drm/nouveau: use ttm_bo_reserve_slowpath in validate_init, v2

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.

Changes since v1:
 - Increase the seqno before calling ttm_bo_reserve_slowpath

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>

1 files changed, 17 insertions, 5 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 9fcfcb2a020c..7fa6882c2942 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -320,9 +320,10 @@ 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;
 
-retry:
         sequence = atomic_add_return(1, &drm->ttm.validate_sequence);
+retry:
         if (++trycnt > 100000) {
                 NV_ERROR(drm, "%s failed and gave up.\n", __func__);
                 return -EINVAL;
@@ -340,6 +341,11 @@ 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 "
@@ -352,15 +358,19 @@ 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)) {
+                                sequence = atomic_add_return(1, &drm->ttm.validate_sequence);
+                                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;
@@ -382,6 +392,8 @@ retry:
                         validate_fini(op, NULL);
                         return -EINVAL;
                 }
+                if (nvbo == res_bo)
+                        goto retry;
         }
 
         return 0;