Re: [PATCH] drm/amd/powerplay: use ARRAY_SIZE() for size of array

From: Muhammad Falak R Wani
Date: Fri May 13 2016 - 13:17:32 EST


On Thu, May 12, 2016 at 12:53:48PM +0300, Jani Nikula wrote:
> On Wed, 11 May 2016, Muhammad Falak R Wani <falakreyaz@xxxxxxxxx> wrote:
> > Use ARRAY_SIZE() for the size calculation of the array. Also move the
> > condition evaulation function out of the for loop.
> > Although, any respectable c-compiler would optimize this and evaluate
> > the function only once outside the loop, but the optimzation engine
> > of gcc is bit brain-dead, and at times needs some hand holding.
>
> This just caught my eye. ARRAY_SIZE is a macro that expands to a compile
> time constant. Arguably adding the the local variable here gives GCC
> more chances to go wrong than keeping the ARRAY_SIZE in the loop
> condition.
>
> BR,
> Jani.
>
> >
> > Signed-off-by: Muhammad Falak R Wani <falakreyaz@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/amd/powerplay/smumgr/cz_smumgr.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/amd/powerplay/smumgr/cz_smumgr.c b/drivers/gpu/drm/amd/powerplay/smumgr/cz_smumgr.c
> > index da18f44..718a551 100644
> > --- a/drivers/gpu/drm/amd/powerplay/smumgr/cz_smumgr.c
> > +++ b/drivers/gpu/drm/amd/powerplay/smumgr/cz_smumgr.c
> > @@ -636,10 +636,11 @@ static int cz_smu_populate_firmware_entries(struct pp_smumgr *smumgr)
> > int ret;
> > enum cgs_ucode_id ucode_id;
> > struct cgs_firmware_info info = {0};
> > + int n = ARRAY_SIZE(firmware_list);
> >
> > cz_smu->driver_buffer_length = 0;
> >
> > - for (i = 0; i < sizeof(firmware_list)/sizeof(*firmware_list); i++) {
> > + for (i = 0; i < n; i++) {
> >
> > firmware_type = cz_translate_firmware_enum_to_arg(smumgr,
> > firmware_list[i]);
>
> --
> Jani Nikula, Intel Open Source Technology Center
Should i send a new patch, with these modifications. Sorry for my
childish mistake, i got a little too carried away.