On Tue, Mar 14, 2017 at 10:13:37AM +0100, Christian König wrote:
Am 14.03.2017 um 09:45 schrieb Daniel Vetter:
On Tue, Mar 14, 2017 at 10:50:51AM +1000, Dave Airlie wrote:
From: Dave Airlie airlied@redhat.com
This isn't needed currently, but to reuse sync file for Vulkan permanent shared semaphore semantics, we need to be able to swap the fence backing a sync file. This patch adds a mutex to the sync file and uses to protect accesses to the fence and cb members.
Signed-off-by: Dave Airlie airlied@redhat.com
We've gone to pretty great lengths to rcu-protect all the fence stuff, so that a peek-only is entirely lockless. Can we haz the same for this pls?
Yes, just wanted to suggest the same thing.
Basically you just need the following to retrieve the fence:
while (sync_file->fence && !(fence = fence_get_rcu(sync_file->fence));
We even have a helper for that:
fence = dma_fence_get_rcu_safe(&sync_file->fence);
(Still going to suggest using a reservation_object rather than an exclusive-only implementation.) -Chris