1 files changed, 43 insertions, 35 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_execbuf_util.c b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
index cd9e4523dc56..7b90def15674 100644
--- a/drivers/gpu/drm/ttm/ttm_execbuf_util.c
+++ b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
@@ -82,22 +82,6 @@ static void ttm_eu_list_ref_sub(struct list_head *list)
         }
 }
 
-static int ttm_eu_wait_unreserved_locked(struct list_head *list,
-                                         struct ttm_buffer_object *bo)
-{
-        struct ttm_bo_global *glob = bo->glob;
-        int ret;
-
-        ttm_eu_del_from_lru_locked(list);
-        spin_unlock(&glob->lru_lock);
-        ret = ttm_bo_wait_unreserved(bo, true);
-        spin_lock(&glob->lru_lock);
-        if (unlikely(ret != 0))
-                ttm_eu_backoff_reservation_locked(list);
-        return ret;
-}
-
-
 void ttm_eu_backoff_reservation(struct list_head *list)
 {
         struct ttm_validate_buffer *entry;
@@ -145,47 +129,65 @@ int ttm_eu_reserve_buffers(struct list_head *list)
         entry = list_first_entry(list, struct ttm_validate_buffer, head);
         glob = entry->bo->glob;
 
-retry:
         spin_lock(&glob->lru_lock);
         val_seq = entry->bo->bdev->val_seq++;
 
+retry:
         list_for_each_entry(entry, list, head) {
                 struct ttm_buffer_object *bo = entry->bo;
 
-retry_this_bo:
-                ret = ttm_bo_reserve_locked(bo, true, true, true, val_seq);
+                /* already slowpath reserved? */
+                if (entry->reserved)
+                        continue;
+
+                ret = ttm_bo_reserve_nolru(bo, true, true, true, val_seq);
                 switch (ret) {
                 case 0:
                         break;
                 case -EBUSY:
-                        ret = ttm_eu_wait_unreserved_locked(list, bo);
-                        if (unlikely(ret != 0)) {
-                                spin_unlock(&glob->lru_lock);
-                                ttm_eu_list_ref_sub(list);
-                                return ret;
-                        }
-                        goto retry_this_bo;
+                        ttm_eu_del_from_lru_locked(list);
+                        spin_unlock(&glob->lru_lock);
+                        ret = ttm_bo_reserve_nolru(bo, true, false,
+                                                   true, val_seq);
+                        spin_lock(&glob->lru_lock);
+                        if (!ret)
+                                break;
+
+                        if (unlikely(ret != -EAGAIN))
+                                goto err;
+
+                        /* fallthrough */
                 case -EAGAIN:
                         ttm_eu_backoff_reservation_locked(list);
+
+                        /*
+                         * temporarily increase sequence number every retry,
+                         * to prevent us from seeing our old reservation
+                         * sequence when someone else reserved the buffer,
+                         * but hasn't updated the seq_valid/seqno members yet.
+                         */
+                        val_seq = entry->bo->bdev->val_seq++;
+
                         spin_unlock(&glob->lru_lock);
                         ttm_eu_list_ref_sub(list);
-                        ret = ttm_bo_wait_unreserved(bo, true);
+                        ret = ttm_bo_reserve_slowpath_nolru(bo, true, val_seq);
                         if (unlikely(ret != 0))
                                 return ret;
+                        spin_lock(&glob->lru_lock);
+                        entry->reserved = true;
+                        if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
+                                ret = -EBUSY;
+                                goto err;
+                        }
                         goto retry;
                 default:
-                        ttm_eu_backoff_reservation_locked(list);
-                        spin_unlock(&glob->lru_lock);
-                        ttm_eu_list_ref_sub(list);
-                        return ret;
+                        goto err;
                 }
 
                 entry->reserved = true;
                 if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
-                        ttm_eu_backoff_reservation_locked(list);
-                        spin_unlock(&glob->lru_lock);
-                        ttm_eu_list_ref_sub(list);
-                        return -EBUSY;
+                        ret = -EBUSY;
+                        goto err;
                 }
         }
 
@@ -194,6 +196,12 @@ retry_this_bo:
         ttm_eu_list_ref_sub(list);
 
         return 0;
+
+err:
+        ttm_eu_backoff_reservation_locked(list);
+        spin_unlock(&glob->lru_lock);
+        ttm_eu_list_ref_sub(list);
+        return ret;
 }
 EXPORT_SYMBOL(ttm_eu_reserve_buffers);