Re: [PATCH for-next 3/9] RDMA/hns: Add return statement when kzalloc return NULL in hns_roce_v1_recreate_lp_qp

[Wei Hu (Xavier)]

On 2017/9/28 20:59, Leon Romanovsky wrote:
> On Thu, Sep 28, 2017 at 07:56:59PM +0800, Wei Hu (Xavier) wrote:
> > On 2017/9/28 17:13, Leon Romanovsky wrote:
> > > On Thu, Sep 28, 2017 at 12:57:28PM +0800, Wei Hu (Xavier) wrote:
> > > > From: Lijun Ou <oulijun@xxxxxxxxxx>
> > > >
> > > > When lp_qp_work is NULL, it should be returned ENOMEM. This patch
> > > > mainly fixes it.
> > > >
> > > > Ihis patch fixes the smatch error as below:
> > > > drivers/infiniband/hw/hns/hns_roce_hw_v1.c:918 hns_roce_v1_recreate_lp_qp()
> > > > error: potential null dereference 'lp_qp_work'.  (kzalloc returns null)
> > > >
> > > > Signed-off-by: Lijun Ou <oulijun@xxxxxxxxxx>
> > > > Signed-off-by: Wei Hu (Xavier) <xavier.huwei@xxxxxxxxxx>
> > > > Signed-off-by: Shaobo Xu <xushaobo2@xxxxxxxxxx>
> > > > ---
> > > >    drivers/infiniband/hw/hns/hns_roce_hw_v1.c | 2 ++
> > > >    1 file changed, 2 insertions(+)
> > > >
> > > > diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v1.c b/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
> > > > index 95f5c88..1071fa2 100644
> > > > --- a/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
> > > > +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
> > > > @@ -912,6 +912,8 @@ static int hns_roce_v1_recreate_lp_qp(struct hns_roce_dev *hr_dev)
> > > >
> > > >    	lp_qp_work = kzalloc(sizeof(struct hns_roce_recreate_lp_qp_work),
> > > >    			     GFP_KERNEL);
> > > > +	if (!lp_qp_work)
> > > > +		return -ENOMEM;
> > > You will treat this error in the same was as you will treat timeout,
> > > which is wrong.
> > Thanks,  Leon
> > We will send v2 to fix the compatible warn info.
> No, you missed the point.
>  From the code flow below the behavior of hns_roce_v1_recreate_lp_qp
> for ENOMEM and ETIMEOUT returns will be the same and it is wrong.
>
> For the ETIMEOUT, you can continue, for ENOMEM, you should properly
> unfold the whole flow.
>
> Thanks
Hi, Leon
    We prepare to modify the warn info as bleow:

        if (hr_dev->hw->dereg_mr && hns_roce_v1_recreate_lp_qp(hr_dev))
            dev_warn(&hr_dev->pdev->dev, "recreate lp qp failed!\n");

    for -ETIMEDOUT,  there is a warn info as blow, but there isn't this 
one for -ENOMEM.
        dev_warn(dev, "recreate lp qp failed 20s timeout and return 
failed!\n");

        static int hns_roce_v1_recreate_lp_qp(struct hns_roce_dev *hr_dev)
        {
            <snip>
            lp_qp_work = kzalloc(sizeof(struct 
hns_roce_recreate_lp_qp_work),
                 GFP_KERNEL);
            if (!lp_qp_work)
                return -ENOMEM;

            <snip>
            dev_warn(dev, "recreate lp qp failed 20s timeout and return 
failed!\n");
            return -ETIMEDOUT;
        }

    Regards
Wei Hu
> > > 1656          */
> > > 1657         if (hr_dev->hw->dereg_mr && hns_roce_v1_recreate_lp_qp(hr_dev))
> > > 1658                 dev_warn(&hr_dev->pdev->dev, "recreate lp qp timeout!\n");
> > > 1659
> > > 1660         p = (u32 *)(&addr[0]);
> > >
> > >
> > > >    	INIT_WORK(&(lp_qp_work->work), hns_roce_v1_recreate_lp_qp_work_fn);
> > > >
> > > > --
> > > > 1.9.1
> > > >
> > > > --
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