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

Kefeng Wang
2022-10-09T11:14:01Z

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?
> - 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...
> 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?
> return;
>
> if (is_vmalloc_addr(vaddr))