Jeff Garzik wrote:

Bartlomiej Zolnierkiewicz wrote:

quoted

[PATCH] libata: add ops->qc_transport for SAS

* add ->qc_transport to struct ata_port_operations
* add default ata_qc_transport() and update all host drivers

Thanks to this change we won't have to depend on host_set
and host_set->lock for devices attached to SAS HBAs.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Seems sane at a quick glance, though I'm a bit disappointed we have to 
add yet another level of indirection to the hot path.

You made a good point, though, by pointing out that all the ata_qc_xxx 
stuff is essentially completely inside a single lock domain.

Other notes:  There may be other dependencies such as wanting to 
reference the struct device pointer in host_set and similar details that 
need handling.  Also, I was planning to move some of the ata_port_ops 
into a separate host_set ops, since they (hooks such as ->irq_clear or 
->host_stop) are really host-wide hooks, not per-port hooks.

Jeff,

Is this patch on its way into one of your trees, or should I just pick
it up add it to my libata SAS patchset so you can just grab the whole
patchset once it is ready?

Brian

-- 
Brian King
eServer Storage I/O
IBM Linux Technology Center