From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Anderson Subject: Re: When must the io_request_lock be held? Date: Wed, 7 Aug 2002 11:06:28 -0700 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20020807180628.GD2182@beaverton.ibm.com> References: <20020807121846.F10872@redhat.com> <200208071648.g77GmGH03563@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <200208071648.g77GmGH03563@localhost.localdomain> List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: linux-scsi@vger.kernel.org James Bottomley [James.Bottomley@steeleye.com] wrote: > > Well, that's just semantics, I won't get into the argument... > > Note also that 2.5 already has per queue locks (that means per individual SCSI > devices) which are lock pointers. In 2.5 current, all the devices that hang > off an individual host have their queue_locks initialised to point to the > single host->host_lock. However, drivers which can do it (the type of > multi-threaded multi-mailbox ones) will be permitted to use individual and > separate queue_locks, rather than the single host_lock, to protect their > mailbox registers. If you are never going to do this, the difference between > using host_lock and queue_lock is irrelevant to you. If you are, you need to > begin using the queue_locks. James, Maybe I am mis-reading something. Why would we want to go back to a model of having LL drivers using locks outside there domain (queue_lock). Should we not be moving toward having drivers use there own locks. I would think a future model might be to have queue_locks for queue operations and possible shared as a scsi device lock, a host_lock for host data, and LL driver locks used where the driver needs them. -Mike -- Michael Anderson andmike@us.ibm.com