sync: allow async waits to be canceled

In order to allow drivers to cleanly handled teardown we need to allow them
to cancel pending async waits.  To do this cleanly, we move allocation of
sync_fence_waiter to the driver calling sync_async_wait().

Change-Id: Ifcd95648be6ec07026d67f810070a4310f099989
Signed-off-by: Erik Gilling <konkers@android.com>
sync: export sync API symbols

This is needed to allow modules to link against the sync subsystem

Change-Id: I15c1818de329f24e4113ef1d0923413b22fd0eff
Signed-off-by: Erik Gilling <konkers@android.com>
sync: reorder sync_fence_release

Previously fence's pts were freed before the were the fence was removed from the
global fence list.  This led to a race with the debugfs support where it would
iterate over sync_pts that had been freed.

Change-Id: Ia3ddbf77de42ca593fc2dc353b5d04e42ddf3946
Signed-off-by: Erik Gilling <konkers@android.com>
sync: optimize fence merges

If the two fences being merged contain sync_pts from the same timeline,
those two pts will be collapsed into a single pt representing the latter
of the two.

Change-Id: Iced7ebb7e5a17a0c8b1a2969ba3388a4edb9ecaf
Signed-off-by: Erik Gilling <konkers@android.com>
sync: add internal refcounting to fences

If a fence is released while a timeline that one of it's pts is on is being
signaled, it is possible for that fence to be deleted before it is signaled.
This patch adds a refcount for internal references such as signaled pt
processing.

Change-Id: Ie8605e6fd2ac026c207220a03d84e1c1078ec719
Signed-off-by: Erik Gilling <konkers@android.com>
sync: add reference counting to timelines

If a timeline is destroyed while fences still hold pts on it, the reworked
fence release handler can cause the timeline to be freed before all it's points
are freed.

Change-Id: I1cd8ddb638eded7db9db446ff6b37f3dd165d6c4
Signed-off-by: Erik Gilling <konkers@android.com>
sync: Fix error paths

Check the return value of get_unused_fd to make sure a valid
file descriptor is returned.

Make sure to call put_unused_fd even if an error occurs before
the fd can be used.

Change-Id: I0fe8f78d9e30ecfc4d271c5d875424543dae2d0f
Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
sync: change wait timeout to mirror poll semantics

Change-Id: Ib38e6d339d41885a33027752690d65a52b6897f6
Signed-off-by: Erik Gilling <konkers@android.com>
sync: fix erase-o in sync_fence_wait

Change-Id: I189707cf658a9f1f2943515c891b43961994e774
Signed-off-by: Erik Gilling <konkers@android.com>
sync: clean up compiler warnings

Change-Id: I8a2ec5db652c61fd04571402067b37273b91e78f
Signed-off-by: Erik Gilling <konkers@android.com>
sync: dump sync state to console on timeout

Change-Id: I74bca6b4a2afa7ed5b1f5233c5165d2edddf269a
Signed-off-by: Erik Gilling <konkers@android.com>
sync: use correct signed type when handling SYNC_IOC_WAIT

Change-Id: Ic7d5adf9b145765e52b23186b8c3c793ccf29be7
Signed-off-by: Erik Gilling <konkers@android.com>
sync: improve timeout dumps

Change-Id: I3b378d63c324c7b5862dd214f380b5e91131cc2a
Signed-off-by: Erik Gilling <konkers@android.com>
sync: dump sync state of fence errors

Change-Id: I297a43aadf83504993040ea875c7f22d988628f1
Signed-off-by: Erik Gilling <konkers@android.com>
sync: protect unlocked access to fence status

Fence status is checked outside of locks in both sync_fence_wait and
sync_fence_poll.  This patch adds propper barrier protection in these
cases to avoid seeing stale status.

Change-Id: I9d8b6ce6accb415e797df58068a1ccd54e6be445
Signed-off-by: Erik Gilling <konkers@android.com>