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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>usb_alloc_urb</title><meta name="generator" content="DocBook XSL Stylesheets V1.76.1" /><link rel="home" href="index.html" title="The Linux-USB Host Side API" /><link rel="up" href="usbcore.html" title="Chapter 5. USB Core APIs" /><link rel="prev" href="API-usb-init-urb.html" title="usb_init_urb" /><link rel="next" href="API-usb-free-urb.html" title="usb_free_urb" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>usb_alloc_urb</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-usb-init-urb.html">Prev</a> </td><th width="60%" align="center">Chapter 5. USB Core APIs</th><td width="20%" align="right"> <a accesskey="n" href="API-usb-free-urb.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="usb_alloc_urb"><a id="API-usb-alloc-urb"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>usb_alloc_urb —
creates a new urb for a USB driver to use
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" class="funcprototype-table"><tr><td><code class="funcdef">struct urb * <strong>fsfuncusb_alloc_urb </strong>(</code></td><td>int <var class="pdparam">iso_packets</var>, </td></tr><tr><td> </td><td>gfp_t <var class="pdparam">mem_flags</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2984468"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>iso_packets</code></em></span></dt><dd><p>
number of iso packets for this urb
</p></dd><dt><span class="term"><em class="parameter"><code>mem_flags</code></em></span></dt><dd><p>
the type of memory to allocate, see <code class="function">kmalloc</code> for a list of
valid options for this.
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id2984517"></a><h2>Description</h2><p>
Creates an urb for the USB driver to use, initializes a few internal
structures, incrementes the usage counter, and returns a pointer to it.
</p><p>
If no memory is available, NULL is returned.
</p><p>
If the driver want to use this urb for interrupt, control, or bulk
endpoints, pass '0' as the number of iso packets.
</p><p>
The driver must call <code class="function">usb_free_urb</code> when it is finished with the urb.
</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-init-urb.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="usbcore.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="API-usb-free-urb.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>usb_init_urb</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>usb_free_urb</span></td></tr></table></div></body></html>
