1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>usb_hcd_check_unlink_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="hcd.html" title="Chapter 6. Host Controller APIs"><link rel="prev" href="API-usb-hcd-link-urb-to-ep.html" title="usb_hcd_link_urb_to_ep"><link rel="next" href="API-usb-hcd-unlink-urb-from-ep.html" title="usb_hcd_unlink_urb_from_ep"></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_hcd_check_unlink_urb</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-usb-hcd-link-urb-to-ep.html">Prev</a> </td><th width="60%" align="center">Chapter 6. Host Controller APIs</th><td width="20%" align="right"> <a accesskey="n" href="API-usb-hcd-unlink-urb-from-ep.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-usb-hcd-check-unlink-urb"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_hcd_check_unlink_urb — 2 check whether an URB may be unlinked 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">usb_hcd_check_unlink_urb </b>(</code></td><td>struct usb_hcd * <var class="pdparam">hcd</var>, </td></tr><tr><td> </td><td>struct urb * <var class="pdparam">urb</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">status</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idp1116738252"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>hcd</code></em></span></dt><dd><p> 4 host controller to which <em class="parameter"><code>urb</code></em> was submitted 5 </p></dd><dt><span class="term"><em class="parameter"><code>urb</code></em></span></dt><dd><p> 6 URB being checked for unlinkability 7 </p></dd><dt><span class="term"><em class="parameter"><code>status</code></em></span></dt><dd><p> 8 error code to store in <em class="parameter"><code>urb</code></em> if the unlink succeeds 9 </p></dd></dl></div></div><div class="refsect1"><a name="idp1116742580"></a><h2>Description</h2><p> 10 Host controller drivers should call this routine in their <code class="function">dequeue</code> 11 method. The HCD's private spinlock must be held and interrupts must 12 be disabled. The actions carried out here are required for making 13 sure than an unlink is valid. 14</p></div><div class="refsect1"><a name="idp1116743772"></a><h2>Return</h2><p> 15 0 for no error, otherwise a negative error code (in which case 16 the <code class="function">dequeue</code> method must fail). The possible error codes are: 17 </p><p> 18 19 -EIDRM: <em class="parameter"><code>urb</code></em> was not submitted or has already completed. 20 The completion function may not have been called yet. 21 </p><p> 22 23 -EBUSY: <em class="parameter"><code>urb</code></em> has already been unlinked. 24</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API-usb-hcd-link-urb-to-ep.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="hcd.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="API-usb-hcd-unlink-urb-from-ep.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">usb_hcd_link_urb_to_ep</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span class="phrase">usb_hcd_unlink_urb_from_ep</span></td></tr></table></div></body></html> 25