[PATCH v2] checkpatch: do not apply "initialise globals to 0" check to BPF progs

From: Song Liu
Date: Tue Feb 09 2021 - 12:01:40 EST


BPF programs explicitly initialise global variables to 0 to make sure
clang (v10 or older) do not put the variables in the common section.
Skip "initialise globals to 0" check for BPF programs to elimiate error
messages like:

ERROR: do not initialise globals to 0
#19: FILE: samples/bpf/tracex1_kern.c:21:

Cc: Andy Whitcroft <apw@xxxxxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Signed-off-by: Song Liu <songliubraving@xxxxxx>

---
Changes v1 => v2:
1. Add function exclude_global_initialisers() to keep the code clean.
---
scripts/checkpatch.pl | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 1afe3af1cc097..c46a3d2713062 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2428,6 +2428,15 @@ sub get_raw_comment {
return $comment;
}

+sub exclude_global_initialisers {
+ my ($realfile) = @_;
+
+ # Do not check for BPF programs (tools/testing/selftests/bpf/progs/*.c, samples/bpf/*_kern.c, *.bpf.c).
+ return $realfile =~ /^tools\/testing\/selftests\/bpf\/progs\/.*\.c/ ||
+ $realfile =~ /^samples\/bpf\/.*_kern.c/ ||
+ $realfile =~ /.bpf.c$/;
+}
+
sub process {
my $filename = shift;

@@ -4323,7 +4332,8 @@ sub process {
}

# check for global initialisers.
- if ($line =~ /^\+$Type\s*$Ident(?:\s+$Modifier)*\s*=\s*($zero_initializer)\s*;/) {
+ if ($line =~ /^\+$Type\s*$Ident(?:\s+$Modifier)*\s*=\s*($zero_initializer)\s*;/ &&
+ !exclude_global_initialisers($realfile)) {
if (ERROR("GLOBAL_INITIALISERS",
"do not initialise globals to $1\n" . $herecurr) &&
$fix) {
--
2.24.1