The <linux/agp_backend.h> header provides dummy functions and
fallbacks, so no need for screaming macros.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Call drm_pci_agp_destroy directly, there's no point in the
indirection. Long term we want to shuffle this into each driver's
unload logic, but that needs cleared-up drm lifetime rules first.
v2: Add a dummy function for !CONFIG_PCI, spotted my David Herrmann.
v3: Fixup for the coding style police.
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The PCI bus helper is the only user of it. Call it directly before
device-registration to get rid of the callback.
Note that all drm_agp_*() calls are locked with the drm-global-mutex so we
need to explicitly lock it during initialization. It's not really clear
why it's needed, but lets be safe.
v2: Rebase on top of the agp_init interface change.
v3: Remove the rebase-fail where I've accidentally killed the ->irq_by_busid
callback a bit too early.
Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com> (v1)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Thanks to the removal of REQUIRE_AGP we can use a void return value
and shed a bit of complexity.
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Only the two intel drivers need this and they can easily check for
working agp support in their driver ->load callbacks.
This is the only reason why agp initialization could fail, so allows
us to rip out a bit of error handling code in the next patch.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
There's really no need for the drm core to keep a list of all
devices of a given driver - the linux device model keeps perfect
track of this already for us.
The exception is old legacy ums drivers using pci shadow attaching.
So rename the lists to make the use case clearer and rip out everything
else.
v2: Rebase on top of David Herrmann's drm device register changes.
Also drop the bogus dev_set_drvdata for platform drivers that somehow
crept into the original version - drivers really should be in full
control of that field.
v3: Initialize driver->legacy_dev_list outside of the loop, spotted by
David Herrmann.
v4: Rebase on top of the newly created host1x drm_bus for tegra.
Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This very much looks like a remnant of the old legady ums shadow
attach days. Now with the last users gone we can rip it out since
we won't ever support an ums drm driver again.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
In case where debugfs support is disabled, define dummy functions to
avoid the need for #ifdefery in drivers.
Based on an earlier patch by Arnd Bergmann.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
For error traces in situations that can run away, it is nice to have a
rate-limited version of DRM_ERROR() to avoid massive log flooding.
Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drm_get_minor() is only used in one file. Make it static and add a
kernel-doc comment which documents the current semantics.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Allow passing NULL as minor to simplify DRM destruction paths. Also remove
the double-pointer reset as it is no longer needed. drm_put_minor() is
only called when the underlying object is destroyed. Hence, resetting
minors to NULL is not necessary.
As drm_put_minor() is no longer used by other DRM files, we can make it
static, too.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Replace the sparse array of booleans with a bitfield.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
When a second process opens the device and master transferrence is
complete, we walk the list of open devices and remove their
authentication. This also revokes our root privilege. Instead of simply
dropping the authentication, this patch reverts the authenticated state
back to its original value.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Those structures are not used anywhere.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Those functions are just reading data from those pointers.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
A change in locking of some kms drivers (currently intel-kms) make
the old approach too inaccurate and also incompatible with the
PREEMPT_RT realtime kernel patchset.
The driver->get_scanout_position() method of intel-kms now needs
to aquire a spinlock, which clashes badly with the former
preempt_disable() calls in the drm, and it also introduces larger
delays and timing uncertainty on a contended lock than acceptable.
This patch changes the prototype of driver->get_scanout_position()
to require/allow kms drivers to perform the ktime_get() system time
queries which go along with actual scanout position readout in a way
that provides maximum precision and to return those timestamps to
the drm. kms drivers implementations of get_scanout_position() are
asked to implement timestamping and scanoutpos readout in a way
that is as precise as possible and compatible with preempt_disable()
on a PREMPT_RT kernel. A driver should follow this pattern in
get_scanout_position() for precision and compatibility:
spin_lock...(...);
preempt_disable_rt(); // On a PREEMPT_RT kernel, otherwise omit.
if (stime) *stime = ktime_get();
... Minimum amount of MMIO register reads to get scanout position ...
