linux-kernel - Re: [PATCH v3 00/27] kill devm_ioremap

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Date:   Sun, 24 Dec 2017 10:05:08 +0100
From:   christophe leroy <christophe.leroy@....fr>
To:     Greg KH <gregkh@...uxfoundation.org>,
        Yisheng Xie <xieyisheng1@...wei.com>
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Subject: Re: [PATCH v3 00/27] kill devm_ioremap_nocache



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);}

Christophe

> 
> thanks,
> 
> greg k-h
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