linux-stable.git/drivers/dma-buf/sync_file.c, branch v4.13.2

dma-buf/sync_file: Allow multiple sync_files to wrap a single dma-fence

2017-07-31T13:55:24+00:00

Up until recently sync_file were create to export a single dma-fence to
userspace, and so we could canabalise a bit insie dma-fence to mark
whether or not we had enable polling for the sync_file itself. However,
with the advent of syncobj, we do allow userspace to create multiple
sync_files for a single dma-fence. (Similarly, that the sw-sync
validation framework also started returning multiple sync-files wrapping
a single dma-fence for a syncpt also triggering the problem.)

This patch reverts my suggestion in commit e24165537312
("dma-buf/sync_file: only enable fence signalling on poll()") to use a
single bit in the shared dma-fence and restores the sync_file->flags for
tracking the bits individually.

Reported-by: Gustavo Padovan 
Fixes: f1e8c67123cf ("dma-buf/sw-sync: Use an rbtree to sort fences in the timeline")
Fixes: e9083420bbac ("drm: introduce sync objects (v4)")
Signed-off-by: Chris Wilson 
Cc: Sumit Semwal 
Cc: Sean Paul 
Cc: Gustavo Padovan 
Cc: dri-devel@lists.freedesktop.org
Cc:  # v4.13-rc1+
Signed-off-by: Gustavo Padovan 
Link: http://patchwork.freedesktop.org/patch/msgid/20170728212951.7818-1-chris@chris-wilson.co.uk
(cherry picked from commit db1fc97ca0c0d3fdeeadf314d99a26188438940a)

Merge branch 'drm-misc-next-fixes' into drm-misc-fixes

2017-07-17T15:56:07+00:00

Pick up

1ed134e6526b drm/vc4: Fix VBLANK handling in crtc->enable() path

From drm-misc-next-fixes, it was applied after the last pull request
was sent from that branch. We'll send it through drm-fixes instead.

dma-buf/fence: Avoid use of uninitialised timestamp

2017-07-14T19:09:55+00:00

[  236.821534] WARNING: kmemcheck: Caught 64-bit read from uninitialized memory (ffff8802538683d0)
[  236.828642] 420000001e7f0000000000000000000000080000000000000000000000000000
[  236.839543]  i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
[  236.850420]                                  ^
[  236.854123] RIP: 0010:[]  [] fence_signal+0x17/0xd0
[  236.861313] RSP: 0018:ffff88024acd7ba0  EFLAGS: 00010282
[  236.865027] RAX: ffffffff812f6a90 RBX: ffff8802527ca800 RCX: ffff880252cb30e0
[  236.868801] RDX: ffff88024ac5d918 RSI: ffff880252f780e0 RDI: ffff880253868380
[  236.872579] RBP: ffff88024acd7bc0 R08: ffff88024acd7be0 R09: 0000000000000000
[  236.876407] R10: 0000000000000000 R11: 0000000000000000 R12: ffff880253868380
[  236.880185] R13: ffff8802538684d0 R14: ffff880253868380 R15: ffff88024cd48e00
[  236.883983] FS:  00007f1646d1a740(0000) GS:ffff88025d000000(0000) knlGS:0000000000000000
[  236.890959] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  236.894702] CR2: ffff880251360318 CR3: 000000024ad21000 CR4: 00000000001406f0
[  236.898481]  [] i915_gem_request_retire+0x1cd/0x230
[  236.902439]  [] i915_gem_request_alloc+0xa3/0x2f0
[  236.906435]  [] i915_gem_do_execbuffer.isra.41+0xb6d/0x18b0
[  236.910434]  [] i915_gem_execbuffer2+0x95/0x1e0
[  236.914390]  [] drm_ioctl+0x1e5/0x460
[  236.918275]  [] do_vfs_ioctl+0x8f/0x5c0
[  236.922168]  [] SyS_ioctl+0x3c/0x70
[  236.926090]  [] entry_SYSCALL_64_fastpath+0x17/0x93
[  236.930045]  [] 0xffffffffffffffff

We only set the timestamp before we mark the fence as signaled. It is
done before to avoid observers having a window in which they may see the
fence as complete but no timestamp. Having it does incur a potential for
the timestamp to be written twice, and even for it to be corrupted if
the u64 write is not atomic. Instead use a new bit to record the
presence of the timestamp, and teach the readers to wait until it is set
if the fence is complete. There still remains a race where the timestamp
for the signaled fence may be shown before the fence is reported as
signaled, but that's a pre-existing error.

