gpu: nvgpu: Greatly simplify the semaphore detection

Greatly simplify and make more robust the gpu semaphore detection
in sync_fences. Instead of using a magic number use the parent
timeline of sync_pts.

This will also work with multi-GPU setups using nvgpu since the
timeline ops pointer will be the same across all instances of
nvgpu.

Bug 1732449

Reviewed-on: http://git-master/r/1203834
(cherry picked from commit 66eeb577eae5d10741fd15f3659e843c70792cd6)
Change-Id: I4c6619d70b5531e2676e18d1330724e8f8b9bcb3
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/1221042
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 1 insertions, 18 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_sync_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_sync_gk20a.c
index 98363c88..0eff4e2f 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_sync_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_sync_gk20a.c
@@ -510,24 +510,7 @@ static int gk20a_channel_semaphore_wait_syncpt(
         return -ENODEV;
 }
 
-/*
- * UGHHH - the sync_fence underlying implementation changes from 3.10 to 3.18.
- * But since there's no API for getting the underlying sync_pts we have to do
- * some conditional compilation.
- */
 #ifdef CONFIG_SYNC
-static struct gk20a_semaphore *sema_from_sync_fence(struct sync_fence *f)
-{
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3,18,0)
-        struct sync_pt *pt;
-
-        pt = list_first_entry(&f->pt_list_head, struct sync_pt, pt_list);
-        return gk20a_sync_pt_inst_get_sema(pt);
-#else
-        return gk20a_sync_pt_inst_get_sema(f->cbs[0].sync_pt);
-#endif
-}
-
 /*
  * Attempt a fast path for waiting on a sync_fence. Basically if the passed
  * sync_fence is backed by a gk20a_semaphore then there's no reason to go
@@ -551,7 +534,7 @@ static int __semaphore_wait_fd_fast_path(struct channel_gk20a *c,
         if (!gk20a_is_sema_backed_sync_fence(fence))
                 return -ENODEV;
 
-        sema = sema_from_sync_fence(fence);
+        sema = gk20a_sync_fence_get_sema(fence);
 
         /*
          * If there's no underlying sema then that means the underlying sema has