drm/i915: Record which client owns a VM

To enable accounting of indirect client memory usage (such as page tables)
in the following patch, lets start recording the creator of each PPGTT.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231107101806.608990-2-tvrtko.ursulin@linux.intel.com

drm/i915: refactor deprecated strncpy

`strncpy` is deprecated for use on NUL-terminated destination strings [1].

We should prefer more robust and less ambiguous string interfaces.

A suitable replacement is `strscpy` [2] due to the fact that it
guarantees NUL-termination on the destination buffer without
unnecessarily NUL-padding. `ctx` is zero allocated and as such strncpy's
NUL-padding behavior was strictly a performance hit which is now
resolved.

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drm/i915: Remove the vm open count

vms are not getting properly closed. Rather than fixing that,
Remove the vm open count and instead rely on the vm refcount.

The vm open count existed solely to break the strong references the
vmas had on the vms. Now instead make those references weak and
ensure vmas are destroyed when the vm is destroyed.

Unfortunately if the vm destructor and the object destructor both
wants to destroy a vma, that may lead to a race in that the vm
destructor just unbinds the vma and leaves the actual vma destruction
to the object destructor. However in order for the object destructor
to ensure the vma is unbound it needs to grab the vm mutex. In order
to keep the vm mutex alive until the object destructor is done with
it, somewhat hackishly grab a vm_resv refcount that is released late
in the vma destruction process, when the vm mutex is no longer needed.

v2: Address review-comments from Niranjana
- Clarify that the struct i915_address_space::skip_pte_rewrite is a hack
and should ideally be replaced in an upcoming patch.
- Remove an unneeded continue in clear_vm_list and update comment.

v3:
- Documentation update
- Commit message formatting

Co-developed-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220304082641.308069-2-thomas.hellstrom@linux.intel.com

drm/i915: split out i915_file_private.h from i915_drv.h

Limit the scope of struct drm_i915_file_private to the files that
actually need it.

Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e375859dc1729a1b988036e4103e5b1bd48caa00.1644507885.git.jani.nikula@intel.com

drm/i915/pxp: interfaces for using protected objects

This api allow user mode to create protected buffers and to mark
contexts as making use of such objects. Only when using contexts
marked in such a way is the execution guaranteed to work as expected.

Contexts can only be marked as using protected content at creation time
(i.e. the parameter is immutable) and they must be both bannable and not
recoverable. Given that the protected session gets invalidated on
suspend, contexts created this way hold a runtime pm wakeref until
they're either destroyed or invalidated.

All protected objects and contexts will be considered invalid when the
PXP session is destroyed and all new submissions using them will be
rejected. All intel contexts within the invalidated gem contexts will be
marked banned. Userspace can detect that an invalidation has occurred via
the RESET_STATS ioctl, where we report it the same way as a ban due to a
hang.

v5: squash patches, rebase on proto_ctx, update kerneldoc

v6: rebase on obj create_ext changes

v7: Use session counter to check if an object it valid, hold wakeref in
context, don't add a new flag to RESET_STATS (Daniel)

v8: don't increase guilty count for contexts banned during pxp
invalidation (Rodrigo)

v9: better comments, avoid wakeref put race between pxp_inval and
context_close, add usage examples (Rodrigo)

v10: modify internal set/get-protected-context functions to not
return -ENODEV when setting PXP param to false or getting param
when running on pxp-unsupported hw or getting param when i915
was built with CONFIG_PXP off

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Bommu Krishnaiah <krishnaiah.bommu@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210924191452.1539378-11-alan.previn.teres.alexis@intel.com

drm/i915: Release i915_gem_context from a worker

The only reason for this really is the i915_gem_engines->fence
callback engines_notify(), which exists purely as a fairly funky
reference counting scheme for that. Otherwise all other callers are
from process context, and generally fairly benign locking context.

Unfortunately untangling that requires some major surgery, and we have
a few i915_gem_context reference counting bugs that need fixing, and
they blow in the current hardirq calling context, so we need a
stop-gap measure.

