gpu: nvgpu: cde: cancel ctx deleter when using it

Cancel the temporary context deleter work when acquiring a channel for
use, to prevent re-scheduling when the same context would be quickly
re-used and finished twice or more in a row before deletion.

Change-Id: Iadd8230d9462adc451e506152a24c50a920a59e3
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: http://git-master/r/600273
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 14 insertions, 7 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/cde_gk20a.c b/drivers/gpu/nvgpu/gk20a/cde_gk20a.c
index cb8f1c1e..c4793335 100644
--- a/drivers/gpu/nvgpu/gk20a/cde_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/cde_gk20a.c
@@ -91,7 +91,7 @@ __must_hold(&cde_app->mutex)
         kfree(cde_ctx);
 }
 
-static void gk20a_cde_prepare_ctx_remove(struct gk20a_cde_ctx *cde_ctx)
+static void gk20a_cde_cancel_deleter(struct gk20a_cde_ctx *cde_ctx)
 __releases(&cde_app->mutex)
 __acquires(&cde_app->mutex)
 {
@@ -101,14 +101,12 @@ __acquires(&cde_app->mutex)
         if (!cde_ctx->is_temporary)
                 return;
 
-        /* safe to go off the mutex since app is deinitialised. deleter works
-         * may be only at waiting for the mutex or before, going to abort */
         mutex_unlock(&cde_app->mutex);
 
         /* the deleter can rearm itself */
-        do {
+        while (delayed_work_pending(&cde_ctx->ctx_deleter_work)) {
                 cancel_delayed_work_sync(&cde_ctx->ctx_deleter_work);
-        } while (delayed_work_pending(&cde_ctx->ctx_deleter_work));
+        }
 
         mutex_lock(&cde_app->mutex);
 }
@@ -119,15 +117,19 @@ __must_hold(&cde_app->mutex)
         struct gk20a_cde_app *cde_app = &g->cde_app;
         struct gk20a_cde_ctx *cde_ctx, *cde_ctx_save;
 
+        /* safe to go off the mutex in cancel_deleter since app is
+         * deinitialised; no new jobs are started. deleter works may be only at
+         * waiting for the mutex or before, going to abort */
+
         list_for_each_entry_safe(cde_ctx, cde_ctx_save,
                         &cde_app->free_contexts, list) {
-                gk20a_cde_prepare_ctx_remove(cde_ctx);
+                gk20a_cde_cancel_deleter(cde_ctx);
                 gk20a_cde_remove_ctx(cde_ctx);
         }
 
         list_for_each_entry_safe(cde_ctx, cde_ctx_save,
                         &cde_app->used_contexts, list) {
-                gk20a_cde_prepare_ctx_remove(cde_ctx);
+                gk20a_cde_cancel_deleter(cde_ctx);
                 gk20a_cde_remove_ctx(cde_ctx);
         }
 }
@@ -799,10 +801,15 @@ __must_hold(&cde_app->mutex)
                                 cde_ctx, cde_app->ctx_count,
                                 cde_app->ctx_usecount,
                                 cde_app->ctx_count_top);
+
                 /* deleter work may be scheduled, but in_use prevents it */
                 cde_ctx->in_use = true;
                 list_move(&cde_ctx->list, &cde_app->used_contexts);
                 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);
                 return cde_ctx;
         }