Re: [PATCH] reduce stack usage in ixgb_ethtool_ioctl

[Jeff Garzik <jgarzik@xxxxxxxxx>]

Dave Dillow wrote:
> On Sun, 2004-09-19 at 13:33, Denis Vlasenko wrote:
>
> > Stack usage is still high because gcc will
> > allocate too much space for these cases:
> >
> >        case ETHTOOL_GSET:{
> >                        struct ethtool_cmd ecmd = { ETHTOOL_GSET };
> >                        ixgb_ethtool_gset(adapter, &ecmd);
> >                        if (copy_to_user(addr, &ecmd, sizeof(ecmd)))
> >                                return -EFAULT;
> >                        return 0;
> >                }
> >        case ETHTOOL_SSET:{
> >                        struct ethtool_cmd ecmd;
> >                        if (copy_from_user(&ecmd, addr, sizeof(ecmd)))
> >                                return -EFAULT;
> >                        return ixgb_ethtool_sset(adapter, &ecmd);
> >                }
> >
> > There will be space for _two_ ecmd's on stack.
> >
> > Shall it be worked around with ugly union of structs
> > or we'll just wait for better gcc?
>
> You could convert it to use ethtool_ops.
Check -mm to make sure viro hasn't already converted it to ethtool_ops...

        Jeff