no broadcast device available
  tick/broadcast: Make idle check independent from mode and config
  tick/broadcast: Sanity check the shutdown of the local clock_event
  tick/broadcast: Prevent hrtimer recursion
  clockevents: Allow set-state callbacks to be optional
  clocksource/imx: Define clocksource for mx27

Pull irq fix from Thomas Gleixner:
 "A single fix for a cpu hotplug race vs. interrupt descriptors:

  Prevent irq setup/teardown across the cpu starting/dying parts of cpu
  hotplug so that the starting/dying cpu has a stable view of the
  descriptor space.  This has been an issue for all architectures in the
  cpu dying phase, where interrupts are migrated away from the dying
  cpu.  In the starting phase its mostly a x86 issue vs the vector space
  update"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  hotplug: Prevent alloc/free of irq descriptors during cpu up/down

	Normally opening a file, unlinking it and then closing will have
the inode freed upon close() (provided that it's not otherwise busy and
has no remaining links, of course).  However, there's one case where that
does *not* happen.  Namely, if you open it by fhandle with cold dcache,
then unlink() and close().

	In normal case you get d_delete() in unlink(2) notice that dentry
is busy and unhash it; on the final dput() it will be forcibly evicted from
dcache, triggering iput() and inode removal.  In this case, though, we end
up with *two* dentries - disconnected (created by open-by-fhandle) and
regular one (used by unlink()).  The latter will have its reference to inode
dropped just fine, but the former will not - it's considered hashed (it
is on the ->s_anon list), so it will stay around until the memory pressure
will finally do it in.  As the result, we have the final iput() delayed
indefinitely.  It's trivial to reproduce -

void flush_dcache(void)
{
        system("mount -o remount,rw /");
}

static char buf[20 * 1024 * 1024];

main()
{
        int fd;
        union {
                struct file_handle f;
                char buf[MAX_HANDLE_SZ];
        } x;
        int m;

        x.f.handle_bytes = sizeof(x);
        chdir("/root");
        mkdir("foo", 0700);
        fd = open("foo/bar", O_CREAT | O_RDWR, 0600);
        close(fd);
        name_to_handle_at(AT_FDCWD, "foo/bar", &x.f, &m, 0);
        flush_dcache();
        fd = open_by_handle_at(AT_FDCWD, &x.f, O_RDWR);
        unlink("foo/bar");
        write(fd, buf, sizeof(buf));
        system("df .");			/* 20Mb eaten */
        close(fd);
        system("df .");			/* should've freed those 20Mb */
        flush_dcache();
        system("df .");			/* should be the same as #2 */
}

will spit out something like
Filesystem     1K-blocks   Used Available Use% Mounted on
/dev/root         322023 303843      1131 100% /
Filesystem     1K-blocks   Used Available Use% Mounted on
/dev/root         322023 303843      1131 100% /
Filesystem     1K-blocks   Used Available Use% Mounted on
/dev/root         322023 283282     21692  93% /
- inode gets freed only when dentry is finally evicted (here we trigger
than by remount; normally it would've happened in response to memory
pressure hell knows when).

Cc: stable@vger.kernel.org # v2.6.38+; earlier ones need s/kill_it/unhash_it/
Acked-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

when opening a directory we want the overlayfs inode, not one from
the topmost layer.
Reported-By: Andrey Jr. Melnikov <temnota.am@gmail.com>
Tested-By: Andrey Jr. Melnikov <temnota.am@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Cc: stable@vger.kernel.org # all branches
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull libnvdimm fixes from Dan Williams:
 "1) Fixes for a handful of smatch reports (Thanks Dan C.!) and minor
     bug fixes (patches 1-6)

  2) Correctness fixes to the BLK-mode nvdimm driver (patches 7-10).

     Granted these are slightly large for a -rc update.  They have been
     out for review in one form or another since the end of May and were
     deferred from the merge window while we settled on the "PMEM API"
     for the PMEM-mode nvdimm driver (ie memremap_pmem, memcpy_to_pmem,
     and wmb_pmem).

