linux-kernel - Re: [v2] lib/string: add memrchr function

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Date:   Wed, 13 Feb 2019 03:19:40 +0800
From:   xiang xiao <xiaoxiang781216@...il.com>
To:     Greg KH <gregkh@...uxfoundation.org>
Cc:     alexander.shishkin@...ux.intel.com,
        andriy.shevchenko@...ux.intel.com, linux-kernel@...r.kernel.org,
        Xiang Xiao <xiaoxiang@...omi.com>
Subject: Re: [v2] lib/string: add memrchr function

On Wed, Feb 13, 2019 at 3:12 AM Greg KH <gregkh@...uxfoundation.org> wrote:
>
> On Wed, Feb 13, 2019 at 02:54:43AM +0800, Xiang Xiao wrote:
> > Here is the detailed description for memrchr:
> >
> > void *memrchr(const void *s, int c, size_t n);
> >
> > The memrchr() function is like the memchr() function, except
> > that it searches backward from the end of the n bytes pointed
> > to by s instead of forward from the beginning.
> >
> > The memrchr() functions return a pointer to the matching byte
> > or NULL if the character does not occur in the given memory
> > area.
> >
> > Signed-off-by: Xiang Xiao <xiaoxiang@...omi.com>
> > ---
> >  include/linux/string.h |  1 +
> >  lib/string.c           | 21 +++++++++++++++++++++
> >  2 files changed, 22 insertions(+)
> >
> > diff --git a/include/linux/string.h b/include/linux/string.h
> > index 7927b87..f380f4b 100644
> > --- a/include/linux/string.h
> > +++ b/include/linux/string.h
> > @@ -167,6 +167,7 @@ static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt)
> >       memcpy(dst, src, cnt);
> >  }
> >  #endif
> > +void *memrchr(const void *s, int c, size_t n);
> >  void *memchr_inv(const void *s, int c, size_t n);
> >  char *strreplace(char *s, char old, char new);
>
> Also, if you really need this, why not also provide the arch-specific
> versions as well?
>

Good point, I will make the arch-specific overwrite possible.

> thanks,
>
> greg k-h