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Date: Tue, 25 Sep 2018 16:58:46 +0800
From: Baoquan He <bhe@redhat.com>
Subject: Re: [PATCH 3/3] resource: Fix find_next_iomem_res() iteration issue
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To: Bjorn Helgaas <helgaas@kernel.org>
Cc: dan.j.williams@intel.com, brijesh.singh@amd.com, Lianbo Jiang <lijiang@redhat.com>, thomas.lendacky@amd.com, tiwai@suse.de, x86@kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, mingo@redhat.com, baiyaowei@cmss.chinamobile.com, hpa@zytor.com, tglx@linutronix.de, bp@suse.de, dyoung@redhat.com, akpm@linux-foundation.org, Vivek Goyal <vgoyal@redhat.com>

Hi Bjorn,

On 09/24/18 at 05:15pm, Bjorn Helgaas wrote:
> @@ -359,32 +362,31 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc,
>  	read_unlock(&resource_lock);
>  	if (!p)
>  		return -1;
> +
>  	/* copy data */
> -	if (res->start < p->start)
> -		res->start = p->start;
> -	if (res->end > p->end)
> -		res->end = p->end;
> +	res->start = max(start, p->start);
> +	res->end = min(end, p->end);
>  	res->flags = p->flags;

I think this fix is good. However, is it OK to keep res->flags always,
never touch it in find_next_iomem_res()? We just iterate and update
region, its start and end. So just removing that "res->flags = p->flags;"
line might involve much less code changes.

Thanks
Baoquan

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