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SubjectRe: [PATCH v4 4/6] mm: ioremap: Add ioremap/iounmap_allowed()
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On 2022/6/6 23:14, Baoquan He wrote:
> On 06/06/22 at 03:48pm, Kefeng Wang wrote:
>> Add special hook for architecture to verify addr, size or prot
>> when ioremap() or iounmap(), which will make the generic ioremap
>> more useful.
>>
>> ioremap_allowed() return an int,
>> - NULL means continue to remap
>> - error code means skip remap and return directly
>> iounmap_allowed() return an int,
>> - 0 means continue to vunmap
>> - error code means skip vunmap and return directly
> Aren't they bool type function and better return bool value?

Ok, let's keep it simple, back to v1's version , use bool, if we want to
extend

them,  do it later.

>
>> Acked-by: Andrew Morton <akpm@linux-foundation.org>
>> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
>> ---
>> include/asm-generic/io.h | 25 +++++++++++++++++++++++++
>> mm/ioremap.c | 13 ++++++++++---
>> 2 files changed, 35 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
>> index e6ffa2519f08..9429387a3e65 100644
>> --- a/include/asm-generic/io.h
>> +++ b/include/asm-generic/io.h
>> @@ -964,6 +964,31 @@ static inline void iounmap(volatile void __iomem *addr)
>> #elif defined(CONFIG_GENERIC_IOREMAP)
>> #include <linux/pgtable.h>
>>
>> +/*
>> + * Arch code can implement the following two special hooks when using GENERIC_IOREMAP
>> + * ioremap_allowed() return an int,
>> + * - 0 means continue to remap
>> + * - error code means skip remap and return directly
>> + * iounmap_allowed() return an int,
>> + * - 0 means continue to vunmap
>> + * - error code means skip vunmap and return directly
>> + */
>> +#ifndef ioremap_allowed
>> +#define ioremap_allowed ioremap_allowed
>> +static inline int ioremap_allowed(phys_addr_t phys_addr, size_t size, unsigned long prot)
>> +{
>> + return 0;
>> +}
>> +#endif
>> +
>> +#ifndef iounmap_allowed
>> +#define iounmap_allowed iounmap_allowed
>> +static inline int iounmap_allowed(void __iomem *addr)
>> +{
>> + return 0;
>> +}
>> +#endif
>> +
>> void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, unsigned long prot);
>> void iounmap(volatile void __iomem *addr);
>>
>> diff --git a/mm/ioremap.c b/mm/ioremap.c
>> index 7cb9996b0c12..196c93c0beb8 100644
>> --- a/mm/ioremap.c
>> +++ b/mm/ioremap.c
>> @@ -27,8 +27,10 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, unsigned long pro
>> phys_addr -= offset;
>> size = PAGE_ALIGN(size + offset);
>>
>> - area = get_vm_area_caller(size, VM_IOREMAP,
>> - __builtin_return_address(0));
>> + if (ioremap_allowed(phys_addr, size, prot))
>> + return NULL;
>> +
>> + area = get_vm_area_caller(size, VM_IOREMAP, __builtin_return_address(0));
>> if (!area)
>> return NULL;
>> vaddr = (unsigned long)area->addr;
>> @@ -45,6 +47,11 @@ EXPORT_SYMBOL(ioremap_prot);
>>
>> void iounmap(volatile void __iomem *addr)
>> {
>> - vunmap((void *)((unsigned long)addr & PAGE_MASK));
>> + void __iomem *vaddr = (void __iomem *)((unsigned long)addr & PAGE_MASK);
>> +
>> + if (iounmap_allowed(vaddr))
>> + return;
>> +
>> + vunmap((void __force *)vaddr);
>> }
>> EXPORT_SYMBOL(iounmap);
>> --
>> 2.35.3
>>
>>
> .

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