drm/nouveau: add reservation to nouveau_gem_ioctl_cpu_prep

Apart from some code inside ttm itself and nouveau_bo_vma_del,
this is the only place where ttm_bo_wait is used without a reservation.
Fix this so we can remove the fence_lock later on.

After the switch to rcu the reservation lock will be
removed again.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 18 insertions, 4 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 292a677bfed4..0054315eb879 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -884,17 +884,31 @@ nouveau_gem_ioctl_cpu_prep(struct drm_device *dev, void *data,
         struct drm_gem_object *gem;
         struct nouveau_bo *nvbo;
         bool no_wait = !!(req->flags & NOUVEAU_GEM_CPU_PREP_NOWAIT);
-        int ret = -EINVAL;
+        int ret;
+        struct nouveau_fence *fence = NULL;
 
         gem = drm_gem_object_lookup(dev, file_priv, req->handle);
         if (!gem)
                 return -ENOENT;
         nvbo = nouveau_gem_object(gem);
 
-        spin_lock(&nvbo->bo.bdev->fence_lock);
-        ret = ttm_bo_wait(&nvbo->bo, true, true, no_wait);
-        spin_unlock(&nvbo->bo.bdev->fence_lock);
+        ret = ttm_bo_reserve(&nvbo->bo, true, false, false, NULL);
+        if (!ret) {
+                spin_lock(&nvbo->bo.bdev->fence_lock);
+                ret = ttm_bo_wait(&nvbo->bo, true, true, true);
+                if (!no_wait && ret)
+                        fence = nouveau_fence_ref(nvbo->bo.sync_obj);
+                spin_unlock(&nvbo->bo.bdev->fence_lock);
+
+                ttm_bo_unreserve(&nvbo->bo);
+        }
         drm_gem_object_unreference_unlocked(gem);
+
+        if (fence) {
+                ret = nouveau_fence_wait(fence, true, no_wait);
+                nouveau_fence_unref(&fence);
+        }
+
         return ret;
 }