1<html><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 V1.78.1"><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-preload.html" title="idr_preload"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><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-preload.html">Next</a></td></tr></table><hr></div><div class="sect1"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="idr"></a>idr/ida Functions</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="refentrytitle"><a href="API-idr-preload.html"><span class="phrase">idr_preload</span></a></span><span class="refpurpose"> — 2 preload for <code class="function">idr_alloc</code> 3 </span></dt><dt><span class="refentrytitle"><a href="API-idr-alloc.html"><span class="phrase">idr_alloc</span></a></span><span class="refpurpose"> — 4 allocate new idr entry 5 </span></dt><dt><span class="refentrytitle"><a href="API-idr-alloc-cyclic.html"><span class="phrase">idr_alloc_cyclic</span></a></span><span class="refpurpose"> — 6 allocate new idr entry in a cyclical fashion 7 </span></dt><dt><span class="refentrytitle"><a href="API-idr-remove.html"><span class="phrase">idr_remove</span></a></span><span class="refpurpose"> — 8 remove the given id and free its slot 9 </span></dt><dt><span class="refentrytitle"><a href="API-idr-destroy.html"><span class="phrase">idr_destroy</span></a></span><span class="refpurpose"> — 10 release all cached layers within an idr tree 11 </span></dt><dt><span class="refentrytitle"><a href="API-idr-for-each.html"><span class="phrase">idr_for_each</span></a></span><span class="refpurpose"> — 12 iterate through all stored pointers 13 </span></dt><dt><span class="refentrytitle"><a href="API-idr-get-next.html"><span class="phrase">idr_get_next</span></a></span><span class="refpurpose"> — 14 lookup next object of id to given id. 15 </span></dt><dt><span class="refentrytitle"><a href="API-idr-replace.html"><span class="phrase">idr_replace</span></a></span><span class="refpurpose"> — 16 replace pointer for given id 17 </span></dt><dt><span class="refentrytitle"><a href="API-idr-init.html"><span class="phrase">idr_init</span></a></span><span class="refpurpose"> — 18 initialize idr handle 19 </span></dt><dt><span class="refentrytitle"><a href="API-ida-pre-get.html"><span class="phrase">ida_pre_get</span></a></span><span class="refpurpose"> — 20 reserve resources for ida allocation 21 </span></dt><dt><span class="refentrytitle"><a href="API-ida-get-new-above.html"><span class="phrase">ida_get_new_above</span></a></span><span class="refpurpose"> — 22 allocate new ID above or equal to a start id 23 </span></dt><dt><span class="refentrytitle"><a href="API-ida-remove.html"><span class="phrase">ida_remove</span></a></span><span class="refpurpose"> — 24 remove the given ID 25 </span></dt><dt><span class="refentrytitle"><a href="API-ida-destroy.html"><span class="phrase">ida_destroy</span></a></span><span class="refpurpose"> — 26 release all cached layers within an ida tree 27 </span></dt><dt><span class="refentrytitle"><a href="API-ida-simple-get.html"><span class="phrase">ida_simple_get</span></a></span><span class="refpurpose"> — 28 get a new id. 29 </span></dt><dt><span class="refentrytitle"><a href="API-ida-simple-remove.html"><span class="phrase">ida_simple_remove</span></a></span><span class="refpurpose"> — 30 remove an allocated id. 31 </span></dt><dt><span class="refentrytitle"><a href="API-ida-init.html"><span class="phrase">ida_init</span></a></span><span class="refpurpose"> — 32 initialize ida handle 33 </span></dt></dl></div><p> 34 idr synchronization (stolen from radix-tree.h) 35 </p><p> 36 <code class="function">idr_find</code> is able to be called locklessly, using RCU. The caller must 37 ensure calls to this function are made within <code class="function">rcu_read_lock</code> regions. 38 Other readers (lock-free or otherwise) and modifications may be running 39 concurrently. 40 </p><p> 41 It is still required that the caller manage the synchronization and 42 lifetimes of the items. So if RCU lock-free lookups are used, typically 43 this would mean that the items have their own locks, or are amenable to 44 lock-free access; and that the items are freed by RCU (or only freed after 45 having been deleted from the idr tree *and* a <code class="function">synchronize_rcu</code> grace 46 period). 47</p><p> 48 IDA - IDR based ID allocator 49 </p><p> 50 This is id allocator without id -> pointer translation. Memory 51 usage is much lower than full blown idr because each id only 52 occupies a bit. ida uses a custom leaf node which contains 53 IDA_BITMAP_BITS slots. 54 </p><p> 55 2007-04-25 written by Tejun Heo <htejun<em class="parameter"><code>gmail</code></em>.com> 56</p></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API-crc-ccitt.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="kernel-lib.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="API-idr-preload.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">crc_ccitt</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span class="phrase">idr_preload</span></td></tr></table></div></body></html> 57