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>

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 9fcfcb2..7fa6882 100644 (file)
--- 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;