Commit abb08a53 authored Dec 10, 2014 by Joe Perches Committed by Linus Torvalds Dec 10, 2014

checkpatch: try to avoid mask and shift errors



Shift has a higher precedence that mask so warn when a mask then shift
operation is done without parentheses around the mask.

This test works well for a right shift, but the left shift is pretty
commonly done correctly so only warn on the right shift.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 36061e38

scripts/checkpatch.pl

+8 −0

Original line number	Diff line number	Diff line
		@@ -4482,6 +4482,14 @@ sub process {
		}
		}

		# check for mask then right shift without a parentheses
		if ($^V && $^V ge 5.10.0 &&
		$line =~ /$LvalOrFunc\s\&\s($LvalOrFunc)\s*>>/ &&
		$4 !~ /^\&/) { # $LvalOrFunc may be &foo, ignore if so
		WARN("MASK_THEN_SHIFT",
		"Possible precedence defect with mask then right shift - may need parentheses\n" . $herecurr);
		}

		# check for bad placement of section $InitAttribute (e.g.: __initdata)
		if ($line =~ /(\b$InitAttribute\b)/) {
		my $attr = $1;