Re: [PATCH v4 00/14] mpt3sas driver NVMe support:

From: Martin K. Petersen
Date: Tue Aug 22 2017 - 22:19:19 EST



Suganath,

> mpt3sas: SGL to PRP Translation for I/Os to NVMe devices

I'm still confused about this patch.

- I don't understand why you go through all these hoops to decide
whether to use PRPs or IEEE scatterlists. If the firmware translation
is slow, why even bother with the SG format in the first place? Set
the max I/O size to match MDTS and you're done.

- What's the benefit of using SG for regular I/O commands?

- If the unmap translation in firmware is slow, why don't you translate
WRITE SAME/w UNMAP set to DSM DEALLOCATE without requiring
applications to do encapsulated passthrough?

Also make sure you attribute your patches correctly (From: root
<root@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>). And you don't need that
long CC: list. Just send the patch series to linux-scsi@xxxxxxxxxxxxxxxx

Thanks!

--
Martin K. Petersen Oracle Linux Engineering