dma_buf_map_attachment and dma_buf_vmap can return NULL or
ERR_PTR on a error. This encourages a common buggy pattern in
callers:
sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
if (IS_ERR_OR_NULL(sgt))
return PTR_ERR(sgt);
This causes the caller to return 0 on an error. IS_ERR_OR_NULL
is almost always a sign of poorly-defined error handling.
This patch converts dma_buf_map_attachment to always return
ERR_PTR, and fixes the callers that incorrectly handled NULL.
There are a few more callers that were not checking for NULL
at all, which would have dereferenced a NULL pointer later.
There are also a few more callers that correctly handled NULL
and ERR_PTR differently, I left those alone but they could also
be modified to delete the NULL check.
This patch also converts dma_buf_vmap to always return NULL.
All the callers to dma_buf_vmap only check for NULL, and would
have dereferenced an ERR_PTR and panic'd if one was ever
returned. This is not consistent with the rest of the dma buf
APIs, but matches the expectations of all of the callers.
Signed-off-by: Colin Cross <ccross@android.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull drm updates from Dave Airlie:
"Been a bit busy, first week of kids school, and waiting on other trees
to go in before I could send this, so its a bit later than I'd
normally like.
Highlights:
- core:
timestamp fixes, lots of misc cleanups
- new drivers:
bochs virtual vga
- vmwgfx:
major overhaul for their nextgen virt gpu.
- i915:
runtime D3 on HSW, watermark fixes, power well work, fbc fixes,
bdw is no longer prelim.
- nouveau:
gk110/208 acceleration, more pm groundwork, old overlay support
- radeon:
dpm rework and clockgating for CIK, pci config reset, big endian
fixes
- tegra:
panel support and DSI support, build as module, prime.
- armada, omap, gma500, rcar, exynos, mgag200, cirrus, ast:
fixes
- msm:
hdmi support for mdp5"
* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (595 commits)
drm/nouveau: resume display if any later suspend bits fail
drm/nouveau: fix lock unbalance in nouveau_crtc_page_flip
drm/nouveau: implement hooks for needed for drm vblank timestamping support
drm/nouveau/disp: add a method to fetch info needed by drm vblank timestamping
drm/nv50: fill in crtc mode struct members from crtc_mode_fixup
drm/radeon/dce8: workaround for atom BlankCrtc table
drm/radeon/DCE4+: clear bios scratch dpms bit (v2)
drm/radeon: set si_notify_smc_display_change properly
drm/radeon: fix DAC interrupt handling on DCE5+
drm/radeon: clean up active vram sizing
drm/radeon: skip async dma init on r6xx
drm/radeon/runpm: don't runtime suspend non-PX cards
drm/radeon: add ring to fence trace functions
drm/radeon: add missing trace point
drm/radeon: fix VMID use tracking
drm: ast,cirrus,mgag200: use drm_can_sleep
drm/gma500: Lock struct_mutex around cursor updates
drm/i915: Fix the offset issue for the stolen GEM objects
DRM: armada: fix missing DRM_KMS_FB_HELPER select
drm/i915: Decouple GPU error reporting from ring initialisation
...
DRM_HZ and DRM_WAKEUP macros are removed, but they still remained.
So this patch fixes build errors by replacing the macros.
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
This patch resolves potential deadlock issue that can be incurred
by changing file->f_op and filp->private_data to exynos specific
mapper ops and gem object temporarily.
To resolve this issue, this patch creates a new anon file dedicated
to exynos specific mmaper, and making it used instead of existing one.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Correct spelling typo in various part of kernel
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
We don't have any userspace interfaces that use HZ as a time unit, so
having our own DRM define is useless.
Remove this remnant from the shared drm core days.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
I didn't find any user of the driver data yet, so store the
drm_device pointer in there.
Cc: Inki Dae <inki.dae@samsung.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This patch resolves a dead lock issue that could be incurred when
exynos_drm_crtc_dpms function was called.
The exynos_drm_crtc_dpms function waits for the completion of pended
page flip events. However, preclose callback - this releases all unhandled
page flip events - is called prior to the exynos_drm_crtc_dpms function call
when drm is closed. So at this time, this will make the exynos_drm_crtc_dpms
to wait infiniately for the completion of the page flip events.
This patch releases the unhandled page flip events at postclose instead
of preclose so that exynos_drm_crtc_dpms function can be waked up.
Changelog v2:
- fix a memory leak when drm is closed.
. it has a memory leak when a requeste page flip is handled after
drm_events_release() is called and before drm_fb_release()
is called. At this time, a drm_pending_event will not be freed.