     Now that those apis are merged we implement them in the BLK driver
     to guarantee that mmio aperture moves stay ordered with respect to
     incoming read/write requests, and that writes are flushed through
     those mmio-windows and platform-buffers to be persistent on media.

  These pass the sub-system unit tests with the updates to
  tools/testing/nvdimm, and have received a successful build-report from
  the kbuild robot (468 configs).

  With acks from Rafael for the touches to drivers/acpi/"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm:
  nfit: add support for NVDIMM "latch" flag
  nfit: update block I/O path to use PMEM API
  tools/testing/nvdimm: add mock acpi_nfit_flush_address entries to nfit_test
  tools/testing/nvdimm: fix return code for unimplemented commands
  tools/testing/nvdimm: mock ioremap_wt
  pmem: add maintainer for include/linux/pmem.h
  nfit: fix smatch "use after null check" report
  nvdimm: Fix return value of nvdimm_bus_init() if class_create() fails
  libnvdimm: smatch cleanups in __nd_ioctl
  sparse: fix misplaced __pmem definition

Pull i2c fixes from Wolfram Sang:
 "Mostly slight adjusments for new drivers, but also one core fix for
  which finally the dependencies are now available as well"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: Mark instantiated device nodes with OF_POPULATE
  i2c: jz4780: Fix return value if probe fails
  i2c: xgene-slimpro: Fix missing mbox_free_channel call in probe error path
  i2c: I2C_MT65XX should depend on HAS_DMA

Pull input fixes from Dmitry Torokhov:
 "A fix (revert) for a recent regression in Synaptics driver and a fix
  for Elan i2c touchpad driver"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Revert "Input: synaptics - allocate 3 slots to keep stability in image sensors"
  Input: elan_i2c - change the hover event from MT to ST

Pull clk fixes from Stephen Boyd:
 "A small set of fixes for problems found by smatch in new drivers that
  we added this rc and a handful of driver fixes that came in during the
  merge window"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  drivers: clk: st: Incorrect register offset used for lock_status
  clk: mediatek: mt8173: Fix enabling of critical clocks
  drivers: clk: st: Fix mux bit-setting for Cortex A9 clocks
  drivers: clk: st: Add CLK_GET_RATE_NOCACHE flag to clocks
  drivers: clk: st: Fix flexgen lock init
  drivers: clk: st: Fix FSYN channel values
  drivers: clk: st: Remove unused code
  clk: qcom: Use parent rate when set rate to pixel RCG clock
  clk: at91: do not leak resources
  clk: stm32: Fix out-by-one error path in the index lookup
  clk: iproc: fix bit manipulation arithmetic
  clk: iproc: fix memory leak from clock name

Pull drm fixes from Dave Airlie:
 "A bunch of fixes for radeon, intel, omap and one amdkfd fix.

  Radeon fixes are all over, but it does fix some cursor corruption
  across suspend/resume.  i915 should fix the second warn you were
  seeing, so let us know if not.  omap is a bunch of small fixes"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: (28 commits)
  drm/radeon: disable vce init on cayman (v2)
  drm/amdgpu: fix timeout calculation
  drm/radeon: check if BO_VA is set before adding it to the invalidation list
  drm/radeon: allways add the VM clear duplicate
  Revert "Revert "drm/radeon: dont switch vt on suspend""
  drm/radeon: Fold radeon_set_cursor() into radeon_show_cursor()
  drm/radeon: unpin cursor BOs on suspend and pin them again on resume (v2)
  drm/radeon: Clean up reference counting and pinning of the cursor BOs
  drm/amdkfd: validate pdd where it acquired first
  Revert "drm/i915: Allocate context objects from stolen"
  drm/i915: Declare the swizzling unknown for L-shaped configurations
  drm/radeon: fix underflow in r600_cp_dispatch_texture()
  drm/radeon: default to 2048 MB GART size on SI+
  drm/radeon: fix HDP flushing
  drm/radeon: use RCU query for GEM_BUSY syscall
  drm/amdgpu: Handle irqs only based on irq ring, not irq status regs.
  drm/radeon: Handle irqs only based on irq ring, not irq status regs.
  drm/i915: Use crtc_state->active in primary check_plane func
  drm/i915: Check crtc->active in intel_crtc_disable_planes
  drm/i915: Restore all GGTT VMAs on resume
  ...

