1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>__copy_to_user_inatomic</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="ch04s02.html" title="User Space Memory Access"><link rel="prev" href="ch04s02.html" title="User Space Memory Access"><link rel="next" href="API---copy-to-user.html" title="__copy_to_user"></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">__copy_to_user_inatomic</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch04s02.html">Prev</a>&#160;</td><th width="60%" align="center">User Space Memory Access</th><td width="20%" align="right">&#160;<a accesskey="n" href="API---copy-to-user.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API---copy-to-user-inatomic"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>__copy_to_user_inatomic &#8212; 
2  Copy a block of data into user space, with less checking.
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">unsigned long <b class="fsfunc">__copy_to_user_inatomic </b>(</code></td><td>void __user * <var class="pdparam">to</var>, </td></tr><tr><td>&#160;</td><td>const void * <var class="pdparam">from</var>, </td></tr><tr><td>&#160;</td><td>unsigned long <var class="pdparam">n</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1123894052"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>to</code></em></span></dt><dd><p>
4     Destination address, in user space.
5    </p></dd><dt><span class="term"><em class="parameter"><code>from</code></em></span></dt><dd><p>
6     Source address, in kernel space.
7    </p></dd><dt><span class="term"><em class="parameter"><code>n</code></em></span></dt><dd><p>
8     Number of bytes to copy.
9    </p></dd></dl></div></div><div class="refsect1"><a name="idp1123897668"></a><h2>Context</h2><p>
10   User context only.
11</p></div><div class="refsect1"><a name="idp1123898292"></a><h2>Description</h2><p>
12   Copy data from kernel space to user space.  Caller must check
13   the specified block with <code class="function">access_ok</code> before calling this function.
14   The caller should also make sure he pins the user space address
15   so that we don't result in page fault and sleep.
16   </p><p>
17
18   Here we special-case 1, 2 and 4-byte copy_*_user invocations.  On a fault
19   we return the initial request size (1, 2 or 4), as copy_*_user should do.
20   If a store crosses a page boundary and gets a fault, the x86 will not write
21   anything, so this is accurate.
22</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="ch04s02.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="ch04s02.html">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="API---copy-to-user.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">User Space Memory Access&#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">__copy_to_user</span></td></tr></table></div></body></html>
23