1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>wait_on_atomic_t</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="Linux Device Drivers"><link rel="up" href="ch01s04.html" title="Wait queues and Wake events"><link rel="prev" href="API-wait-on-bit-lock-action.html" title="wait_on_bit_lock_action"><link rel="next" href="API---wake-up.html" title="__wake_up"></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">wait_on_atomic_t</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-wait-on-bit-lock-action.html">Prev</a>&#160;</td><th width="60%" align="center">Wait queues and Wake events</th><td width="20%" align="right">&#160;<a accesskey="n" href="API---wake-up.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-wait-on-atomic-t"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>wait_on_atomic_t &#8212; 
2     Wait for an atomic_t to become 0
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">wait_on_atomic_t </b>(</code></td><td>atomic_t * <var class="pdparam">val</var>, </td></tr><tr><td>&#160;</td><td>int (*<var class="pdparam">action</var>)
4     <code>(</code>atomic_t *<code>)</code>, </td></tr><tr><td>&#160;</td><td>unsigned <var class="pdparam">mode</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1107416052"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>val</code></em></span></dt><dd><p>
5     The atomic value being waited on, a kernel virtual address
6    </p></dd><dt><span class="term"><em class="parameter"><code>action</code></em></span></dt><dd><p>
7     the function used to sleep, which may take special actions
8    </p></dd><dt><span class="term"><em class="parameter"><code>mode</code></em></span></dt><dd><p>
9     the task state to sleep in
10    </p></dd></dl></div></div><div class="refsect1"><a name="idp1107419692"></a><h2>Description</h2><p>
11   Wait for an atomic_t to become 0.  We abuse the bit-wait waitqueue table for
12   the purpose of getting a waitqueue, but we set the key to a bit number
13   outside of the target 'word'.
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