gpu: nvgpu: Fix semaphore refcounting

This patch fixes a refcounting issue in semaphore handling.

Change-Id: I03327c60ed6923a90663f0b845566e81af4b94d4
Signed-off-by: Arto Merilainen <amerilainen@nvidia.com>
Reviewed-on: http://git-master/r/453056
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

2 files changed, 5 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_sync_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_sync_gk20a.c
index 4d366fa9..ef9e3a37 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_sync_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_sync_gk20a.c
@@ -458,6 +458,9 @@ static int gk20a_channel_semaphore_wait_fd(
                 goto fail;
         }
 
+        /* worker takes one reference */
+        gk20a_semaphore_get(w->sema);
+
         gk20a_channel_alloc_priv_cmdbuf(c, 8, &wait_cmd);
         if (wait_cmd == NULL) {
                 gk20a_err(dev_from_gk20a(c->g),
diff --git a/drivers/gpu/nvgpu/gk20a/fence_gk20a.c b/drivers/gpu/nvgpu/gk20a/fence_gk20a.c
index 1a28e660..3b1f1024 100644
--- a/drivers/gpu/nvgpu/gk20a/fence_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/fence_gk20a.c
@@ -139,6 +139,7 @@ static const struct gk20a_fence_ops gk20a_semaphore_fence_ops = {
         .is_expired = &gk20a_semaphore_fence_is_expired,
 };
 
+/* This function takes ownership of the semaphore */
 struct gk20a_fence *gk20a_fence_from_semaphore(
                 struct sync_timeline *timeline,
                 struct gk20a_semaphore *semaphore,
@@ -163,7 +164,7 @@ struct gk20a_fence *gk20a_fence_from_semaphore(
 #endif
                 return NULL;
         }
-        gk20a_semaphore_get(semaphore);
+
         f->semaphore = semaphore;
         f->semaphore_wq = semaphore_wq;
         return f;