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 <[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
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 <[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)?/) {
