[PATCH 6/6] drm/vmwgfx: reject empty VRAM ranges

[Jiale Yao]

A VRAM size smaller than a page becomes a zero-page TTM range and
causes drm_mm_init() to hit its zero-range BUG check. Reject such a
range before creating the VRAM manager.

Fixes: 37205891d84f ("drm/ttm: make ttm_range_man_init/takedown take type + 
args")
Signed-off-by: Jiale Yao <yaojial...@163.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c 
b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 0f101aedb49a..33284a776fa6 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -692,6 +692,10 @@ static int vmw_dma_masks(struct vmw_private *dev_priv)
 static int vmw_vram_manager_init(struct vmw_private *dev_priv)
 {
        int ret;
+
+       if (dev_priv->vram_size < PAGE_SIZE)
+               return -EINVAL;
+
        ret = ttm_range_man_init(&dev_priv->bdev, TTM_PL_VRAM, false,
                                 dev_priv->vram_size >> PAGE_SHIFT);
        ttm_resource_manager_set_used(ttm_manager_type(&dev_priv->bdev, 
TTM_PL_VRAM), false);
-- 
2.34.1