Messages in this thread | | | Subject | Re: [RFC PATCH] scripts: checkpatch.pl: remove obsolete in_atomic rule | From | "Yang Shi" <> | Date | Sat, 04 Nov 2017 06:41:29 +0800 |
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On 11/3/17 12:41 PM, Joe Perches wrote: > On Sat, 2017-11-04 at 03:08 +0800, Yang Shi wrote: >> checkpatch.pl still reports the below in_atomic warning: >> >> WARNING: use of in_atomic() is incorrect outside core kernel code >> + if (in_atomic()) >> >> But, in_atomic() has been used outside kernel dir for a long time, and >> even drivers. So, remove the obsolete rule even though they can be >> ignored. > > Removing in_atomic() from checkpatch does not make sense > without also updating include/linux/preempt.h > > Jonathon Corbet added this comment in > > commit 8c703d35fa91911dd92a18c31a718853f483ad80 > Author: Jonathan Corbet <corbet@lwn.net> > Date: Fri Mar 28 14:15:49 2008 -0700 > > in_atomic(): document why it is unsuitable for general use > > Discourage people from inappropriately using in_atomic() > > Signed-off-by: Jonathan Corbet <corbet@lwn.net> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> > --- > include/linux/hardirq.h | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h > index 49829988bfa0..897f723bd222 100644 > --- a/include/linux/hardirq.h > +++ b/include/linux/hardirq.h > @@ -72,6 +72,13 @@ > #define in_softirq() (softirq_count()) > #define in_interrupt() (irq_count()) > > +/* > + * Are we running in atomic context? WARNING: this macro cannot > + * always detect atomic context; in particular, it cannot know about > + * held spinlocks in non-preemptible kernels. Thus it should not be
This part looks changed. CONFIG_PREEMPT_COUNT might be enabled with non-preemptible kernel, so that in_atomic() could know if kernel held spinlocks or not.
Yang
> + * used in the general case to determine whether sleeping is possible. > + * Do not use in_atomic() in driver code. > + */ > > Maybe he remembers why... > >> Signed-off-by: Yang Shi <yang.s@alibaba-inc.com> >> CC: Andrew Morton <akpm@linux-foundation.org> >> --- >> Not sure if removing the obsolete rule is preferred by checkpatch.pl, anyway >> it sounds not make sense to keep invalid rule. >> >> scripts/checkpatch.pl | 11 ----------- >> 1 file changed, 11 deletions(-) >> >> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl >> index 8b80bac..e8cf94f 100755 >> --- a/scripts/checkpatch.pl >> +++ b/scripts/checkpatch.pl >> @@ -6231,17 +6231,6 @@ sub process { >> "Using $1 should generally have parentheses around the comparison\n" . $herecurr); >> } >> >> -# whine mightly about in_atomic >> - if ($line =~ /\bin_atomic\s*\(/) { >> - if ($realfile =~ m@^drivers/@) { >> - ERROR("IN_ATOMIC", >> - "do not use in_atomic in drivers\n" . $herecurr); >> - } elsif ($realfile !~ m@^kernel/@) { >> - WARN("IN_ATOMIC", >> - "use of in_atomic() is incorrect outside core kernel code\n" . $herecurr); >> - } >> - } >> - >> # whine about ACCESS_ONCE >> if ($^V && $^V ge 5.10.0 && >> $line =~ /\bACCESS_ONCE\s*$balanced_parens\s*(=(?!=))?\s*($FuncArg)?/) {
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