Date: Tue, 8 Jan 2008 14:48:37 -0800
From: Greg KH <gregkh@suse.de>
To: Dave Young <hidave.darkstar@gmail.com>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>,
       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 <david-b@pacbell.net>, 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: <20080108224837.GA19623@suse.de>
References: <20080103055019.GA4885@darkstar.te-china.tietoenator.com> <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> <a8e1da0801072305x3378c195qeb0bb7027030254c@mail.gmail.com>
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On Tue, Jan 08, 2008 at 03:05:10PM +0800, Dave Young wrote:
> On Jan 8, 2008 1:20 AM, Greg KH <gregkh@suse.de> 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))

Eeek, just make the thing a function please, where you pass the iterator
function in, like the driver core has (driver_for_each_device)

thanks,

greg k-h
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