Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933199Ab2EOQEA (ORCPT ); Tue, 15 May 2012 12:04:00 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:45608 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S933186Ab2EOQD6 (ORCPT ); Tue, 15 May 2012 12:03:58 -0400 Date: Tue, 15 May 2012 12:03:56 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Lin Ming cc: Jens Axboe , Kernel development list , Linux-pm mailing list , SCSI development list Subject: Re: [RFC PATCH 1/3] block: add a flag to identify PM request In-Reply-To: <1337095985.3515.1.camel@chief-river-32> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1487 Lines: 39 On Tue, 15 May 2012, Lin Ming wrote: > On Tue, 2012-05-15 at 10:35 -0400, Alan Stern wrote: > > On Tue, 15 May 2012, Lin Ming wrote: > > > > > Add a flag REQ_PM to identify the request is PM related. > > > As an example, modify scsi code to use this flag. > > > > There already is such a flag; you don't need to add one. In fact, > > there already are _two_ such flags, and it would be best to remove one > > of them. In include/linux/blkdev.h: > > > > REQ_TYPE_PM_SUSPEND, /* suspend request */ > > REQ_TYPE_PM_RESUME, /* resume request */ > > > > Apparently they had been used by the old ide driver, but they don't > > seem to be used anywhere now. > > IDE code still uses both types and they are used for system > suspend/resume. See generic_ide_suspend and generic_ide_resume. You're right, of course. I searched for "BLK_TYPE_PM_" instead of "REQ_TYPE_PM_". :-( > But we need a flag to check whether it is runtime suspend/resume > request. It should be possible to fix up the IDE code so that it uses the same flag for both suspend and resume. After all, there's no real danger of confusion -- you never get into a situation where you're not sure whether the current PM action is a suspend or a resume. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/