On Mon, Nov 19 2007, Alan Stern wrote: > On Mon, 19 Nov 2007, Matthew Wilcox wrote: > > > On Mon, Nov 19, 2007 at 10:36:19AM -0500, Alan Stern wrote: > > > These are conflicting requirements. How can we send the START-STOP > > > UNIT commands to spin the disk up/down through the request queue while > > > delaying or failing all others? > > > > You can insert commands at the head of a request queue. > > Sure. But that won't do any good if the requests get held on the queue > (or failed immediately) because the disk is supposedly "suspended". > Somehow those requests have to be allowed to proceed while all others > are forced to wait (or to fail). Yeah, head-of-queue or not has no relevance. But the SCSI layer has had the notion of 'allow some commands, disallow others' for quite some time already - grep for REQ_PREEMPT in scsi/ -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
