[PATCH v3 15/15] nvme: Ensure atomic writes will be executed atomically

[Christoph Hellwig]

If we don't end up doing the checks in the block layer:

> +	/*
> +	 * Ensure that nothing has been sent which cannot be executed
> +	 * atomically.
> +	 */
> +	if (req->cmd_flags & REQ_ATOMIC) {
> +		struct nvme_ns_head *head = ns->head;
> +		u32 boundary_bytes = head->atomic_boundary;

... please split the checks into a helper.  And merge them into the
previous patch.