Re: [PATCH v7 1/4] lib/percpu-list: Per-cpu list with associated per-cpu locks

[Waiman Long]

On 04/14/2016 07:33 PM, Boqun Feng wrote:
> On Wed, Apr 13, 2016 at 01:38:33PM -0400, Waiman Long wrote:
> > On 04/12/2016 10:09 PM, Boqun Feng wrote:
> > > Hi Waiman,
> > >
> > > On Tue, Apr 12, 2016 at 06:54:43PM -0400, Waiman Long wrote:
> > > [...]
> > > > +
> > > > +/*
> > > > + * Initialize the per-cpu list head
> > > > + */
> > > > +int init_pcpu_list_head(struct pcpu_list_head **ppcpu_head)
> > > > +{
> > > > +	struct pcpu_list_head *pcpu_head = alloc_percpu(struct pcpu_list_head);
> > > > +	int cpu;
> > > > +
> > > > +	if (!pcpu_head)
> > > > +		return -ENOMEM;
> > > > +
> > > > +	for_each_possible_cpu(cpu) {
> > > > +		struct pcpu_list_head *head = per_cpu_ptr(pcpu_head, cpu);
> > > > +
> > > > +		INIT_LIST_HEAD(&head->list);
> > > > +		head->lock = __SPIN_LOCK_UNLOCKED(&head->lock);
> > > > +		lockdep_set_class(&head->lock,&percpu_list_key);
> > > > +	}
> > > > +
> > > > +	*ppcpu_head = pcpu_head;
> > > > +	return 0;
> > > > +}
> > > The first time I looked at this patch, I had a hard time to figure out
> > > which "struct pcpu_list_head" pointer is pointing to percpu data(the
> > > pointer could be the parameter for per/this_cpu_ptr()), and which
> > > pointer is pointing to actual structure. For example, 'pcpu_head' and
> > > 'head' above are different types of pointers.
> > >
> > > So besides improving my code reading skills, I think the following patch
> > > helps ;-) Also it can resolve several splats of sparse when running
> > > 'make C=1 lib/'.
> > >
> > > Thoughts?
> > Yes, I think your patch is helpful. I will include your patch in my
> > patchset.
> Given that a renaming will happen in the next version, carrying this as
> a standalone patch will be a pain, I think. So feel free to squash this
> into the patch #1, if that could make your job eariser ;-)
>
> Regards,
> Boqun

That is not a problem. I do want to acknowledge your contribution to 
this patchset.

Cheers,
Longman