> -----Original Message-----
> From: Jakub Kicinski <k...@kernel.org>
> Sent: Sunday, November 8, 2020 1:05 AM
> To: Radhey Shyam Pandey <radh...@xilinx.com>
> Cc: da...@davemloft.net; Michal Simek <mich...@xilinx.com>;
> netdev@vger.kernel.org; linux-arm-ker...@lists.infradead.org; linux-
> ker...@vger.kernel.org; git <g...@xilinx.com>; Shravya Kumbham
> <shrav...@xilinx.com>
> Subject: Re: [PATCH net-next] net: emaclite: Add error handling for
> of_address_ and phy read functions
>
> On Tue, 3 Nov 2020 19:01:05 +0530 Radhey Shyam Pandey wrote:
> > From: Shravya Kumbham <shravya.kumb...@xilinx.com>
> >
> > Add ret variable, conditions to check the return value and it's error
> > path for of_address_to_resource() and phy_read() functions.
> >
> > Addresses-Coverity: Event check_return value.
> > Signed-off-by: Shravya Kumbham <shravya.kumb...@xilinx.com>
> > Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pan...@xilinx.com>
>
> Any reason not to apply this to net as a fix?
Yes, it can be applied to net as a fix.
>
> > diff --git a/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > b/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > index 0c26f5b..fc5ccd1 100644
> > --- a/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > +++ b/drivers/net/ethernet/xilinx/xilinx_emaclite.c
> > @@ -820,7 +820,7 @@ static int xemaclite_mdio_write(struct mii_bus
> > *bus, int phy_id, int reg, static int xemaclite_mdio_setup(struct
> > net_local *lp, struct device *dev) {
> > struct mii_bus *bus;
> > - int rc;
> > + int rc, ret;
> > struct resource res;
> > struct device_node *np = of_get_parent(lp->phy_node);
> > struct device_node *npp;
> > @@ -834,7 +834,13 @@ static int xemaclite_mdio_setup(struct net_local
> *lp, struct device *dev)
> > }
> > npp = of_get_parent(np);
> >
> > - of_address_to_resource(npp, 0, &res);
> > + ret = of_address_to_resource(npp, 0, &res);
> > + if (ret) {
> > + dev_err(dev, "%s resource error!\n",
> > + dev->of_node->full_name);
> > + of_node_put(lp->phy_node);
>
> I'm always confused by the of_* refcounting. Why do you need to put
> phy_node here, and nowhere else in this function?
Initially, we added of_node_put(phy_node) thinking about this
particular coverity change. But agree it has to be added for
all error path i.e better place would be in xemaclite_of_probe()
error label.
>
> > + return ret;
> > + }
>
> > /* Restart auto negotiation */
> > bmcr = phy_read(lp->phy_dev, MII_BMCR);
> > + if (bmcr < 0) {
> > + dev_err(&lp->ndev->dev, "phy_read failed\n");
> > + phy_disconnect(lp->phy_dev);
> > + lp->phy_dev = NULL;
> > +
> > + return bmcr;
> > + }
> > bmcr |= (BMCR_ANENABLE | BMCR_ANRESTART);
> > phy_write(lp->phy_dev, MII_BMCR, bmcr);
>
> Does it really make much sense to validate the return value of
> phy_read() but not check any errors from phy_write()s?
Error handling was added for phy_read as it was using return value
and reported by coverity. But yes we in a follow-up patch we
can extend error handling for phy_write as well.
