On Tue, Apr 12, 2022 at 12:53:36PM -0300, Jason Gunthorpe wrote: > + if (WARN_ON(!READ_ONCE(vdev->open_count))) > + return -EINVAL; I think all the WARN_ON()s in this patch need to be WARN_ON_ONCE, otherwise there will be too many backtraces to be useful if a driver ever gets the API wrong. Otherwise looks good: Reviewed-by: Christoph Hellwig <hch@xxxxxx>