Re: [PATCH V3 2/2] mm/mmap: Drop generic protection_map[] array

From: Anshuman Khandual
Date: Thu Jun 16 2022 - 23:29:39 EST




On 6/16/22 11:42, hch@xxxxxxxxxxxxx wrote:
> On Thu, Jun 16, 2022 at 05:45:39AM +0000, Christophe Leroy wrote:
>>> +/* Note due to the way vm flags are laid out, the bits are XWR */
>>> +pgprot_t protection_map[16] = {
>>
>> Was const previously, now back to non const ? Maybe due to a conflict
>> with linux/mm.h ? At least it should be __ro_after_init.
>
> Maybe we just need to duplicate vm_get_page_prot in all the
> architectures and thus avoid making protection_map global in a
> common header entirely. That certainly seems like the cleaner
> interface.

Agreed, also it does free up the platforms to provide any appropriate
qualifiers for the protection_map[] array i.e __ro_after_init, const
etc without impacting generic declaration used in a generic function.