gpu: nvgpu: cancel clean up before update_fn_work

In gk20a_channel_suspend(), we first cancel worker
thread update_fn_work and then cancel job clean up worker

But it is possible that we re-schedule update_fn_work from
job cleanup worker after it was cancelled
And in that case worker update_fn_work might run after
we poweroff GPU

Fix this by first cancelling job clean up worker and
then update_fn_work worker

Bug 200187905

Change-Id: Ia192c515702f14becf60d92c6471d8c0e892551e
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/1120426
(cherry picked from commit b132b6c5aa9ab88c6733f36906f1b874114ec72d)
Reviewed-on: http://git-master/r/1134888
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
index d94e12a2..9e023e16 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
@@ -2778,11 +2778,10 @@ int gk20a_channel_suspend(struct gk20a *g)
                         g->ops.fifo.disable_channel(ch);
                         /* preempt the channel */
                         g->ops.fifo.preempt_channel(g, chid);
-                        /* wait for channel update notifiers */
-                        if (ch->update_fn &&
-                                        work_pending(&ch->update_fn_work))
-                                flush_work(&ch->update_fn_work);
                         gk20a_channel_cancel_job_clean_up(ch, true);
+                        /* wait for channel update notifiers */
+                        if (ch->update_fn)
+                                cancel_work_sync(&ch->update_fn_work);
 
                         channels_in_use = true;