RE: [EXTERNAL] Re: [net-next PATCH v3 3/9] octeontx2-pf: Create representor netdev

[Geethasowjanya Akula]

> -----Original Message-----
> From: Simon Horman <horms@xxxxxxxxxx>
> Sent: Wednesday, May 1, 2024 11:37 PM
> To: Geethasowjanya Akula <gakula@xxxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; kuba@xxxxxxxxxx;
> davem@xxxxxxxxxxxxx; pabeni@xxxxxxxxxx; edumazet@xxxxxxxxxx; Sunil
> Kovvuri Goutham <sgoutham@xxxxxxxxxxx>; Subbaraya Sundeep Bhatta
> <sbhatta@xxxxxxxxxxx>; Hariprasad Kelam <hkelam@xxxxxxxxxxx>; Dan
> Carpenter <dan.carpenter@xxxxxxxxxx>
> Subject: [EXTERNAL] Re: [net-next PATCH v3 3/9] octeontx2-pf: Create
> representor netdev
> 
> ----------------------------------------------------------------------
> + Dan Carpenter
> 
> On Sun, Apr 28, 2024 at 04:23:06PM +0530, Geetha sowjanya wrote:
> > Adds initial devlink support to set/get the switchdev mode.
> > Representor netdevs are created for each rvu devices when the switch
> > mode is set to 'switchdev'. These netdevs are be used to control and
> > configure VFs.
> >
> > Signed-off-by: Geetha sowjanya <gakula@xxxxxxxxxxx>
> 
> Hi Geetha,
> 
> Some minor feedback from my side.
> 
> ...
> 
> > diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/rep.c
> > b/drivers/net/ethernet/marvell/octeontx2/nic/rep.c
> 
> ...
> 
> > +int rvu_rep_create(struct otx2_nic *priv, struct netlink_ext_ack
> > +*extack) {
> > +	int rep_cnt = priv->rep_cnt;
> > +	struct net_device *ndev;
> > +	struct rep_dev *rep;
> > +	int rep_id, err;
> > +	u16 pcifunc;
> > +
> > +	priv->reps = devm_kcalloc(priv->dev, rep_cnt, sizeof(struct
> > +rep_dev), GFP_KERNEL);
> 
> It looks like the size argument should be sizeof(struct rep_dev *) or
> sizeof(*priv->reps).
> 
> Flagged by Coccinelle.
> 
> Please consider limiting lines in Networking code to 80 columns wide where it
> can be achieved without too much bother.
Ack. Will fix it in next version.
> 
> > +	if (!priv->reps)
> > +		return -ENOMEM;
> > +
> > +	for (rep_id = 0; rep_id < rep_cnt; rep_id++) {
> > +		ndev = alloc_etherdev(sizeof(*rep));
> > +		if (!ndev) {
> > +			NL_SET_ERR_MSG_FMT_MOD(extack, "PFVF
> representor:%d creation failed\n",
> > +					       rep_id);
> > +			err = -ENOMEM;
> > +			goto exit;
> > +		}
> > +
> > +		rep = netdev_priv(ndev);
> > +		priv->reps[rep_id] = rep;
> > +		rep->mdev = priv;
> > +		rep->netdev = ndev;
> > +		rep->rep_id = rep_id;
> > +
> > +		ndev->min_mtu = OTX2_MIN_MTU;
> > +		ndev->max_mtu = priv->hw.max_mtu;
> > +		pcifunc = priv->rep_pf_map[rep_id];
> > +		rep->pcifunc = pcifunc;
> > +
> > +		snprintf(ndev->name, sizeof(ndev->name), "r%dp%d", rep_id,
> > +			 rvu_get_pf(pcifunc));
> > +
> > +		eth_hw_addr_random(ndev);
> > +		err = register_netdev(ndev);
> > +		if (err) {
> > +			NL_SET_ERR_MSG_MOD(extack, "PFVF reprentator
> registration
> > +failed\n");
> 
> I don't think the string passed to NL_SET_ERR_MSG_MOD needs a trailing
> '\n'.
> I'm unsure if this also applies to NL_SET_ERR_MSG_FMT_MOD or not.
Ack.
> 
> Flagged by Coccinelle.
> 
> 
> The current ndev appears to be leaked here, as it does not appear to be
> covered by the unwind loop below.
> 
> I think this can be resolved using:
> 
> 			free_netdev(ndev);
> 
> > +			goto exit;
> > +		}
> > +	}
> > +	err = rvu_rep_napi_init(priv, extack);
> > +	if (err)
> > +		goto exit;
> 
> Even with the above fixed, Smatch complains that:
> 
> .../rep.c:180 rvu_rep_create() warn: 'ndev' from alloc_etherdev_mqs() not
> released on lines: 180.
> .../rep.c:180 rvu_rep_create() warn: 'ndev' from register_netdev() not
> released on lines: 180.
> 
> Where line 180 is the very last line of the funciton: return err;
> 
> I think this is triggered by the error handling above.
> However, I also think it is a false positive.
> I've CCed Dan Carpenter as I'd value a second opinion on this one.
> 
> > +
> > +	return 0;
> > +exit:
> > +	while (--rep_id >= 0) {
> > +		rep = priv->reps[rep_id];
> > +		unregister_netdev(rep->netdev);
> > +		free_netdev(rep->netdev);
> > +	}
> > +	return err;
> > +}
> 
> ...