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authorJoe Perches <joe@perches.com>2015-06-25 15:02:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-25 17:00:41 -0700
commitcb426e99ff9225e94fb56bd4c5cfcce8b78a3904 (patch)
treea7e47c66d32182613e9c9735ae32e48421b24b2e /scripts/checkpatch.pl
parentcbdc281019b8c5c905ef597511471b18e0fd4a15 (diff)
downloadlinux-cb426e99ff9225e94fb56bd4c5cfcce8b78a3904.tar.bz2
checkpatch: check for uncommented waitqueue_active()
Linus sayeth: : Pretty much every single time people use this "if : (waitqueue_active())" model, it tends to be a bug, because it means : that there is zero serialization with people who are just about to go : to sleep. It's fundamentally racy against all the "wait_event()" loops : that carefully do memory barriers between testing conditions and going : to sleep, because the memory barriers now don't exist on the waking : side. : : So I'm making a new rule: if you use waitqueue_active(), I want an : explanation for why it's not racy with the waiter. A big comment about : the memory ordering, or about higher-level locks that are held by the : caller, or something. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'scripts/checkpatch.pl')
-rwxr-xr-xscripts/checkpatch.pl7
1 files changed, 7 insertions, 0 deletions
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index c5ec977b9c37..3f2ff26c631c 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4898,6 +4898,13 @@ sub process {
"memory barrier without comment\n" . $herecurr);
}
}
+# check for waitqueue_active without a comment.
+ if ($line =~ /\bwaitqueue_active\s*\(/) {
+ if (!ctx_has_comment($first_line, $linenr)) {
+ WARN("WAITQUEUE_ACTIVE",
+ "waitqueue_active without comment\n" . $herecurr);
+ }
+ }
# check of hardware specific defines
if ($line =~ m@^.\s*\#\s*if.*\b(__i386__|__powerpc64__|__sun__|__s390x__)\b@ && $realfile !~ m@include/asm-@) {
CHK("ARCH_DEFINES",