gpu: nvgpu: Optimize sync fence creation

Only create sync-fences in the semaphore synchronization path
when they are actually needed (i.e requested by userspace).

Bug 1795076

Reviewed-on: http://git-master/r/1201564
(cherry picked from commit dc52d424a839e6c064c02b7f02905dd6a59a50af)
Change-Id: Ieac6aef415678d4ea982683a955897c64959436e
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/1221041
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/fence_gk20a.c b/drivers/gpu/nvgpu/gk20a/fence_gk20a.c
index fbbaa2a7..596dc549 100644
--- a/drivers/gpu/nvgpu/gk20a/fence_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/fence_gk20a.c
@@ -148,17 +148,19 @@ struct gk20a_fence *gk20a_fence_from_semaphore(
                 struct gk20a_semaphore *semaphore,
                 wait_queue_head_t *semaphore_wq,
                 struct sync_fence *dependency,
-                bool wfi)
+                bool wfi, bool need_sync_fence)
 {
         struct gk20a_fence *f;
         struct sync_fence *sync_fence = NULL;
 
 #ifdef CONFIG_SYNC
-        sync_fence = gk20a_sync_fence_create(timeline, semaphore,
+        if (need_sync_fence) {
+                sync_fence = gk20a_sync_fence_create(timeline, semaphore,
                                         dependency, "f-gk20a-0x%04x",
                                         gk20a_semaphore_gpu_ro_va(semaphore));
-        if (!sync_fence)
-                return NULL;
+                if (!sync_fence)
+                        return NULL;
+        }
 #endif
 
         f  = gk20a_alloc_fence(&gk20a_semaphore_fence_ops, sync_fence, wfi);