drm/syncobj: use dma_fence_get_stub

Extract of useful code from the timeline work. Let's use just a single
stub fence instance instead of allocating a new one all the time.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Link: https://patchwork.freedesktop.org/patch/265248/

1 files changed, 14 insertions, 44 deletions

diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index e2c5b3ca4824..5c5ba1f14307 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -56,22 +56,6 @@
 #include "drm_internal.h"
 #include <drm/drm_syncobj.h>
 
-struct drm_syncobj_stub_fence {
-        struct dma_fence base;
-        spinlock_t lock;
-};
-
-static const char *drm_syncobj_stub_fence_get_name(struct dma_fence *fence)
-{
-        return "syncobjstub";
-}
-
-static const struct dma_fence_ops drm_syncobj_stub_fence_ops = {
-        .get_driver_name = drm_syncobj_stub_fence_get_name,
-        .get_timeline_name = drm_syncobj_stub_fence_get_name,
-};
-
-
 /**
  * drm_syncobj_find - lookup and reference a sync object.
  * @file_private: drm file private pointer
@@ -190,23 +174,18 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
 }
 EXPORT_SYMBOL(drm_syncobj_replace_fence);
 
-static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
+/**
+ * drm_syncobj_assign_null_handle - assign a stub fence to the sync object
+ * @syncobj: sync object to assign the fence on
+ *
+ * Assign a already signaled stub fence to the sync object.
+ */
+static void drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
 {
-        struct drm_syncobj_stub_fence *fence;
-        fence = kzalloc(sizeof(*fence), GFP_KERNEL);
-        if (fence == NULL)
-                return -ENOMEM;
+        struct dma_fence *fence = dma_fence_get_stub();
 
-        spin_lock_init(&fence->lock);
-        dma_fence_init(&fence->base, &drm_syncobj_stub_fence_ops,
-                       &fence->lock, 0, 0);
-        dma_fence_signal(&fence->base);
-
-        drm_syncobj_replace_fence(syncobj, 0, &fence->base);
-
-        dma_fence_put(&fence->base);
-
-        return 0;
+        drm_syncobj_replace_fence(syncobj, 0, fence);
+        dma_fence_put(fence);
 }
 
 /**
@@ -274,7 +253,6 @@ EXPORT_SYMBOL(drm_syncobj_free);
 int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
                        struct dma_fence *fence)
 {
-        int ret;
         struct drm_syncobj *syncobj;
 
         syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL);
@@ -285,13 +263,8 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
         INIT_LIST_HEAD(&syncobj->cb_list);
         spin_lock_init(&syncobj->lock);
 
-        if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) {
-                ret = drm_syncobj_assign_null_handle(syncobj);
-                if (ret < 0) {
-                        drm_syncobj_put(syncobj);
-                        return ret;
-                }
-        }
+        if (flags & DRM_SYNCOBJ_CREATE_SIGNALED)
+                drm_syncobj_assign_null_handle(syncobj);
 
         if (fence)
                 drm_syncobj_replace_fence(syncobj, 0, fence);
@@ -982,11 +955,8 @@ drm_syncobj_signal_ioctl(struct drm_device *dev, void *data,
         if (ret < 0)
                 return ret;
 
-        for (i = 0; i < args->count_handles; i++) {
-                ret = drm_syncobj_assign_null_handle(syncobjs[i]);
-                if (ret < 0)
-                        break;
-        }
+        for (i = 0; i < args->count_handles; i++)
+                drm_syncobj_assign_null_handle(syncobjs[i]);
 
         drm_syncobj_array_free(syncobjs, args->count_handles);