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Subject: Re: [PATCH -mm 2/4] x86_64 boot: Add linked list of struct
	setup_data
From: "Huang, Ying" <ying.huang@intel.com>
To: Paul Jackson <pj@sgi.com>
Cc: hpa@zytor.com, andi@firstfloor.org, mingo@redhat.com, tglx@linutronix.de,
       linux-kernel@vger.kernel.org
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References: <1206601748.3067.22.camel@caritas-dev.intel.com>
	 <20080327062539.5cbcb925.pj@sgi.com>
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Date: Fri, 28 Mar 2008 10:08:37 +0800
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On Thu, 2008-03-27 at 06:25 -0500, Paul Jackson wrote:
> Huang wrote:
> +	while (pa_data) {
> +		data = early_ioremap(pa_data, PAGE_SIZE);
> +		switch (data->type) {
> +		default:
> +			break;
> +		}
> 
> Isn't that switch statement equivalent to -always- breaking, as in:
> 
> +	while (pa_data) {
> +		data = early_ioremap(pa_data, PAGE_SIZE);
> +		break;
> 
> I doubt you want to do that.  I suppose what you want to do is check for
> data == NULL instead, as in:
> 
> +	while (pa_data) {
> +		data = early_ioremap(pa_data, PAGE_SIZE);
> +		if (!data)
> +			break;

This break will break the switch instead of while. When setup_data
processing code is added, the code will looks like:

#define SETUP_DATA_E820_EXT	1

while (pa_data) {
	data = early_ioremap(pa_data, PAGE_SIZE);
	switch (data->type) {
	case SETUP_DATA_E820_EXT:
		parse_e820_ext(data, pa_data);
		break;
	default:
		break;
	}
...

Best Regards,
Huang Ying