gpu: nvgpu: fix channel leak with immediate close

If a GPU channel is closed immediately after opening without
performing any operation on it, we leak that channel

e.g. below command leaks a channel
echo > /dev/nvhost-gpu

Fix this leak by releasing the channel before returning

Change-Id: I2598e3cabec6996cb1cf8066a1e6d7d5864ae02b
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/743235
(cherry picked from commit 428771509b4431ebe88e38061b495cabc5192327)
Reviewed-on: http://git-master/r/744279
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Sachin Nikam <snikam@nvidia.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
index 5691a7cd..f311a91a 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
@@ -577,7 +577,7 @@ void gk20a_free_channel(struct channel_gk20a *ch, bool finish)
         mutex_unlock(&f->deferred_reset_mutex);
 
         if (!ch->bound)
-                return;
+                goto release;
 
         if (!gk20a_channel_as_bound(ch))
                 goto unbind;
@@ -652,6 +652,7 @@ unbind:
 
         mutex_unlock(&ch->dbg_s_lock);
 
+release:
         /* ALWAYS last */
         release_used_channel(f, ch);
 }