[PATCH 3/4] NVMe: End-to-end data protection

[Keith Busch]

On Tue, 12 Mar 2013, Martin K. Petersen wrote:

>>>>>> "Keith" == Keith Busch <keith.busch at intel.com> writes:
>
> Keith> The DIF meta-data generate and verify functions don't specify the
> Keith> size meta-data per sector, so we can't handle anything that isn't
> Keith> a DIF tuple size of 8 bytes.
>
> The sector_size parameter in struct blk_interity defines the number of
> bytes in each block. The tuple_size defines the size of the metadata per
> block. I.e. 8 bytes for T10 PI.
>
> -- 
> Martin K. Petersen	Oracle Linux Engineering
>

That's true, but the generate/verify functions receive a struct
blk_integrity_exchg parameter, and there is no information there on how
large a tuple is. The existing generate and verify functions in sd_dif.c
increment through the bix->prot_buf as if the meta-data size per sector
was the size of the struct sd_dif_tuple, so I don't think it will work
if I have additional meta-data space beyond the DIF tuple.