From mboxrd@z Thu Jan  1 00:00:00 1970
From: Mark Lord <liml@rtr.ca>
Subject: Correct use of  ap->lock  versus  ap->host->lock ?
Date: Thu, 06 Mar 2008 10:48:02 -0500
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To: Tejun Heo <htejun@gmail.com>, Jeff Garzik <jgarzik@pobox.com>, Alan Cox <alan@redhat.com>, IDE/ATA development list <linux-ide@vger.kernel.org>

Jeff / Tejun / Alan,

I'm trying to sort out the spinlocks in sata_mv.

In some places, the existing code uses ap->lock.
But in others, notably the interrupt handling, it uses ap->host->lock.

This looks buggy to me, and I'm wondering how to make it bulletproof.

The interrupt handler for each port should really be using ap->lock, right?
But accesses to the host-level (shared among ports) interrupt registers
probably requires ap->host->lock.  Right again?

>>From a libata core point of view, what does ap->host->lock protect?

???

Thanks