Pull selinux fixes from James Morris.

* 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  selinux: fix mprotect PROT_EXEC regression caused by mm change
  selinux: don't waste ebitmap space when importing NetLabel categories

Pull btrfs fixes from Chris Mason:
 "This is an assortment of fixes.  Most of the commits are from Filipe
  (fsync, the inode allocation cache and a few others).  Mark kicked in
  a series fixing corners in the extent sharing ioctls, and everyone
  else fixed up on assorted other problems"

* 'for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix wrong check for btrfs_force_chunk_alloc()
  Btrfs: fix warning of bytes_may_use
  Btrfs: fix hang when failing to submit bio of directIO
  Btrfs: fix a comment in inode.c:evict_inode_truncate_pages()
  Btrfs: fix memory corruption on failure to submit bio for direct IO
  btrfs: don't update mtime/ctime on deduped inodes
  btrfs: allow dedupe of same inode
  btrfs: fix deadlock with extent-same and readpage
  btrfs: pass unaligned length to btrfs_cmp_data()
  Btrfs: fix fsync after truncate when no_holes feature is enabled
  Btrfs: fix fsync xattr loss in the fast fsync path
  Btrfs: fix fsync data loss after append write
  Btrfs: fix crash on close_ctree() if cleaner starts new transaction
  Btrfs: fix race between caching kthread and returning inode to inode cache
  Btrfs: use kmem_cache_free when freeing entry in inode cache
  Btrfs: fix race between balance and unused block group deletion
  btrfs: add error handling for scrub_workers_get()
  btrfs: cleanup noused initialization of dev in btrfs_end_bio()
  btrfs: qgroup: allow user to clear the limitation on qgroup

Pull ARM SoC fixes from Kevin Hilman:
 "A fairly random colletion of fixes based on -rc1 for OMAP, sunxi and
  prima2 as well as a few arm64-specific DT fixes.

  This series also includes a late to support a new Allwinner (sunxi)
  SoC, but since it's rather simple and isolated to the
  platform-specific code, it's included it for this -rc"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  arm64: dts: add device tree for ARM SMM-A53x2 on LogicTile Express 20MG
  arm: dts: vexpress: add missing CCI PMU device node to TC2
  arm: dts: vexpress: describe all PMUs in TC2 dts
  GICv3: Add ITS entry to THUNDER dts
  arm64: dts: Add poweroff button device node for APM X-Gene platform
  ARM: dts: am4372.dtsi: disable rfbi
  ARM: dts: am57xx-beagle-x15: Provide supply for usb2_phy2
  ARM: dts: am4372: Add emif node
  Revert "ARM: dts: am335x-boneblack: disable RTC-only sleep"
  ARM: sunxi: Enable simplefb in the defconfig
  ARM: Remove deprecated symbol from defconfig files
  ARM: sunxi: Add Machine support for A33
  ARM: sunxi: Introduce Allwinner H3 support
  Documentation: sunxi: Update Allwinner SoC documentation
  ARM: prima2: move to use REGMAP APIs for rtciobrg
  ARM: dts: atlas7: add pinctrl and gpio descriptions
  ARM: OMAP2+: Remove unnessary return statement from the void function, omap2_show_dma_caps
  memory: omap-gpmc: Fix parsing of devices

Dan reported that the recent changes to the broadcast code introduced
a potential NULL dereference.

Add the proper check.

