Re: [PATCH 1/2] libiscsi, iser: Adjust data_length to include protection information

[Sagi Grimberg <sagig-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org>]

On 6/4/2014 1:18 AM, Martin K. Petersen wrote:
>>>>>> "Mike" == Mike Christie <michaelc-hcNo3dDEHLuVc3sceRu5cw@public.gmane.org> writes:
> Mike> On 06/01/2014 11:19 AM, Sagi Grimberg wrote:
>>> +/*
>>> + * data integrity helpers
>>> + */
>>> +static inline unsigned +iscsi_prot_len(unsigned data_len, unsigned
>>> sector_size) +{
>>> + switch (sector_size) {
>>> + case 512:
>>> + return (data_len >> 9) * 8;
>>> + case 1024:
>>> + return (data_len >> 10) * 8;
>>> + case 2048:
>>> + return (data_len >> 11) * 8;
>>> + case 4096:
>>> + return (data_len >> 12) * 8;
>>> + default:
>>> + return (data_len >> ilog2(sector_size)) * 8;
>>> + }
>>> +}
>>> #endif
> Mike> I do not think this should not be in the iscsi code.
>
> In the data integrity update I posted there's a flag saying "transfer PI
> on the wire". That was meant to be the thing driver's should key off of
> to adjust transfer length. But I'm also happy to provide a unsigned int
> scsi_transfer_length(struct scsi_cmnd *) thingy that returns the right
> byte count. Just bear in mind that the host-facing DIX transfer length
> may be different.
>

OK, let me prepare v1 moving this logic to a scsi helper and we'll have 
another round of comments.

Thanks,
Sagi.
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