No one outside of drm should use this, the official interfaces are
drm_gem_handle_create and drm_gem_handle_delete. The handle refcounting
is purely an implementation detail of gem.
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

This is the 2nd attempt, I've always been a bit dissatisified with the
tricky nature of the first one:

http://lists.freedesktop.org/archives/dri-devel/2012-July/025451.html

The issue is that the flink ioctl can race with calling gem_close on
the last gem handle. In that case we'll end up with a zero handle
count, but an flink name (and it's corresponding reference). Which
results in a neat space leak.

In my first attempt I've solved this by rechecking the handle count.
But fundamentally the issue is that ->handle_count isn't your usual
refcount - it can be resurrected from 0 among other things.

For those special beasts atomic_t often suggest way more ordering that
it actually guarantees. To prevent being tricked by those hairy
semantics take the easy way out and simply protect the handle with the
existing dev->object_name_lock.

With that change implemented it's dead easy to fix the flink vs. gem
close reace: When we try to create the name we simply have to check
whether there's still officially a gem handle around and if not refuse
to create the flink name. Since the handle count decrement and flink
name destruction is now also protected by that lock the reace is gone
and we can't ever leak the flink reference again.

Outside of the drm core only the exynos driver looks at the handle
count, and tbh I have no idea why (it's just for debug dmesg output
luckily).

I've considered inlining the drm_gem_object_handle_free, but I plan to
add more name-like things (like the exported dma_buf) to this scheme,
so it's clearer to leave the handle freeing in its own function.

This is exercised by the new gem_flink_race i-g-t testcase, which on
my snb leaks gem objects at a rate of roughly 1k objects/s.

v2: Fix up the error path handling in handle_create and make it more
robust by simply calling object_handle_unreference.

v3: Fix up the handle_unreference logic bug - atomic_dec_and_test
retursn 1 for 0. Oops.

v4: Squash in inlining of drm_gem_object_handle_reference as suggested
by Dave Airlie and add a note that we now have a testcase.

Cc: Dave Airlie <airlied@gmail.com>
Cc: Inki Dae <inki.dae@samsung.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

It's only used in drm_platform.c.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

This function is only used in drm_fb_cma_helper.c.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

These were introduced in the very first DRM commit:

  commit f453ba04
  Author: Dave Airlie <airlied@redhat.com>
  Date:   Fri Nov 7 14:05:41 2008 -0800

      DRM: add mode setting support

      Add mode setting support to the DRM layer.

But are unused.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

It's only used in drm_crtc.c.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

The last user was removed in

  commit 575dc34e
  Author: Dave Airlie <airlied@redhat.com>
  Date:   Mon Sep 7 18:43:26 2009 +1000

      drm/kms: remove old std mode fallback code.

      The new code adds modes in the helper, which makes more sense
      I disliked the non-driver code adding modes.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

This was last used by nouveau, replaced by a driver-specific property
in:

  commit de691855
  Author: Ben Skeggs <bskeggs@redhat.com>
  Date:   Mon Oct 17 12:23:41 2011 +1000

      drm/nouveau: improve dithering properties, and implement proper auto mode
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

A few prototypes have been left in the headers, their function friends
long gone.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

So almost two years ago I've tried to nuke the procfs code already
once before:

http://lists.freedesktop.org/archives/dri-devel/2011-October/015707.html

The conclusion was that userspace drivers (specifically libdrm device
node detection) stopped relying on procfs in 2001. But after some
digging it turned out that the drmstat tool in libdrm is still using
those files (but only when certain options are set). So we've decided
to keep profcs.

But I when I've started to dig around again what exactly this tool
does I've noticed that it tries to read the "mem", "vm", and "vma"
files from procfs. Now as far my git history digging shows "mem" never
did anything useful (at least in the version that first showed up in
upstream history in 2004) and the file was remove in

commit 955b12de
Author: Ben Gamari <bgamari@gmail.com>
Date:   Tue Feb 17 20:08:49 2009 -0500

    drm: Convert proc files to seq_file and introduce debugfs

Which means that for over 4 years drmstat has been broken, and no one
cared. In my opinion that's proof enough that no one is actually using
drmstat, and so that we can savely nuke the procfs support from drm.

While at it fix up the error case cleanup for debugfs in drm_get_minor.

v2: Fix dates, libdrm stopped relying on procfs for drm node detection
in 2001.

v3: fixup compilation warning for !CONFIG_DEBUG_FS, reported by
Fengguang Wu.

Cc: kbuild test robot <fengguang.wu@intel.com>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

We might as well have a real ioctl function which checks for the
callbacks. This seems to be a remnant from back in the days when each
drm driver had their own complete ioctl table, with no shared core
drm table at all.

