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

[Richard Cochran]

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.carpen...@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