1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>bitmap_find_free_region</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#idp1123213284" title="Bitmap Operations"><link rel="prev" href="API-bitmap-fold.html" title="bitmap_fold"><link rel="next" href="API-bitmap-release-region.html" title="bitmap_release_region"></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">bitmap_find_free_region</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-bitmap-fold.html">Prev</a>&#160;</td><th width="60%" align="center">Bitmap Operations</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-bitmap-release-region.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-bitmap-find-free-region"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>bitmap_find_free_region &#8212; 
2     find a contiguous aligned mem region
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">bitmap_find_free_region </b>(</code></td><td>unsigned long * <var class="pdparam">bitmap</var>, </td></tr><tr><td>&#160;</td><td>unsigned int <var class="pdparam">bits</var>, </td></tr><tr><td>&#160;</td><td>int <var class="pdparam">order</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1123400020"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>bitmap</code></em></span></dt><dd><p>
4     array of unsigned longs corresponding to the bitmap
5    </p></dd><dt><span class="term"><em class="parameter"><code>bits</code></em></span></dt><dd><p>
6     number of bits in the bitmap
7    </p></dd><dt><span class="term"><em class="parameter"><code>order</code></em></span></dt><dd><p>
8     region size (log base 2 of number of bits) to find
9    </p></dd></dl></div></div><div class="refsect1"><a name="idp1123403756"></a><h2>Description</h2><p>
10   Find a region of free (zero) bits in a <em class="parameter"><code>bitmap</code></em> of <em class="parameter"><code>bits</code></em> bits and
11   allocate them (set them to one).  Only consider regions of length
12   a power (<em class="parameter"><code>order</code></em>) of two, aligned to that power of two, which
13   makes the search algorithm much faster.
14   </p><p>
15
16   Return the bit offset in bitmap of the allocated region,
17   or -errno on failure.
18</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API-bitmap-fold.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="kernel-lib.html#idp1123213284">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="API-bitmap-release-region.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">bitmap_fold</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">bitmap_release_region</span></td></tr></table></div></body></html>
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