To make really sure no mis-guided user in a kms driver pops up again
explicitly check for that in the new ioctl implementation.

v2: Drop the unused variable I've accidentally left in the code,
spotted by David Herrmann.

Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

The new arch_phys_wc_add/del functions do the right thing both with
and without MTRR support in the kernel. So we can drop these
additional checks.

David Herrmann suggest to also kill the DRIVER_USE_MTRR flag since
it's now unused, which spurred me to do a bit a better audit of the
affected drivers. David helped a lot in that. Quoting our mail
discussion:

On Wed, Jul 10, 2013 at 5:41 PM, David Herrmann <dh.herrmann@gmail.com> wrote:
> On Wed, Jul 10, 2013 at 5:22 PM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>> On Wed, Jul 10, 2013 at 3:51 PM, David Herrmann <dh.herrmann@gmail.com> wrote:
>>>> -#if __OS_HAS_MTRR
>>>> -static inline int drm_core_has_MTRR(struct drm_device *dev)
>>>> -{
>>>> -       return drm_core_check_feature(dev, DRIVER_USE_MTRR);
>>>> -}
>>>> -#else
>>>> -#define drm_core_has_MTRR(dev) (0)
>>>> -#endif
>>>> -
>>>
>>> That was the last user of DRIVER_USE_MTRR (apart from drivers setting
>>> it in .driver_features). Any reason to keep it around?
>>
>> Yeah, I guess we could rip things out. Which will also force me to
>> properly audit drivers for the eventual behaviour change this could
>> entail (in case there's an x86 driver which did not ask for an mtrr,
>> but iirc there isn't).
>
> david@david-mb ~/dev/kernel/linux $ for i in drivers/gpu/drm/* ; do if
> test -d "$i" ; then if ! grep -q USE_MTRR -r $i ; then echo $i ; fi ;
> fi ; done
> drivers/gpu/drm/exynos
> drivers/gpu/drm/gma500
> drivers/gpu/drm/i2c
> drivers/gpu/drm/nouveau
> drivers/gpu/drm/omapdrm
> drivers/gpu/drm/qxl
> drivers/gpu/drm/rcar-du
> drivers/gpu/drm/shmobile
> drivers/gpu/drm/tilcdc
> drivers/gpu/drm/ttm
> drivers/gpu/drm/udl
> drivers/gpu/drm/vmwgfx
> david@david-mb ~/dev/kernel/linux $
>
> So for x86 gma500,nouveau,qxl,udl,vmwgfx don't set DRIVER_USE_MTRR.
> But I cannot tell whether they break if we call arch_phys_wc_add/del,
> anyway. At least nouveau seemed to work here, but it doesn't use AGP
> or drm_bufs, I guess.

Cool, thanks a lot for stitching together the list of drivers to look
at. So for real KMS drivers it's the drives responsibility to add an
mtrr if it needs one. nouvea, radeon, mgag200, i915 and vmwgfx do that
already. Somehow the savage driver also ends up doing that, I have no
idea why.

Note that gma500 as a pure KMS driver doesn't need MTRR setup since
the platforms that it supports all support PAT. So no MTRRs needed to
get wc iomappings.

The mtrr support in the drm core is all for legacy mappings of garts,
framebuffers and registers. All legacy drivers set the USE_MTRR flag,
so we're good there.

All in all I think we can really just ditch this

/endquote

v2: Also kill DRIVER_USE_MTRR as suggested by David Herrmann

v3: Rebase on top of David Herrmann's agp setup/cleanup changes.

Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NAndy Lutomirski <luto@amacapital.net>
Reviewed-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

We have three callers of this function now and it's neither
performance critical nor really small. So an inline function feels
like overkill and unecessarily separates the different parts of the
code.

Since all callers of drm_gem_object_handle_free are now in drm_gem.c
we can make that static (and remove the unused EXPORT_SYMBOL). To
avoid a forward declaration move it (and drm_gem_object_free_bug) up a
bit.
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Lifetime rules seem to be solid around ->import_attach. So this patch
just properly documents them.

Note that pointing directly at the attachment might have issues for
devices that have multiple struct device *dev parts constituting the
logical gpu and so might need multiple attachment points. Similarly
for drm devices which don't need a dma attachment at all (like udl).

But fixing that up is material for different patches.
Reviewed-by: NRob Clark <robdclark@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Note that this is slightly tricky since both drivers store their
native objects in dma_buf->priv. But both also embed the base
drm_gem_object at the first position, so the implicit cast is ok.

To use the release helper we need to export it, too.