Signed-off-by: Chris Wilson 
Cc: Sumit Semwal 
Cc: Gustavo Padovan 
Cc: Daniel Vetter 
Reported-by: Rafael Antognolli 
Signed-off-by: Gustavo Padovan 
Link: http://patchwork.freedesktop.org/patch/msgid/20170214124001.1930-1-chris@chris-wilson.co.uk

dma-buf/sync-file: Defer creation of sync_file->name

2017-05-24T16:08:29+00:00

Constructing the name takes the majority of the time for allocating a
sync_file to wrap a fence, and the name is very rarely used (only via
the sync_file status user interface). To reduce the impact on the common
path (that of creating sync_file to pass around), defer the construction
of the name until it is first used.

v2: Update kerneldoc (kbuild test robot)
v3: sync_debug.c was peeking at the name
v4: Comment upon the potential race between two users of
sync_file_get_name() and claim that such a race is below the level of
notice. However, to prevent any future nuisance, use a global spinlock
to serialize the assignment of the name.
v5: Completely avoid the read/write race by only storing the name passed
in from the user inside sync_file->user_name and passing in a buffer to
dynamically construct the name otherwise.

Signed-off-by: Chris Wilson 
Cc: Sumit Semwal 
Cc: Gustavo Padovan 
Cc: Daniel Vetter 
Cc: David Herrmann 
Reviewed-by: Daniel Vetter 
Signed-off-by: Gustavo Padovan 
Link: http://patchwork.freedesktop.org/patch/msgid/20170516111042.24719-1-chris@chris-wilson.co.uk

sync_file: get rid of internal reference count.

2017-04-18T13:27:38+00:00

sync_file uses the reference count of the file, the internal
kref was never getting moved past 1.

We can reintroduce this if we decide we need it later.

[airlied: fix buildbot warnings]

Reviewed-by: Chris Wilson 
Signed-off-by: Dave Airlie 
Acked-by: Sumit Semwal 
Signed-off-by: Gustavo Padovan 
Link: http://patchwork.freedesktop.org/patch/msgid/20170413014144.637-2-airlied@gmail.com

dma-fence: Wrap querying the fence->status

2017-01-09T14:36:58+00:00

The fence->status is an optional field that is only valid once the fence
has been signaled. (Driver may fill the fence->status with an error code
prior to calling dma_fence_signal().) Given the restriction upon its
validity, wrap querying of the fence->status into a helper
dma_fence_get_status().

Signed-off-by: Chris Wilson 
Reviewed-by: Daniel Vetter 
Reviewed-by: Sumit Semwal 
Signed-off-by: Sumit Semwal 
Link: http://patchwork.freedesktop.org/patch/msgid/20170104141222.6992-2-chris@chris-wilson.co.uk

dma-buf: Reorganize device dma access docs

2016-12-13T11:39:51+00:00

- Put the initial overview for dma-buf into dma-buf.rst.
- Put all the comments about detailed semantics into the right
  kernel-doc comment for functions or ops structure member.
- To allow that detail, switch the reworked kerneldoc to inline style
  for dma_buf_ops.
- Tie everything together into a much more streamlined overview
  comment, relying on the hyperlinks for all the details.
- Also sprinkle some links into the kerneldoc for dma_buf and
  dma_buf_attachment to tie it all together.

Cc: linux-doc@vger.kernel.org
Cc: Jonathan Corbet 
Cc: Sumit Semwal 
Signed-off-by: Daniel Vetter 
Signed-off-by: Sumit Semwal 
Link: http://patchwork.freedesktop.org/patch/msgid/20161209185309.1682-4-daniel.vetter@ffwll.ch

dma-buf: Update kerneldoc for sync_file_create

2016-12-13T11:39:39+00:00

This was missed when adding a dma_fence_get call. While at it also
remove the kerneldoc for the static inline helper - no point
documenting internals down to every detail.

