Re: [PATCH 21/21] nvme: Support atomic writes

[Christoph Hellwig <hch@lst.de>]

> +			if (le16_to_cpu(id->nabspf))
> +				boundary = (le16_to_cpu(id->nabspf) + 1) * bs;
> +
> +			if (is_power_of_2(boundary) || !boundary) {
> +				blk_queue_atomic_write_max_bytes(disk->queue, atomic_bs);
> +				blk_queue_atomic_write_unit_min_sectors(disk->queue, 1);
> +				blk_queue_atomic_write_unit_max_sectors(disk->queue,
> +									atomic_bs / bs);
> +				blk_queue_atomic_write_boundary_bytes(disk->queue, boundary);
> +			} else {
> +				dev_err(ns->ctrl->device, "Unsupported atomic boundary=0x%x\n",
> +					boundary);
> +			}

Please figure out a way to split the atomic configuration into a
helper and avoid all those crazy long lines,  preferable also avoid
the double calls to the block helpers as well while you're at it.

Also I really want a check in the NVMe I/O path that any request
with the atomic flag set actually adhers to the limits to at least
partially paper over the annoying lack of a separate write atomic
command in nvme.