what time does host will re-used the prplist memory region.

[HavenYang]

Dear Matthew

Thank you for your feedback, it's very important to me.
I suggest your comment for my first question should be wrote to the spec, 
otherwise, there maybe others confused for this issue and go to the wrong way.



At 2015-08-04 21:40:00, "Matthew Wilcox" <willy at linux.intel.com> wrote:
>On Tue, Aug 04, 2015 at 11:29:47AM +0800, HavenYang wrote:
>> It says the SQhead indicate Submission Queue entries may be re-used, but it not say the PRPlist related to this command may be re-used or not, I confused.
>> 
>> my question is:
>> 1. from host side, what is the condition can host re-used the prplist memory region for a host command, SQHead or command complete?
>
>The host can only reuse the PRP list memory when the command has been
>completed.  The device is entitled to use the PRP list throughout
>execution of the command.
>
>> 2. from device side, what is the condition to update SQHead, fetched command head(simple) or fetched all prp from prplist(complex)?
>
>The first; the host only takes this as an indication that it can reuse
>the SQ entry.