From: Joe Perches <joe@xxxxxxxxxxx>
Subject: checkpatch: whine about ACCESS_ONCE
Add a test for use of ACCESS_ONCE that could be written using READ_ONCE or
WRITE_ONCE.
--fix it too if desired.
The WRITE_ONCE fixes are less correct than the coccinelle script below as
checkpatch cannot have a completely correct "expression" mechanism because
checkpatch works on patches and not complete files.
$ cat access_once.cocci
@@
expression e1;
expression e2;
@@
- ACCESS_ONCE(e1) = e2
+ WRITE_ONCE(e1, e2)
@@
expression e1;
@@
- ACCESS_ONCE(e1)
+ READ_ONCE(e1)
Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
Cc: Julia Lawall <julia.lawall@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
scripts/checkpatch.pl | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff -puN scripts/checkpatch.pl~checkpatch-whine-about-access_once scripts/checkpatch.pl
--- a/scripts/checkpatch.pl~checkpatch-whine-about-access_once
+++ a/scripts/checkpatch.pl
@@ -5850,6 +5850,28 @@ sub process {
}
}
+# whine about ACCESS_ONCE
+ if ($^V && $^V ge 5.10.0 &&
+ $line =~ /\bACCESS_ONCE\s*$balanced_parens\s*(=(?!=))?\s*($FuncArg)?/) {
+ my $par = $1;
+ my $eq = $2;
+ my $fun = $3;
+ $par =~ s/^\(\s*(.*)\s*\)$/$1/;
+ if (defined($eq)) {
+ if (WARN("PREFER_WRITE_ONCE",
+ "Prefer WRITE_ONCE(<FOO>, <BAR>) over ACCESS_ONCE(<FOO>) = <BAR>\n" . $herecurr) &&
+ $fix) {
+ $fixed[$fixlinenr] =~ s/\bACCESS_ONCE\s*\(\s*\Q$par\E\s*\)\s*$eq\s*\Q$fun\E/WRITE_ONCE($par, $fun)/;
+ }
+ } else {
+ if (WARN("PREFER_READ_ONCE",
+ "Prefer READ_ONCE(<FOO>) over ACCESS_ONCE(<FOO>)\n" . $herecurr) &&
+ $fix) {
+ $fixed[$fixlinenr] =~ s/\bACCESS_ONCE\s*\(\s*\Q$par\E\s*\)/READ_ONCE($par)/;
+ }
+ }
+ }
+
# check for lockdep_set_novalidate_class
if ($line =~ /^.\s*lockdep_set_novalidate_class\s*\(/ ||
$line =~ /__lockdep_no_validate__\s*\)/ ) {
_
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