sync_file_ioctl_fence_info has a race between filling the status
of the underlying fences and the overall status of the sync_file.
If fence transitions in the time frame between its sync_fill_fence_info
and the later dma_fence_is_signaled for the sync_file, the returned
information is inconsistent showing non-signaled underlying fences but
an overall signaled state.
This patch changes sync_file_ioctl_fence_info to track what has been
encoded and using that as the overall sync_file status.
Tested-by: Vamsidhar Reddy Gaddam <vamsidhar.gaddam@arm.com>
Signed-off-by: John Einar Reitan <john.reitan@arm.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171009134936.27219-1-john.reitan@arm.com
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 e241655373
("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 <gustavo.padovan@collabora.com>
Fixes: f1e8c67123 ("dma-buf/sw-sync: Use an rbtree to sort fences in the timeline")
Fixes: e9083420bb ("drm: introduce sync objects (v4)")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: dri-devel@lists.freedesktop.org
Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.13-rc1+
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170728212951.7818-1-chris@chris-wilson.co.uk
(cherry picked from commit db1fc97ca0)
Pick up
1ed134e652 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.
[ 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:[<ffffffff81396f07>] [<ffffffff81396f07>] 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] [<ffffffff8130d1ad>] i915_gem_request_retire+0x1cd/0x230
[ 236.902439] [<ffffffff8130e2b3>] i915_gem_request_alloc+0xa3/0x2f0
[ 236.906435] [<ffffffff812fb1bd>] i915_gem_do_execbuffer.isra.41+0xb6d/0x18b0
[ 236.910434] [<ffffffff812fc265>] i915_gem_execbuffer2+0x95/0x1e0
[ 236.914390] [<ffffffff812ad625>] drm_ioctl+0x1e5/0x460
[ 236.918275] [<ffffffff8110d4cf>] do_vfs_ioctl+0x8f/0x5c0
[ 236.922168] [<ffffffff8110da3c>] SyS_ioctl+0x3c/0x70
[ 236.926090] [<ffffffff814b7a5f>] entry_SYSCALL_64_fastpath+0x17/0x93
[ 236.930045] [<ffffffffffffffff>] 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 <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Reported-by: Rafael Antognolli <rafael.antognolli@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170214124001.1930-1-chris@chris-wilson.co.uk
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 <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170516111042.24719-1-chris@chris-wilson.co.uk
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 <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170413014144.637-2-airlied@gmail.com
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 <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170104141222.6992-2-chris@chris-wilson.co.uk
- 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 <corbet@lwn.net>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20161209185309.1682-4-daniel.vetter@ffwll.ch
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: 30cd85dd6e ("dma-buf/sync_file: hold reference to fence when creating sync_file")
Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: linux-doc@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20161209185309.1682-3-daniel.vetter@ffwll.ch
This reverts commit ecebca79f6.
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 <chris@chris-wilson.co.uk>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1479457603-30758-1-git-send-email-gustavo@padovan.org
fence referencing was out of balance. It was not taking any ref to the
fence at creating time, but it was putting a reference when freeing the
sync file.
This patch fixes the balancing issue by getting a reference for the fence
when creating the sync_file.
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1476899313-22241-1-git-send-email-gustavo@padovan.org
When merging sync_files there is a case when we can end up with only one
fence in the merged sync_file: when all fences belong to the same
timeline.
So for this case a fence_array is not created instead we just assigned the
fence to sync_file->fence. Then we do not use the fences array anymore nor
does free it.
This patch frees the array.
Reported-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1474442419-6040-1-git-send-email-gustavo@padovan.org
When we merge several fences, if all of them are signaled already, we
still keep one of them. So instead of using add_fence(), which will not
increase the refcount of signaled fences, we should explicitly call
fence_get() for the fence we are keeping.
This patch fixes a kernel panic that can be triggered by creating a fence
that is expired (or increasing the timeline until it expires), then
creating a merged fence out of it, and deleting the merged fence. This
will make the original expired fence's refcount go to zero.
Testcase: igt/sw_sync/sync_expired_merge
Signed-off-by: Rafael Antognolli <rafael.antognolli@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1473966865-4508-1-git-send-email-rafael.antognolli@intel.com
If we being polled with a timeout of zero, a nonblocking busy query,
we don't need to install any fence callbacks as we will not be waiting.
As we only install the callback once, the overhead comes from the atomic
bit test that also causes serialisation between threads.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20160829181613.30722-1-chris@chris-wilson.co.uk
Signalling doesn't need to be enabled at sync_file creation, it is only
required if userspace waiting the fence to signal through poll().
Thus we delay fence_add_callback() until poll is called. It only adds the
callback the first time poll() is called. This avoid re-adding the same
callback multiple times.
v2: rebase and update to work with new fence support for sync_file
v3: use atomic operation to set enabled and protect fence_add_callback()
v4: use user bit from fence flags (comment from Chris Wilson)
v5: use ternary if on poll return (comment from Chris Wilson)
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
[sumits: remove unused var status]
Link: http://patchwork.freedesktop.org/patch/msgid/1470404378-27961-1-git-send-email-gustavo@padovan.org
Creates a function that given an sync file descriptor returns a
fence containing all fences in the sync_file.
v2: Comments by Daniel Vetter
- Adapt to new version of fence_collection_init()
- Hold a reference for the fence we return
v3:
- Adapt to use fput() directly
- rename to sync_file_get_fence() as we always return one fence
v4: Adapt to use fence_array
v5: set fence through fence_get()
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Create sync_file->fence to abstract the type of fence we are using for
each sync_file. If only one fence is present we use a normal struct fence
but if there is more fences to be added to the sync_file a fence_array
is created.
This change cleans up sync_file a bit. We don't need to have sync_file_cb
array anymore. Instead, as we always have one fence, only one fence
callback is registered per sync_file.
v2: Comments from Chris Wilson and Christian König
- Not using fence_ops anymore
- fence_is_array() was created to differentiate fence from fence_array
- fence_array_teardown() is now exported and used under fence_is_array()
- struct sync_file lost num_fences member
v3: Comments from Chris Wilson and Christian König
- struct sync_file lost status member in favor of fence_is_signaled()
- drop use of fence_array_teardown()
- use sizeof(*fence) to allocate only an array on fence pointers
v4: Comments from Chris Wilson
- use sizeof(*fence) to reallocate array
- fix typo in comments
- protect num_fences sum against overflows
- use array->base instead of casting the to struct fence
v5: fixes checkpatch warnings
v6: fix case where all fences are signaled.
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
sync_file is useful to connect one or more fences to the file. The file is
used by userspace to track fences between drivers that share DMA bufs.
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
John Einar Reitan