Re: [PATCH v3 1/2] io_uring: Move from hlist to io_wq_work_node

[Breno Leitao <leitao@debian.org>]

Hello Krisman, thanks for the review

On Thu, Feb 23, 2023 at 04:02:25PM -0300, Gabriel Krisman Bertazi wrote:
> Breno Leitao <leitao@debian.org> writes:

> >  static inline struct io_cache_entry *io_alloc_cache_get(struct io_alloc_cache *cache)
> >  {
> > -	if (!hlist_empty(&cache->list)) {
> > -		struct hlist_node *node = cache->list.first;
> > +	if (cache->list.next) {
> > +		struct io_cache_entry *entry;
> >  
> > -		hlist_del(node);
> > -		return container_of(node, struct io_cache_entry, node);
> > +		entry = container_of(cache->list.next, struct io_cache_entry, node);
> > +		cache->list.next = cache->list.next->next;
> > +		return entry;
> >  	}
> 
> From a quick look, I think you could use wq_stack_extract() here

True, we can use wq_stack_extract() in this patch, but, we would need to
revert to back to this code in the next patch. Remember that
wq_stack_extract() touches the stack->next->next, which will be
poisoned, causing a KASAN warning.

Here is relevant part of the code:

	struct io_wq_work_node *wq_stack_extract(struct io_wq_work_node *stack)
	{
		struct io_wq_work_node *node = stack->next;
		stack->next = node->next;