linux-kernel - Re: [PATCH 3/3] ACPI: fix acpi_parse_entries_array() so it reports overflow correctly

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Message-ID: <707a387c-43a0-daf4-a2c5-98e1d016f2b4@redhat.com>
Date:	Fri, 1 Jul 2016 15:44:01 -0600
From:	Al Stone <ahs3@...hat.com>
To:	"Rafael J. Wysocki" <rafael@...nel.org>
Cc:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>
Subject: Re: [PATCH 3/3] ACPI: fix acpi_parse_entries_array() so it reports
 overflow correctly

On 07/01/2016 03:40 PM, Rafael J. Wysocki wrote:
> On Fri, Jul 1, 2016 at 11:21 PM, Al Stone <ahs3@...hat.com> wrote:
>> The function acpi_parse_entries_array() has a limiting parameter,
>> max_entries, which tells the function to stop looking at subtables
>> once that limit has been reached.  Further, if the limit is reached,
>> it is reported.  However, the logic is incorrect in that the loop
>> to examine all subtables will always stop when exactly max_entries
>> have been found, regardless of whether or not there are still subtables
>> to examine, and it will always report that zero subtables have been
>> ignored.  This change allows the loop to continue to look at all
>> subtables and count all the ones of interest; if we have already
>> reached the number of max_entries, though, we will not invoke the
>> callback functions.  If the max_entries limit has been exceeded,
>> report on that, as before, but more accurately, listing how many
>> subtables of interest there are in total (as was meant), and how
>> many entries each subtable type occupied.
> 
> The problem appears to be that, if max_entries has been reached, it
> prints "ignored 0", although it should count all of the entries in
> that case too in principle.  Do I think correctly?
> 

Exactly.  That's how I interpreted the comments.  And it fit what I
needed it to do if the comments were correct.

Of course, it could be the code was correct and the comments were
wrong :).  I preferred not to think that.

-- 
ciao,
al
-----------------------------------
Al Stone
Software Engineer
Red Hat, Inc.
ahs3@...hat.com
-----------------------------------