linux-kernel - [RFC 0/5] rework fences on struct sync

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Date:	Thu, 23 Jun 2016 12:29:45 -0300
From:	Gustavo Padovan <gustavo@...ovan.org>
To:	dri-devel@...ts.freedesktop.org
Cc:	linux-kernel@...r.kernel.org, Daniel Stone <daniels@...labora.com>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Rob Clark <robdclark@...il.com>,
	Greg Hackmann <ghackmann@...gle.com>,
	John Harrison <John.C.Harrison@...el.com>,
	laurent.pinchart@...asonboard.com, seanpaul@...gle.com,
	marcheu@...gle.com, m.chehab@...sung.com,
	Sumit Semwal <sumit.semwal@...aro.org>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Gustavo Padovan <gustavo.padovan@...labora.co.uk>
Subject: [RFC 0/5] rework fences on struct sync_file

From: Gustavo Padovan <gustavo.padovan@...labora.co.uk>

Hi all,

This is an attempt to improve fence support on Sync File. The basic idea
is to have only sync_file->fence and store all fences there, either as
normal fences or fence_arrays. That way we can remove some potential
duplication when using fence_array with sync_file: the duplication of the array
of fences and the duplication of fence_add_callback() for all fences. 

Now when creating a new sync_file during the merge process sync_file_set_fence()
will set sync_file->fence based on the number of fences for that sync_file. If
there is more than one fence a fence_array is created. One important advantage
approach is that we only add one fence callback now, no matter how many fences
there are in a sync_file - the individual callbacks are added by fence_array.

Two fence ops had to be created to help abstract the difference between handling
fences and fences_arrays: .teardown() and .get_fences(). The former run needed
on fence_array, and the latter just return a copy of all fences in the fence.
I'm not so sure about adding those two, speacially .get_fences(). What do you
think?

Please comment! Thanks.

	Gustavo
---

Gustavo Padovan (5):
  dma-buf/fence: add .teardown() ops
  dma-buf/fence-array: add fence_array_teardown()
  dma-buf/fence: add .get_fences() ops
  dma-buf/fence-array: add fence_array_get_fences()
  dma-buf/sync_file: rework fence storage in struct file

 drivers/dma-buf/fence-array.c        |  30 ++++++++
 drivers/dma-buf/fence.c              |  21 ++++++
 drivers/dma-buf/sync_file.c          | 129 +++++++++++++++++++++++++----------
 drivers/staging/android/sync_debug.c |   5 +-
 include/linux/fence.h                |  10 +++
 include/linux/sync_file.h            |  12 ++--
 6 files changed, 161 insertions(+), 46 deletions(-)

-- 
2.5.5