Re: [PATCH v3 00/27] kill devm_ioremap_nocache

[Christophe LEROY <christophe.leroy@xxxxxx>]

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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