So also this chage releases the drm_pending_event at postclose().
And it calls drm_vblank_put() for pair if there is any unhandled page
flip event.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
This patch releases a vma object when cleaning up userptr resources.
A new vma object was allocated and copied when getting userptr pages
so the new vma object should be freed properly if the userptr pages
aren't used anymore.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Pull drm updates from Dave Airlie:
"This is a combo of -next and some -fixes that came in in the
intervening time.
Highlights:
New drivers:
ARM Armada driver for Marvell Armada 510 SOCs
Intel:
Broadwell initial support under a default off switch,
Stereo/3D HDMI mode support
Valleyview improvements
Displayport improvements
Haswell fixes
initial mipi dsi panel support
CRC support for debugging
build with CONFIG_FB=n
Radeon:
enable DPM on a number of GPUs by default
secondary GPU powerdown support
enable HDMI audio by default
Hawaii support
Nouveau:
dynamic pm code infrastructure reworked, does nothing major yet
GK208 modesetting support
MSI fixes, on by default again
PMPEG improvements
pageflipping fixes
GMA500:
minnowboard SDVO support
VMware:
misc fixes
MSM:
prime, plane and rendernodes support
Tegra:
rearchitected to put the drm driver into the drm subsystem.
HDMI and gr2d support for tegra 114 SoC
QXL:
oops fix, and multi-head fixes
DRM core:
sysfs lifetime fixes
client capability ioctl
further cleanups to device midlayer
more vblank timestamp fixes"
* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (789 commits)
drm/nouveau: do not map evicted vram buffers in nouveau_bo_vma_add
drm/nvc0-/gr: shift wrapping bug in nvc0_grctx_generate_r406800
drm/nouveau/pwr: fix missing mutex unlock in a failure path
drm/nv40/therm: fix slowing down fan when pstate undefined
drm/nv11-: synchronise flips to vblank, unless async flip requested
drm/nvc0-: remove nasty fifo swmthd hack for flip completion method
drm/nv10-: we no longer need to create nvsw object on user channels
drm/nouveau: always queue flips relative to kernel channel activity
drm/nouveau: there is no need to reserve/fence the new fb when flipping
drm/nouveau: when bailing out of a pushbuf ioctl, do not remove previous fence
drm/nouveau: allow nouveau_fence_ref() to be a noop
drm/nvc8/mc: msi rearm is via the nvc0 method
drm/ttm: Fix vma page_prot bit manipulation
drm/vmwgfx: Fix a couple of compile / sparse warnings and errors
drm/vmwgfx: Resource evict fixes
drm/edid: compare actual vrefresh for all modes for quirks
drm: shmob_drm: Convert to clk_prepare/unprepare
drm/nouveau: fix 32-bit build
drm/i915/opregion: fix build error on CONFIG_ACPI=n
Revert "drm/radeon/audio: don't set speaker allocation on DCE4+"
...
Pull DMA mask updates from Russell King:
"This series cleans up the handling of DMA masks in a lot of drivers,
fixing some bugs as we go.
Some of the more serious errors include:
- drivers which only set their coherent DMA mask if the attempt to
set the streaming mask fails.
- drivers which test for a NULL dma mask pointer, and then set the
dma mask pointer to a location in their module .data section -
which will cause problems if the module is reloaded.
To counter these, I have introduced two helper functions:
- dma_set_mask_and_coherent() takes care of setting both the
streaming and coherent masks at the same time, with the correct
error handling as specified by the API.
- dma_coerce_mask_and_coherent() which resolves the problem of
drivers forcefully setting DMA masks. This is more a marker for
future work to further clean these locations up - the code which
creates the devices really should be initialising these, but to fix
that in one go along with this change could potentially be very
disruptive.
The last thing this series does is prise away some of Linux's addition
to "DMA addresses are physical addresses and RAM always starts at
zero". We have ARM LPAE systems where all system memory is above 4GB
physical, hence having DMA masks interpreted by (eg) the block layers
as describing physical addresses in the range 0..DMAMASK fails on
these platforms. Santosh Shilimkar addresses this in this series; the
patches were copied to the appropriate people multiple times but were
ignored.
