Re: [PATCH RESEND 0/1] AHCI: Optimize interrupt processing

From: Nicholas A. Bellinger
Date: Mon Jul 29 2013 - 15:05:21 EST


On Mon, 2013-07-29 at 07:50 -0400, Tejun Heo wrote:
> Yo,
>
> On Fri, Jul 26, 2013 at 05:43:13PM -0700, Nicholas A. Bellinger wrote:
> > Considering there can be more than a single ata_device hanging off each
> > ata_port, the '*sdev = ap->link.device[0].sdev' in __ata_qc_from_tag()
> > is definitely bogus, but I'm not sure how else to correlate
> > blk-mq/scsi-mq per device descriptors to existing code expecting
> > ata_port->qcmd[] descriptors to be shared across multiple devices..
> >
> > Tejun..?
>
> I have no idea. Let's please just do simpler conversion and worry
> about embedding qc's into scsi_cmnds later. libata isn't a normal
> SCSI driver and has a rather its own thick midlayer doing the
> impedance matching inbetween && I really don't think there is too much
> benefit to be reaped from embedding qc's into scsi_cmnds.
>

That is essentially the same conclusion that I came to, but wanted to at
least give you a chance to comment here. ;)

So that said, I'll include a simple conversion for libata into the
scsi-mq WIP branch, and folks who are interested in more detailed
conversions can pursue them as separate items.

--nab

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