linux-kernel - Re: [PATCH v3] lib/string: Introduce sysfs

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Date:   Thu, 8 Apr 2021 15:06:53 +0200
From:   Gioh Kim <gi-oh.kim@...os.com>
To:     Jinpu Wang <jinpu.wang@...os.com>
Cc:     open list <linux-kernel@...r.kernel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Dan Williams <dan.j.williams@...el.com>,
        laniel_francis@...vacyrequired.com,
        Kees Cook <keescook@...omium.org>, dja@...ens.net,
        Andrew Morton <akpm@...ux-foundation.org>,
        Haris Iqbal <haris.iqbal@...os.com>
Subject: Re: [PATCH v3] lib/string: Introduce sysfs_streqcase

Hi Jinpu,

I removed #ifdef CONFIG_SYSFS ~ #endif.
Could you please review again?

On Thu, Apr 8, 2021 at 12:50 PM Jinpu Wang <jinpu.wang@...os.com> wrote:
>
> On Thu, Apr 8, 2021 at 11:34 AM Gioh Kim <gi-oh.kim@...os.com> wrote:
> >
> > As the name shows, it checks if strings are equal in case insensitive
> > manner.
> >
> > For example, drivers/infiniband/ulp/rtrs/rtrs-clt-sysfs.c uses
> > strncasecmp to check that the input via sysfs is "mi". But it would
> > work even-if the input is "min-wrongcommand".
> >
> > I found some more cases using strncasecmp to check the entire string
> > such as rtrs-clt-sysfs.c does. drivers/pnp/interface.c checks
> > "disable" command with strncasecmp but it would also work if the
> > command is "disable-wrong".
> >
> > Signed-off-by: Gioh Kim <gi-oh.kim@...os.com>
> It looks good to me.
> Reviewed-by: Jack Wang <jinpu.wang@...os.com>
> > ---
> >  include/linux/string.h |  1 +
> >  lib/string.c           | 38 ++++++++++++++++++++++++++++++--------
> >  2 files changed, 31 insertions(+), 8 deletions(-)
> >
> > diff --git a/include/linux/string.h b/include/linux/string.h
> > index 4fcfb56abcf5..36d00ff8013e 100644
> > --- a/include/linux/string.h
> > +++ b/include/linux/string.h
> > @@ -184,6 +184,7 @@ extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
> >  extern void argv_free(char **argv);
> >
> >  extern bool sysfs_streq(const char *s1, const char *s2);
> > +extern bool sysfs_streqcase(const char *s1, const char *s2);
> >  extern int kstrtobool(const char *s, bool *res);
> >  static inline int strtobool(const char *s, bool *res)
> >  {
> > diff --git a/lib/string.c b/lib/string.c
> > index 7548eb715ddb..cb53845cc4ac 100644
> > --- a/lib/string.c
> > +++ b/lib/string.c
> > @@ -687,6 +687,18 @@ char *strsep(char **s, const char *ct)
> >  EXPORT_SYMBOL(strsep);
> >  #endif
> >
> > +#ifdef CONFIG_SYSFS
> > +static inline bool __streq_terminal(const char *s1, const char *s2)
> > +{
> > +       if (*s1 == *s2)
> > +               return true;
> > +       if (!*s1 && *s2 == '\n' && !s2[1])
> > +               return true;
> > +       if (*s1 == '\n' && !s1[1] && !*s2)
> > +               return true;
> > +       return false;
> > +}
> > +
> >  /**
> >   * sysfs_streq - return true if strings are equal, modulo trailing newline
> >   * @s1: one string
> > @@ -703,17 +715,27 @@ bool sysfs_streq(const char *s1, const char *s2)
> >                 s1++;
> >                 s2++;
> >         }
> > -
> > -       if (*s1 == *s2)
> > -               return true;
> > -       if (!*s1 && *s2 == '\n' && !s2[1])
> > -               return true;
> > -       if (*s1 == '\n' && !s1[1] && !*s2)
> > -               return true;
> > -       return false;
> > +       return __streq_terminal(s1, s2);
> >  }
> >  EXPORT_SYMBOL(sysfs_streq);
> >
> > +/**
> > + * sysfs_streqcase - same to sysfs_streq and case insensitive
> > + * @s1: one string
> > + * @s2: another string
> > + *
> > + */
> > +bool sysfs_streqcase(const char *s1, const char *s2)
> > +{
> > +       while (*s1 && tolower(*s1) == tolower(*s2)) {
> > +               s1++;
> > +               s2++;
> > +       }
> > +       return __streq_terminal(s1, s2);
> > +}
> > +EXPORT_SYMBOL(sysfs_streqcase);
> > +#endif
> > +
> >  /**
> >   * match_string - matches given string in an array
> >   * @array:     array of strings
> > --
> > 2.25.1
> >