Re: [PATCH RFC v2 02/10] IB/core: Introduce Signature Verbs API

[Sagi Grimberg <sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>]

On 11/1/2013 5:13 PM, Bart Van Assche wrote:
> On 31/10/2013 5:24, Sagi Grimberg wrote:
>> +/**
>> + * struct ib_sig_domain - Parameters specific for T10-DIF
>> + *     domain.
>> + * @sig_type: specific signauture type
>> + * @sig: union of all signature domain attributes that may
>> + *      be used to set domain layout.
>> + *      @dif:
>> + *         @type: T10-DIF type (0|1|2|3)
>> + *         @bg_type: T10-DIF block guard type (CRC|CSUM)
>> + *         @block_size: block size in signature domain.
>> + *         @app_tag: if app_tag is owned be the user,
>> + *             HCA will take this value to be app_tag.
>> + *         @ref_tag: initial ref_tag of signature handover.
>> + *         @type3_inc_reftag: T10-DIF type 3 does not state
>> + *            about the reference tag, it is the user
>> + *            choice to increment it or not.
>> + */
>> +struct ib_sig_domain {
>> +    enum ib_signature_type     sig_type;
>> +    union {
>> +        struct {
>> +            enum ib_t10_dif_type    type;
>> +            enum ib_t10_dif_bg_type bg_type;
>> +            u16            block_size;
>> +            u16            bg;
>> +            u16            app_tag;
>> +            u32            ref_tag;
>> +            bool            type3_inc_reftag;
>> +        } dif;
>> +    } sig;
>> +};
>
> My understanding from SPC-4 is that in that when using protection 
> information such information is inserted after every protection 
> interval. A protection interval can be smaller than a logical block. 
> Shouldn't the name "block_size" be changed into something like 
> "pi_interval" to avoid confusion with the logical block size ?
>
> Bart.
>

True, for DIF types 2,3 protection interval is not restricted to be 
logical block length and may be smaller.
I agree with pi_interval naming.

Note that pi_intervals smaller than 512 bytes are not supported at the 
moment.

Sagi.
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