Re: [PATCH 0/2 RESEND v7] add reserved e820 ranges to the kdump kernel e820 table

From: lijiang
Date: Mon Nov 26 2018 - 21:59:00 EST

å 2018å11æ27æ 02:54, Dave Hansen åé:
> On 11/23/18 9:12 PM, Lianbo Jiang wrote:
>> These patches add the new I/O resource descriptor 'IORES_DESC_RESERVED'
>> for the iomem resources search interfaces, and in order to make it still
>> work after the new descriptor is added, these codes originally related
>> to 'IORES_DESC_NONE' have been updated.
> This is rather anemic "0/" text. Could you please include some more
> background in here? The 2/2 patch is pretty good in this regard, but it
> needs to be here, too.

Thanks for your comment.

Originally, this patch added the e820 reserved ranges by accurately comparing
a string. It only modifies fewer code paths. Please refer to patch v6.

Because the string comparison is fragile and error-prone, this patch used the
solution that adds a new descriptor 'IORES_DESC_RESERVED'. Please refer to this

When passing the e820 reserved ranges to the second kernel, why does it need to
compare strings accurately or add a new descriptor 'IORES_DESC_RESERVED'?

-The reason is that it can not exactly match the e820 reserved resource ranges
when walking through iomem resources with the descriptor 'IORES_DESC_NONE'.