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checkpatch: whine about ACCESS_ONCE

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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@perches.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joe Perches 2016-05-20 17:04:08 -07:00 committed by Linus Torvalds
parent a91e8994f2
commit 481aea5c59
1 changed files with 22 additions and 0 deletions
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22
scripts/checkpatch.pl
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@ -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*\(/ ||
$line =~ /__lockdep_no_validate__\s*\)/ ) {