[RFC PATCH v1 13/16] drm/nouveau: use rcu in nouveau_gem_ioctl_cpu_prep

[Maarten Lankhorst]

With the conversion to the reservation api this should be safe.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>
---
 drivers/gpu/drm/nouveau/nouveau_gem.c |   28 ++++++++++++----------------
 1 file changed, 12 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c 
b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 4beaa897adad..c2ca894f6507 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -863,33 +863,29 @@ 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);
+       bool write = !!(req->flags & NOUVEAU_GEM_CPU_PREP_WRITE);
        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);

-       ret = ttm_bo_reserve(&nvbo->bo, true, false, false, 0);
-       if (!ret) {
-               ret = ttm_bo_wait(&nvbo->bo, true, true, true);
-               if (!no_wait && ret) {
-                       struct fence *excl;
-
-                       excl = reservation_object_get_excl(nvbo->bo.resv);
-                       fence = nouveau_fence_ref((struct nouveau_fence *)excl);
-               }
+       if (no_wait)
+               ret = reservation_object_test_signaled_rcu(nvbo->bo.resv, 
write) ? 0 : -EBUSY;
+       else {
+               long lret;

-               ttm_bo_unreserve(&nvbo->bo);
+               lret = reservation_object_wait_timeout_rcu(nvbo->bo.resv, 
write, true, 30 * HZ);
+               if (!lret)
+                       ret = -EBUSY;
+               else if (lret > 0)
+                       ret = 0;
+               else
+                       ret = lret;
        }
        drm_gem_object_unreference_unlocked(gem);

-       if (fence) {
-               ret = nouveau_fence_wait(fence, true, no_wait);
-               nouveau_fence_unref(&fence);
-       }
-
        return ret;
 }