Re: [PATCH v3 03/11] mm/ioremap: change the return value of io[re|un]map_allowed and rename

Kefeng Wang
2022-10-10T00:55:14Z

On 2022/10/10 8:25, Baoquan He wrote:
> On 10/09/22 at 07:13pm, Kefeng Wang wrote:
>> On 2022/10/9 18:31, Baoquan He wrote:
>>> Currently, hooks ioremap_allowed() and iounmap_allowed() are used to
>>> check if it's qualified to do ioremap, and now this is done on ARM64.
>>> However, in oder to convert more architectures to take GENERIC_IOREMAP
>>> method, several more things need be done in those two hooks:
>>> 1) The io address mapping need be handled specifically on architectures,
>>> e.g arc, ia64, s390;
>>> 2) The original physical address passed into ioremap_prot() need be
>>> fixed up, e.g arc;
>>> 3) The 'prot' passed into ioremap_prot() need be adjusted, e.g on arc
>>> and xtensa.
>>>
>>> To handle these three issues,
>>>
>>> 1) Rename ioremap_allowed() and iounmap_allowed() to arch_ioremap()
>>> and arch_iounmap() since the old name can't reflect their
>>> functionality after change;
>>> 2) Change the return value of arch_ioremap() so that arch can add
>>> specifical io address mapping handling inside and return the maped
>>> address. Now their returned value means:
>>> ===
>>> arch_ioremap() return a bool,
>> pointer?
> Right, I forgot fixing it again. Thanks.
>
>>> - IS_ERR means return an error
>>> - 0 means continue to remap
>>> - a non-zero, non-IS_ERR pointer is returned directly
>>> arch_iounmap() return a bool,
>>> - true means continue to vunmap
>>> - false means skip vunmap and return directly
>> ...
>>> /*
>>> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
>>> index a68f8fbf423b..2ae16906f3be 100644
>>> --- a/include/asm-generic/io.h
>>> +++ b/include/asm-generic/io.h
>>> @@ -1049,25 +1049,26 @@ static inline void iounmap(volatile void __iomem *addr)
>>> /*
>>> * Arch code can implement the following two hooks when using GENERIC_IOREMAP
>>> - * ioremap_allowed() return a bool,
>>> - * - true means continue to remap
>>> - * - false means skip remap and return directly
>>> - * iounmap_allowed() return a bool,
>>> + * arch_ioremap() return a bool,
>> ditto...
> Will change.
>
>>> area = get_vm_area_caller(size, VM_IOREMAP,
>>> __builtin_return_address(0));
>>> if (!area)
>>> @@ -52,7 +57,7 @@ void iounmap(volatile void __iomem *addr)
>>> {
>>> void *vaddr = (void *)((unsigned long)addr & PAGE_MASK);
>>> - if (!iounmap_allowed(vaddr))
>>> + if (!arch_iounmap((void __iomem *)addr))
>> vaddr?
> No, it's intentional. Alexander suggested this, both of you discussed
> this in v1, see below thread.
ok, please ignore it.
> https://lore.kernel.org/all/Yu4mYxpV0GWRTjQp@li-4a3a4a4c-28e5-11b2-a85c-a8d192c6f089.ibm.com/T/#u
>
>>> return;
>>> if (is_vmalloc_addr(vaddr))
>
> .