lkml.org 
[lkml]   [2021]   [Dec]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v4 05/66] Maple Tree: Add new data structure
From
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);

\
 
 \ /
  Last update: 2021-12-15 13:55    [W:3.163 / U:0.064 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site