drm/amdgpu: fix lru size grouping v2

Adding a BO can make it the insertion point for larger sizes as well.

v2: add a comment about the guard structure.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index bdc76e2..5447973 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -946,6 +946,8 @@
 	struct list_head *res = lru->lru[tbo->mem.mem_type];
 
 	lru->lru[tbo->mem.mem_type] = &tbo->lru;
+	while ((++lru)->lru[tbo->mem.mem_type] == res)
+		lru->lru[tbo->mem.mem_type] = &tbo->lru;
 
 	return res;
 }
@@ -956,6 +958,8 @@
 	struct list_head *res = lru->swap_lru;
 
 	lru->swap_lru = &tbo->swap;
+	while ((++lru)->swap_lru == res)
+		lru->swap_lru = &tbo->swap;
 
 	return res;
 }
@@ -1003,6 +1007,10 @@
 		lru->swap_lru = &adev->mman.bdev.glob->swap_lru;
 	}
 
+	for (j = 0; j < TTM_NUM_MEM_TYPES; ++j)
+		adev->mman.guard.lru[j] = NULL;
+	adev->mman.guard.swap_lru = NULL;
+
 	adev->mman.initialized = true;
 	r = ttm_bo_init_mm(&adev->mman.bdev, TTM_PL_VRAM,
 				adev->mc.real_vram_size >> PAGE_SHIFT);