<?xml version="1.0" encoding="ANSI_X3.4-1968" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>blk_queue_max_hw_sectors</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="The Linux Kernel API" /><link rel="up" href="ch14.html" title="Chapter 14. Block Devices" /><link rel="prev" href="re542.html" title="blk_queue_bounce_limit" /><link rel="next" href="re544.html" title="blk_queue_max_discard_sectors" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>blk_queue_max_hw_sectors</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="re542.html">Prev</a> </td><th width="60%" align="center">Chapter 14. Block Devices</th><td width="20%" align="right"> <a accesskey="n" href="re544.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="blk_queue_max_hw_sectors"><a id="API-blk-queue-max-hw-sectors"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>blk_queue_max_hw_sectors — set max sectors for a request for this queue </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">void <b class="fsfunc">blk_queue_max_hw_sectors </b>(</code></td><td>struct request_queue * <var class="pdparam">q</var>, </td></tr><tr><td> </td><td>unsigned int <var class="pdparam">max_hw_sectors</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1" title="Arguments"><a id="id2702536"></a><h2>Arguments</h2><div class="variablelist"><dl><dt><span class="term"><em class="parameter"><code>q</code></em></span></dt><dd><p> the request queue for the device </p></dd><dt><span class="term"><em class="parameter"><code>max_hw_sectors</code></em></span></dt><dd><p> max hardware sectors in the usual 512b unit </p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id2702581"></a><h2>Description</h2><p> Enables a low level driver to set a hard upper limit, max_hw_sectors, on the size of requests. max_hw_sectors is set by the device driver based upon the combined capabilities of I/O controller and storage device. </p><p> max_sectors is a soft limit imposed by the block layer for filesystem type requests. This value can be overridden on a per-device basis in /sys/block/<device>/queue/max_sectors_kb. The soft limit can not exceed max_hw_sectors. </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="re542.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="ch14.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="re544.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span>blk_queue_bounce_limit</span> </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> <span>blk_queue_max_discard_sectors</span></td></tr></table></div></body></html>