linux-kernel - Re: [ patch 00/21 ] support multiple, pending ddebugs at kernel-boot

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Message-ID: <CAJfuBxwET2zVWBJCBsUsEu661h+rzfHhtgvRY7SuBG7nPQLZnw@mail.gmail.com>
Date:	Tue, 12 Jul 2011 01:39:19 -0600
From:	Jim Cromie <jim.cromie@...il.com>
To:	Bart Van Assche <bvanassche@....org>
Cc:	jbaron@...hat.com, linux-kernel@...r.kernel.org, joe@...ches.com,
	gregkh@...e.de, gnb@...h.org
Subject: Re: [ patch 00/21 ] support multiple, pending ddebugs at kernel-boot

On Mon, Jul 11, 2011 at 11:53 PM, Bart Van Assche <bvanassche@....org> wrote:
> On Mon, Jul 11, 2011 at 9:06 PM, Jim Cromie <jim.cromie@...il.com> wrote:
>> On Mon, Jul 11, 2011 at 12:30 PM, Bart Van Assche <bvanassche@....org> wrote:
>>> As far as I can see with v2 of this patch set a query gets on the
>>> pending list if either +a has been specified or no matches were found
>>> the first time a query is run. Are both mechanisms necessary ? If not,
>>> I propose to leave out the second. That will not only allow to
>>> simplify the code somewhat but will also reduce confusion for
>>> dynamic_printk users.
>>>
>>
>> Both conditions are necessary:
>> - 'a' flag required,
>> - query not directly applicable.
>>
>> root@...age:~# echo "module nosuch +p" > /dbg/dynamic_debug/control
>> root@...age:~# cat /sys/module/dynamic_debug/parameters/pending_ct
>> 0
>>
>> root@...age:~# echo "module nosuch +ap" > /dbg/dynamic_debug/control
>> root@...age:~# cat /sys/module/dynamic_debug/parameters/pending_ct
>> 1
>
> The above example contradicts the following code added in patch 09/21:
>
>        /* actually go and implement the change */
>        nfound = ddebug_change(&query, flags, mask);
> +
> +       pr_info("nfound %d on %s\n", nfound, show_ddebug_query(&query));
> +       if (!nfound)
> +               return ddebug_save_pending(&query, flags, mask);
> +
>        return 0;
>
> Bart.
>

In patch 13, that becomes

+	if (!nfound) {
+		if (flags & _DPRINTK_FLAGS_APPEND)
+			return ddebug_save_pending(&query, flags, mask);
+		else
+			pr_warn("no match on: %s\n",
+				show_ddebug_query(&query));
+	}
 	return 0;
 }


its altered once more, when I add filter-flags,
but that doesnt really change my assertion.

 	nfound = ddebug_change(&query, flags, mask, filter);
 	if (!nfound) {
-		if (flags & _DPRINTK_FLAGS_APPEND)
+		if (flags & _DPRINTK_FLAGS_APPEND ||
+			filter & _DPRINTK_FLAGS_APPEND)
 			rc = ddebug_save_pending(&query, flags, mask);
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