Cc: Inki Dae <inki.dae@samsung.com>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

This makes it so that reloading a module does not cause all the
connector ids to change, which are user-visible and sometimes used
for configuration.
Signed-off-by: NIlia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Basically just extracting some code duplicated in gma500, omapdrm, udl,
and upcoming msm driver.
Signed-off-by: NRob Clark <robdclark@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Variant of drm_gem_create_mmap_offset() which doesn't make the
assumption that virtual size and physical size (obj->size) are the same.
This is needed in omapdrm to deal with tiled buffers.  And lets us get
rid of a duplicated and slightly modified version of
drm_gem_create_mmap_offset() in omapdrm.
Signed-off-by: NRob Clark <robdclark@gmail.com>
Reviewed-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

A small helper to queue up work to do, from workqueue context, after a
flip.  Typically useful to defer unreffing buffers that may be read by
the display controller until vblank.

v1: original
v2: wire up docbook + couple docbook fixes
Signed-off-by: NRob Clark <robdclark@gmail.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

This function is unused.
Signed-off-by: NStéphane Marchesin <marcheu@chromium.org>
Reviewed-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

The gma500 driver somehow set the DRIVER_IRQ_VBL flag, but since
there's no code at all to check for this we can kill it. The other two
are completely unused.
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

No driver ever sets that flag, so good riddance!
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

So I've stumbled over drm_fasync and wondered what it does. Digging
that up is quite a story.

First I've had to read up on what this does and ended up being rather
bewildered why peopled loved signals so much back in the days that
they've created SIGIO just for that ...

Then I wondered how this ever works, and what that strange "No-op."
comment right above it should mean. After all calling the core fasync
helper is pretty obviously not a noop. After reading through the
kernels FASYNC implementation I've noticed that signals are only sent
out to the processes attached with FASYNC by calling kill_fasync.

No merged drm driver has ever done that.

After more digging I've found out that the only driver that ever used
this is the so called GAMMA driver. I've frankly never heard of such a
gpu brand ever before. Now FASYNC seems to not have been the only bad
thing with that driver, since Dave Airlie removed it from the drm
driver with prejudice:

commit 1430163b4bbf7b00367ea1066c1c5fe85dbeefed
Author: Dave Airlie <airlied@linux.ie>
Date:   Sun Aug 29 12:04:35 2004 +0000

    Drop GAMMA DRM from a great height ...

Long story short, the drm fasync support seems to be doing absolutely
nothing. And the only user of it was never merged into the upstream
kernel. And we don't need any fops->fasync callback since the fcntl
implementation in the kernel already implements the noop case
correctly.

So stop this particular cargo-cult and rip it all out.

v2: Kill drm_fasync assignments in rcar (newly added) and imx drivers
(somehow I've missed that one in staging). Also drop the reference in
the drm DocBook. ARM compile-fail reported by Rob Clark.

v3: Move the removal of dev->buf_asnyc assignment in drm_setup to this
patch here.

v4: Actually git add ... tsk.

Cc: Dave Airlie <airlied@linux.ie>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Rob Clark <robdclark@gmail.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

So after a lot of digging around in git histories it looks like this
has only ever be used by dri1 render clients. Hence we can fully
disable the entire thing for modesetting drivers and so greatly reduce
the attack surface for potential exploits (or at least tools like
trinity ...).

Also add the drm_legacy prefix for functions which are called from
common code. To further reduce the impact on common code also extract
all the ctx release handling into a function (instead of only
releasing individual handles) and make ctxbitmap_cleanup return void -
it can never fail.
Reviewed-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

And hide the checks a bit better. This was already disallowed for
modesetting drivers, so no functinal change here.
Reviewed-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

I've decided that some clear markers for what's legacy dri1/non-gem
code is useful. I've opted to use the drm_legacy prefix and then hide
all the checks in that function for better readability in the common
code.
Reviewed-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Totally unused, so just rip it out. Anyway, we want drivers to be
fully backwards compatible, allowing them to change behaviour is just
a recipe for them to break badly.
Reviewed-by: NEric Anholt <eric@anholt.net>
Reviewed-by: NRob Clark <robdclark@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

This patch adds tda998x specific parameters to allow it to be configured
for different boards using it. Also, this implements rudimentary audio
support for S/PDIF attached controllers.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NSebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: NDarren Etheridge <detheridge@ti.com>
Tested-by: NRussell King <rmk_kernel@arm.linux.org.uk>
Tested-by: NRussell King <rmk_kernel@arm.linux.org.uk>
Signed-off-by: NDave Airlie <airlied@redhat.com>

We currently rely on gcc dead-code elimination so the drm_agp_* helpers
are not called if drm_core_has_AGP() is false. That's ugly as hell so
provide "static inline" dummies for the case that AGP is disabled.

