Re: [PATCH v6 15/25] rnbd: private headers with rnbd protocol structs and helpers

Bart Van Assche
2020-01-02T22:43:34Z

On 12/30/19 2:29 AM, Jack Wang wrote:
> + * @device_id: device_id on server side to identify the device

Is this a number that only has a meaning inside the RTRS software? Is
the role of this number perhaps similar to an NVMe namespace or SCSI
LUN? If so, please mention this. Additionally, does this number start
from zero or from one?

> + * @max_segments: max segments hardware support in one transfer

Which "hardware" does this comment refer to? The RDMA adapter or the
block device in the server? In the latter case, what if the block device
has been implemented in software?

What kind of transfer does this comment refer to? A DMA transfer? If so,
please mention this.

> +struct rnbd_msg_open_rsp {
> + struct rnbd_msg_hdr hdr;
> + __le32 device_id;
> + __le64 nsectors;
> + __le32 max_hw_sectors;
> + __le32 max_write_same_sectors;
> + __le32 max_discard_sectors;
> + __le32 discard_granularity;
> + __le32 discard_alignment;
> + __le16 physical_block_size;
> + __le16 logical_block_size;
> + __le16 max_segments;
> + __le16 secure_discard;
> + u8 rotational;
> + u8 reserved[11];
> +};

Thanks,

Bart.