Put a FIXME comment in when this should be removable again.

v2: Fix mock_context(), noticed by intel-gfx-ci.

Acked-by: Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20210902142057.929669-1-daniel.vetter@ffwll.ch

drm/i915/gem: Roll all of context creation together

Now that we have the whole engine set and VM at context creation time,
we can just assign those fields instead of creating first and handling
the VM and engines later. This lets us avoid creating useless VMs and
engine sets and lets us get rid of the complex VM setting code.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-30-jason@jlekstrand.net

drm/i915/selftests: Take a VM in kernel_context()

This better models where we want to go with contexts in general where
things like the VM and engine set are create parameters instead of being
set after the fact.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-28-jason@jlekstrand.net

drm/i915/gem: Delay context creation (v3)

The current context uAPI allows for two methods of setting context
parameters: SET_CONTEXT_PARAM and CONTEXT_CREATE_EXT_SETPARAM. The
former is allowed to be called at any time while the later happens as
part of GEM_CONTEXT_CREATE. Currently, everything settable via one is
settable via the other. While some params are fairly simple and setting
them on a live context is harmless such as the context priority, others
are far trickier such as the VM or the set of engines. In order to swap
out the VM, for instance, we have to delay until all current in-flight
work is complete, swap in the new VM, and then continue. This leads to
a plethora of potential race conditions we'd really rather avoid.

In previous patches, we added a i915_gem_proto_context struct which is
capable of storing and tracking all such create parameters. This commit
delays the creation of the actual context until after the client is done
configuring it with SET_CONTEXT_PARAM. From the perspective of the
client, it has the same u32 context ID the whole time. From the
perspective of i915, however, it's an i915_gem_proto_context right up
until the point where we attempt to do something which the proto-context
can't handle. Then the real context gets created.

This is accomplished via a little xarray dance. When GEM_CONTEXT_CREATE
is called, we create a proto-context, reserve a slot in context_xa but
leave it NULL, the proto-context in the corresponding slot in
proto_context_xa. Then, whenever we go to look up a context, we first
check context_xa. If it's there, we return the i915_gem_context and
we're done. If it's not, we look in proto_context_xa and, if we find it
there, we create the actual context and kill the proto-context.

In order for this dance to work properly, everything which ever touches
a proto-context is guarded by drm_i915_file_private::proto_context_lock,
including context creation. Yes, this means context creation now takes
a giant global lock but it can't really be helped and that should never
be on any driver's fast-path anyway.

v2 (Daniel Vetter):
- Commit message grammatical fixes.
- Use WARN_ON instead of GEM_BUG_ON
- Rename lazy_create_context_locked to finalize_create_context_locked
- Rework the control-flow logic in the setparam ioctl
- Better documentation all around

v3 (kernel test robot):
- Make finalize_create_context_locked static

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-25-jason@jlekstrand.net

drm/i915/gem: Optionally set SSEU in intel_context_set_gem

For now this is a no-op because everyone passes in a null SSEU but it
lets us get some of the error handling and selftest refactoring plumbed
through.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-19-jason@jlekstrand.net

drm/i915/gem: Add an intermediate proto_context struct (v5)

The current context uAPI allows for two methods of setting context
parameters: SET_CONTEXT_PARAM and CONTEXT_CREATE_EXT_SETPARAM. The
former is allowed to be called at any time while the later happens as
part of GEM_CONTEXT_CREATE. Currently, everything settable via one is
settable via the other. While some params are fairly simple and setting
them on a live context is harmless such the context priority, others are
far trickier such as the VM or the set of engines. In order to swap out
the VM, for instance, we have to delay until all current in-flight work
is complete, swap in the new VM, and then continue. This leads to a
plethora of potential race conditions we'd really rather avoid.

