1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>drm_gem_create_mmap_offset_size</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="Linux DRM Developer's Guide"><link rel="up" href="drm-memory-management.html#idp1122600572" title="GEM Function Reference"><link rel="prev" href="API-drm-gem-free-mmap-offset.html" title="drm_gem_free_mmap_offset"><link rel="next" href="API-drm-gem-create-mmap-offset.html" title="drm_gem_create_mmap_offset"></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">drm_gem_create_mmap_offset_size</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-drm-gem-free-mmap-offset.html">Prev</a>&#160;</td><th width="60%" align="center">GEM Function Reference</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-drm-gem-create-mmap-offset.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-drm-gem-create-mmap-offset-size"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>drm_gem_create_mmap_offset_size &#8212; 
2     create a fake mmap offset for an object
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">drm_gem_create_mmap_offset_size </b>(</code></td><td>struct drm_gem_object * <var class="pdparam">obj</var>, </td></tr><tr><td>&#160;</td><td>size_t <var class="pdparam">size</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1122659412"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>obj</code></em></span></dt><dd><p>
4     obj in question
5    </p></dd><dt><span class="term"><em class="parameter"><code>size</code></em></span></dt><dd><p>
6     the virtual size
7    </p></dd></dl></div></div><div class="refsect1"><a name="idp1122661892"></a><h2>Description</h2><p>
8   GEM memory mapping works by handing back to userspace a fake mmap offset
9   it can use in a subsequent mmap(2) call.  The DRM core code then looks
10   up the object based on the offset and sets up the various memory mapping
11   structures.
12   </p><p>
13
14   This routine allocates and attaches a fake offset for <em class="parameter"><code>obj</code></em>, in cases where
15   the virtual size differs from the physical size (ie. obj-&gt;size).  Otherwise
16   just use <code class="function">drm_gem_create_mmap_offset</code>.
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