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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>idr/ida Functions</title><meta name="generator" content="DocBook XSL Stylesheets V1.76.1" /><link rel="home" href="index.html" title="The Linux Kernel API" /><link rel="up" href="kernel-lib.html" title="Chapter 3. Basic Kernel Library Functions" /><link rel="prev" href="API-crc-ccitt.html" title="crc_ccitt" /><link rel="next" href="API-idr-pre-get.html" title="idr_pre_get" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">idr/ida Functions</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-crc-ccitt.html">Prev</a> </td><th width="60%" align="center">Chapter 3. Basic Kernel Library Functions</th><td width="20%" align="right"> <a accesskey="n" href="API-idr-pre-get.html">Next</a></td></tr></table><hr /></div><div class="sect1" title="idr/ida Functions"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="idr"></a>idr/ida Functions</h2></div></div></div><div class="toc"><dl><dt><span class="refentrytitle"><a href="API-idr-pre-get.html"><span>idr_pre_get</span></a></span><span class="refpurpose"> —
reserve resources for idr allocation
</span></dt><dt><span class="refentrytitle"><a href="API-idr-get-new-above.html"><span>idr_get_new_above</span></a></span><span class="refpurpose"> —
allocate new idr entry above or equal to a start id
</span></dt><dt><span class="refentrytitle"><a href="API-idr-get-new.html"><span>idr_get_new</span></a></span><span class="refpurpose"> —
allocate new idr entry
</span></dt><dt><span class="refentrytitle"><a href="API-idr-remove.html"><span>idr_remove</span></a></span><span class="refpurpose"> —
remove the given id and free its slot
</span></dt><dt><span class="refentrytitle"><a href="API-idr-remove-all.html"><span>idr_remove_all</span></a></span><span class="refpurpose"> —
remove all ids from the given idr tree
</span></dt><dt><span class="refentrytitle"><a href="API-idr-destroy.html"><span>idr_destroy</span></a></span><span class="refpurpose"> —
release all cached layers within an idr tree
</span></dt><dt><span class="refentrytitle"><a href="API-idr-find.html"><span>idr_find</span></a></span><span class="refpurpose"> —
return pointer for given id
</span></dt><dt><span class="refentrytitle"><a href="API-idr-for-each.html"><span>idr_for_each</span></a></span><span class="refpurpose"> —
iterate through all stored pointers
</span></dt><dt><span class="refentrytitle"><a href="API-idr-get-next.html"><span>idr_get_next</span></a></span><span class="refpurpose"> —
lookup next object of id to given id.
</span></dt><dt><span class="refentrytitle"><a href="API-idr-replace.html"><span>idr_replace</span></a></span><span class="refpurpose"> —
replace pointer for given id
</span></dt><dt><span class="refentrytitle"><a href="API-idr-init.html"><span>idr_init</span></a></span><span class="refpurpose"> —
initialize idr handle
</span></dt><dt><span class="refentrytitle"><a href="API-ida-pre-get.html"><span>ida_pre_get</span></a></span><span class="refpurpose"> —
reserve resources for ida allocation
</span></dt><dt><span class="refentrytitle"><a href="API-ida-get-new-above.html"><span>ida_get_new_above</span></a></span><span class="refpurpose"> —
allocate new ID above or equal to a start id
</span></dt><dt><span class="refentrytitle"><a href="API-ida-get-new.html"><span>ida_get_new</span></a></span><span class="refpurpose"> —
allocate new ID
</span></dt><dt><span class="refentrytitle"><a href="API-ida-remove.html"><span>ida_remove</span></a></span><span class="refpurpose"> —
remove the given ID
</span></dt><dt><span class="refentrytitle"><a href="API-ida-destroy.html"><span>ida_destroy</span></a></span><span class="refpurpose"> —
release all cached layers within an ida tree
</span></dt><dt><span class="refentrytitle"><a href="API-ida-init.html"><span>ida_init</span></a></span><span class="refpurpose"> —
initialize ida handle
</span></dt></dl></div><p>
idr synchronization (stolen from radix-tree.h)
</p><p>
<code class="function">idr_find</code> is able to be called locklessly, using RCU. The caller must
ensure calls to this function are made within <code class="function">rcu_read_lock</code> regions.
Other readers (lock-free or otherwise) and modifications may be running
concurrently.
</p><p>
It is still required that the caller manage the synchronization and
lifetimes of the items. So if RCU lock-free lookups are used, typically
this would mean that the items have their own locks, or are amenable to
lock-free access; and that the items are freed by RCU (or only freed after
having been deleted from the idr tree *and* a <code class="function">synchronize_rcu</code> grace
period).
</p><p>
IDA - IDR based ID allocator
</p><p>
This is id allocator without id -> pointer translation. Memory
usage is much lower than full blown idr because each id only
occupies a bit. ida uses a custom leaf node which contains
IDA_BITMAP_BITS slots.
</p><p>
2007-04-25 written by Tejun Heo <htejun<em class="parameter"><code>gmail</code></em>.com>
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