Fixes: e0454311 "tick/broadcast: Sanity check the shutdown of the local clock_event"
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Pull parisc fixes from Helge Deller:
 "We have one important patch from Dave Anglin and myself which fixes
  PTE/TLB race conditions which caused random segmentation faults on our
  debian buildd servers, and one patch from Alex Ivanov which speeds up
  the graphical text console on the STI framebuffer driver"

* 'parisc-4.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Fix some PTE/TLB race conditions and optimize __flush_tlb_range based on timing results
  stifb: Implement hardware accelerated copyarea

commit 66fc1303 ("mm: shmem_zero_setup
skip security check and lockdep conflict with XFS") caused a regression
for SELinux by disabling any SELinux checking of mprotect PROT_EXEC on
shared anonymous mappings.  However, even before that regression, the
checking on such mprotect PROT_EXEC calls was inconsistent with the
checking on a mmap PROT_EXEC call for a shared anonymous mapping.  On a
mmap, the security hook is passed a NULL file and knows it is dealing
with an anonymous mapping and therefore applies an execmem check and no
file checks.  On a mprotect, the security hook is passed a vma with a
non-NULL vm_file (as this was set from the internally-created shmem
file during mmap) and therefore applies the file-based execute check
and no execmem check.  Since the aforementioned commit now marks the
shmem zero inode with the S_PRIVATE flag, the file checks are disabled
and we have no checking at all on mprotect PROT_EXEC.  Add a test to
the mprotect hook logic for such private inodes, and apply an execmem
check in that case.  This makes the mmap and mprotect checking
consistent for shared anonymous mappings, as well as for /dev/zero and
ashmem.

Cc: <stable@vger.kernel.org> # 4.1.x
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <pmoore@redhat.com>

Pull arm64 fixes and clean-up from Catalin Marinas:
 - ACPI fix when checking the validity of the GICC MADT subtable
 - handle debug exceptions in the el*_inv exception entries
 - remove pointless register assignment in two compat syscall wrappers
 - unnecessary include path
 - defconfig update

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: entry32: remove pointless register assignment
  arm64: entry: handle debug exceptions in el*_inv
  arm64: Keep the ARM64 Kconfig selects sorted
  ACPI / ARM64 : use the new BAD_MADT_GICC_ENTRY macro
  ACPI / ARM64: add BAD_MADT_GICC_ENTRY() macro
  arm64: defconfig: Add Ceva ahci to the defconfig
  arm64: remove another unnecessary libfdt include path

The increased use of pdtlb/pitlb instructions seemed to increase the
frequency of random segmentation faults building packages. Further, we
had a number of cases where TLB inserts would repeatedly fail and all
forward progress would stop. The Haskell ghc package caused a lot of
trouble in this area. The final indication of a race in pte handling was
this syslog entry on sibaris (C8000):

 swap_free: Unused swap offset entry 00000004
 BUG: Bad page map in process mysqld  pte:00000100 pmd:019bbec5
 addr:00000000ec464000 vm_flags:00100073 anon_vma:0000000221023828 mapping: (null) index:ec464
 CPU: 1 PID: 9176 Comm: mysqld Not tainted 4.0.0-2-parisc64-smp #1 Debian 4.0.5-1
 Backtrace:
  [<0000000040173eb0>] show_stack+0x20/0x38
  [<0000000040444424>] dump_stack+0x9c/0x110
  [<00000000402a0d38>] print_bad_pte+0x1a8/0x278
  [<00000000402a28b8>] unmap_single_vma+0x3d8/0x770
  [<00000000402a4090>] zap_page_range+0xf0/0x198
  [<00000000402ba2a4>] SyS_madvise+0x404/0x8c0

Note that the pte value is 0 except for the accessed bit 0x100. This bit
shouldn't be set without the present bit.

It should be noted that the madvise system call is probably a trigger for many
of the random segmentation faults.

In looking at the kernel code, I found the following problems:

1) The pte_clear define didn't take TLB lock when clearing a pte.
2) We didn't test pte present bit inside lock in exception support.
3) The pte and tlb locks needed to merged in order to ensure consistency
between page table and TLB. This also has the effect of serializing TLB
broadcasts on SMP systems.

