linux-kernel - Re: [RFC PATCH v1 07/12] efi: Replace strstarts() by str_has

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Date:   Fri, 04 Dec 2020 18:19:17 +0100
From:   Francis Laniel <laniel_francis@...vacyrequired.com>
To:     Ard Biesheuvel <ardb@...nel.org>
Cc:     linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH v1 07/12] efi: Replace strstarts() by str_has_prefix().

Le vendredi 4 décembre 2020, 18:07:11 CET Ard Biesheuvel a écrit :
> On Fri, 4 Dec 2020 at 18:06, <laniel_francis@...vacyrequired.com> wrote:
> > From: Francis Laniel <laniel_francis@...vacyrequired.com>
> > 
> > The two functions indicates if a string begins with a given prefix.
> > The only difference is that strstarts() returns a bool while
> > str_has_prefix() returns the length of the prefix if the string begins
> > with it or 0 otherwise.
> Why?

The code works fine actually with the two functions, it is a fact.

Not long ago, I read string.h and saw that there was two functions doing the 
same thing.
At this moment, I thought that it can be a good idea to replace one by another 
so there is only one remaining function.

I think the benefit of this patch is that it makes the code a bit simpler.
I agree that this is not a huge benefit and that the code can stay in its 
actual state.
I also marked this patch as RFC to get people's opinion about if they find it 
useful or not.

> > Signed-off-by: Francis Laniel <laniel_francis@...vacyrequired.com>
> > ---
> > 
> >  drivers/firmware/efi/libstub/efi-stub-helper.c |  2 +-
> >  drivers/firmware/efi/libstub/gop.c             | 10 +++++-----
> >  2 files changed, 6 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c
> > b/drivers/firmware/efi/libstub/efi-stub-helper.c index
> > aa8da0a49829..a502f549d900 100644
> > --- a/drivers/firmware/efi/libstub/efi-stub-helper.c
> > +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
> > @@ -230,7 +230,7 @@ efi_status_t efi_parse_options(char const *cmdline)
> > 
> >                         if (parse_option_str(val, "debug"))
> >                         
> >                                 efi_loglevel = CONSOLE_LOGLEVEL_DEBUG;
> >                 
> >                 } else if (!strcmp(param, "video") &&
> > 
> > -                          val && strstarts(val, "efifb:")) {
> > +                          val && str_has_prefix(val, "efifb:")) {
> > 
> >                         efi_parse_option_graphics(val + strlen("efifb:"));
> >                 
> >                 }
> >         
> >         }
> > 
> > diff --git a/drivers/firmware/efi/libstub/gop.c
> > b/drivers/firmware/efi/libstub/gop.c index ea5da307d542..fbe95b3cc96a
> > 100644
> > --- a/drivers/firmware/efi/libstub/gop.c
> > +++ b/drivers/firmware/efi/libstub/gop.c
> > @@ -39,7 +39,7 @@ static bool parse_modenum(char *option, char **next)
> > 
> >  {
> >  
> >         u32 m;
> > 
> > -       if (!strstarts(option, "mode="))
> > +       if (!str_has_prefix(option, "mode="))
> > 
> >                 return false;
> >         
> >         option += strlen("mode=");
> >         m = simple_strtoull(option, &option, 0);
> > 
> > @@ -65,10 +65,10 @@ static bool parse_res(char *option, char **next)
> > 
> >         h = simple_strtoull(option, &option, 10);
> >         if (*option == '-') {
> >         
> >                 option++;
> > 
> > -               if (strstarts(option, "rgb")) {
> > +               if (str_has_prefix(option, "rgb")) {
> > 
> >                         option += strlen("rgb");
> >                         pf = PIXEL_RGB_RESERVED_8BIT_PER_COLOR;
> > 
> > -               } else if (strstarts(option, "bgr")) {
> > +               } else if (str_has_prefix(option, "bgr")) {
> > 
> >                         option += strlen("bgr");
> >                         pf = PIXEL_BGR_RESERVED_8BIT_PER_COLOR;
> >                 
> >                 } else if (isdigit(*option))
> > 
> > @@ -90,7 +90,7 @@ static bool parse_res(char *option, char **next)
> > 
> >  static bool parse_auto(char *option, char **next)
> >  {
> > 
> > -       if (!strstarts(option, "auto"))
> > +       if (!str_has_prefix(option, "auto"))
> > 
> >                 return false;
> >         
> >         option += strlen("auto");
> >         if (*option && *option++ != ',')
> > 
> > @@ -103,7 +103,7 @@ static bool parse_auto(char *option, char **next)
> > 
> >  static bool parse_list(char *option, char **next)
> >  {
> > 
> > -       if (!strstarts(option, "list"))
> > +       if (!str_has_prefix(option, "list"))
> > 
> >                 return false;
> >         
> >         option += strlen("list");
> >         if (*option && *option++ != ',')
> > 
> > --
> > 2.20.1