... no taking of locks allowed here! ...
if (etime) *etime = ktime_get();
preempt_enable_rt(); // On PREEMPT_RT kernel, otherwise omit.
spin_unlock...(...);
v2: Fix formatting of new multi-line code comments.
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The biggest part of the changes is the decoupling of the host1x and DRM
drivers followed by the move of Tegra DRM back to drivers/gpu/drm/tegra
from whence it came. There is a lot of cleanup as well, and the drivers
can now be properly unloaded and reloaded.
HDMI support for the Tegra114 SoC was contributed by Mikko Perttunen.
gr2d support was extended to Tegra114 and the gr3d driver that has been
in the works for quite some time finally made it in. All pieces to run
an OpenGL driver on top of an upstream kernel are now available.
Support for syncpoint bases was added by Arto Merilainen. This is useful
for synchronizing between command streams from different engines such as
gr2d and gr3d.
Erik Faye-Lund and Wei Yongjun contributed various small fixes. Thanks!
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Merge tag 'drm/for-3.13-rc1' of git://anongit.freedesktop.org/tegra/linux into drm-next
drm/tegra: Changes for v3.13-rc1
The biggest part of the changes is the decoupling of the host1x and DRM
drivers followed by the move of Tegra DRM back to drivers/gpu/drm/tegra
from whence it came. There is a lot of cleanup as well, and the drivers
can now be properly unloaded and reloaded.
HDMI support for the Tegra114 SoC was contributed by Mikko Perttunen.
gr2d support was extended to Tegra114 and the gr3d driver that has been
in the works for quite some time finally made it in. All pieces to run
an OpenGL driver on top of an upstream kernel are now available.
Support for syncpoint bases was added by Arto Merilainen. This is useful
for synchronizing between command streams from different engines such as
gr2d and gr3d.
Erik Faye-Lund and Wei Yongjun contributed various small fixes. Thanks!
* tag 'drm/for-3.13-rc1' of git://anongit.freedesktop.org/tegra/linux: (45 commits)
drm/tegra: Reserve syncpoint base for gr3d
drm/tegra: Reserve base for gr2d
drm/tegra: Deliver syncpoint base to user space
gpu: host1x: Add syncpoint base support
gpu: host1x: Add 'flags' field to syncpt request
drm/tegra: Disable clock on probe failure
gpu: host1x: Disable clock on probe failure
drm/tegra: Support bottom-up buffer objects
drm/tegra: Add support for tiled buffer objects
drm/tegra: Add 3D support
drm/tegra: Introduce tegra_drm_submit()
drm/tegra: Use symbolic names for gr2d registers
drm/tegra: Start connectors with correct DPMS mode
drm/tegra: hdmi: Enable VDD earlier for hotplug/DDC
drm/tegra: hdmi: Fix build warnings
drm/tegra: hdmi: Detect DVI-only displays
drm/tegra: Add Tegra114 HDMI support
drm/tegra: hdmi: Parameterize based on compatible property
drm/tegra: hdmi: Rename tegra{2,3} to tegra{20,30}
gpu: host1x: Add support for Tegra114
...
The Tegra DRM driver currently uses some infrastructure to defer the DRM
core initialization until all required devices have registered. The same
infrastructure can potentially be used by any other driver that requires
more than a single sub-device of the host1x module.
Make the infrastructure more generic and keep only the DRM specific code
in the DRM part of the driver. Eventually this will make it easy to move
the DRM driver part back to the DRM subsystem.
Signed-off-by: Thierry Reding <treding@nvidia.com>
So drm was abusing device lifetimes, by having embedded device structures
in the minor and connector it meant that the lifetime of the internal drm
objects (drm_minor and drm_connector) were tied to the lifetime of the device
files in sysfs, so if something kept those files opened the current code
would kfree the objects and things would go downhill from there.
Now in reality there is no need for these lifetimes to be so intertwined,
especailly with hotplugging of devices where we wish to remove the sysfs
and userspace facing pieces before we can unwind the internal objects due
to open userspace files or mmaps, so split the objects out so the struct
device is no longer embedded and do what fbdev does and just allocate
and remove the sysfs inodes separately.
