Re: [PATCH v2] ptp: fix an IS_ERR() vs NULL check

Richard Cochran
2018-12-04T04:42:57Z

On Mon, Dec 03, 2018 at 01:55:06PM +0300, Dan Carpenter wrote:
> We recently modified pps_register_source() to return error pointers
> instead of NULL but this check wasn't updated.

But it *was* updated!

> Fixes: 3b1ad360acad ("pps: using ERR_PTR instead of NULL while pps_register_source fails")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: Use the correct Fixes tag. Add Greg to the CC list, because he
> is maintaining this driver.

What driver? (I am maintaining drivers/ptp/ptp_clock.c)

> drivers/ptp/ptp_clock.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
> index 8a81eecc0ecd..48f3594a7458 100644
> --- a/drivers/ptp/ptp_clock.c
> +++ b/drivers/ptp/ptp_clock.c
> @@ -265,8 +265,8 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
> pps.mode = PTP_PPS_MODE;
> pps.owner = info->owner;
> ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
> - if (!ptp->pps_source) {
> - err = -EINVAL;
> + if (IS_ERR(ptp->pps_source)) {
> + err = PTR_ERR(ptp->pps_source);
> pr_err("failed to register pps source\n");
> goto no_pps;
> }

YueHaibing's patch has the following hunk. It really is already
there. I don't see it yet on Linus' master branch, but the patch
should update drivers/pps/kapi.c and the callers all in one commit.

diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 8a81eec..48f3594 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -265,8 +265,8 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
pps.mode = PTP_PPS_MODE;
pps.owner = info->owner;
ptp->pps_source = pps_register_source(&pps, PTP_PPS_DEFAULTS);
- if (!ptp->pps_source) {
- err = -EINVAL;
+ if (IS_ERR(ptp->pps_source)) {
+ err = PTR_ERR(ptp->pps_source);
pr_err("failed to register pps source\n");
goto no_pps;
}

Thanks,
Richard