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    SubjectRe: [PATCH v4 05/66] Maple Tree: Add new data structure
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    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);

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