1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>usb_block_urb</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="The Linux-USB Host Side API"><link rel="up" href="usbcore.html" title="Chapter&#160;5.&#160;USB Core APIs"><link rel="prev" href="API-usb-poison-urb.html" title="usb_poison_urb"><link rel="next" href="API-usb-kill-anchored-urbs.html" title="usb_kill_anchored_urbs"></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">usb_block_urb</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-usb-poison-urb.html">Prev</a>&#160;</td><th width="60%" align="center">Chapter&#160;5.&#160;USB Core APIs</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-usb-kill-anchored-urbs.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-usb-block-urb"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_block_urb &#8212; 
2     reliably prevent further use of an URB
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">void <b class="fsfunc">usb_block_urb </b>(</code></td><td>struct urb * <var class="pdparam">urb</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1116034228"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>urb</code></em></span></dt><dd><p>
4     pointer to URB to be blocked, may be NULL
5    </p></dd></dl></div></div><div class="refsect1"><a name="idp1116035820"></a><h2>Description</h2><p>
6   After the routine has run, attempts to resubmit the URB will fail
7   with error -EPERM.  Thus even if the URB's completion handler always
8   tries to resubmit, it will not succeed and the URB will become idle.
9   </p><p>
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11   The URB must not be deallocated while this routine is running.  In
12   particular, when a driver calls this routine, it must insure that the
13   completion handler cannot deallocate the URB.
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