[PATCH 0/2] dma-buf/sync_file: rework fences on struct sync_file

From: Gustavo Padovan
Date: Thu Jun 30 2016 - 11:19:43 EST


From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>

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.

Please review! Thanks!

Gustavo

Changes since RFC v2 (Comments from Chris Wilson and Christian KÃnig):
- 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

Changes since RFC v1 (Comments from Chris Wilson and Christian KÃnig):
- 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

Gustavo Padovan (2):
dma-buf/fence-array: add fence_is_array()
dma-buf/sync_file: rework fence storage in struct file

drivers/dma-buf/sync_file.c | 163 ++++++++++++++++++++++-------------
drivers/staging/android/sync_debug.c | 13 ++-
include/linux/fence-array.h | 10 +++
include/linux/sync_file.h | 17 ++--
4 files changed, 128 insertions(+), 75 deletions(-)

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