Re: [RFC PATCH v5 3/4] nvme: add simple copy support

[Matthew Wilcox]

On Fri, Feb 19, 2021 at 06:15:16PM +0530, SelvaKumar S wrote:
> +	struct nvme_copy_range *range = NULL;
[...]
> +	range = kmalloc_array(nr_range, sizeof(*range),
> +			GFP_ATOMIC | __GFP_NOWARN);
[...]
> +	req->special_vec.bv_page = virt_to_page(range);
> +	req->special_vec.bv_offset = offset_in_page(range);
> +	req->special_vec.bv_len = sizeof(*range) * nr_range;
[...]
> +struct nvme_copy_range {
> +	__le64			rsvd0;
> +	__le64			slba;
> +	__le16			nlb;
> +	__le16			rsvd18;
> +	__le32			rsvd20;
> +	__le32			eilbrt;
> +	__le16			elbat;
> +	__le16			elbatm;
> +};

so ... at 32 bytes, you can get 128 per 4kB page.  What happens if you
try to send down a command that attempts to copy 129 ranges?