The attached change implements the above and a few other tweaks to try
to improve performance. Based on the timing code, TLB purges are very
slow (e.g., ~ 209 cycles per page on rp3440). Thus, I think it
beneficial to test the split_tlb variable to avoid duplicate purges.
Probably, all PA 2.0 machines have combined TLBs.

I dropped using __flush_tlb_range in flush_tlb_mm as I realized all
applications and most threads have a stack size that is too large to
make this useful. I added some comments to this effect.

Since implementing 1 through 3, I haven't had any random segmentation
faults on mx3210 (rp3440) in about one week of building code and running
as a Debian buildd.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # v3.18+
Signed-off-by: Helge Deller <deller@gmx.de>

This patch adds hardware assisted scrolling. The code is based upon the
following investigation: https://parisc.wiki.kernel.org/index.php/NGLE#Blitter

A simple 'time ls -la /usr/bin' test shows 1.6x speed increase over soft
copy and 2.3x increase over FBINFO_READS_FAST (prefer soft copy over
screen redraw) on Artist framebuffer.
Signed-off-by: Alex Ivanov <lausgans@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>

Pull powerpc fixes from Michael Ellerman:
 - opal-prd mmap fix from Vaidy
 - set kernel taint for MCEs from Daniel
 - alignment exception description from Anton
 - ppc4xx_hsta_msi build fix from Daniel
 - opal-elog interrupt fix from Alistair
 - core_idle_state race fix from Shreyas
 - hv-24x7 lockdep fix from Sukadev
 - multiple cxl fixes from Daniel, Ian, Mikey & Maninder
 - update MAINTAINERS to point at shared tree

* tag 'powerpc-4.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  cxl: Check if afu is not null in cxl_slbia
  powerpc: Update MAINTAINERS to point at shared tree
  powerpc/perf/24x7: Fix lockdep warning
  cxl: Fix off by one error allowing subsequent mmap page to be accessed
  cxl: Fail mmap if requested mapping is larger than assigned problem state area
  cxl: Fix refcounting in kernel API
  powerpc/powernv: Fix race in updating core_idle_state
  powerpc/powernv: Fix opal-elog interrupt handler
  powerpc/ppc4xx_hsta_msi: Include ppc-pci.h to fix reference to hose_list
  powerpc: Add plain English description for alignment exception oopses
  cxl: Test the correct mmio space before unmapping
  powerpc: Set the correct kernel taint on machine check errors
  cxl/vphb.c: Use phb pointer after NULL check
  powerpc/powernv: Fix vma page prot flags in opal-prd driver

Add support in the NFIT BLK I/O path for the "latch" flag
defined in the "Get Block NVDIMM Flags" _DSM function:

http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf

This flag requires the driver to read back the command register after it
is written in the block I/O path.  This ensures that the hardware has
fully processed the new command and moved the aperture appropriately.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Update the nfit block I/O path to use the new PMEM API and to adhere to
the read/write flows outlined in the "NVDIMM Block Window Driver
Writer's Guide":

http://pmem.io/documents/NVDIMM_Driver_Writers_Guide.pdf

This includes adding support for targeted NVDIMM flushes called "flush
hints" in the ACPI 6.0 specification:

http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf

For performance and media durability the mapping for a BLK aperture is
moved to a write-combining mapping which is consistent with
memcpy_to_pmem() and wmb_blk().
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

In preparation for fixing the BLK path to properly use "directed
pcommit" enable the unit test infrastructure to emit mock "flush"
tables.  Writes to these flush addresses trigger a memory controller to
flush its internal buffers to persistent media, similar to the x86
"pcommit" instruction.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The implementation for the new "DIMM Flags" DSM relies on the -ENOTTY
return code to indicate that the flags are unimplimented and to fall
back to a safe default.  As is the -ENXIO error code erroneoously
indicates to fail enabling a BLK region.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

In the 4.2-rc1 merge the default_memremap_pmem() implementation switched
from ioremap_nocache() to ioremap_wt().  Add it to the list of mocked
routines to restore the ability to run the unit tests.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>