[PATCH 5/6] drm/nouveau: use ttm_bo_reserve_slowpath in validate_init

[Maarten Lankhorst]

Similar rationale to the identical commit in drm/ttm.
Instead of only waiting for unreservation, we make sure we actually
own the reservation, then retry to get the rest.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>
---
 drivers/gpu/drm/nouveau/nouveau_gem.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c 
b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 7b9364b..6f58604 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -321,6 +321,7 @@ validate_init(struct nouveau_channel *chan, struct drm_file 
*file_priv,
        uint32_t sequence;
        int trycnt = 0;
        int ret, i;
+       struct nouveau_bo *res_bo = NULL;

        sequence = atomic_add_return(1, &drm->ttm.validate_sequence);
 retry:
@@ -341,6 +342,11 @@ retry:
                        return -ENOENT;
                }
                nvbo = gem->driver_private;
+               if (nvbo == res_bo) {
+                       res_bo = NULL;
+                       drm_gem_object_unreference_unlocked(gem);
+                       continue;
+               }

                if (nvbo->reserved_by && nvbo->reserved_by == file_priv) {
                        NV_ERROR(drm, "multiple instances of buffer %d on "
@@ -353,15 +359,18 @@ retry:
                ret = ttm_bo_reserve(&nvbo->bo, true, false, true, sequence);
                if (ret) {
                        validate_fini(op, NULL);
-                       if (unlikely(ret == -EAGAIN))
-                               ret = ttm_bo_wait_unreserved(&nvbo->bo, true);
-                       drm_gem_object_unreference_unlocked(gem);
+                       if (unlikely(ret == -EAGAIN)) {
+                               ret = ttm_bo_reserve_slowpath(&nvbo->bo, true,
+                                                             sequence);
+                               if (!ret)
+                                       res_bo = nvbo;
+                       }
                        if (unlikely(ret)) {
+                               drm_gem_object_unreference_unlocked(gem);
                                if (ret != -ERESTARTSYS)
                                        NV_ERROR(drm, "fail reserve\n");
                                return ret;
                        }
-                       goto retry;
                }

                b->user_priv = (uint64_t)(unsigned long)nvbo;
@@ -383,6 +392,8 @@ retry:
                        validate_fini(op, NULL);
                        return -EINVAL;
                }
+               if (nvbo == res_bo)
+                       goto retry;
        }

        return 0;
-- 
1.8.0