Signed-off-by: Dave Airlie <airlied@redhat.com>
The conflict in intel_drv.h tripped me up a bit since a patch in dinq
moves all the functions around, but another one in drm-next removes a
single function. So I'ev figured backing this into a backmerge would
be good.
i915_dma.c is just adjacent lines changed, nothing nefarious there.
Conflicts:
drivers/gpu/drm/i915/i915_dma.c
drivers/gpu/drm/i915/intel_drv.h
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The user of these counters was killed in
commit d79cdc8312
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Thu Aug 8 15:41:32 2013 +0200
drm: no-op out GET_STATS ioctl
so clean up the leftovers as well.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
We can get the PCI vendor and device IDs via dev->pdev. So we can drop
the duplicated information.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The only user of ctx_count is the via driver, and we can replace that
use with list_is_singular().
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
'map_count' and 'work' are never used. Kill them both.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
irq_enabled is only ever 0 or 1, so make it a bool.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drm_vblank_init() is too ugly. Make it a bit easier on the eye by
collecting all the per-crtc vblank counters, timestamps etc. to
a structure and just allocate an array of those.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
vblank_enabled is only ever 0 or 1, so make it a bool.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
vblank_inmodeset is a bitmask, with only two bits mind you, but better
make it unsigned anyway.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
vblank_disable_allowed is only ever 0 or 1, so make it a bool.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Analog to drm_dev_register(), we now provide drm_dev_unregister() which
does the reverse. drm_dev_put() is still in place and combines the calls
to drm_dev_unregister() and drm_dev_free() so buses don't have to change.
*_get() and *_put() are used for reference-counting in the kernel.
However, drm_dev_put() definitely does not do any kind of ref-counting.
Hence, use the more appropriate *_register(), *_unregister(), *_alloc()
and *_free() names.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The error paths in DRM bus drivers currently leak memory as they don't
correctly revert drm_dev_alloc(). Introduce drm_dev_free() to free DRM
devices which haven't been registered, yet.
We must be careful not to introduce any side-effects with cleanups done in
drm_dev_free(). drm_ht_remove(), drm_ctxbitmap_cleanup() and
drm_gem_destroy() are all fine in that regard.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
All bus drivers do device setup themselves. This requires us to adjust all
of them if we introduce new core features. Thus, merge all these into a
uniform drm_dev_register() helper.
Note that this removes the drm_lastclose() error path for AGP as it is
horribly broken. Moreover, no bus driver called this in any other error
path either. Instead, we use the recently introduced AGP cleanup helpers.
We also keep a DRIVER_MODESET condition around pci_set_drvdata() to keep
semantics.
[airlied: keep passing flags through so drivers don't oops on load]
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Instead of managing device allocation+initialization in each bus-driver,
we should do that in a central place. drm_fill_in_dev() already does most
of it, but also requires the global drm lock for partial AGP device
registration.
Split both apart so we have a clean device initialization/allocation
phase, and a registration phase.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
All drivers embed gem-objects into their own buffer objects. There is no
reason to keep drm_gem_object_alloc(), gem->driver_private and
->gem_init_object() anymore.
New drivers are highly encouraged to do the same. There is no benefit in
allocating gem-objects separately.
Cc: Dave Airlie <airlied@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Ben Skeggs <skeggsb@gmail.com>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This capability allows user space to control the delivery of modes with
the 3D flags set. This is to not play games with current user space
users not knowing anything about stereo 3D flags and that could try
to set a mode with one or several of those bits set.
So, the plan is to remove the stereo modes from the list of modes we
give to DRM clients by default, and let them through if we are being
told otherwise.
stereo_allowed is bound to the drm_file structure to make it a
per-client setting, not a global one.
v2: Replace clearing 3D flags by discarding the stereo modes now that
they are regular modes.
v3: SET_CAP -> SET_CLIENT_CAP rename (Chris Wilson)
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This ioctl can be used to turn some knobs in a DRM driver. The client
can ask the DRM core for an alternate view of the reality: it can be
useful to be able to instruct the core that the DRM client can handle
new functionnality that would otherwise break current ABI.
v2: Rename to ioctl from SET_CAP to SET_CLIENT_CAP (Chris Wilson)
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This reverts commit 7c510133d9.
