Messages in this thread | | | Date | Wed, 15 Dec 2021 13:54:45 +0100 | Subject | Re: [PATCH v4 05/66] Maple Tree: Add new data structure | From | Vlastimil Babka <> |
| |
On 12/1/21 15:29, Liam Howlett wrote: > +/* > + * mt_find() - Search from the start up until an entry is found. > + * @mt: The maple tree > + * @*index: Pointer which contains the start location of the search > + * @max: The maximum value to check > + * > + * Handles locking. > + * > + * Return: The entry at or after the @*index or %NULL
Noticed later that the comment doesn't say how *index is updated.
> + */ > +void *mt_find(struct maple_tree *mt, unsigned long *index, unsigned long max) > +{ > + MA_STATE(mas, mt, *index, *index); > + void *entry; > +#ifdef CONFIG_DEBUG_MAPLE_TREE > + unsigned long copy = *index; > +#endif > + > + trace_ma_read(__func__, &mas); > + > + if ((*index) > max) > + return NULL; > + > + rcu_read_lock(); > +retry: > + entry = mas_state_walk(&mas); > + if (mas_is_start(&mas)) > + goto retry; > + > + if (unlikely(xa_is_zero(entry))) > + entry = NULL; > + > + if (entry) > + goto unlock; > + > + while (mas_searchable(&mas) && (mas.index < max)) { > + entry = mas_next_entry(&mas, max); > + if (likely(entry && !xa_is_zero(entry))) > + break; > + } > + > + if (unlikely(xa_is_zero(entry))) > + entry = NULL; > +unlock: > + rcu_read_unlock(); > + if (likely(entry)) { > + *index = mas.last + 1; > +#ifdef CONFIG_DEBUG_MAPLE_TREE > + if ((*index) && (*index) <= copy) > + printk("index not increased! %lx <= %lx\n", > + *index, copy); > + MT_BUG_ON(mt, (*index) && ((*index) <= copy)); > +#endif > + } > + > + return entry; > +} > +EXPORT_SYMBOL(mt_find);
| |