Re: [Qemu-devel] [PULL 01/19] s390 vfio-ccw: Add bootindex property and IPLB data

[Eduardo Habkost]

On Tue, Apr 30, 2019 at 05:54:49PM +0100, Peter Maydell wrote:
> On Thu, 25 Apr 2019 at 14:21, Cornelia Huck <address@hidden> wrote:
[...]
> > -        SCSIDevice *sd = (SCSIDevice *) object_dynamic_cast(OBJECT(dev_st),
> > -                                                            
> > TYPE_SCSI_DEVICE);
> > -
> > -        if (sd) {
> > +        switch (devtype) {
> > +        case CCW_DEVTYPE_SCSI:
> > +            sd = (SCSIDevice *) object_dynamic_cast(OBJECT(dev_st),
> > +                                                           
> > TYPE_SCSI_DEVICE);
> 
> Coverity doesn't like the use of object_dynamic_cast() without a
> check that the return value isn't NULL before we dereference
> it a few lines further down.
> 
> I think that if we know this cast must always succeed, we
> could instead just write
>   SCSIDevice *sd = SCSI_DEVICE(dev_st);
> 
> On the other hand if the cast might not succeed because dev_st
> isn't necessarily of the right type, then we should check it
> for NULL and handle that appropriately.

s390_get_ccw_device() will set devtype=CCW_DEVTYPE_SCSI only if
dev_st is TYPE_SCSI_DEVICE, so the cast must always succeed and
we should use SCSI_DEVICE(dev_st) here.

-- 
Eduardo