Well looks like not enough digging was done, libdrm_nouveau before 2.4.33
used contexts,
292da616fe1f936ca78a3fa8e1b1b19883e343b6 nouveau: pull in major libdrm rewrite
got rid of them,
Reported-by: Paul Zimmerman <Paul.Zimmerman@synopsys.com>
Reported-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Render nodes provide an API for userspace to use non-privileged GPU
commands without any running DRM-Master. It is useful for offscreen
rendering, GPGPU clients, and normal render clients which do not perform
modesetting.
Compared to legacy clients, render clients no longer need any
authentication to perform client ioctls. Instead, user-space controls
render/client access to GPUs via filesystem access-modes on the
render-node. Once a render-node was opened, a client has full access to
the client/render operations on the GPU. However, no modesetting or ioctls
that affect global state are allowed on render nodes.
To prevent privilege-escalation, drivers must explicitly state that they
support render nodes. They must mark their render-only ioctls as
DRM_RENDER_ALLOW so render clients can use them. Furthermore, they must
support clients without any attached master.
If filesystem access-modes are not enough for fine-grained access control
to render nodes (very unlikely, considering the versaitlity of FS-ACLs),
you may still fall-back to fd-passing from server to client (which allows
arbitrary access-control). However, note that revoking access is
currently impossible and unlikely to get implemented.
Note: Render clients no longer have any associated DRM-Master as they are
supposed to be independent of any server state. DRM core highly depends on
file_priv->master to be non-NULL for modesetting/ctx/etc. commands.
Therefore, drivers must be very careful to not require DRM-Master if they
support DRIVER_RENDER.
So far render-nodes are protected by "drm_rnodes". As long as this
module-parameter is not set to 1, a driver will not create render nodes.
This allows us to experiment with the API a bit before we stabilize it.
v2: drop insecure GEM_FLINK to force use of dmabuf
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
... not only when the dma-buf is freshly created. In contrived
examples someone else could have exported/imported the dma-buf already
and handed us the gem object with a flink name. If such on object gets
reexported as a dma_buf we won't have it in the handle cache already,
which breaks the guarantee that for dma-buf imports we always hand
back an existing handle if there is one.
This is exercised by igt/prime_self_import/with_one_bo_two_files
Now if we extend the locked sections just a notch more we can also
plug th racy buf/handle cache setup in handle_to_fd:
If evil userspace races a concurrent gem close against a prime export
operation we can end up tearing down the gem handle before the dma buf
handle cache is set up. When handle_to_fd gets around to adding the
handle to the cache there will be no one left to clean it up,
effectily leaking the bo (and the dma-buf, since the handle cache
holds a ref on the dma-buf):
Thread A Thread B
handle_to_fd:
lookup gem object from handle
creates new dma_buf
gem_close on the same handle
obj->dma_buf is set, but file priv buf
handle cache has no entry
obj->handle_count drops to 0
drm_prime_add_buf_handle sets up the handle cache
-> We have a dma-buf reference in the handle cache, but since the
handle_count of the gem object already dropped to 0 no on will clean
it up. When closing the drm device fd we'll hit the WARN_ON in
drm_prime_destroy_file_private.
The important change is to extend the critical section of the
filp->prime.lock to cover the gem handle lookup. This serializes with
a concurrent gem handle close.
This leak is exercised by igt/prime_self_import/export-vs-gem_close-race
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
... and move it to the top of the function to avoid a forward
declaration.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
with the reworking semantics and locking of the obj->dma_buf pointer
this pointer is always set as long as there's still a gem handle
around and a dma_buf associated with this gem object.
Also, the per file-priv lookup-cache for dma-buf importing is also
unified between foreign and native objects.
Hence we don't need to special case the clean any more and can simply
drop the clause which only runs for foreing objects, i.e. with
obj->import_attach set.
