Re: [PATCH] sched: add parentheses to if clause

[Weiguo Li <liwg06@foxmail.com>]

On Sat, 26 Feb 2022 09:31:37 -0800, Stephen Hemminger wrote:

> > Add parentheses to 'if' clause, otherwise will enlarged the
> > chance of error return.
> > 
> > Fixes: 44c730b0e37971 ("sched: add PIE based congestion management")
> > 
> > Signed-off-by: Weiguo Li <liwg06@foxmail.com>
> > ---
> >  lib/sched/rte_pie.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/lib/sched/rte_pie.c b/lib/sched/rte_pie.c
> > index cdb7bab697..51df403a25 100644
> > --- a/lib/sched/rte_pie.c
> > +++ b/lib/sched/rte_pie.c
> > @@ -18,10 +18,10 @@ rte_pie_rt_data_init(struct rte_pie *pie)
> >  		/* Allocate memory to use the PIE data structure */
> >  		pie = rte_malloc(NULL, sizeof(struct rte_pie), 0);
> >  
> > -		if (pie == NULL)
> > +		if (pie == NULL) {
> >  			RTE_LOG(ERR, SCHED, "%s: Memory allocation fails\n", __func__);
> > -
> > -		return -1;
> > +			return -1;
> > +		}
> >  	}
> >  
> >  	pie->active = 0;
> 
> This will make the test in test_pie.c fail.
> 
> The concept of passing NULL to the routine and expecting allocation
> is bad idea because the allocated structure is never initialized.
> 
> Since rte_pie_rt_data_init(NULL) always returned -1.
> It would make more sense to take out the rte_malloc().
> And document it.
> 
> P.s: the routing should return a negative rte_errno instead of -1
> as well.
> 

Hi Stephen,

The 'rte_malloc' and null check is really misleading at the first sight...

Thanks for your suggestion!

-Weiguo