Unfortunately, both methods of setting the VM and the engine set are in
active use today so we can't simply disallow setting the VM or engine
set vial SET_CONTEXT_PARAM. In order to work around this wart, this
commit adds a proto-context struct which contains all the context create
parameters.

v2 (Daniel Vetter):
- Better commit message
- Use __set/clear_bit instead of set/clear_bit because there's no race
and we don't need the atomics

v3 (Daniel Vetter):
- Use manual bitops and BIT() instead of __set_bit

v4 (Daniel Vetter):
- Add a changelog to the commit message
- Better hyperlinking in docs
- Create the default PPGTT in i915_gem_create_context

v5 (Daniel Vetter):
- Hand-roll the initialization of UCONTEXT_PERSISTENCE

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-17-jason@jlekstrand.net

drm/i915/gem: Split the context's obj:vma lut into its own mutex

Rather than reuse the common ctx->mutex for locking the execbuffer LUT,
split it into its own lock to avoid being taken [as part of ctx->mutex]
at inappropriate times. In particular to avoid the inversion from taking
the timeline->mutex for the whole execbuf submission in the next patch.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200703004306.11117-1-chris@chris-wilson.co.uk

drm/i915/selftests: Exercise all copy engines with the blt routines

Just to remove an obnoxious HAS_ENGINES(), and in the process make the
code agnostic to the availabilty of any particular engine by making it
exercise any and all such engines declared on the system.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200604123641.767-1-chris@chris-wilson.co.uk

drm/i915/gem: Consolidate ctx->engines[] release

Use the same engine_idle_release() routine for cleaning all old
ctx->engine[] state, closing any potential races with concurrent execbuf
submission.

v2ish: Use the ce->pin_count to close the execbuf gap.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/1241
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200303080546.1140508-1-chris@chris-wilson.co.uk

drm/i915/selftests: Disable capturing forced error states

When we are forcing the error for a selftest, we don't need to capture
the GPU state (typically).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200209230838.361154-1-chris@chris-wilson.co.uk

drm/i915/selftest: Ensure string fits within name[]

Shrink the strncpy bounds to ensure the NUL-terminator can fit within
the embedded array:

In file included from drivers/gpu/drm/i915/gem/i915_gem_context.c:2475:
drivers/gpu/drm/i915/gem/selftests/mock_context.c: In function ‘mock_context’:
drivers/gpu/drm/i915/gem/selftests/mock_context.c:40:3: error: ‘strncpy’ specified bound 24 equals destination size [-Werror=stringop-truncation]
40 | strncpy(ctx->name, name, sizeof(ctx->name));

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200203181625.589118-1-chris@chris-wilson.co.uk

drm/i915: Skip capturing errors from internal contexts

We don't want to report errors on the internal contexts to userspace,
suppressing their own, so treat them as simulated errors. These mostly
arise inside selftests and so are simulated anyway. For the rest, we can
rely on the normal debug channels in CI.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200128113426.3711294-1-chris@chris-wilson.co.uk

drm/i915: Switch context id allocation directly to xarray

IDR internally uses xarray so we can use it directly which simplifies our
code by removing the need to do external locking.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191224095920.2386297-1-chris@chris-wilson.co.uk

drm/i915: Remove i915->kernel_context

Allocate only an internal intel_context for the kernel_context, forgoing
a global GEM context for internal use as we only require a separate
address space (for our own protection).

Now having weaned GT from requiring ce->gem_context, we can stop
referencing it entirely. This also means we no longer have to create random
and unnecessary GEM contexts for internal use.

GEM contexts are now entirely for tracking GEM clients, and intel_context
the execution environment on the GPU.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Acked-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191221160324.1073045-1-chris@chris-wilson.co.uk

drm/i915/gem: Embed context/timeline name inside the GEM context

Use a small char buffer inside the i915_gem_context to store the user
friendly name so that ctx->name has the same lifetime as the RCU
protected GEM context. That is, e.g. when using print_request() that
prints the timeline name (ctx->name), the name will not be prematurely
freed upon the context being closed and the last reference dropped.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191111114323.5833-2-chris@chris-wilson.co.uk

drm/i915/selftests: Complete transition to a real struct file mock

Since drm provided us with a real struct file we can use for our
anonymous internal clients (mock_file), complete our transition to using
that as the primary interface (and not the mocked up struct drm_file we
previous were using).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191107213929.23286-1-chris@chris-wilson.co.uk

drm/i915/gem: Make context persistence optional

Our existing behaviour is to allow contexts and their GPU requests to
persist past the point of closure until the requests are complete. This
allows clients to operate in a 'fire-and-forget' manner where they can
setup a rendering pipeline and hand it over to the display server and
immediately exit. As the rendering pipeline is kept alive until
completion, the display server (or other consumer) can use the results
in the future and present them to the user.

