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 <[email protected]> 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 <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> --- 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 + * 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 <[email protected]> > CC: Andrew Morton <[email protected]> > --- > 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)?/) {
