From: Dwaipayan Ray <dwaipayanray1@gmail.com>
To: joe@perches.com
Cc: linux-kernel-mentees@lists.linuxfoundation.org,
dwaipayanray1@gmail.com, linux-kernel@vger.kernel.org,
lukas.bulwahn@gmail.com
Subject: [PATCH v3] checkpatch: add warning for unnecessary use of %h[xudi] and %hh[xudi]
Date: Sat, 28 Nov 2020 23:08:50 +0530 [thread overview]
Message-ID: <20201128173850.66509-1-dwaipayanray1@gmail.com> (raw)
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.
Also add a fix option to the check.
Link: https://lore.kernel.org/lkml/4910042649a4f3ab22fac93191b8c1fa0a2e17c3.camel@perches.com/
Suggested-by: Joe Perches <joe@perches.com>
Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com>
---
Changes in v3:
- Change warning message
- Fix regex match to include capture group
- Warn on every unnecesary use of %h on a line
- Add fix option when the format line matches current line
Changes in v2:
- Use $logFunctions instead of the manual list.
- Relocate the check to after logging continuations check.
- Remove perl_version_ok check
scripts/checkpatch.pl | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 7dc094445d83..dc25d32f0c5f 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6027,6 +6027,22 @@ 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@@;
+ for (my $cur_ln = $linenr; $cur_ln <= $linenr + $lc; $cur_ln++) {
+ my $cur_rawline = raw_line($cur_ln, 0);
+ while ($cur_rawline =~ /^\+.*\"[^\"]*(%[\d\.\*\-]*h+[idux])/g) {
+ if (WARN("INTEGER_PROMOTION",
+ "Using 'h' in $1 is unnecessary\n" . "$cur_rawline\n") &&
+ $fix && ($cur_ln == $linenr)) {
+ $fixed[$fixlinenr] =~ s/(\"[^\"]*%[\d\.\*\-]*)h+([idux])/$1$2/;
+ }
+ }
+ }
+ }
+
# check for mask then right shift without a parentheses
if ($perl_version_ok &&
$line =~ /$LvalOrFunc\s*\&\s*($LvalOrFunc)\s*>>/ &&
--
2.27.0
next reply other threads:[~2020-11-28 22:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-28 17:38 Dwaipayan Ray [this message]
2020-11-28 18:46 ` [PATCH v3] checkpatch: add warning for unnecessary use of %h[xudi] and %hh[xudi] Joe Perches
2020-11-28 19:04 ` Dwaipayan Ray
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