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drm/ttm: Fix a deadlock if the target BO is not idle during swap

The ret value might be -EBUSY, caller will think lru lock is still
locked but actually NOT. So return -ENOSPC instead. Otherwise we hit
list corruption.

ttm_bo_cleanup_refs might fail too if BO is not idle. If we return 0,
caller(ttm_tt_populate -> ttm_global_swapout ->ttm_device_swapout) will
be stuck as we actually did not free any BO memory. This usually happens
when the fence is not signaled for a long time.

Signed-off-by: xinhui pan <xinhui.pan@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Fixes: ebd59851c7 ("drm/ttm: move swapout logic around v3")
Link: https://patchwork.freedesktop.org/patch/msgid/20210907040832.1107747-1-xinhui.pan@amd.com
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
xinhui pan 2021-09-07 12:08:32 +08:00 committed by Dave Airlie
parent b011522c8a
commit 70982eef4d

View File

@ -1160,9 +1160,9 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
}
if (bo->deleted) {
ttm_bo_cleanup_refs(bo, false, false, locked);
ret = ttm_bo_cleanup_refs(bo, false, false, locked);
ttm_bo_put(bo);
return 0;
return ret == -EBUSY ? -ENOSPC : ret;
}
ttm_bo_del_from_lru(bo);
@ -1216,7 +1216,7 @@ out:
if (locked)
dma_resv_unlock(bo->base.resv);
ttm_bo_put(bo);
return ret;
return ret == -EBUSY ? -ENOSPC : ret;
}
void ttm_bo_tt_destroy(struct ttm_buffer_object *bo)