[PATCH] drm/ttm: fix error handling if no BO can be swapped out

[Shiwu Zhang]

In case that all pre-allocated BOs are busy, just continue to populate
BOs since likely half of system memory in total is still free.

Signed-off-by: Shiwu Zhang <shiwu.zhang at amd.com>
---
 drivers/gpu/drm/ttm/ttm_device.c | 4 ++--
 drivers/gpu/drm/ttm/ttm_tt.c     | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index 1f2024164d72..0200709db9be 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -133,7 +133,7 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
 	struct ttm_resource_manager *man;
 	struct ttm_buffer_object *bo;
 	unsigned i, j;
-	int ret;
+	int ret=-EBUSY;
 
 	spin_lock(&bdev->lru_lock);
 	for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {
@@ -161,7 +161,7 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
 		}
 	}
 	spin_unlock(&bdev->lru_lock);
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL(ttm_device_swapout);
 
diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index 48c407cff112..4e1e06a04428 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -329,6 +329,8 @@ int ttm_tt_populate(struct ttm_device *bdev,
 	       ttm_dma32_pages_limit) {
 
 		ret = ttm_global_swapout(ctx, GFP_KERNEL);
+		if (ret == -EBUSY)
+			break;
 		if (ret < 0)
 			goto error;
 	}
-- 
2.17.1