Fixes a build-regression introduced by:

  commit 28ec711c
  Author: David Herrmann <dh.herrmann@gmail.com>
  Date:   Sat Jul 27 16:37:00 2013 +0200

      drm/agp: move AGP cleanup paths to drm_agpsupport.c

v2: switch #ifdef -> #if (spotted by Stephen)

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Tested-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@gmail.com>

We used to pre-allocate drm_mm nodes and save them in a linked list for
later usage so we always have spare ones in atomic contexts. However, this
is really racy if multiple threads are in an atomic context at the same
time and we don't have enough spare nodes. Moreover, all remaining users
run in user-context and just lock drm_mm with a spinlock. So we can easily
preallocate the node, take the spinlock and insert the node.

This may have worked well with BKL in place, however, with today's
infrastructure it really doesn't make any sense. Besides, most users can
easily embed drm_mm_node into their objects so no allocation is needed at
all.

Thus, remove the old pre-alloc API and all the helpers that it provides.
Drivers have already been converted and we should not use the old API for
new code, anymore.
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Introduce two new helpers, drm_agp_clear() and drm_agp_destroy() which
clear all AGP mappings and destroy the AGP head. This allows to reduce the
AGP code in core DRM and move it all to drm_agpsupport.c.
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Because, there is no reason for it not to be const.

v1: original
v2: fix compile break in vmwgfx, and couple related cleanups suggested
    by Ville Syrjälä
Signed-off-by: NRob Clark <robdclark@gmail.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Add a "best_match" flag similar to the drm_mm_search_*() helpers so we
can convert TTM to use them in follow up patches. We can also inline the
non-generic helpers and move them into the header to allow compile-time
optimizations.

To make calls to drm_mm_{search,insert}_node() more readable, this
converts the boolean argument to a flagset. There are pending patches that
add additional flags for top-down allocators and more.

v2:
 - use flag parameter instead of boolean "best_match"
 - convert *_search_free() helpers to also use flags argument
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

We can apply the same optimisation tricks as kref_put_mutex() in our
local equivalent function. However, we have a different locking semantic
(we unlock ourselves, in kref_put_mutex() the callee unlocks) so that we
can use the same callbacks for both locked and unlocked kref_put()s and
so can not simply convert to using kref_put_mutex() directly.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

All the gem based kms drivers really want the same function to
destroy a dumb framebuffer backing storage object.

So give it to them and roll it out in all drivers.

This still leaves the option open for kms drivers which don't use GEM
for backing storage, but it does decently simplify matters for gem
drivers.
Acked-by: NInki Dae <inki.dae@samsung.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Cc: Ben Skeggs <skeggsb@gmail.com>
Reviwed-by: NRob Clark <robdclark@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Acked-by: NPatrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@redhat.com>

We need BUG_ON(), spinlock_t and standard kernel data-types so include the
right headers.

Subject: [drm-intel:drm-intel-nightly 154/166] include/drm/drm_mm.h:67:2:
 error: unknown type name 'spinlock_t'
Message-ID: <51f14693.g5HGdcuw2v3m8FOd%fengguang.wu@intel.com>

In case it didn't link to it correctly. Somehow this bug doesn't occur
here on my machine, hmm. But I think fixing drm_mm.h is better than
changing the include-order in drm_vma_manager.h, so this is what I
did.
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Instead of unmapping the nodes in TTM and GEM users manually, we provide
a generic wrapper which does the correct thing for all vma-nodes.

v2: remove bdev->dev_mapping test in ttm_bo_unmap_virtual_unlocked() as
ttm_mem_io_free_vm() does nothing in that case (io_reserved_vm is 0).
v4: Fix docbook comments
v5: use drm_vma_node_size()

Cc: Dave Airlie <airlied@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@gmail.com>

Use the new vma-manager infrastructure. This doesn't change any
implementation details as the vma-offset-manager is nearly copied 1-to-1
from TTM.

The vm_lock is moved into the offset manager so we can drop it from TTM.
During lookup, we use the vma locking helpers to take a reference to the
found object.
In all other scenarios, locking stays the same as before. We always
guarantee that drm_vma_offset_remove() is called only during destruction.
Hence, helpers like drm_vma_node_offset_addr() are always safe as long as
the node has a valid offset.

This also drops the addr_space_offset member as it is a copy of vm_start
in vma_node objects. Use the accessor functions instead.

v4:
 - remove vm_lock
 - use drm_vma_offset_lock_lookup() to protect lookup (instead of vm_lock)

Cc: Dave Airlie <airlied@redhat.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Martin Peres <martin.peres@labri.fr>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDave Airlie <airlied@gmail.com>