Path: utzoo!mnetor!tmsoft!torsqnt!lethe!yunexus!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!cs.utexas.edu!romp!auschs!awdprime!doorstop.austin.ibm.com!tif
From: tif@doorstop.austin.ibm.com (Paul Chamberlain)
Newsgroups: comp.unix.internals
Subject: Re: Help with 4.3 mod to kill uninteruptable procs.
Message-ID: <5583@awdprime.UUCP>
Date: 25 Feb 91 14:19:50 GMT
References: <1991Feb19.001941.29928@lynx.CS.ORST.EDU> <1991Feb21.152845.29019@cbnews.att.com> <5558@awdprime.UUCP>
Sender: news@awdprime.UUCP
Reply-To: tif@doorstop.austin.ibm.com (Paul Chamberlain)
Organization: IBM AWD, Austin
Lines: 21

In article <5558@awdprime.UUCP> jfh@greenber.austin.ibm.com (John F Haugh II) writes:
>A typical sleep loop looks something like
>
>	while (some_status & some_busy_flag)
>		sleep (&some_status, PRI_O_MINE);
>
>	some_status |= some_busy_flag;

John, perhaps it obvious, but I've seen several places that neglect to do
this right, and I don't want it to become anymore widespread.  Unless you
like drivers that hang sometimes, this is the way it should be:

	DISABLE_INTERRUPTS;
	while (some_status & some_busy_flag)
		sleep (&some_status, PRI_O_MINE);
	ENABLE_INTERRUPTS;

	some_status |= some_busy_flag;

Paul Chamberlain | I do NOT speak for IBM.          IBM VNET: PAULCC AT AUSTIN
512/838-9662     | ...!cs.utexas.edu!ibmchs!auschs!doorstop.austin.ibm.com!tif


Brought to you by Super Global Mega Corp .com