Fixing this also gets rid of some ARM weirdness in the setup of the
max*pfn variables, and brings ARM into line with every other Linux
architecture as far as those go"
* 'for-linus-dma-masks' of git://git.linaro.org/people/rmk/linux-arm: (52 commits)
ARM: 7805/1: mm: change max*pfn to include the physical offset of memory
ARM: 7797/1: mmc: Use dma_max_pfn(dev) helper for bounce_limit calculations
ARM: 7796/1: scsi: Use dma_max_pfn(dev) helper for bounce_limit calculations
ARM: 7795/1: mm: dma-mapping: Add dma_max_pfn(dev) helper function
ARM: 7794/1: block: Rename parameter dma_mask to max_addr for blk_queue_bounce_limit()
ARM: DMA-API: better handing of DMA masks for coherent allocations
ARM: 7857/1: dma: imx-sdma: setup dma mask
DMA-API: firmware/google/gsmi.c: avoid direct access to DMA masks
DMA-API: dcdbas: update DMA mask handing
DMA-API: dma: edma.c: no need to explicitly initialize DMA masks
DMA-API: usb: musb: use platform_device_register_full() to avoid directly messing with dma masks
DMA-API: crypto: remove last references to 'static struct device *dev'
DMA-API: crypto: fix ixp4xx crypto platform device support
DMA-API: others: use dma_set_coherent_mask()
DMA-API: staging: use dma_set_coherent_mask()
DMA-API: usb: use new dma_coerce_mask_and_coherent()
DMA-API: usb: use dma_set_coherent_mask()
DMA-API: parport: parport_pc.c: use dma_coerce_mask_and_coherent()
DMA-API: net: octeon: use dma_coerce_mask_and_coherent()
DMA-API: net: nxp/lpc_eth: use dma_coerce_mask_and_coherent()
...
The correct way for a driver to specify the coherent DMA mask is
not to directly access the field in the struct device, but to use
dma_set_coherent_mask(). Only arch and bus code should access this
member directly.
Convert all direct write accesses to using the correct API.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
For drivers which might want to disable fbdev legacy support.
Select the new option in all drivers for now, so this shouldn't result
in any change. Drivers need some work anyway to make fbdev support
optional (if they have it implemented, that is), so the recommended
way to expose this is by adding per-driver options. At least as long
as most drivers don't support disabling the fbdev support.
v2: Update for new drm drivers msm and rcar-du. Note that Rob's msm
driver can already take advantage of this, which allows us to build
msm without any fbdev depencies in the kernel!
v3: Move the MODULE_* stuff from the fbdev helper file to
drm_crtc_helper.c.
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Acked-by: Dave Airlie <airlied@linux.ie>
Reviewed-by: Chon Ming Lee <chon.ming.lee@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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>
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>
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>
In case of error, the function drm_prime_pages_to_sg() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should
be replaced with IS_ERR().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Now that DRM_EXYNOS depends on OF, we do not need individual
drivers to depend on it.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
exynos_drm_connector.c now uses videomode helper API. Hence select
VIDEOMODE_HELPERS at DRM_EXYNOS level itself instead of at
DRM_EXYNOS_FIMD to avoid the following compilation error when FIMD
is not selected (introduced by commit cf796235a6 "drm/exynos: fimd:
replace struct fb_videomode with videomode"):
drivers/built-in.o: In function `exynos_drm_connector_get_modes':
drivers/gpu/drm/exynos/exynos_drm_connector.c:86:
undefined reference to `drm_display_mode_from_videomode'
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Since commit 383ffda2fa ("ARM: EXYNOS: no more support non-DT
for EXYNOS SoCs"), Exynos platform is DT only. Hence remove
all the conditional macros and make the driver DT only.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Since commit 383ffda2fa ("ARM: EXYNOS: no more support non-DT
for EXYNOS SoCs"), Exynos platform is DT only. Hence remove
all the conditional macros and make the driver DT only.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Since commit 383ffda2fa ("ARM: EXYNOS: no more support non-DT
for EXYNOS SoCs"), Exynos platform is DT only. Hence remove
all the conditional macros and make the driver DT only.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Since commit 383ffda2fa ("ARM: EXYNOS: no more support non-DT
for EXYNOS SoCs"), Exynos platform is DT only. Hence remove
all the conditional macros and make the driver DT only.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Since commit 383ffda2fa ("ARM: EXYNOS: no more support non-DT
for EXYNOS SoCs"), Exynos platform is DT only. Hence remove
all the conditional macros and make the driver DT only.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Exynos is a DT-only platform. Add this info to Kconfig.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
To address the case where physically contiguous memory
MAY NOT be a mandatory requirement for framebuffer for
the application calling exynos_drm_gem_dumb_create,
the patch adds a feature to get non physically contiguous
memory for framebuffer, if physically contiguous memory
allocation fails and if IOMMU is supported.
Signed-off-by: Vikas Sajjan <vikas.sajjan@linaro.org>
Signed-off-by: Arun Kumar <arun.kk@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
The patch moves platfrom_data and device tree parsing
to separate function.
