Messages in this thread Patch in this message | | | From | Dwaipayan Ray <> | Subject | [PATCH v2] checkpatch: add warning for unnecessary use of %h[xudi] and %hh[xudi] | Date | Thu, 26 Nov 2020 14:16:23 +0530 |
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Modifiers %h and %hh should never be used.
Commit cbacb5ab0aa0 ("docs: printk-formats: Stop encouraging use of unnecessary %h[xudi] and %hh[xudi]") specifies that:
"Standard integer promotion is already done and %hx and %hhx is useless so do not encourage the use of %hh[xudi] or %h[xudi]."
"The "h" and "hh" things should never be used. The only reason for them being used if you have an "int", but you want to print it out as a "char" (and honestly, that is a really bad reason, you'd be better off just using a proper cast to make the code more obvious)."
Add a new check to emit a warning on finding an unneeded use of %h or %hh modifier.
Link: https://lore.kernel.org/lkml/4910042649a4f3ab22fac93191b8c1fa0a2e17c3.camel@perches.com/
Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com> --- Changes in v2: - Use $logFunctions instead of the manual list. - Relocate the check to after logging continuations check. - Remove perl_version_ok condition which is unneeded here.
scripts/checkpatch.pl | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index 7dc094445d83..d1ecb852f384 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -6027,6 +6027,18 @@ sub process { "Avoid logging continuation uses where feasible\n" . $herecurr); } +# check for unnecessary use of %h[xudi] and %hh[xudi] in logging functions + if (defined $stat && + $line =~ /\b$logFunctions\s*\(/) { + my $lc = $stat =~ tr@\n@@; + $lc = $lc + $linenr; + my $stat_real = get_stat_real($linenr, $lc); + if ($stat_real =~ /\"[^\"]*%[\d\.\*\-]*h+[idux].*\"/i) { + WARN("UNNECESSARY_MODIFIER", + "Unnecessary use of modifiers %h[xudi] or %hh[xudi]\n" . "$here\n$stat_real\n"); + } + } + # check for mask then right shift without a parentheses if ($perl_version_ok && $line =~ /$LvalOrFunc\s*\&\s*($LvalOrFunc)\s*>>/ && -- 2.27.0
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