Hi Rodrigo,
On Thu, Mar 28, 2024 at 09:39:17PM -0400, Rodrigo Vivi wrote:
> On Thu, Mar 28, 2024 at 10:41:55PM +0100, Andi Shyti wrote:
> > On Thu, Mar 28, 2024 at 05:31:07PM -0400, Rodrigo Vivi wrote:
> > > This null check is bogus because we are already using 'ce' stuff
> > > in many places before this function is called.
> > >
> > > Having this here is useless and confuses static analyzer tools
> > > that can see:
> > >
> > > struct intel_engine_cs *engine = ce->engine;
> > >
> > > before this check, in the same function.
> > >
> > > Fixes: cec82816d0d0 ("drm/i915/guc: Use context hints for GT frequency")
> >
> > there is no need to have the Fixes tag here.
>
> why not? I imagine distros that have this commit cec82816d0d0 and use
> static analyzers would also want this patch ported to silent those, no?!
Still... it's not a bug. The tag "Fixes:" should be used when a
bug is fixed, but not for harmless static analyzer reports.
Besides, if we want to keep the Fixes tag we should also Cc
stable, i guess checkpatch.pl complains about it.
(BTW, Cc'ed in this mail we have the inventor of the tag and he
can confirm after having had his morning coffee :-) ).
> > > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > > Closes: https://lore.kernel.org/r/202403101225.7AheJhZJ-lkp@xxxxxxxxx/
> > > Cc: Vinay Belgaumkar <vinay.belgaumkar@xxxxxxxxx>
> > > Cc: John Harrison <John.C.Harrison@xxxxxxxxx>
> > > Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> > > ---
> > > drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > > index 01d0ec1b30f2..24a82616f844 100644
> > > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > > @@ -2677,7 +2677,7 @@ static int guc_context_policy_init_v70(struct intel_context *ce, bool loop)
> > > execution_quantum = engine->props.timeslice_duration_ms * 1000;
> > > preemption_timeout = engine->props.preempt_timeout_ms * 1000;
> > >
> > > - if (ce && (ce->flags & BIT(CONTEXT_LOW_LATENCY)))
> > > + if (ce->flags & BIT(CONTEXT_LOW_LATENCY))
> >
> > We could keep the check but make it earlier.
>
> yes, that's another alternative.
>
>
> -struct intel_engine_cs *engine = ce->engine;
> +struct intel_engine_cs *engine;
>
> if (!ce)
> return;
>
> engine = ce->engine.
this is what I meant...
> But looking to the 2 places where this function is getting called,
> we already have ce->something used.
... and I also checked where the function is called and how it's
called: I see that if we get here then for sure 'ce' is not NULL.
But for robustness we could still keep it.
Either way I think your patch is good except for the "Fixes:"
tag:
Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
Thanks,
Andi
> I can make the change to be like that if you believe that there's
> a possibility in the future that we change that, just to be on
> the safe side.
>
> or anything else I might be missing?
>
> Thanks for looking into this,
> Rodrigo.
>
> >
> > Thanks,
> > Andi
> >
> > > slpc_ctx_freq_req |= SLPC_CTX_FREQ_REQ_IS_COMPUTE;
> > >
> > > __guc_context_policy_start_klv(&policy, ce->guc_id.id);
> > > --
> > > 2.44.0