Fixes: 30cd85dd6edc ("dma-buf/sync_file: hold reference to fence when creating sync_file")
Cc: Gustavo Padovan 
Cc: Sean Paul 
Cc: linux-doc@vger.kernel.org
Cc: Jonathan Corbet 
Cc: Sumit Semwal 
Signed-off-by: Daniel Vetter 
Reviewed-by: Gustavo Padovan 
Signed-off-by: Sumit Semwal 
Link: http://patchwork.freedesktop.org/patch/msgid/20161209185309.1682-3-daniel.vetter@ffwll.ch

Revert "dma-buf/sync-file: Avoid enable fence signaling if poll(.timeout=0)"

2016-11-18T09:35:58+00:00

This reverts commit ecebca79f6976ddaddfd054d699272515869ea28.

Do not enable fence callback on poll() when using fence_array causes the
fence_array to not signal.

For now we will revert the change and enable signaling everytime time
poll is called with timeout=0 as well.

Cc: Chris Wilson 
Signed-off-by: Gustavo Padovan 
Acked-by: Chris Wilson 
Signed-off-by: Daniel Vetter 
Link: http://patchwork.freedesktop.org/patch/msgid/1479457603-30758-1-git-send-email-gustavo@padovan.org

dma-buf: Rename struct fence to dma_fence

2016-10-25T12:40:39+00:00

I plan to usurp the short name of struct fence for a core kernel struct,
and so I need to rename the specialised fence/timeline for DMA
operations to make room.

A consensus was reached in
https://lists.freedesktop.org/archives/dri-devel/2016-July/113083.html
that making clear this fence applies to DMA operations was a good thing.
Since then the patch has grown a bit as usage increases, so hopefully it
remains a good thing!

(v2...: rebase, rerun spatch)
v3: Compile on msm, spotted a manual fixup that I broke.
v4: Try again for msm, sorry Daniel

coccinelle script:
@@

@@
- struct fence
+ struct dma_fence
@@

@@
- struct fence_ops
+ struct dma_fence_ops
@@

@@
- struct fence_cb
+ struct dma_fence_cb
@@

@@
- struct fence_array
+ struct dma_fence_array
@@

@@
- enum fence_flag_bits
+ enum dma_fence_flag_bits
@@

@@
(
- fence_init
+ dma_fence_init
|
- fence_release
+ dma_fence_release
|
- fence_free
+ dma_fence_free
|
- fence_get
+ dma_fence_get
|
- fence_get_rcu
+ dma_fence_get_rcu
|
- fence_put
+ dma_fence_put
|
- fence_signal
+ dma_fence_signal
|
- fence_signal_locked
+ dma_fence_signal_locked
|
- fence_default_wait
+ dma_fence_default_wait
|
- fence_add_callback
+ dma_fence_add_callback
|
- fence_remove_callback
+ dma_fence_remove_callback
|
- fence_enable_sw_signaling
+ dma_fence_enable_sw_signaling
|
- fence_is_signaled_locked
+ dma_fence_is_signaled_locked
|
- fence_is_signaled
+ dma_fence_is_signaled
|
- fence_is_later
+ dma_fence_is_later
|
- fence_later
+ dma_fence_later
|
- fence_wait_timeout
+ dma_fence_wait_timeout
|
- fence_wait_any_timeout
+ dma_fence_wait_any_timeout
|
- fence_wait
+ dma_fence_wait
|
- fence_context_alloc
+ dma_fence_context_alloc
|
- fence_array_create
+ dma_fence_array_create
|
- to_fence_array
+ to_dma_fence_array
|
- fence_is_array
+ dma_fence_is_array
|
- trace_fence_emit
+ trace_dma_fence_emit
|
- FENCE_TRACE
+ DMA_FENCE_TRACE
|
- FENCE_WARN
+ DMA_FENCE_WARN
|
- FENCE_ERR
+ DMA_FENCE_ERR
)
 (
 ...
 )

Signed-off-by: Chris Wilson 
Reviewed-by: Gustavo Padovan 
Acked-by: Sumit Semwal 
Acked-by: Christian König 
Signed-off-by: Daniel Vetter 
Link: http://patchwork.freedesktop.org/patch/msgid/20161025120045.28839-1-chris@chris-wilson.co.uk