checkpatch: add --strict "pointer comparison to NULL" test
It seems there are more and more uses of "if (!ptr)" in preference to "if
(ptr == NULL)" so add a --strict test to emit a message when using the
latter form.
This also finds (ptr != NULL).
Fix it too if desired.
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 5e63dce..6d85c7b 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4522,6 +4522,20 @@
"Possible precedence defect with mask then right shift - may need parentheses\n" . $herecurr);
}
+# check for pointer comparisons to NULL
+ if ($^V && $^V ge 5.10.0) {
+ while ($line =~ /\b$LvalOrFunc\s*(==|\!=)\s*NULL\b/g) {
+ my $val = $1;
+ my $equal = "!";
+ $equal = "" if ($4 eq "!=");
+ if (CHK("COMPARISON_TO_NULL",
+ "Comparison to NULL could be written \"${equal}${val}\"\n" . $herecurr) &&
+ $fix) {
+ $fixed[$fixlinenr] =~ s/\b\Q$val\E\s*(?:==|\!=)\s*NULL\b/$equal$val/;
+ }
+ }
+ }
+
# check for bad placement of section $InitAttribute (e.g.: __initdata)
if ($line =~ /(\b$InitAttribute\b)/) {
my $attr = $1;