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From: ado@elsie.UUCP (Arthur David Olson)
Newsgroups: net.unix-wizards
Subject: Wanted: spl()ing checkers
Message-ID: <5237@elsie.UUCP>
Date: Mon, 7-Oct-85 11:00:42 EDT
Article-I.D.: elsie.5237
Posted: Mon Oct  7 11:00:42 1985
Date-Received: Wed, 9-Oct-85 06:07:43 EDT
Organization: NIH-LEC, Bethesda, MD
Lines: 22
Keywords: 4.2bsd VAX splx

The 4.2bsd version of the kernel function "bflush" calls "spl6",
goes through some gyrations, and eventually may call one of the disk "strategy"
functions.  One of these in particular, "hpstrategy", calls "spl5".

Now it seems to me that theoretically the spl5 call when things are chugging
along at priority level 6 is a no-no--although in this case there doesn't seem
to be any bad effect in practice.

And so some questions to all you wizards:

1.	Should "bflush" actually be doing a "spl5" call?
2.	Should "hpstrategy" actually be doing a "spl6" call?
3.	Should "bflush" be doing a "splx(s)" call (to restore the processor
	level to its entry value) before calling the disk strategy function?
4.	Should spl4, spl5, spl6, and spl7 check to ensure that the priority
	level is being raised before changing the priority level?
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