gpu: nvgpu: channel_worker_enqueue: warn to info

gk20a_channel_worker_enqueue currently WARNS if the call to gk20a_channel_get
fails. But in fact a failure here is legitimate, in particular if the channel
is in the process of being freed, and the referenceable flag changed between
the time the caller grabbed a reference to the channel and the time this
function tries to grab its own reference.

Instead, turn the warning into an info message.

Bug 200329971

Change-Id: Iab4ca6b32bb98f42f05b12b7971538db962b9795
Signed-off-by: Peter Daifuku <pdaifuku@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1540458
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
index d96872f3..5f81b441 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
@@ -1903,10 +1903,13 @@ static void gk20a_channel_worker_enqueue(struct channel_gk20a *ch)
 
         /*
          * Ref released when this item gets processed. The caller should hold
-         * one ref already, so can't fail.
+         * one ref already, so normally shouldn't fail, but the channel could
+         * end up being freed between the time the caller got its reference and
+         * the time we end up here (e.g., if the client got killed); if so, just
+         * return.
          */
-        if (WARN_ON(!gk20a_channel_get(ch))) {
-                nvgpu_warn(g, "cannot get ch ref for worker!");
+        if (!gk20a_channel_get(ch)) {
+                nvgpu_info(g, "cannot get ch ref for worker!");
                 return;
         }