The compute model is a little different. They have little to no buffer
sharing between processes as their kernels tend to operate on a
continuous stream, feeding the results back to the client application.
These kernels operate for an indeterminate length of time, with many
clients wishing that the kernel was always running for as long as they
keep feeding in the data, i.e. acting like a DSP.

Not all clients want this persistent "desktop" behaviour and would prefer
that the contexts are cleaned up immediately upon closure. This ensures
that when clients are run without hangchecking (e.g. for compute kernels
of indeterminate runtime), any GPU hang or other unexpected workloads
are terminated with the process and does not continue to hog resources.

The default behaviour for new contexts is the legacy persistence mode,
as some desktop applications are dependent upon the existing behaviour.
New clients will have to opt in to immediate cleanup on context
closure. If the hangchecking modparam is disabled, so is persistent
context support -- all contexts will be terminated on closure.

We expect this behaviour change to be welcomed by compute users, who
have often been caught between a rock and a hard place. They disable
hangchecking to avoid their kernels being "unfairly" declared hung, but
have also experienced true hangs that the system was then unable to
clean up. Naturally, this leads to bug reports.

Testcase: igt/gem_ctx_persistence
Link: https://github.com/intel/compute-runtime/pull/228
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029202338.8841-1-chris@chris-wilson.co.uk

drm/i915: Move context management under GEM

Keep track of the GEM contexts underneath i915->gem.contexts and assign
them their own lock for the purposes of list management.

v2: Focus on lock tracking; ctx->vm is protected by ctx->mutex
v3: Correct split with removal of logical HW ID

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-15-chris@chris-wilson.co.uk

drm/i915: Remove logical HW ID

With the introduction of ctx->engines[] we allow multiple logical
contexts to be used on the same engine (e.g. with virtual engines).
According to bspec, aach logical context requires a unique tag in order
for context-switching to occur correctly between them. [Simple
experiments show that it is not so easy to trick the HW into performing
a lite-restore with matching logical IDs, though my memory from early
Broadwell experiments do suggest that it should be generating
lite-restores.]

We only need to keep a unique tag for the active lifetime of the
context, and for as long as we need to identify that context. The HW
uses the tag to determine if it should use a lite-restore (why not the
LRCA?) and passes the tag back for various status identifies. The only
status we need to track is for OA, so when using perf, we assign the
specific context a unique tag.

v2: Calculate required number of tags to fill ELSP.

Fixes: 976b55f0e1db ("drm/i915: Allow a context to define its set of engines")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111895
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-14-chris@chris-wilson.co.uk

drm/i915: Rename i915_hw_ppgtt to i915_ppgtt

Keeping the _hw_ in there does not help to distinguish it from its
only brethren i915_ggtt, so drop it.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190611091238.15808-2-chris@chris-wilson.co.uk

drm/i915: Pull kref into i915_address_space

Make the kref common to both derived structs (i915_ggtt and i915_ppgtt)
so that we can safely reference count an abstract ctx->vm address space.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190611091238.15808-1-chris@chris-wilson.co.uk

drm/i915: Move object close under its own lock

Use i915_gem_object_lock() to guard the LUT and active reference to
allow us to break free of struct_mutex for handling GEM_CLOSE.

Testcase: igt/gem_close_race
Testcase: igt/gem_exec_parallel
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190606112320.9704-1-chris@chris-wilson.co.uk

drm/i915: Move more GEM objects under gem/

Continuing the theme of separating out the GEM clutter.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528092956.14910-8-chris@chris-wilson.co.uk