2020-11-12 15:00:41

by Yue Haibing

[permalink] [raw]

Subject: [PATCH] net: dsa: sja1105: Fix return value check in sja1105_ptp_clock_register()

---

drivers/net/dsa/sja1105/sja1105_ptp.c:869 sja1105_ptp_clock_register() warn: passing zero to 'PTR_ERR'

ptp_clock_register() returns ERR_PTR() and never returns
NULL. The NULL test should be removed.

Fixes: bb77f36ac21d ("net: dsa: sja1105: Add support for the PTP clock")
Signed-off-by: YueHaibing <[email protected]>
---
drivers/net/dsa/sja1105/sja1105_ptp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/dsa/sja1105/sja1105_ptp.c b/drivers/net/dsa/sja1105/sja1105_ptp.c
index 1b90570b257b..1e41d491c854 100644
--- a/drivers/net/dsa/sja1105/sja1105_ptp.c
+++ b/drivers/net/dsa/sja1105/sja1105_ptp.c
@@ -865,7 +865,7 @@ int sja1105_ptp_clock_register(struct dsa_switch *ds)
spin_lock_init(&tagger_data->meta_lock);

ptp_data->clock = ptp_clock_register(&ptp_data->caps, ds->dev);
- if (IS_ERR_OR_NULL(ptp_data->clock))
+ if (IS_ERR(ptp_data->clock))
return PTR_ERR(ptp_data->clock);

ptp_data->cmd.corrclk4ts = true;
--
2.17.1

2020-11-13 07:12:53

by Kurt Kanzenbach

[permalink] [raw]

Subject: Re: [PATCH] net: dsa: sja1105: Fix return value check in sja1105_ptp_clock_register()

---

On Thu Nov 12 2020, YueHaibing wrote:
> drivers/net/dsa/sja1105/sja1105_ptp.c:869 sja1105_ptp_clock_register() warn: passing zero to 'PTR_ERR'
>
> ptp_clock_register() returns ERR_PTR() and never returns
> NULL. The NULL test should be removed.

Which is not true. From the documentation:

* Returns a valid pointer on success or PTR_ERR on failure. If PHC
* support is missing at the configuration level, this function
* returns NULL, and drivers are expected to gracefully handle that
* case separately.

Please, always Cc Richard for PTP patches.

Actually you can have a look at this discussion here:

https://lkml.kernel.org/netdev/[email protected]/

>
> Fixes: bb77f36ac21d ("net: dsa: sja1105: Add support for the PTP clock")
> Signed-off-by: YueHaibing <[email protected]>
> ---
> drivers/net/dsa/sja1105/sja1105_ptp.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/dsa/sja1105/sja1105_ptp.c b/drivers/net/dsa/sja1105/sja1105_ptp.c
> index 1b90570b257b..1e41d491c854 100644
> --- a/drivers/net/dsa/sja1105/sja1105_ptp.c
> +++ b/drivers/net/dsa/sja1105/sja1105_ptp.c
> @@ -865,7 +865,7 @@ int sja1105_ptp_clock_register(struct dsa_switch *ds)
> spin_lock_init(&tagger_data->meta_lock);
>
> ptp_data->clock = ptp_clock_register(&ptp_data->caps, ds->dev);
> - if (IS_ERR_OR_NULL(ptp_data->clock))
> + if (IS_ERR(ptp_data->clock))

When you do this, you'll have to make sure that the driver handles the
NULL case "gracefully".

Thanks,
Kurt

---

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