Re: [PATCH] [SCSI] FlashPoint: optimize string comparison

[Khalid Aziz]

On 07/07/2015 02:45 AM, Frans Klaver wrote:
> On Tue, Jul 7, 2015 at 7:39 AM, Christophe JAILLET
> <christophe.jaillet@xxxxxxxxxx> wrote:
> > Stop comparing the strings as soon as we know that they don't match.
> >
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> >   drivers/scsi/FlashPoint.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/scsi/FlashPoint.c b/drivers/scsi/FlashPoint.c
> > index 5c74e4c..24a4d1a 100644
> > --- a/drivers/scsi/FlashPoint.c
> > +++ b/drivers/scsi/FlashPoint.c
> > @@ -6280,8 +6280,10 @@ static unsigned char FPT_scmachid(unsigned char p_card,
> >                  match = 1;
> >
> >                  for (k = 0; k < ID_STRING_LENGTH; k++) {
> > -                       if (p_id_string[k] != FPT_scamInfo[i].id_string[k])
> > +                       if (p_id_string[k] != FPT_scamInfo[i].id_string[k]) {
> >                                  match = 0;
> > +                               break;
> > +                       }
> >                  }
> >
> >                  if (match) {
>
> Why doesn't this use strncmp?
>
> Thanks,
> Frans

I suspect that is how this code came from Mylex many years ago. Using 
strncmp would indeed be a better way to clean this up. Also, further 
down in the same routine:

                if (FPT_scamInfo[match].state == ID_UNUSED) {
                        for (k = 0; k < ID_STRING_LENGTH; k++) {
                                FPT_scamInfo[match].id_string[k] =
                                    p_id_string[k];
                        }


This should use strncpy instead. There is another similar spot further down.

Christophe, if you can send a new patch with these clean-ups, that would 
be great.

Thanks,
Khalid
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