LKML: Ashutosh Naik: [PATCH] kernel/module.c Getting rid of the redundant spinlock in resolve

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <!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=UTF-8" /><title>LKML: Ashutosh Naik: [PATCH] kernel/module.c Getting rid of the redundant spinlock in resolve_symbol()</title><link href="/css/message.css" rel="stylesheet" type="text/css" /><link href="/css/wrap.css" rel="alternate stylesheet" type="text/css" title="wrap" /><link href="/css/nowrap.css" rel="stylesheet" type="text/css" title="nowrap" /><link href="/favicon.ico" rel="shortcut icon" /><script src="/js/simple-calendar.js" type="text/javascript"></script><script src="/js/styleswitcher.js" type="text/javascript"></script><link rel="alternate" type="application/rss+xml" title="lkml.org : last 100 messages" href="/rss.php" /><link rel="alternate" type="application/rss+xml" title="lkml.org : last messages by Ashutosh Naik" href="/groupie.php?aid=29150" /><script> var _paq = window._paq = window._paq || []; /* tracker methods like "setCustomDimension" should be called before "trackPageView" */ _paq.push(["setDoNotTrack", true]); _paq.push(["disableCookies"]); _paq.push(['trackPageView']); _paq.push(['enableLinkTracking']); (function() { var u="//m.lkml.org/"; _paq.push(['setTrackerUrl', u+'matomo.php']); _paq.push(['setSiteId', '1']); var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0]; g.async=true; g.src=u+'matomo.js'; s.parentNode.insertBefore(g,s); })(); </script></head><body onload="es.jasper.simpleCalendar.init();" itemscope="itemscope" itemtype="http://schema.org/BlogPosting"><table border="0" cellpadding="0" cellspacing="0"><tr><td width="180" align="center"><a href="/"><img style="border:0;width:135px;height:32px" src="/images/toprowlk.gif" alt="lkml.org" /></a></td><td width="32">聽</td><td class="nb"><div><a class="nb" href="/lkml"> [lkml]</a> 聽 <a class="nb" href="/lkml/2005"> [2005]</a> 聽 <a class="nb" href="/lkml/2005/12"> [Dec]</a> 聽 <a class="nb" href="/lkml/2005/12/15"> [15]</a> 聽 <a class="nb" href="/lkml/last100"> [last100]</a> 聽 <a href="/rss.php"><img src="/images/rss-or.gif" border="0" alt="RSS Feed" /></a></div><div>Views: <a href="#" class="nowrap" onclick="setActiveStyleSheet('wrap');return false;">[wrap]</a><a href="#" class="wrap" onclick="setActiveStyleSheet('nowrap');return false;">[no wrap]</a> 聽 <a class="nb" href="/lkml/mheaders/2005/12/15/450" onclick="this.href='/lkml/headers'+'/2005/12/15/450';">[headers]</a>聽 <a href="/lkml/bounce/2005/12/15/450">[forward]</a>聽 </div></td><td width="32">聽</td></tr><tr><td valign="top"><div class="es-jasper-simpleCalendar" baseurl="/lkml/"></div><div class="threadlist">Messages in this thread</div><ul class="threadlist"><li class="root"><a href="/lkml/2005/12/15/450">First message in thread</a></li><li class="origin"><a href="">Ashutosh Naik</a></li></ul><div class="threadlist">Patch in this message</div><ul class="threadlist"><li><a href="/lkml/diff/2005/12/15/450/1">Get diff 1</a></li></ul></td><td width="32" rowspan="2" class="c" valign="top"><img src="/images/icornerl.gif" width="32" height="32" alt="/" /></td><td class="c" rowspan="2" valign="top" style="padding-top: 1em"><table><tr><td><table><tr><td class="lp">Date</td><td class="rp" itemprop="datePublished">Thu, 15 Dec 2005 10:02:42 +0530</td></tr><tr><td class="lp">From</td><td class="rp" itemprop="author">Ashutosh Naik <></td></tr><tr><td class="lp">Subject</td><td class="rp" itemprop="name">[PATCH] kernel/module.c Getting rid of the redundant spinlock in resolve_symbol()</td></tr></table></td><td></td></tr></table><pre itemprop="articleBody">On 12/15/05, Rusty Russell <rusty@rustcorp.com.au> wrote:<br />> On Wed, 2005-12-14 at 11:16 +0530, Ashutosh Naik wrote:<br />> > On 12/14/05, Rusty Russell <rusty@rustcorp.com.au> wrote:<br />> > Was just wondering, in that case, if we really need the spinlock in<br />> > resolve_symbol() function, where there exists a spinlock around the<br />> > __find_symbol() function<br />><br />> Yes, I think that's redundant as well. We're not altering the module<br />> list itself, so either of the two locks is sufficient, and we have the<br />> semaphore.<br /><br />Changelog -<br /><br />This patch gets rid of the redundant spinlock in the function<br />resolve_symbol() as we are not altering the module list, and we<br />already hold the semaphore.<br /><br />Signed-off-by: Ashutosh Naik <ashutosh.naik@gmail.com><br />diff -Naurp linux-2.6.15-rc5-vanilla/kernel/module.c linux-2.6.15-rc5/kernel/module.c<br />--- linux-2.6.15-rc5-vanilla/kernel/module.c 2005-12-14 10:14:08.000000000 +0530<br />+++ linux-2.6.15-rc5/kernel/module.c 2005-12-15 09:41:59.000000000 +0530<br />@@ -958,7 +958,6 @@ static unsigned long resolve_symbol(Elf_<br /> unsigned long ret;<br /> const unsigned long *crc;<br /> <br />- spin_lock_irq(&modlist_lock);<br /> ret = __find_symbol(name, &owner, &crc, mod->license_gplok);<br /> if (ret) {<br /> /* use_module can fail due to OOM, or module unloading */<br />@@ -966,7 +965,6 @@ static unsigned long resolve_symbol(Elf_<br /> !use_module(mod, owner))<br /> ret = 0;<br /> }<br />- spin_unlock_irq(&modlist_lock);<br /> return ret;<br /> }<br /> </pre></td><td width="32" rowspan="2" class="c" valign="top"><img src="/images/icornerr.gif" width="32" height="32" alt="\" /></td></tr><tr><td align="right" valign="bottom"> 聽 </td></tr><tr><td align="right" valign="bottom">聽</td><td class="c" valign="bottom" style="padding-bottom: 0px"><img src="/images/bcornerl.gif" width="32" height="32" alt="\" /></td><td class="c">聽</td><td class="c" valign="bottom" style="padding-bottom: 0px"><img src="/images/bcornerr.gif" width="32" height="32" alt="/" /></td></tr><tr><td align="right" valign="top" colspan="2"> 聽 </td><td class="lm">Last update: 2005-12-16 04:33 聽聽 [from the cache]<br />漏2003-2020 <a href="http://blog.jasper.es/"><span itemprop="editor">Jasper Spaans</span></a>|hosted at <a href="https://www.digitalocean.com/?refcode=9a8e99d24cf9">Digital Ocean</a> and my Meterkast|<a href="http://blog.jasper.es/categories.html#lkml-ref">Read the blog</a></td><td>聽</td></tr></table><script language="javascript" src="/js/styleswitcher.js" type="text/javascript"></script></body></html>

CINXE.COM

LKML: Ashutosh Naik: [PATCH] kernel/module.c Getting rid of the redundant spinlock in resolve_symbol()