Messages in this thread | | | From | Joakim Zhang <> | Subject | RE: [PATCH net 1/2] net: fec_ptp: add clock rate zero check | Date | Wed, 16 Jun 2021 11:40:29 +0000 |
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Hi Russell,
> -----Original Message----- > From: Russell King <linux@armlinux.org.uk> > Sent: 2021年6月16日 18:21 > To: Joakim Zhang <qiangqing.zhang@nxp.com> > Cc: davem@davemloft.net; kuba@kernel.org; peppe.cavallaro@st.com; > alexandre.torgue@foss.st.com; joabreu@synopsys.com; > mcoquelin.stm32@gmail.com; netdev@vger.kernel.org; > linux-kernel@vger.kernel.org; linux-stm32@st-md-mailman.stormreply.com; > linux-arm-kernel@lists.infradead.org; dl-linux-imx <linux-imx@nxp.com> > Subject: Re: [PATCH net 1/2] net: fec_ptp: add clock rate zero check > > On Wed, Jun 16, 2021 at 05:14:25PM +0800, Joakim Zhang wrote: > > From: Fugang Duan <fugang.duan@nxp.com> > > > > Add clock rate zero check to fix coverity issue of "divide by 0". > > > > Fixes: commit 85bd1798b24a ("net: fec: fix spin_lock dead lock") > > Signed-off-by: Fugang Duan <fugang.duan@nxp.com> > > Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com> > > --- > > drivers/net/ethernet/freescale/fec_ptp.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/net/ethernet/freescale/fec_ptp.c > > b/drivers/net/ethernet/freescale/fec_ptp.c > > index 1753807cbf97..7326a0612823 100644 > > --- a/drivers/net/ethernet/freescale/fec_ptp.c > > +++ b/drivers/net/ethernet/freescale/fec_ptp.c > > @@ -604,6 +604,10 @@ void fec_ptp_init(struct platform_device *pdev, int > irq_idx) > > fep->ptp_caps.enable = fec_ptp_enable; > > > > fep->cycle_speed = clk_get_rate(fep->clk_ptp); > > + if (!fep->cycle_speed) { > > + fep->cycle_speed = NSEC_PER_SEC; > > + dev_err(&fep->pdev->dev, "clk_ptp clock rate is zero\n"); > > If this is supposed to be an error message, it doesn't convey that something is > really wrong to the user. Maybe something like this would be more meaningful > to the user: > > "PTP clock rate should not be zero, using 1GHz instead. PTP > clock may be unreliable.\n" Make Sense.
> It may be appropriate not to publish PTP support for the interface if we don't > have a valid clock rate, which is probably the safer approach and would > probably make the problem more noticable to the end user so it gets fixed.
Do you mean that print an error message then return directly? It seems better.
if (!fep->cycle_speed) { dev_err(&fep->pdev->dev, "PTP clock rate should not be zero!\n"); return; }
Best Regards, Joakim Zhang > -- > RMK's Patch system: > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ar > mlinux.org.uk%2Fdeveloper%2Fpatches%2F&data=04%7C01%7Cqiangqin > g.zhang%40nxp.com%7Cb3c85322e359446e4eee08d930b06701%7C686ea1d3 > bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637594356476903644%7CUnknow > n%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1ha > WwiLCJXVCI6Mn0%3D%7C1000&sdata=TH4fZJRu8Ii6w7y05N8CHWoQR > R9OegsYB7VAwgSpTcU%3D&reserved=0 > FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
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