On 12/17/20 7:15 PM, Joe Perches wrote: > On Thu, 2020-12-17 at 18:42 +0100, Helge Deller wrote: >> On 12/17/20 6:27 PM, Joe Perches wrote: >>> On Thu, 2020-12-17 at 18:11 +0100, Helge Deller wrote: >>>> In most cases people use lookup_symbol_name() to resolve a kernel symbol >>>> and then print it via printk(). >>>> >>>> In such cases using the %ps, %pS, %pSR or %pB printk formats are easier >>>> to use and thus should be preferred. >>> [] >>>> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl >>> [] >>>> @@ -4317,6 +4317,12 @@ sub process { >>>> "LINUX_VERSION_CODE should be avoided, code should >>>> be for the version to which it is merged\n" . $herecurr); >>>> } >>>> >>>> +# avoid lookup_symbol_name() >>>> + if ($line =~ /\blookup_symbol_name\b/) { >>>> + WARN("PREFER_PRINTK_FORMAT", >>>> + "If possible prefer %ps or %pS printk format >>>> string to print symbol name instead of using lookup_symbol_name()\n" . >>>> $herecurr); >>>> + } >>>> + >>>> # check for uses of printk_ratelimit >>>> if ($line =~ /\bprintk_ratelimit\s*\(/) { >>>> WARN("PRINTK_RATELIMITED", >>> >>> Huh? nak. >>> >>> lookup_symbol_name is used in the kernel a grand total of 3 times. >> >> Yes, there were much more in the past which got fixed by patches I submitted. > > Hi Helge. > > Much more may be a bit of an overstatement. > > I found 3 instances of lookup_symbol_name removals in 2 patches. > > commit 36dbca148bf8e3b8658982aa2256bdc7ef040256 > - lookup_symbol_name((ulong)pm_power_off, symname); > - lookup_symbol_name((ulong)pm_power_off, symname); > commit da88f9b3113620dcd30fc203236aa53d5430ee98 > - if (lookup_symbol_name((unsigned long)sym, symname) < 0) > > There's a tension between adding tests and newbies that consider > checkpatch warnings as dicta that must be followed so there would > be patches submitted eventually against the existing correct uses. > > So thanks, but given the very few existing all correct uses of > this function and the low probability of new uses I'd prefer not > to apply this.
Ok. Thanks! Helge