[PATCH 1/6] drm/vram-helper: reject empty VRAM ranges

[Jiale Yao]

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

Fixes: 37205891d84f ("drm/ttm: make ttm_range_man_init/takedown take type + 
args")
Signed-off-by: Jiale Yao <yaojial...@163.com>
---
 drivers/gpu/drm/drm_gem_vram_helper.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c 
b/drivers/gpu/drm/drm_gem_vram_helper.c
index bca802ccddee..f8bf2d002236 100644
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -851,6 +851,9 @@ static int drm_vram_mm_init(struct drm_vram_mm *vmm, struct 
drm_device *dev,
 {
        int ret;
 
+       if (vram_size < PAGE_SIZE)
+               return -EINVAL;
+
        vmm->vram_base = vram_base;
        vmm->vram_size = vram_size;
 
-- 
2.34.1