Re: [PATCH 3/4] drivers/base: devres.c: use devm_kmemdup() from with devm_kstrdup()

[Rob Jones]

On 19/06/14 16:59, Joe Perches wrote:
> On Thu, 2014-06-19 at 16:46 +0100, Rob Jones wrote:
> > Avoid code duplication by using devm_kmemdup() to copy data instead
> > of having a separate loop within devm_kstrdup().
> >
> > Reviewed-by: Ian Molton <ian.molton@xxxxxxxxxxxxxxx>
> > Signed-off-by: Rob Jones <rob.jones@xxxxxxxxxxxxxxx>
> []
> > diff --git a/drivers/base/devres.c b/drivers/base/devres.c
> []
> > @@ -802,17 +802,10 @@ EXPORT_SYMBOL_GPL(devm_kmalloc);
> >    */
> >   char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
> >   {
> []
> > +	return devm_kmemdup(dev, s, (strlen(s) + 1), gfp);
> >   }
> >   EXPORT_SYMBOL_GPL(devm_kstrdup);
> Making this static inline in the header and dropping
> EXPORT_SYMBOL_GPL might be smaller code.
>
> static inline
> char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
> {
> 	return devm_kmemdup(dev, s, strlen(s) + 1, gfp);
> }

Is it wise not to check for (s == NULL)? Surely the behaviour of 
strlen(NULL) is undefined.

Consequently, I am, on balance, against making the function static 
inline. Given that inline is only a recommendation to the compiler, it 
may well not inline it anyway if the NULL test is present, in which case 
we would end up with a copy of the code in each module that uses it 
rather than a single, global, copy. If it didn't need the NULL test, I 
would agree that it would be best as a static inline but I think it does 
need it.

--
Rob Jones
Project Manager
Codethink Ltd
mailto:rob.jones@xxxxxxxxxxxxxxx
tel:+44 161 236 5575

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