Re: [PATCH 0/7] convert semaphore to mutex in struct class

[Dave Young]

On Wed, Jan 09, 2008 at 09:32:48AM +0800, Dave Young wrote:
> On Jan 9, 2008 6:48 AM, Greg KH <gregkh@xxxxxxx> wrote:
> > On Tue, Jan 08, 2008 at 03:05:10PM +0800, Dave Young wrote:
> > > On Jan 8, 2008 1:20 AM, Greg KH <gregkh@xxxxxxx> 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
> >
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