[media] vb2: add in-fence support to QBUF

[media] vb2: add in-fence support to QBUF

Receive in-fence from userspace and add support for waiting on them
before queueing the buffer to the driver. Buffers can't be queued to the
driver before its fences signal. And a buffer can't be queue to the
driver
out of the order they were queued from userspace. That means that even
if
it fence signal it must wait all other buffers, ahead of it in the
queue,
to signal first.

If the fence for some buffer fails we do not queue it to the driver,
instead we mark it as error and wait until the previous buffer is done
to notify userspace of the error. We wait here to deliver the buffers
back
to userspace in order.

v9:	- rename fence to in_fence in many places
	- handle fences signalling with error better (Hans Verkuil)

v8:	- improve comments and docs (Hans Verkuil)
	- fix unlocking of vb->fence_cb_lock on vb2_core_qbuf (Hans
	  Verkuil)
	- move in-fences code that was in the out-fences patch here
	  (Alex)

v8:	- improve comments about fences with errors

v7:
	- get rid of the fence array stuff for ordering and just use
	get_num_buffers_ready() (Hans)
	- fix issue of queuing the buffer twice (Hans)
	- avoid the dma_fence_wait() in core_qbuf() (Alex)
	- merge preparation commit in

v6:
	- With fences always keep the order userspace queues the
	  buffers.
	- Protect in_fence manipulation with a lock (Brian Starkey)
	- check if fences have the same context before adding a fence
	  array
	- Fix last_fence ref unbalance in __set_in_fence() (Brian
	  Starkey)
	- Clean up fence if __set_in_fence() fails (Brian Starkey)
	- treat -EINVAL from dma_fence_add_callback() (Brian Starkey)

v5:	- use fence_array to keep buffers ordered in vb2 core when
	needed (Brian Starkey)
	- keep backward compat on the reserved2 field (Brian Starkey)
	- protect fence callback removal with lock (Brian Starkey)

v4:
	- Add a comment about dma_fence_add_callback() not returning a
	error (Hans)
	- Call dma_fence_put(vb->in_fence) if fence signaled (Hans)
	- select SYNC_FILE under config VIDEOBUF2_CORE (Hans)
	- Move dma_fence_is_signaled() check to __enqueue_in_driver()
	  (Hans)
	- Remove list_for_each_entry() in __vb2_core_qbuf() (Hans)
	-  Remove if (vb->state != VB2_BUF_STATE_QUEUED) from
	vb2_start_streaming() (Hans)
	- set IN_FENCE flags on __fill_v4l2_buffer (Hans)
	- Queue buffers to the driver as soon as they are ready (Hans)
	- call fill_user_buffer() after queuing the buffer (Hans)
	- add err: label to clean up fence
	- add dma_fence_wait() before calling vb2_start_streaming()

v3:	- document fence parameter
	- remove ternary if at vb2_qbuf() return (Mauro)
	- do not change if conditions behaviour (Mauro)

v2:
	- fix vb2_queue_or_prepare_buf() ret check
	- remove check for VB2_MEMORY_DMABUF only (Javier)
	- check num of ready buffers to start streaming
	- when queueing, start from the first ready buffer
	- handle queue cancel

Change-Id: I2c45f8f98e7d3a3026286e25934e64d0bebfc4f4
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Signed-off-by: Janghyuck Kim <janghyuck.kim@samsung.com>