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
The patch adds code to get signal polarization setting
from device tree display-timings node.
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
The patch replaces all occurrences of struct fb_videomode by
more accurate struct videomode. The change allows to remove
mode conversion function and simplifies clock divider calculation.
Clock configuration is moved to separate function.
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
This patch checks if a requested window supports alpha channel or not.
In case of s3c64xx, window 0 doesn't support alpha channel so if
the request pixel format is ARGB8888 then change it to XRGB8888.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
This patch fixes wrong pixel format setting.
A pixel format is decided according to bpp and depth, or user-requested
format but fimd driver considered only bpp value to decide a proper pixel
format. So this patch makes a proper pixel format to be set according
to drm_framebuffer's pixel_format which is set by addfb with bpp and
depth, or addfb2 with user-requested format.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
The exynos4 platform is only dt-based since 3.10, we should convert driver data
and ids to dt-based parsing methods. The rotator driver has a limit table to get
size limit of input picture. Each SoCs has slightly different limit value
compared with any others.
For example, exynos4210's max_size of RGB888 is 16k x 16k. But, others have
8k x 8k. Another example the exynos5250 should have multiple of 2 pixel size
for its X/Y axis. Thus, we should keep different tables for each of them.
This patch also includes desciptions of each nodes for the rotator and specifies
a example how to bind it.
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Ensure that all externally accessed functions are correctly prototyped
when defined in each file by making sure the headers with the protoypes
are included in the file with the definition.
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
This patch makes g2d power domain and clock to be controlled
through pm runtime interfaces instead of controlling them
respectively.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
While trying to get boot-logo up on exynos5420 SMDK which has eDP panel
connected with resolution 2560x1600, following error occured even with
IOMMU enabled:
[0.880000] [drm:lowlevel_buffer_allocate] *ERROR* failed to allocate buffer.
[0.890000] [drm] Initialized exynos 1.0.0 20110530 on minor 0
To address the cases where physically contiguous memory MAY NOT be a
mandatory requirement for fb, the patch adds a feature to get non physically
contiguous memory for fb if physically contiguous memory allocation fails
and if IOMMU is supported.
Signed-off-by: Vikas Sajjan <vikas.sajjan@linaro.org>
Signed-off-by: Arun Kumar <arun.kk@samsung.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Alex writes:
This is the radeon drm-next request. Big changes include:
- support for dpm on CIK parts
- support for ASPM on CIK parts
- support for berlin GPUs
- major ring handling cleanup
- remove the old 3D blit code for bo moves in favor of CP DMA or sDMA
- lots of bug fixes
[airlied: fix up a bunch of conflicts from drm_order removal]
* 'drm-next-3.12' of git://people.freedesktop.org/~agd5f/linux: (898 commits)
drm/radeon/dpm: make sure dc performance level limits are valid (CI)
drm/radeon/dpm: make sure dc performance level limits are valid (BTC-SI) (v2)
drm/radeon: gcc fixes for extended dpm tables
drm/radeon: gcc fixes for kb/kv dpm
drm/radeon: gcc fixes for ci dpm
drm/radeon: gcc fixes for si dpm
drm/radeon: gcc fixes for ni dpm
drm/radeon: gcc fixes for trinity dpm
drm/radeon: gcc fixes for sumo dpm
drm/radeonn: gcc fixes for rv7xx/eg/btc dpm
drm/radeon: gcc fixes for rv6xx dpm
drm/radeon: gcc fixes for radeon_atombios.c
drm/radeon: enable UVD interrupts on CIK
drm/radeon: fix init ordering for r600+
drm/radeon/dpm: only need to reprogram uvd if uvd pg is enabled
drm/radeon: check the return value of uvd_v1_0_start in uvd_v1_0_init
drm/radeon: split out radeon_uvd_resume from uvd_v4_2_resume
radeon kms: fix uninitialised hotplug work usage in r100_irq_process()
drm/radeon/audio: set up the sads on DCE3.2 asics
drm/radeon: fix handling of variable sized arrays for router objects
...
Conflicts:
drivers/gpu/drm/i915/i915_dma.c
drivers/gpu/drm/i915/i915_gem_dmabuf.c
drivers/gpu/drm/i915/intel_pm.c
drivers/gpu/drm/radeon/cik.c
drivers/gpu/drm/radeon/ni.c
drivers/gpu/drm/radeon/r600.c
This lets drivers see the flags requested by the application
[airlied: fixup for rcar/imx/msm]
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Dave Airlie <airlied@gmail.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>