Note that with this change (actually with the previous one to always
set up obj->dma_buf even for foreign objects) it is no longer required
to set obj->import_attach when importing a foreing object. So update
comments accordingly, too.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The export dma-buf cache is semantically similar to an flink name. So
semantically it makes sense to treat it the same and remove the name
(i.e. the dma_buf pointer) and its references when the last gem handle
disappears.
Again we need to be careful, but double so: Not just could someone
race and export with a gem close ioctl (so we need to recheck
obj->handle_count again when assigning the new name), but multiple
exports can also race against each another. This is prevented by
holding the dev->object_name_lock across the entire section which
touches obj->dma_buf.
With the new scheme we also need to reinstate the obj->dma_buf link at
import time (in case the only reference userspace has held in-between
was through the dma-buf fd and not through any native gem handle). For
simplicity we don't check whether it's a native object but
unconditionally set up that link - with the new scheme of removing the
obj->dma_buf reference when the last handle disappears we can do that.
To make it clear that this is not just for exported buffers anymore
als rename it from export_dma_buf to dma_buf.
To make sure that now one can race a fd_to_handle or handle_to_fd with
gem_close we use the same tricks as in flink of extending the
dev->object_name_locking critical section. With this change we finally
have a guaranteed 1:1 relationship (at least for native objects)
between gem objects and dma-bufs, even accounting for races (which can
happen since the dma-buf itself holds a reference while in-flight).
This prevent igt/prime_self_import/export-vs-gem_close-race from
Oopsing the kernel. There is still a leak though since the per-file
priv dma-buf/handle cache handling is racy. That will be fixed in a
later patch.
v2: Remove the bogus dma_buf_put from the export_and_register_object
failure path if we've raced with the handle count dropping to 0.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
The gem flink name holds a reference onto the object itself, and this
self-reference would prevent an flink'ed object from every being
freed. To break that loop we remove the flink name when the last
userspace handle disappears, i.e. when obj->handle_count reaches 0.
Now in gem_open we drop the dev->object_name_lock between the flink
name lookup and actually adding the handle. This means a concurrent
gem_close of the last handle could result in the flink name getting
reaped right inbetween, i.e.
Thread 1 Thread 2
gem_open gem_close
flink -> obj lookup
handle_count drops to 0
remove flink name
create_handle
handle_count++
If someone now flinks this object again, we'll get a new flink name.
We can close this race by removing the lock dropping and making the
entire lookup+handle_create sequence atomic. Unfortunately to still be
able to share the handle_create logic this requires a
handle_create_tail function which drops the lock - we can't hold the
object_name_lock while calling into a driver's ->gem_open callback.
Note that for flink fixing this race isn't really important, since
racing gem_open against gem_close is clearly a userspace bug. And no
matter how the race ends, we won't leak any references.
But with dma-buf where the userspace dma-buf fd itself is refcounted
this is a valid sequence and hence we should fix it. Therefore this
patch here is just a warm-up exercise (and for consistency between
flink buffer sharing and dma-buf buffer sharing with self-imports).
Also note that this extension of the critical section in gem_open
protected by dev->object_name_lock only works because it's now a
mutex: A spinlock would conflict with the potential memory allocation
in idr_preload().
This is exercises by igt/gem_flink_race/flink_name.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
I want to wrap the creation of a dma-buf from a gem object in it,
so that the obj->export_dma_buf cache can be atomically filled in.
Instead of creating a new mutex just for that variable I've figured
I can reuse the existing dev->object_name_lock, especially since
the new semantics will exactly mirror the flink obj->name already
protected by that lock.
v2: idr_preload/idr_preload_end is now an atomic section, so need to
move the mutex locking outside.
[airlied: fix up conflict with patch to make debugfs use lock]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
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: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave 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: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
It's only used in drm_platform.c.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
A few prototypes have been left in the headers, their function friends
long gone.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave 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 955b12def4
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: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Daniel Vetter
Thierry Reding
Rob Clark
David Herrmann
Chris Wilson
Lespiau, Damien
Mario Kleiner
Dave Airlie
Thierry Reding
Ville Syrjälä