From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [RFC 0/2] libata: support SATA devices on SAS HBAs Date: Wed, 05 Oct 2005 16:59:05 -0400 Message-ID: <43443E99.4090008@pobox.com> References: <4341A91A.3020000@us.ibm.com> <434251E0.9060000@pobox.com> <58cb370e0510040322q1cb7a13bjfc6c7875140d20a9@mail.gmail.com> <58cb370e0510041356h780e7a5aifda0c232f677471e@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.dvmed.net ([216.237.124.58]:58331 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S932233AbVJEU7N (ORCPT ); Wed, 5 Oct 2005 16:59:13 -0400 In-Reply-To: <58cb370e0510041356h780e7a5aifda0c232f677471e@mail.gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Bartlomiej Zolnierkiewicz Cc: brking@us.ibm.com, linux-ide@vger.kernel.org Bartlomiej Zolnierkiewicz wrote: > [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 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