gpu: nvgpu: tsg: ensure unbound channel is disabled

Multiple threads could be unbinding different channels from
the same tsg at the same time. At the point where we
remove the channel from the tsg's channel list, call
disable_channel again, in case another thread had
re-enabled the channel after we had disabled it.

Bug 200404549

Change-Id: I9abbc08dc11fe1f7a0abada88376c0ef96b56610
Signed-off-by: Peter Daifuku <pdaifuku@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2083337
GVS: Gerrit_Virtual_Submit
Reviewed-by: Alex Waterman <alexw@nvidia.com>
Reviewed-by: Satish Arora <satisha@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
index f4b96b7a..a1844a28 100644
--- a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
@@ -1,7 +1,7 @@
 /*
  * GK20A Graphics FIFO (gr host)
  *
- * Copyright (c) 2011-2018, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2011-2019, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -2193,6 +2193,11 @@ int gk20a_fifo_tsg_unbind_channel(struct channel_gk20a *ch)
         nvgpu_rwsem_down_write(&tsg->ch_list_lock);
         nvgpu_list_del(&ch->ch_entry);
         ch->tsgid = NVGPU_INVALID_TSG_ID;
+
+        /* another thread could have re-enabled the channel because it was
+         * still on the list at that time, so make sure it's truly disabled
+         */
+        g->ops.fifo.disable_channel(ch);
         nvgpu_rwsem_up_write(&tsg->ch_list_lock);
 
         /*