1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>idr_alloc</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="idr.html" title="idr/ida Functions"><link rel="prev" href="API-idr-preload.html" title="idr_preload"><link rel="next" href="API-idr-alloc-cyclic.html" title="idr_alloc_cyclic"></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"><span class="phrase">idr_alloc</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-idr-preload.html">Prev</a>&#160;</td><th width="60%" align="center">idr/ida Functions</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-idr-alloc-cyclic.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-idr-alloc"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>idr_alloc &#8212; 
2     allocate new idr entry
3 </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">idr_alloc </b>(</code></td><td>struct idr * <var class="pdparam">idr</var>, </td></tr><tr><td>&#160;</td><td>void * <var class="pdparam">ptr</var>, </td></tr><tr><td>&#160;</td><td>int <var class="pdparam">start</var>, </td></tr><tr><td>&#160;</td><td>int <var class="pdparam">end</var>, </td></tr><tr><td>&#160;</td><td>gfp_t <var class="pdparam">gfp_mask</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1123580116"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>idr</code></em></span></dt><dd><p>
4     the (initialized) idr
5    </p></dd><dt><span class="term"><em class="parameter"><code>ptr</code></em></span></dt><dd><p>
6     pointer to be associated with the new id
7    </p></dd><dt><span class="term"><em class="parameter"><code>start</code></em></span></dt><dd><p>
8     the minimum id (inclusive)
9    </p></dd><dt><span class="term"><em class="parameter"><code>end</code></em></span></dt><dd><p>
10     the maximum id (exclusive, &lt;= 0 for max)
11    </p></dd><dt><span class="term"><em class="parameter"><code>gfp_mask</code></em></span></dt><dd><p>
12     memory allocation flags
13    </p></dd></dl></div></div><div class="refsect1"><a name="idp1123585844"></a><h2>Description</h2><p>
14   Allocate an id in [start, end) and associate it with <em class="parameter"><code>ptr</code></em>.  If no ID is
15   available in the specified range, returns -ENOSPC.  On memory allocation
16   failure, returns -ENOMEM.
17   </p><p>
18
19   Note that <em class="parameter"><code>end</code></em> is treated as max when &lt;= 0.  This is to always allow
20   using <em class="parameter"><code>start</code></em> + N as <em class="parameter"><code>end</code></em> as long as N is inside integer range.
21   </p><p>
22
23   The user is responsible for exclusively synchronizing all operations
24   which may modify <em class="parameter"><code>idr</code></em>.  However, read-only accesses such as <code class="function">idr_find</code>
25   or iteration can be performed under RCU read lock provided the user
26   destroys <em class="parameter"><code>ptr</code></em> in RCU-safe way after removal from idr.
27</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API-idr-preload.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="idr.html">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="API-idr-alloc-cyclic.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">idr_preload</span>&#160;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">&#160;<span class="phrase">idr_alloc_cyclic</span></td></tr></table></div></body></html>
28