Re: [PATCH] RDMA/hfi: add a judgment on the availability of cpumask

[xiaolinkui]

Thanks for your reply.

When CONFIG_CPUMASK_OFFSTACK=y, "ret" will be false if diff==NULL.

However, when CONFIG_CPUMASK_OFFSTACK=n, these two are not necessarily 
equivalent.

Thanks

On 4/4/23 14:05, Leon Romanovsky wrote:
> On Tue, Apr 04, 2023 at 11:05:25AM +0800, xiaolinkui wrote:
> > From: Linkui Xiao <xiaolinkui@xxxxxxxxxx>
> >
> > When CONFIG_CPUMASK_OFFSTACK is n, cpumask may fail to allocate, cpumask may
> > be NULL, and performing a bitmap operation on cpumask may cause problems at
> > this time.
> >
> > Of course, this is a unlikely event.
> >
> > Signed-off-by: Linkui Xiao <xiaolinkui@xxxxxxxxxx>
> > ---
> >   drivers/infiniband/hw/hfi1/affinity.c | 8 ++++----
> >   1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/infiniband/hw/hfi1/affinity.c b/drivers/infiniband/hw/hfi1/affinity.c
> > index 77ee77d4000f..3caa861f4d1d 100644
> > --- a/drivers/infiniband/hw/hfi1/affinity.c
> > +++ b/drivers/infiniband/hw/hfi1/affinity.c
> > @@ -1047,16 +1047,16 @@ int hfi1_get_proc_affinity(int node)
> >   	 */
> >   
> >   	ret = zalloc_cpumask_var(&diff, GFP_KERNEL);
> > -	if (!ret)
> > +	if (!ret || unlikely(!diff))
> Why do you think that check of "ret" is not enough?
> "ret" will be false if diff == NULL.
>
> Thanks