On 30.08.2024 5:19 PM, Dan Carpenter wrote: > On Fri, Aug 30, 2024 at 12:03:20PM +0200, Konrad Dybcio wrote: >> On 30.08.2024 10:08 AM, Krzysztof Kozlowski wrote: >>> On 29/08/2024 14:48, Yu Jiaoliang wrote: >>>> Error handling in probe() can be a bit simpler with dev_err_probe(). >>>> >>>> Signed-off-by: Yu Jiaoliang <yujiaoliang@xxxxxxxx> >>>> --- >>>> drivers/soc/qcom/qcom-pbs.c | 7 +++---- >>>> 1 file changed, 3 insertions(+), 4 deletions(-) >>>> >>>> diff --git a/drivers/soc/qcom/qcom-pbs.c b/drivers/soc/qcom/qcom-pbs.c >>>> index 77a70d3d0d0b..ab9de12ec901 100644 >>>> --- a/drivers/soc/qcom/qcom-pbs.c >>>> +++ b/drivers/soc/qcom/qcom-pbs.c >>>> @@ -201,10 +201,9 @@ static int qcom_pbs_probe(struct platform_device *pdev) >>>> } >>>> >>>> ret = device_property_read_u32(pbs->dev, "reg", &val); >>>> - if (ret < 0) { >>>> - dev_err(pbs->dev, "Couldn't find reg, ret = %d\n", ret); >>>> - return ret; >>>> - } >>>> + if (ret < 0) >>>> + return dev_err_probe(pbs->dev, ret, "Couldn't find reg\n"); >>> >>> This cannot defer, so not much benefits. And you ignore other place in >>> the probe()... That's like a weird pattern with all your patches change >>> something irrelevant, but leave other places unchanged. >>> >>> That's pointless and churn. >> >> Hm, that's a good point.. Maybe the static checker folks could come up >> with a way that would find functions that call something that can defer >> at one point or another and suggest (not) using dev_err_probe with W=1/2.. >> (although that is probably not going to be very high prio given all the >> other static checker issues we're still yet to resolve) >> >> Unless we have something like that already? +CC Dan > > I believe these patches are from people writing their own Coccinelle scripts to > do the conversions. There aren't any published scripts which care one way or > the other. > > device_property_read_u32() can't return -EPROBE_DEFER. It's documented in a > comment. So this is just a question of preferred style. There isn't a kernel > wide preferred style on this. Some maintainers prefer to not use dev_err_probe() > where it "doesn't make sense because ret isn't -EPROBE_DEFER". Other maintainers > use it all the time even for error code literals like: > return dev_err_probe(pbs->dev, -EINVAL, "invalid input.\n"); > Because "it's cleaner, more uniform and only takes one line". I think Julia > said she didn't want to get involved with this debate and I definitely don't. Personally, I don't mind either.. so longer as it's consistent within the file > > There are a few things which we could do: > > 1) Returning -EPROBE_DEFER to an ioctl or something besides a probe() > This is a bug right? -EPROBE_DEFER is basically kernel internal for probe() > functions. It tried to write this but it was complicated so I gave up. Maybe call_tree.pl can somehow be used with an if name[-5:] == "probe" or something along those lines.. > > 2) Printing an error message for -EPROBE_DEFER warnings > I've written this check and I can test it tonight. > > 3) Not propagating the -EPROBE_DEFER returns > This shouldn't be too hard to write. > > Let me add a KTODO in case anyone wants to do this before I get around to it. > > KTODO: write Smatch EPROBE_DEFER warnings Thanks! Konrad