drm/ttm: Don't count pages in SG BOs against pages_limit

Pages in SG BOs were not allocated by TTM. So don't count them against
TTM's pages limit.
Signed-off-by: NFelix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210414064804.29356-9-Felix.Kuehling@amd.com

drivers/gpu/drm/ttm/ttm_tt.c

@@ -317,9 +317,12 @@ int ttm_tt_populate(struct ttm_device *bdev,
 	if (ttm_tt_is_populated(ttm))
 		return 0;
 
-	atomic_long_add(ttm->num_pages, &ttm_pages_allocated);
-	if (bdev->pool.use_dma32)
-		atomic_long_add(ttm->num_pages, &ttm_dma32_pages_allocated);
+	if (!(ttm->page_flags & TTM_PAGE_FLAG_SG)) {
+		atomic_long_add(ttm->num_pages, &ttm_pages_allocated);
+		if (bdev->pool.use_dma32)
+			atomic_long_add(ttm->num_pages,
+					&ttm_dma32_pages_allocated);
+	}
 
 	while (atomic_long_read(&ttm_pages_allocated) > ttm_pages_limit ||
 	       atomic_long_read(&ttm_dma32_pages_allocated) >
@@ -350,9 +353,12 @@ int ttm_tt_populate(struct ttm_device *bdev,
 	return 0;
 
 error:
-	atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
-	if (bdev->pool.use_dma32)
-		atomic_long_sub(ttm->num_pages, &ttm_dma32_pages_allocated);
+	if (!(ttm->page_flags & TTM_PAGE_FLAG_SG)) {
+		atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
+		if (bdev->pool.use_dma32)
+			atomic_long_sub(ttm->num_pages,
+					&ttm_dma32_pages_allocated);
+	}
 	return ret;
 }
 EXPORT_SYMBOL(ttm_tt_populate);
@@ -382,9 +388,12 @@ void ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm)
 	else
 		ttm_pool_free(&bdev->pool, ttm);
 
-	atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
-	if (bdev->pool.use_dma32)
-		atomic_long_sub(ttm->num_pages, &ttm_dma32_pages_allocated);
+	if (!(ttm->page_flags & TTM_PAGE_FLAG_SG)) {
+		atomic_long_sub(ttm->num_pages, &ttm_pages_allocated);
+		if (bdev->pool.use_dma32)
+			atomic_long_sub(ttm->num_pages,
+					&ttm_dma32_pages_allocated);
+	}
 
 	ttm->page_flags &= ~TTM_PAGE_FLAG_PRIV_POPULATED;
 }