gpu: nvgpu: fix TSG leak from CDE code

In gk20a_cde_remove_ctx(), we unbind the channel from TSG and
close the channel. But we do not drop the TSG refcount leaking
the TSG reference

After allocating sufficient contexts, we see TSG creation fails as below
nvgpu: 17000000.gp10b: gk20a_cde_load:1286 [ERR]  cde: could not create TSG

Fix this by explicitly dropping TSG refcount

Also, do not explicitly unbind the channel from TSG
gk20a_channel_close() will internally unbind the channel from TSG

Bug 200374011

Change-Id: If6d75b20d5e03d710c0597d7a320d1157206a2a5
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1627116
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/cde.c b/drivers/gpu/nvgpu/common/linux/cde.c
index 02ee27bc..5f0dfb0b 100644
--- a/drivers/gpu/nvgpu/common/linux/cde.c
+++ b/drivers/gpu/nvgpu/common/linux/cde.c
@@ -106,12 +106,12 @@ __must_hold(&cde_app->mutex)
         nvgpu_gmmu_unmap(vm, &g->gr.compbit_store.mem,
                          cde_ctx->backing_store_vaddr);
 
-        /* free the channel */
-        if (cde_ctx->tsg && ch) {
-                gk20a_tsg_unbind_channel(cde_ctx->ch);
-        }
-
+        /*
+         * free the channel
+         * gk20a_channel_close() will also unbind the channel from TSG
+         */
         gk20a_channel_close(ch);
+        nvgpu_ref_put(&cde_ctx->tsg->refcount, gk20a_tsg_release);
 
         /* housekeeping on app */
         nvgpu_list_del(&cde_ctx->list);