gpu: nvgpu: cde: wait for ctx deletion before get

Wait for possible temp context deletion to finish properly before
passing contexts around later, to prevent situations where the context
deleter scheduling would have been completed, but running it would not,
and a new one could have been scheduled again. When finished, schedule
the deleter before freeing the context back to use to prevent races.

Warn in impossible situations when these double deletions would happen.

Bug 200054186
Bug 200052943

Change-Id: I23ca0d1081eea77d0e453b9038adc914909b5f48
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/603439
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/cde_gk20a.c b/drivers/gpu/nvgpu/gk20a/cde_gk20a.c
index 24c28029..f4ddc02e 100644
--- a/drivers/gpu/nvgpu/gk20a/cde_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/cde_gk20a.c
@@ -816,7 +816,9 @@ __releases(&cde_app->mutex)
                                 cde_ctx);
                 goto out;
         }
-        cde_ctx->in_use = true;
+
+        WARN(delayed_work_pending(&cde_ctx->ctx_deleter_work),
+                        "double pending %p", cde_ctx);
 
         gk20a_cde_remove_ctx(cde_ctx);
         gk20a_dbg(gpu_dbg_fn | gpu_dbg_cde_ctx,
@@ -858,8 +860,7 @@ __must_hold(&cde_app->mutex)
                 cde_app->ctx_usecount++;
 
                 /* cancel any deletions now that ctx is in use */
-                if (delayed_work_pending(&cde_ctx->ctx_deleter_work))
-                        gk20a_cde_cancel_deleter(cde_ctx, false);
+                gk20a_cde_cancel_deleter(cde_ctx, true);
                 return cde_ctx;
         }
 
@@ -1108,14 +1109,17 @@ __releases(&cde_app->mutex)
                         }
                         mutex_unlock(&cde_app->mutex);
                 }
-        } else {
-                gk20a_cde_ctx_release(cde_ctx);
         }
 
         /* delete temporary contexts later */
-        if (cde_ctx->is_temporary)
+        if (cde_ctx->is_temporary) {
+                WARN_ON(delayed_work_pending(&cde_ctx->ctx_deleter_work));
                 schedule_delayed_work(&cde_ctx->ctx_deleter_work,
                         msecs_to_jiffies(CTX_DELETE_TIME));
+        }
+
+        if (!ch->has_timedout)
+                gk20a_cde_ctx_release(cde_ctx);
 }
 
 static int gk20a_cde_load(struct gk20a_cde_ctx *cde_ctx)