<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"> <HTML ><HEAD ><TITLE >posix_lock_file</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="The Linux Kernel API" HREF="book1.html"><LINK REL="UP" TITLE="File Locks" HREF="x4323.html"><LINK REL="PREVIOUS" TITLE="File Locks" HREF="x4323.html"><LINK REL="NEXT" TITLE="__get_lease" HREF="r4373.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >The Linux Kernel API</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="x4323.html" ACCESSKEY="P" ><<< Previous</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="r4373.html" ACCESSKEY="N" >Next >>></A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="AEN4325" ></A ><SPAN CLASS="phrase" ><SPAN CLASS="PHRASE" >posix_lock_file</SPAN ></SPAN ></H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN4329" ></A ><H2 >Name</H2 >posix_lock_file -- </DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN4332" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN4334" ></A ><P ></P ><P ><CODE ><CODE CLASS="FUNCDEF" >int <TT CLASS="FUNCTION" >posix_lock_file </TT ></CODE >(struct file * <TT CLASS="PARAMETER" ><I >filp</I ></TT >, struct file_lock * <TT CLASS="PARAMETER" ><I >caller</I ></TT >, unsigned int <TT CLASS="PARAMETER" ><I >wait</I ></TT >);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN4344" ></A ><H2 >Arguments</H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="PARAMETER" ><I >filp</I ></TT ></DT ><DD ><P > The file to apply the lock to </P ></DD ><DT ><TT CLASS="PARAMETER" ><I >caller</I ></TT ></DT ><DD ><P > The lock to be applied </P ></DD ><DT ><TT CLASS="PARAMETER" ><I >wait</I ></TT ></DT ><DD ><P > 1 to retry automatically, 0 to return -EAGAIN </P ></DD ></DL ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN4362" ></A ><H2 >Description</H2 ><P > Add a POSIX style lock to a file. We merge adjacent locks whenever possible. POSIX locks are sorted by owner task, then by starting address </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN4365" ></A ><H2 >Kai Petzke writes</H2 ><P > To make freeing a lock much faster, we keep a pointer to the lock before the actual one. But the real gain of the new coding was, that <TT CLASS="FUNCTION" >lock_it</TT > and <TT CLASS="FUNCTION" >unlock_it</TT > became one function. </P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN4370" ></A ><H2 >To all purists</H2 ><P > Yes, I use a few goto's. Just pass on to the next function. </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="x4323.html" ACCESSKEY="P" ><<< Previous</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="book1.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="r4373.html" ACCESSKEY="N" >Next >>></A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >File Locks</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="x4323.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><SPAN CLASS="phrase" ><SPAN CLASS="PHRASE" >__get_lease</SPAN ></SPAN ></TD ></TR ></TABLE ></DIV ></BODY ></HTML >