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.carpenter@xxxxxxxxxx>
> ---
> 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