Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754863AbYAIGKS (ORCPT ); Wed, 9 Jan 2008 01:10:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752201AbYAIGJ7 (ORCPT ); Wed, 9 Jan 2008 01:09:59 -0500 Received: from fg-out-1718.google.com ([72.14.220.157]:16421 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752197AbYAIGJ6 (ORCPT ); Wed, 9 Jan 2008 01:09:58 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version:content-type:content-disposition:in-reply-to:user-agent; b=cXsW4OUa/kdl9T0jHEx0KfejMCYw04HXIttIDgLOKxkHK7LqSfLqQ4xAvJ4tH1hnnL5EumxVY55f1omVF+ytxFPSChbty4MCMabe8SHrOmU8dLmHnKWgIxXhVcuRXArAubC+/ViW00OzeJtwlgnG470NYb/yymCrMCR9DbQMXW0= Date: Wed, 9 Jan 2008 14:13:16 +0800 From: Dave Young To: Greg KH Cc: Stefan Richter , James.Bottomley@hansenpartnership.com, dbrownell@users.sourceforge.net, linux-scsi@vger.kernel.org, a.zummo@towertech.it, peterz@infradead.org, cbou@mail.ru, linux-kernel@vger.kernel.org, David Brownell , krh@redhat.com, stern@rowland.harvard.edu, rtc-linux@googlegroups.com, spi-devel-general@lists.sourceforge.net, linux1394-devel@lists.sourceforge.net, dwmw2@infradead.org, davem@davemloft.net, jarkao2@gmail.com Subject: Re: [PATCH 0/7] convert semaphore to mutex in struct class Message-ID: <20080109061316.GA3249@darkstar.te-china.tietoenator.com> References: <20080107020944.GA3637@darkstar.te-china.tietoenator.com> <20080107084528.GA8365@suse.de> <200801070101.15168.david-b@pacbell.net> <478227D5.8050402@s5r6.in-berlin.de> <20080107154404.GA10880@suse.de> <47825DC1.3090102@s5r6.in-berlin.de> <20080107172009.GA25943@suse.de> <20080108224837.GA19623@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2270 Lines: 51 On Wed, Jan 09, 2008 at 09:32:48AM +0800, Dave Young wrote: > On Jan 9, 2008 6:48 AM, Greg KH wrote: > > On Tue, Jan 08, 2008 at 03:05:10PM +0800, Dave Young wrote: > > > On Jan 8, 2008 1:20 AM, Greg KH wrote: > > > > On Mon, Jan 07, 2008 at 06:13:37PM +0100, Stefan Richter wrote: > > > > > It's already in the driver core to the most part. It remains to be seen > > > > > what is less complicated in the end: Transparent mutex-protected list > > > > > accesses provided by driver core (requires the iterator), or all the > > > > > necessary locking done by the drivers themselves (requires some more > > > > > lock-taking but perhaps fewer lock instances overall in the drivers, and > > > > > respective redefinitions and documentation of the driver core API). > > > > > > > > I favor changing the driver core api and doing this kind of thing there. > > > > It keeps the drivers simpler and should hopefully make their lives > > > > easier. > > > > > > What about this? > > > > > > #define class_for_each_dev(pos, head, member) \ > > > for (mutex_lock(&(container_of(head, struct class, devices))->mutex), po > > > s = list_entry((head)->next, typeof(*pos), member); \ > > > prefetch(pos->member.next), &pos->member != (head) ? 1 : (mutex_unlock(& > > > (container_of(head, struct class, devices))->mutex), 0); \ > > > pos = list_entry(pos->member.next, typeof(*pos), member)) > > > I'm wrong, it's same as before indeed. > > > Eeek, just make the thing a function please, where you pass the iterator > > function in, like the driver core has (driver_for_each_device) > > Ok, so need a new member of knode_class, I will update the patch later. > Thanks. Withdraw my post, sorry :) For now the mutex patch, I will only use the mutex to lock the devices list and write an iterater function. Most of the iterating is for finding some device in the list, so maybe need a match function just like drivers do? Regards dave > > > > > thanks, > > > > greg k-h > > -- 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/