Messages in this thread Patch in this message | | | Subject | [PATCH] checkpatch: Try to avoid mask and shift errors | From | Joe Perches <> | Date | Sun, 26 Oct 2014 22:33:06 -0700 |
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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> --- scripts/checkpatch.pl | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index d94f5d8..9b474d5 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -4478,6 +4478,14 @@ 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;
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