Re: [PATCH v3 00/27] kill devm_ioremap_nocache

[Christophe LEROY <christophe.leroy@c-s.fr>]

Le 25/12/2017 à 02:34, Yisheng Xie a écrit :
> 
> 
> On 2017/12/24 17:05, christophe leroy wrote:
>>
>>
>> Le 23/12/2017 à 14:48, Greg KH a écrit :
>>> On Sat, Dec 23, 2017 at 06:55:25PM +0800, Yisheng Xie wrote:
>>>> Hi all,
>>>>
>>>> When I tried to use devm_ioremap function and review related code, I found
>>>> devm_ioremap and devm_ioremap_nocache is almost the same with each other,
>>>> except one use ioremap while the other use ioremap_nocache.
>>>
>>> For all arches?  Really?  Look at MIPS, and x86, they have different
>>> functions.
>>>
>>>> While ioremap's
>>>> default function is ioremap_nocache, so devm_ioremap_nocache also have the
>>>> same function with devm_ioremap, which can just be killed to reduce the size
>>>> of devres.o(from 20304 bytes to 18992 bytes in my compile environment).
>>>>
>>>> I have posted two versions, which use macro instead of function for
>>>> devm_ioremap_nocache[1] or devm_ioremap[2]. And Greg suggest me to kill
>>>> devm_ioremap_nocache for no need to keep a macro around for the duplicate
>>>> thing. So here comes v3 and please help to review.
>>>
>>> I don't think this can be done, what am I missing?  These functions are
>>> not identical, sorry for missing that before.
>>
>> devm_ioremap() and devm_ioremap_nocache() are quite similar, both use devm_ioremap_release() for the release, why not just defining:
>>
>> static void __iomem *__devm_ioremap(struct device *dev, resource_size_t offset,
>>                 resource_size_t size, bool nocache)
>> {
>> [...]
>>      if (nocache)
>>          addr = ioremap_nocache(offset, size);
>>      else
>>          addr = ioremap(offset, size);
>> [...]
>> }
>>
>> then in include/linux/io.h
>>
>> static inline void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
>>                 resource_size_t size)
>> {return __devm_ioremap(dev, offset, size, false);}
>>
>> static inline void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset,
>>                     resource_size_t size);
>> {return __devm_ioremap(dev, offset, size, true);}
> 
> Yeah, this seems good to me, right now we have devm_ioremap, devm_ioremap_wc, devm_ioremap_nocache
> May be we can use an enum like:
> typedef enum {
> 	DEVM_IOREMAP = 0,
> 	DEVM_IOREMAP_NOCACHE,
> 	DEVM_IOREMAP_WC,
> } devm_ioremap_type;
> 
> static inline void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
>                  resource_size_t size)
>   {return __devm_ioremap(dev, offset, size, DEVM_IOREMAP);}
> 
>   static inline void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset,
>                      resource_size_t size);
>   {return __devm_ioremap(dev, offset, size, DEVM_IOREMAP_NOCACHE);}
> 
>   static inline void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset,
>                      resource_size_t size);
>   {return __devm_ioremap(dev, offset, size, DEVM_IOREMAP_WC);}
> 
>   static void __iomem *__devm_ioremap(struct device *dev, resource_size_t offset,
>                  resource_size_t size, devm_ioremap_type type)
>   {
>       void __iomem **ptr, *addr = NULL;
>   [...]
>       switch (type){
>       case DEVM_IOREMAP:
>           addr = ioremap(offset, size);
>           break;
>       case DEVM_IOREMAP_NOCACHE:
>           addr = ioremap_nocache(offset, size);
>           break;
>       case DEVM_IOREMAP_WC:
>           addr = ioremap_wc(offset, size);
>           break;
>       }
>   [...]
>   }


That looks good to me, will you submit a v4 ?

Christophe

> 
> Thanks
> Yisheng
> 
>>
>> Christophe
>>
>>>
>>> thanks,
>>>
>>> greg k-h
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